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Energetics of vertical migration in Chaoborus trivittatus larvae Swift, Michael Crane 1974

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1. / -  ENERGETICS OF VERTICAL MIGRATION IN CHAOBOBOS TRIVITTATOS LARVAE  by MICHAEL CRANE B. S c . , U n i v e r s i t y M. A., U n i v e r s i t y  SWIFT  of C a l i f o r n i a , of C a l i f o r n i a ,  Davis, Davis,  1966 1968  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE  REQUIREMENTS  FOR THE EEGREE OF  DOCTOR OF PHILOSOPHY in  t h e Department of Zoology  He a c c e p t  this  t h e s i s as conforming  required  THE  t o the  standard  UNIVERSITY OF BRITISH FEBRUARY,  1974  COLOMBIA  In p r e s e n t i n g an  thesis  in partial  f u l f i l m e n t of the  advanced degree at the  University  of B r i t i s h Columbia, I agree  the  Library  this  s h a l l make i t f r e e l y  a v a i l a b l e f o r r e f e r e n c e and  I f u r t h e r agree t h a t p e r m i s s i o n f o r extensive for  s c h o l a r l y p u r p o s e s may  by h i s r e p r e s e n t a t i v e s .  be  thesis for financial  written  permission.  Department  a  t  e  gain  of  The U n i v e r s i t y o f B r i t i s h V a n c o u v e r 8, C a n a d a  D  g r a n t e d by  S4/<^ /??Y ;  the  Head o f my  Columbia  s h a l l not  be  that  thesis  Department  copying or  for  study.  copying of t h i s  I t i s understood that  of t h i s  requirements  or  publication  allowed without  my  i  ABSTRACT One  of the recent theories  vertical  m i g r a t i o n (McLaren  energetic between  advantage  areas  partition  energetic  synchronous,  diel  wide  of at  20oplankton  low  more food  C.  of  and  majority  slowly  of  m i g r a n t s g a i n an  because  by  they  alternating  are  able  efficiently  vertical larvae  to identify  and  In  than  larvae  m i g r a t i o n which  temperature  larvae.  the  trivittatus  night,  to than  migration  of  i n Eunice  Lake,  guantify  this  and prey near  the  fhe  Eunice their  exposes  density.  prey,  biomass  Lake  C.  potential  a  regular,  them  tc  Feeding  surface.  are potential of  undergo  occurs  Although a l l Diajgtomus  in  the  rate  kenai  diet  trivittatus  growth  a  of  larvae  because  of  availability.  Several assimilation  energetics  parameters  including  efficiency,  the  of  respiration  rate,  temperature  on l a r v a l  Carbon  that  value  advantage.  vertical  the  fourth-instar  adaptive  more  trivittatus  i n Eunice Lake  constitutes  grew  growth  were s t u d i e d  Fourth-instar  primarily  non-migrants  into  Chaoborus  Columbia  range  1963) s t a t e s  The e n e r g e t i c s  fourth-instar  hypothesized  the  o f h i g h and low t e m p e r a t u r e s  energy  non-migrants.  British  over  for  assimilation  cladocerans  by  C.  and  the growth  effect  effects were  efficiency trivittatus  of  of  i s about  temperature  ration  measured  carbon  size  cn and  i n the laboratcry.  both  copepods  68%. R e s p i r a t i o n  and rate  increases  linearly  although  there  consumption to  ever  during  interact  tc  20°  prey  temperature  into of  of  growth  frcm  and  larvae  growth  rate.  the  field  and  exposed size  fluctuating density  while  laboratory  computer  migrating  cxygen  ration  prey  growth  simulation  larva.  various  biological  in  rate; cf  5-25°,  are  and  tho  e f f e c t s of  parameters,  the  regardless  a vertically  range  plateau  Temperature  a generalized  the  the  a  range  larval  limited  data  examine  physical  migration.  density  energetics to  the  over  suggestion  limited  incorporated  used  a  determine  Empirical  the  temperature  is  their  temperatures at  with  The  were  model  mcdel  migration  cf was  patterns,  parameters  on  larval  growth. Analysis that, by  on  an  based  laboratory  relict  these larvae  patterns.  migration of  containing  on  growth  with  ililittatus these  near  irigrating  periodicity  agreed  several  energetics  either staying  vertically  cf  of  pattern  No  possible  basis  alone,  growth  the  surface  where  with  a  individual  and  be  maximized  i s feed,  i n Eunice  L a k e do  alternative  selection  follow  hypothesis  and for  this  predators.  results  However,  either  tc explain  I conclude  that  pattern  by  simulations  strategies. not  or  determined  h i s t o r y . The computer  alternative  diurnal vertebrate  will there  feeding  experiments two  s t r a t e g i e s shewed  physiologically  i s attractive?,  previous  migration  of  their  i t  is  a  in  lakes  iii  TABLE OF CONTENTS  Page Abstract Table  i  of Contents  List  of Figures  List  of Tables  i i i vi viii  Acknowledgements  ix  I.  1  General Introduction  II.  General Study  Methods Area,  Controlled Carbon-14 Larval  III.  5  Sampling, Holding Temperature  Facilities  5  Facilities  6  Assays  8 9  Dry W e i g h t s and C a l o r i m e t r y  Nomenclature  10  Field  12  Studies  Introduction  12  Methods  13  Results  15  Temperature  15  Vertical  16  Migration  Zooplankton  Distribution  18  Feeding Larval  20 Growth i n t h e F i e l d  25  Discussion Summary  27 .  v  ••  33  iv  IV.  Energetics  Studies  ..............................  Introduction  34  Methods  37  Strike  Efficiency,  Contact  Efficiency,  Handling  Time  37  Friction  Coefficient  38  Assimilation Respiration  39 Rates  41  Growth  Experiment  I  46  Growth  Experiment  II  47  Results  48  Strike  Efficiency,  Contact  Efficiency,  Handling  Time Energy  48 Cost  Assimilation  of  Vertical  Migration  51  Efficiency  53  Respiration  V.  34  55  Growth  Experiment  I  59  Growth  Experiment  II  61  Discussion  65  Summary  77  Simulation  studies  79  Introduction Theories  79 on  the  Adaptive  Migration The Methods  Simulation  Value  of  Vertical 79  Model  85 86  Results  .  91  Sensitivity  91  The  Effect  o f Food  The  Effect  of Temperature  .  96 ,  101  Discussion  104  Summary  119  Literature  Cited  121  Appendix  I  128  Appendix  II  135  vi  LIST  OF  FIGURES  Figure 1  Page Diel  fluctuating  growth 2  3 4  temperature  experiments  I  Schematic diagram of produce fluctuating water bath. Isotherms in 1971-1972  Eunice  (A)  regime  and  II  for  ( B ) , ........  the apparatus temperatures  used in  to a 8  Lake  i n 1970-1971  and 16  Diel vertical fourth-instar Eunice Lake.  distribution C. t r i v i t t a t u s  of larvae  old in 17  5  Total  6  Time of feeding of £• t r i v i t t a t u s larvae 197T-1972. .7  old on  Depth of feeding of C. t r i v i t t a t u s larvae 1971.  old fourth-instar on 2 0 - 2 1 S e p t e m b e r ,  7  8  9  The  zooplankton i n Eunice  of  Constant  11  Incubation apparatus  14  1972.  ......  19  fourth-instar five dates i n  23  i n Eunice  of of 25  Lake—  ..7  10  13  in  21  Chaoborus l a r v a e  1971-1973.  12  Lake  species composition of the diet f o u r t h - i n s t a r C. t r i v i t t a t u s l a r v a e a n d z o o p l a n k t o n i n E u n i c e L a k e i n 1972.  Growth  7  26  pressure respirometer design. f c r micro-Winkler  42 oxygen  consumption measurements. S t r i k e and c o n t a c t s u c c e s s of fourth-instar C. t r i v i t t a t u s larvae as a f u n c t i o n of prey s i z e .  44  49  R e s p i r a t i o n r a t e s of o l d f o u r t h - i n s t a r l a r v a e (1972 year-class) at different temperatures  56  Respiration rates of young larvae (1972 year-class) temperatures  57  fourth-instar at different  vii  15  L a r v a l growth d u r i n g  Growth  E x p e r i m e n t I . ......  60  16  L a r v a l growth  Growth  E x p e r i m e n t I I . .....  62  17  Generalized model  18  19 20 21 22  The  The The The The  during flow  diagram  o f the s i m u l a t i o n 88  effects of changes i n the parameter values of selected p a r a m e t e r s on l a r v a l growth  92  e f f e c t of migration growth — n a t u r a l prey  pattern on densities  97  effect of m i g r a t i o n p r e y d e n s i t y on l a r v a l  p a t t e r n and s u r f a c e growth. ..............  effect density  of migration pattern p r o f i l e cn l a r v a l growth  larval  and  effect of migration pattern t e m p e r a t u r e p r o f i l e on l a r v a l g r o w t h .  98  prey 100 and .......  102  vi i i  LIST OF TABLES Table  Page  1  C o m p a r i s o n c f f e e d i n g by f o u r t h - i n s t a r d u r i n g t h e day and n i g h t .  2  Mean and s t a n d a r d e r r o r o f t h e time r e q u i r e d for fourth-instar larvae to ingest different p r e y s i z e s and s p e c i e s , and t h e analysis of variance table for the d i f f e r e n c e s between s i z e s and s p e c i e s . . . . . . . . .  50  Experimental measurements of l a r v a l s i n k i n g velocity and calculated friction coefficients.  53  3  larvae 22  I  4  5  6  Carbon assimilation efficiencies of f o u r t h - i n s t a r C. t r i v i t t a t u s l a r v a e f e d on twc p r e y t y p e s . The v a l u e s a r e means + 95?? confidence l i m i t s .  54  Terms of the regression eguaticns: In (B) = l n (a)+b (In (H)) describing the relationship between oxygen consumption (R) and d r y weight (H)  59  Results of a two-way analysis cf variance with ration and temperature as main e f f e c t s i n Growth E x p e r i m e n t I I .  64  ix  ACKNOWLEDGEMENTS  Financial Research  Several  Zoology  the  logistic  completed.  and  thanks  laboratory  of  Regina  Columbia  Clarotto  experiments.  respirometers  on  Dr.  to  T.  G.  i n the Department  The a d m i n i s t r a t i o n  Research  used  the  staff  time  a n d a d v i c e on Kleiber  of  Forest  provided  could  n o t have  computer  apparatus, Turing  a  logic  clear  developed  Drs.  research,  obtained  from  Poland. center  provided one  helpful of  Dolores  Lauriente  cheerfully Carl  the  donated  Walters  and  i n t h e f o r m u l a t i o n and c o n s t r u c t i o n o f was  hours  an  invaluable  throughout  of discussion,  which  source  the course  of  o f my  Kim H y a t t  provided  t o t r y my e n t h u s i a s t i c  but often  ideas.  C. J . W a l t e r s , G. G. E. S c u d d e r ,  E. E f f o r d  recognition  and h e l p i n g w i t h r o u t i n e  programming.  Pierre  against  special  and  and enthusiasm  many  study  Stachurska  of the biology data  s i m u l a t i o n model.  research.  deserves  Dr. T e r e s a  i n the study  helped  this  zooplankton  bioenergetics  and  I.  67-3454  acknowledged.  British  f o rcounting  discussions  poorly  by N a t i o n a l  teaching assistantships  t h e h e l p o f many p e o p l e  been  ideas,  NRC  was p r o v i d e d  support.  Without  the  study  Grant  are gratefully  University  Pierre  f o rthis  C o u n c i l Research  Northcote. of  support  advised  me  during  the  and D r s . W a l t e r s , Scudder,  T. H. C a r e f o o t , a n d  early  stages  and C a r e f o o t  of  the  reviewed the  X  thesis.  Dr.  T.  G.  Northccte  patience,  advice,  research  supervisor.  provided  direction  constructive find  own  My  special  own  would and  involved  judicious  during  this  friendly,  thanks  my  gc  shared  efforts  responsible,  Krebs,  For without  to  in  i n the  r e s e a r c h , and  I  criticism  a  I  am  tenure  extremely  dictating, and  his  mixture  grateful.  criticism  p a t i e n c e enough  as  that  of my He was  t o a l l o w me  to  way.  years  unstinting her  and  my  three  and  provided  her  a great  in this  every field  Fedorenko phase  and  constant  like  to  of  interest  this  in  success  thank  f o r p r o v i d i n g moral  study.  who  laboratory,  e x t e n t , f o r the  especially parents  to A l i c e  Nancy  for  nearly  study.  while  pursuing  Chaoborus of  this  while  are  study.  Kleiber,  support  Her  Kathy I  was  1  I.  GENERAL The  the  INTRODUCTION vertical  most  migration  s t u d i e d and  least  of p l a n k t c n i c animals  understood  biology.  Biologists  have  in  m a r i n e and  f r e s h waters  both  understanding marine the  of the  forms,  been i n t e r e s t e d  migration  techniques  and  understanding  progression  from  descriptive  to  experimental  controlling studies  work  aimed  at  (Russell  Vertical plankton  and  generally  accepted  light,  in  1927, H a u c h l i n e  fish  factors,  the  Russell  migration.  distribution  (Cushing  (1951)  pattern  b a s e d on  light  pattern  has  of  been  early  a  distribution, mechanisms  and  theoretical of  this  1969) .  Light the  of  became  migration,  effects  and  other  work  on  of  vertical  mechanisms.  proposed  a  general  a l l vertically  as t h e i n i t i a t i n g four  has  As  i m p l i c a t e d i n the c o n t r o l  (1927) r e v i e w s  in  1967).  a l l groups  initiating  cn  and  1951).  physiological  has been  and c o n t r o l  Cushing  almost  work  value  and F i s h e r  in  as the s t i m u l u s  environmental  migration  occur  i n conjunction with  vertical  adaptive  Early  represented  there  eliciting  the  migration  years.  (Hutchinson  of  aquatic  from  to experimental  explaining  some  came  advanced,  the s t i m u l i  migrations  250  studies are well  s t u d i e s on  t h e m i g r a t i o n , and  phenomenon  and  on  process  literature  in  in vertical  f o r at least  migration  but f r e s h w a t e r  vertical  phenomena  i s cne  phases:  1)  scheme  migrating  and c o n t r o l l i n g ascent  from  for  the  zcoplanktcn stimulus. His  t h e day  depth,  2)  2  midnight depth.  sinking, This  forms,  3)  dawn r i s e ,  pattern,  i s valid  for  though  4)  sharp  developed  freshwater  descent  to  the  with r e s p e c t to  forms  as  well  day  marine  (Hutchinson  1967). Several adaptive  population  1935,  size  1963,  Kerfcct  1967,  Mauchline  (McLaren  1970),  1974).  and The  (1963)  budget  "energy  1961),  1962),  1969),  predators  social  (Hardy  ccntrol  gain  o f t h e above and  f o r the  transport  energy  of  (McLaren  (Hutchinson  demographic  effects  theories are considered in  hypothesis  for  the a d a p t i v e value c f  of the m i g r a t i n g animal.  boost" accrues to migrants  partitioning  o f energy  "energy  boost"  object of t h i s  s t u d y was  migrating  hypothesized  "energy  determine magnitude.  the  physical  they are  used  and  be  biological  larvae  t h e more  see  factors as  vertical  that  fecundity,  if  which the  etc. of  a  McLaren's  demonstrated,  were c h o s e n  w e l l known  and  energetics  to  that  efficient  temperatures  t o examine t h e  could  that considers concludes  f o r growth,  zooplankter,  boost"  Chaoborus  because  be  He  from  t o growth a t low can  vertically  animal  David  m e r i t s of t h e s e  from  horizontal  a combination  Fisher  escape  m i g r a t i o n i s the o n l y p r o p o s a l t o d a t e  the energy  The  1956,  to account  V.  vertical  this  1973),  (Wynne-Edwards  McLaren's  an  Hardy  been p r o p o s e d  migration:  1959a, b, P e a r r e  Gunther  Section  have  v a l u e of v e r t i c a l  (Manteifel and  theories  and  to  affect i t s  experimental  migrators,  they  3  are  readily  and,  collected  since  easily  study  done  examine  out  i s respiration,  vertical field  3)  was  used  p a r a m e t e r s on  Larvae the  of the  fauna  daylight  laboratory,  consumption  is  laboratory  elements of the  hours b u r i e d  the  since  i t was  aspect  of  their  first  their  1921,  1968,  Sikorowa  been  done  1937,  Teraguchi  on  mud,  and  burrow  has  and  nature  and  Northcote  results  of  various  parameters,  well  dusk  and  into  the is  Ricardo  1936,  c o n t r o l of  1966,  LaRow  spend  the  the  mud  again  biologists on  this  descriptive  Wood  1956, work  migration  1968,  the  migrate  literature still,  known  and  1973). Some q u a n t i t a t i v e e x p e r i m e n t a l the  of  of  fascinated  most o f  b e e n , and and  A is  model  They t y p i c a l l y  emerge a t  migration  Worthington  growth,  growth.  to f e e d ,  b i o l o g y has  the  effects  physical  freshwater.  discovered,  budget  is  midge", C h a o b o r u s , a r e  i n the  water column  energy  m a t e r i a l and  with  and  experiments  simulation  in conjunction  studies  feeding,  (C i s c o n s u m p t i o n , P  larval  "phantom  Field  migration,  2)  strategies,  of l e n t i c  dawn. A l t h o u g h  (Juday  1)  l a b o r a t o r y s t u d i e s t o examine t h e  biological  at  phases.  A g e n e r a l i z e d computer  migration  into  food  F i s feces, U i s excreted  migration  and  larvae.  A=P + R  vertical  in  i n the  their  vertical  t o measure t h e  C=P+R+F+U and  assimilation).  three  the  trivittatus  carried  eguations R  maintained  predators,  c o n s i s t e d of  to  growth o f c . were  are  easily  monitored.  The were  they  and  1969,  Roth has (Eerg 1970,  4  Chaston  1969).  particularly information 1971, been  concerned on  Fedorenko wide  S t u d i e s on  their 1973).  i n scope  and  (Nachtigall  1965),  respiration  (Jonasson  emergence anaerobiosis 1959). Parma  (1970)  fascinating  e c o l o g y of Chaoborus their  feeding  i s available  (Dodscn  Chaoborus  include  following  1972,  1942,  the  (Gersch  includes  animal published  1952,  1971,  most o f before  some  1970,  Montshadsky  Parma  has  but  Parma have  areas: locomotion  1968),  Sikorowa  been  physiology  Welch  bibliography  have  migration,  S t u d i e s on  1943,  (Lindeman  which  with  digestion  (Deonier  A Chaoborus  the  1968,  1945),  pupation Bradshaw and  and 1973),  Prokesova  b e e n c o m p i l e d by R o t h the  information  on  and this  1970.  /  5  II.  GENERAL  Study  METHODS  Area,  Sampling,  Experimental fourth-instar (Loew)  work  larvae  collected  Lake i s a s m a l l Columbia  Holding i n  this  study  o f Chaoborus  from  Forest  near  lake  Haney,  c f 4 8 0 m , h a s a mean d e p t h  cf  and  covered  from  a  surface  methodology  in  lake  Special  described use the  i n  were h e l d  the pertinent i n the dark  laboratory.  when t h e l a r v a e without to  food  be u s e d ;  t e c h n i q u e s used  were  when n e c e s s a r y .  a t an  o f 15.8m, a maximum  o r May. D e t a i l s  of  depth  routine  trivittatus  (Fedorenkc and S w i f t  forspecific Larvae  Larvae  were  1972).  experiments  are  f o re x p e r i m e n t a l  were r u n w i t h i n  on t h e e x p e r i m e n t  were f e d m i x e d  Eritish  lies  a t a constant temperature  captured.  depending  larvae  B. C. T h e l a k e  sections.  A l l experiments  Eunice  of  a n d t h e g e n e r a l e c o l o g y o f C.  are given elsewhere  sampling  Columbia.  o f 18.2 h a . I t i s u s u a l l y i c e  mid-December t o A p r i l  sampling the  area  British  out using trivittatus  i n the University  elevation 42m,  was c a r r i e d  (Shadanojahasma)  Eunice Lake,  oligotrophia  Research  Facilities  of  6°  in  a few days o f held  f o r which  z o o p l a n k t o n from  with  or  they  were  Eunice  Lake  6  in  Controlled  Temperature  Constant  temperatures  Percival  of  bath  water  was  tanks  model  1-42A)  the  tanks  line tank  The w a t e r  each which  wired  were open  (5° t a n k )  (20° t a n k ) . two t i m e  ml)  a s u b m e r s i b l e pump bath.  by s o l e n o i d  s w i t c h e s such  in  The  refrigeration  of  rate  two  (Little  Water  valves  that  900  Giant,  return  (Asco  drain  valve of  the  drain  switches  valves  Model  were  a g a i n s t room  and a g a i n s t a h e a t i n g c o i l  (Intermatic,  each  s e t above  was u n d e r  20°  the control  T101).  Assays  carbon-14  assays  (Nuclear Chicago, guench  were counted  P P O , 2 g POEOP,  bucking  to  Nc. 7 5 9 1 S ,  O n t a r i o ) i n each  units  a  o f m i x i n g o f t h e two  consisted  O p e r a t i o n o f t h e two s y s t e m s  Carbon-m  standard  produced  when t h e pumps w e r e r u n n i n g . W a t e r t e m p e r a t u r e s  temperature  counting  system  t h e water  Fluctuating  and h o t w a t e r .  Ltd., Brantford,  t o time  using  All  cold  maintained  Iowa).  T h e s u b m e r s i b l e pump a n d d r a i n  maintained  of  supply  supplied  Brantford  (Fig. 2). were  Boone,  by t h e d e g r e e  containing  was c o n t r o l l e d  Ascolectric  cycling  controlled  supplies.  liter  (Percival,  (7 - 15° a n d 5 - 2 0 ° , F i g . 1) w e r e  by a l t e r n a t e l y  change  o f 5° a n d 2 0 ° ± 1° w e r e  incubators  temperatures water  Facilities  were done  by  Isocap/300  correction.  o r Mark  scintillation  I) w i t h  external  S o l u b l e aqueous samples  (up t o 1  i n 10 m l o f B r a y ' s  60g n a p t h a l e n e ,  liquid  scintillation  100 m l m e t h a n o l ,  solution  (4g  20 m l e t h y l e n e  7  FIGDRE 1 Diel fluctuating temperature regime f o r growth e x p e r i m e n t s I (A) a n d II (B). Temperatures are s h o w n f o r o n e week i n b o t h c a s e s .  7a  8  FIGURE 2 S c h e m a t i c diagram o f t h e a p p a r a t u s used t o p r c d u c e fluctuating temperatures i n a water bath. Legend: 1. I n l e t h o s e f r o m 2 0 ° t a n k , 2. I n l e t h o s e f r o m 5° t a n k , 3. O u t l e t t o 2 0 ° t a n k , 4. O u t l e t t o 5° t a n k , 5. H e a t i n g c o i l , 6. S u b m e r s i b l e p u m p s , 7, 8, 9. Experimental aguaria.  9  glycol,  made up  material  on  solution  with  a  gel  to  material  was  at  outflow  column. the  scintillation  and has  then  PPO,  be  before  10  of  efficiency various 1  of  minute  10  this  and  and  Carbon  8  ml  1961)  of in  minutes  rinsed  a of  into  a  scintillation  1 liter  with  toluene)  combustion  procedure  particulate  material  the  counts (dpm)  in  toluene  amounts of  Raw  and  to  (Lindberg  Alvarez  was a  *C-gluccse,  100%. per  ml  and  form  recovery  were  was  fcund  converted  corrected  for  to  background  analysis.  Larvae two  60cm s q u a r e  Dry  weeks net.  1971-1972.  and  60°  in  after  Weights  and  Calorimetry  were c o l l e c t e d  of  just  with  virtually  larval  every  (Jeffay  to  oxygen.  collected  POPOP, made up  amounts of  disintegrations  was  Bray's  Particulate  of  stream  solution  The  added  a  trapping  0.3g  silica)  in  furnace  combustion  counted.  known  under  solution  with  counted  i n a tube  Following  vial  been checked  and to  (5g  or  Particulate  material i n suspension.  stream  trapping  U-Cioxane).  divided  combusted  500-600°  ethanolamine  solution  (finely  and  1,  combusted  particulate  dried  flushing,  with  was  Cafc-0-Sil  i n the  Vigreux  1 liter  filters  keep  Hevi-Duty) dioxide  to  1972.  in  1971  and  Several Samples The  capture  using every  samples  week  no  were  larvae  in  were t a k e n  were s o r t e d  larvae  and  diagonal  and  1972  at  from  freshly  from  with  during  dried  separated with  hauls  a  20-0m 30cm  the 100°  or  winter in  1971  potential  food  caught  prey  in  10  their  crops  were  were m e a s u r e d replicate to  10  Cahn  Gram  the  50-100 f o r  fourth  content  in early  Instruments for  with  5 or  instar.  more r e p l i c a t e w e i g h t s number  the  first  of  and  A l l samples  larvae  second  were  per  instars  weighed  cn  a  Electrobalance.  calorimeter  60°  Generally  instar from  the  Caloric measured  per  varying  for  used.  young and  spring  using  (Phillipson  1964)  Inc.,  three  of  Aiken,  d a y s and  a  replicates  of  each  sample  calculated  as  c a l o r i e s per  fourth-instar larvae  Phillipscn  oxygen  manufactured  South  stored  old  by  desiccator  were combusted. gram  dry  microtomb  Gentry-Weigert  C a r o l i n a . Samples in a  was  were d r i e d  until  used.  at  Five  C a l o r i c content  was  weight.  Nomenclature Because (Fedorenko  C.  and  Swift  fourth-instar summer.  I  larvae  are  winter, first  summer o r  degrees various except  used  animals for  those  the  i n the  year are  genera  after  which  two lake  classes. in  their larvae  are  generic they  year  life  during  represented  part  Old  the to  summer  those  referred  in  or  their  to  r e f e r to  first by  of  fourth-instar  second are  of  "young"  names t o are  cycle  year-classes  and  temperatures  I have used  discussed  two  "old"  fourth-instar A l l  a are  terms  that  winter.  Centigrade.  there  the  larvae  young  has  present  between  those  and  1972)  larvae  have  discriminate  trivittatus  are the  mentioned  more t h a n  one  11  species; names.  these  are  r e f e r r e d to by  t h e i r g e n e r i c and  specific  12  III.  FIELD STUDIES  Introduction In value  order  to assess  of v e r t i c a l  timing  and  affect  the  analysis  their field The  of  of those  the  budget  through  is  vertical  the  larval  density feeding,  portion of t h i s 1)  trivittatus  biological  What  is  study the  was d e s i g n e d  to  c h a r a c t e r i s t i c s of the environment  3) What a r e t h e c h a r a c t e r i s t i c s o f l a r v a l  are  t h e c h a r a c t e r i s t i c s o f t h e growth  data cf  The base  r e s u l t s of these f i e l d  studies  f o r use i n t h e c o n s t r u c t i c n of a  a vertically  migrating  through important  Chaoborus l a r v a .  the  larvae.  answer  migration  i n E u n i c e L a k e ? 2) what a r e t h e  that  temperature  o f Chaoborus  of  which  Preliminary  a r e t h e two most  in?  lake?  temporal  distribution,  vertical  the  suggested  various  parameters a f f e c t i n g the e n e r g e t i c s  field  the  migrator.  on  know  parameters  migration  and  to  and  and a b i o t i c of  i n the adaptive  necessary  migration  i t s effect  r a t e s , and p r e y on  i t  biotic  Chaoborus  effect  questions. £•  of  energetic  temperature, dependent  migration,  magnitude  characteristics  the r o l e of e n e r g e t i c s  four  p a t t e r n of  physical  and  the larvae  live  feeding?  4) What  larvae  provide  a  in  the  reference  generalized  model  13  Methods  Temperature, growth  were  (1972). from  monitored  Temperature  May  tc  zooplankton net  with  a  was No.  at  2m  0-20m.  from C-B  the  crop  Swift  and  presence food.  if  they  "fresh" about  three  partial Results crops crops  for  enumerating  i t s  contents  that that  (1973).  of  items  food,  from  identifiable  the  "fresh"  temperature about  one  hours  these  hour,  at  analyses  contained contained  prey  and  summer  times  any fresh  were are  following  were  D.  taken  spaced  every  raising  whose  method  The  kenai  the  digestion  of  as  "fresh"  zooplankters.  rate  was  of  digestion  Bosmina  remained  remained  "fresh"  temperatures. lower  expressed  as  the  and  of  by  exoskeleton  type;  food  dissecting  the  of  at  food.  were  by  individual  surface  of  and  plankton  characterized  longer  amount  larvae  designated  category.  and  weekly  slowly  directly  degree  entire,  animals  by  Swift  moving.  were  the  crops  as  excluded  Crops  and  the  was  and  (C-B)  hauls  made  determined  digestion of  were  larval  measured  Samples  diagonal  was  from  with  net.  using hauls  Fedorenko  Clarke-Bumpus  larvae  the  Prey  macerated  a  and  d i s t r i b u t i o n of  boat  absence  were  were  the  d e f i n i t i o n  varied  diagonal  2m  growth  nylon  midnight  Fedorenko  or  the  This  The  of  while  of and  using  d i s t r i b u t i o n ,  methods  Vertical  (0.08mm)  and  sampler  the  larval  monitored  neon  Food  and  20  vertical  using  November.  weekly  the  plankton  the  for  These  temperatures. percentage percentage  of of  14  The  time  sampling done  on  29  at  frame  day  every  three  and  2m  that  September,  September, made  of  7  a  (1-21)  from  depths  opening  was  held  v e r t i c a l l y  lowered;  the  larval  with  1972  samples  using  which  for  vertical  The with  that  rates  24 of  feeding  on  hour  with  samples  digestion takes  a  to  place.  30cm  when  based  1m  of  period. 8  horizontal square was  sampled the  determined  July,  There  samples time  hour  1971  being  C-B  24  was  17  line.  not  determining  hauls  a  distribution  based  a  In  with  weighted  fed  on  1972.  contamination  well  over and  October,  to  larvae  hours 1971,  intervals  fixed  the  net on from  net  This  August,  this the  with  the  feeding  were  l i t t l e  the  net  raised  method same  6 were  probably  being  was  hauls  because was  by  or  agreed  depths.  In  collected  net.  from  1971  directly  were  used  determine  in the  ccnjuncticn depth  at  15  Results  i  Temperature  The the  temperature  two y e a r s  thermocline The to  sharp  this  decrease  Vertical  The  high  i n  The  instar  and  this  study  are  the  they  spend  the  day at  0900  rise.  diel  migration  (Fedorenko  In  was s i m i l a r  both  early  period  about is  are  C.  years  the July  cf  during  a  stable  summer  mcnths.  1972  three  pattern  form  (1972,  t r i v i t t a t u s  of  was  due  days.  about  been  F i g . 9).  The  larvae  12m,  hour  from  and S w i f t  1972).  begin  to  by  Eunice Cushing  described  by  considered  in  During  move  the  summer  upward at  sink  There  l i t t l e  suggestion  at  This  i s  is  spent  slowly  3m.  November.  throughout  the  In  tc  1800  and then  May t o  distributed  larvae.  in  d i s t r i b u t i o n and  has  (Fig. 4).  found  depth  and  hours,  one  larvae  described  the  old fourth-instar  hours  Only  larvae  i n  a  specific  3m b y 2 1 0 0  dawn  the  Swift  of  the  particular  Fedorenko  by  over  Lake  4m d u r i n g  temperature  follows  i s  depth  3).  about  pattern  migration  reach  (Fig.  at  r a i n f a l l  migration  hours,  i n Eunice  Migration  generally  (1951).  study  developed  extremely  Lake  of  regime  the  day cf  pattern  a of  the  winter  water  column  16  FIGURE 3 Isotherms in Eunice Lake in 1970-1971 and 1971-1972. T e m p e r a t u r e s a r e i n d e g r e e s C e n t i g r a d e .  i  FIGURE 4 Diel vertical distribution of o l d fourth-instar C. t r i v i t t a t u s l a r v a e i n E u n i c e L a k e . The w i d t h o f the kite diagrams represents numbers per 100 l i t e r s ( a f t e r F e d o r e n k o and S w i f t 1972, F i g . 9 ) .  TIME- HOURS 1200 1800 2100 2400 0300 0600 0900  18  Zooplankton  Five  species,  zooplankton These  are  in  4-6  meters.  are  -  but  is  100  l i t e r s  The  1000  generally  low  —  change  spreads day  depth  about  100 about  400 is  0-100 the  and  D.  over of  9m u p  v e r t i c a l rosea the  to  2m  D.  (A.  for  a  100  found water  rosea  than the  water  are  most  time  below column  pers.  as  as  high  June  and  200  is  from  animals  comm.).  per late  hypolimnion some  species,  i t s  as July  during  There  deep  The  above  in  at  and  numerous  the  some  the  (Fig.  in  6m;  and  column  only  density  of  basis.  1972).  is  The  6m  l i t e r s .  the  _ g i b b e r um, Swift  l i t e r s .  migrates  Fedorenko,  t_^relli  epilimnion  distribution are  D.  biomass  the  short  100  year  per  and  and  they  the  deeper  entire  3m a n d  but  per  the  animals  kenai  dominate  and  ]jolo£sdium  in  l i t e r s  Throughout  in  kenai  density  isopleth  September.  D.  per  number  throughout  Fedorenko)  prey  a  (Fedorenko  distributed A.  Chaohcrus,  both  rosea,  tiach^urum  from  600  on  of  Diagtomus  Daphnia  zooplankton data  Lake  copepods  ^il£il3I12Soma  5,  exclusive  Eunice  the  cladocerans  is  Distribution  diel  but  only  night  D.  as  from  i t s  depth  of  20m  day  kenai  FIGURE 5 Total zooplankton lines are zoopl p e r 100 l i t e r s ) . dates indicated Chaoborus larvae  in Eunice Lake in 1972. The ankton density isopleths (number S a m p l i n g was d o n e a t n o o n on the by a r r o w s . N a u p l i i , r o t i f e r s , and are not i n c l u d e d .  >o 03  20  Feeding  Only a  given  had  crops  with  Fig.  sampled  on  the  the  other  if  prey  the  time  Data 1971  to  from  1800  old when  during  the  feeding  occurs  during  slow  low  day-depth  the  digestion  night the  of  prey in 4  In  and  July  no  prey  in  at  any  larvae a l l  number  on  with time  i n  catch  any  their  of  times date  October  significant  Larvae  their  sampling  times)  on  examined in  the  sampling  1).  taken  are  at  1972  crops  at  difference  no of  food the  freshly  in  day  or  caught,  prey  within  over  a  hour  a  24  larvae  depth  of  begin 10m  (Fig.  7).  There  is  day,  but  i t  probably  previously  an  hour  is  captured  some  prey  and  period  feeding continue  evidence an  in  that  artifact  resulting  from  temperatures.  entire  range  size D.  tows  they  C.  to  (first  fourth-instar  Fourth-instar  (0.1mm)  larvae  fresh  difference  was  The  of  feeds  collected.  feed  of  the  fresh  samples  horizontal  hours  40%  feeding  available.  that  1).  (Table  of  zooplankton  4  there  sampled  population  day  had  day;  larval  had  the  (second  larvae  are  only  (Table  capable  they  the  20%  during  the  are  indicate  about  than  1972  more  are  most  night  or  of  significant  crops  dates  concentrated of  no  during  crop  night  was  1971  than  At  less  and  significantly night  6).  and  f u l l  6) in  proportion  (Fig.  There  larvae in  small  day  f u l l  crops.  a  kenai  t r i v i t t a t u s of  prey  (2.3mm).  There  larvae in are  are the  able lake  seasonal  to from  feed  on  rotifers  changes  in  FIGURE 6 Time of feeding of eld fourth-instar C. t r i v i t t a t u s l a r v a e on f i v e d a t e s i n 1971-1972. Percentage f u l l crops ( s o l i d c i r c l e s and sguares) and percentage crops containing fresh prey (open circles) are p l o t t e d against sampling time. The sguares are 1971 data.  BL3  22  Table during  the  1.  Comparison  day and  of  feeding  fourth-instar  larvae  night.  Full  Date  by  d.f.  X  Crops  P  2  Crops containing fresh fcod X2  F  21  Sept.  1971  1  2.37  .  17  July  1972  1  0.308  .5-.75  8 . 26  <.005  8  Aug.  1972  1  0.153  .5-.75  0.35  .5-.75  6  Sept.  1972  1  2.140  .  3 . 05  . 05- . 1  7  Oct.  1972  1  0.65  .25-.5  12.04  <. 005  1-.25  1-.25  •  FIGURE  7  Depth of feeding of old fcurth-instar C. t r i v i t t a t u s l a r v a e on 20-21 September, 1971. Percentage f u l l crops is plotted against depth at each sampling time. At each d e p t h p l o t t e d , n>20.  24  prey  species  types  is  densities,  found  Three  species  most  of  these  three,  great it  is  the D.  the  8b). D.  only  of This  to  hatch  appear  species  emerging year,  pattern  of  raid-June (Fig.  tc  to  June  second their  are  both year  f i r s t  of  year year  year  in  the  cf  as  much  because  biomass  in  eating  the as  in  biomass 70??  (Fig.  much  numerically  Of any  selectively  diet  and  to  from  of  up  8d).  diet  the  feed  is  8a).  eaten  more  the  diet,  C.  the  cn  higher  much is  more  p.  t j r e l l i  t r i v i t t a t u s  larvae  in  the  1972.  The  eggs  same  larvae  short  the  in  (Fig.  eaten  density.  Fedorenko  a  to  prey  Field  the  two  the  or  of  (Fig.  comes  and  Bosmina  i t s  growth  from  for  in  the  and  9,  except  October  in  than  in  found  lake.  essentially  there  do  the  lake  Growth  spring,  their  in  is  lake  Most  30$  summer  are  larvae  larvae  proportionally  in  captured.  fourth-instar  each  the  found  sampled,  the  was  seldom  spectrum  H c l o j j e d i u n i make  tjjrelli  month  abundant  The  is  p.  in  than  Larval  and  the  and  in  constituted  this  in  t_yrelli,  biomass  easily  entire  throughout  D.  kenai  be  the  ccpepod  proportions  field  p.  fcurth-instar  kenai;  roughly  kenai,  old  diet  Old  diet  Holojaedium  large  kenai.  E.  the  almost  zooplankton  extent.  diet  of  --  the  too  in  but  in  grow  (Fig.  grow  9) ;  in  at  these  a  summers  any  the  present are  and  two  fit  before  classes  larvae  for  1973).  time  classes  1971  in  the  time  eggs  two  during  hatch  the  in  lake.  fourth  faster  before  rate  growth  instar. than  the the From In they  patterns  FIGURE 8 The species composition of the diet of fourth-instar C. t r i v i t t a t u s larvae and of z o o p l a n k t o n i n E u n i c e Lake i n 1972. A. Percentage frequency of occurrence of prey i n l a r v a l c r o p s . B. P e r c e n t a g e c o m p o s i t i o n by weight of prey i n larval crops. C. Percentage freguency of o c c u r r e n c e o f some z o o p l a n k t o n i n E u n i c e L a k e . D. Percentage composition by weight of some z o o p l a n k t o n i n E u n i c e Lake. R o t i f e r s and C h a o b o r u s a r e n o t i n c l u d e d i n C and D. The s p e c i e s cede' i s as follows: B — rotifers, B — Bosmina, P — HO-iY-P-hemus , D — Dap__hn i a , H — Hclo^e^l"iS» Di^Jlhanc^onia 3 miscellaneous cladocerans, F — D. K e n a i , T — D. T v r e l l i , 0 — Chaoborus larvae, X — unidentified material. c  a n <  (  o  o  j  o  &  c  o  n  c  o  o  Percent r  o  o  ^  o  Composition c  n  o  c  o  o  of  Prey F  o  O  f  o  e  O  o  l  C  o  O  r  o  o  j  ^  o  m  o  a  )  o  rO  0)  FIGURE 9 Growth of Chaoborus larvae in Eunice Lake— 1971-1973. The p o i n t s a r e mean d r y w e i g h t s ± 95$ confidence limits. The numbers i n d i c a t e t h e y e a r c l a s s of the l a r v a e .  2.0T  1971  1972  1973  27  were  similar  at t h e end  i n both  years of t h i s  of the f i r s t  second  constant  over  potential  t o grow a t a much f a s t e r  experiment  a higher  control  (1.58mg  same w e i g h t  their  three  testing  reached  the  the  and  Although  the  appears  relatively  years studied,  than  rate.  their  as compared  the  the  larvae  In a 28  lake  (1.78mg a s compared  four  during  t o 0.38mg)  eld  the  larvae lake  grew  to  weight  of  course  (Fedorenko  the situ  the  larvae  times the  in  in  t o 1.28mg); young  weight  have  day  densities,  counterparts  the o l d l a r v a e and  counterparts in  experiment  summer  growth a t h i g h f c o d  weight  as  study.  of  the  1973).  Discussion The larvae  most is  prominent  their  migration  f e a t u r e of the b i o l o g y of  regular,  pattern  diel  instead  hours of being  1972).  although  lake  The  physical  (temperature,  density) .  and  cold  flavicans  (Fedorenko  characteristics  consequences biological  oxygen  found  Corbett  a r e n o t as i m p o r t a n t  and  o f the  (1966) in  to that  these l a r v a e  waters  Northcote  descriptive  interesting,  the  deep  that  b u r i e d i n the sediment  physiological  through  the  p a t t e r n i n C.  Columbia.  the  in  Teraguchi  migration  migration.  i n Eunice Lake i s s i m i l a r  most c h a o b o r i d p o p u l a t i o n s e x c e p t daylight  vertical  Chaoborus  in  resulting  of  found  spend  in the  hypolimnion and a  Lake,  Swift similar British  the m i g r a t i o n , this  study  from  migration  g r a d i e n t s present  concentration,  The  light,  in and  as  the prey  28  The small, the  stable deep,  thermocline temperate  thermocline  effect  on  the  throughout  daily  old  range  temperature  (5°  August,  and  a  in  the  thermal  Typically,  and  Eunice  lakes  larvae. of  in  the  Lake summer.  summer  regime  cf  has  the  larvae  -  their  narrower  during  range  in  typical  of  The  presence  of  a  considerable  vertically  fourth-instar 20°)  is  migrating  encounter migration  June,  a  wide  in  July  September,  and  October.  The  entire  throughout oxygen  water  the  year  vertical unlikely  i t  seems  effect  on  vertical  Because  controlling  was  a  (1969) to £*  of  light-dark  Teraguchi  has  for  1970),  and  factor  i n i t i a t e i£ilii£atus  that  the  Northcote  that  c r i t i c a l  migration.  1972).  C.  The  with  Lake  is  like  Eunice  Lake  which  lew  regulatory (LaRow has  any  depth  and  implicated  migration that  of  light  intensity  probably  as  a  zooplankton. intensity  migrations  vertical  Eunice  a  increasing  been  light  in  Although  £ujjctipennis  Chaoborus  low  as  oxygenated  Lake.  suggested  in  well  concentration  long  vertical  factor a  in  Eunice  has  (1966)  is  suggested  oxygen in  Lake  Swift  attenuation  light in  and  migration  light  cycle,  Eunice  been  migration  controlling showed  in  (Fedorenko  concentration  mechanism  the  column  was  and  LaRow  required  migration  of  under  photoperiodic  low  transparency  control.  In  lakes  have  a  29  (Secchi  depth  5-6m), most p r i m a r y  the s u r f a c e i n the layer  also  zooplankton total  supports —  of  the  migration  to f e e d  Lake  (Hardy  depth  predator the  two  different  feeding  prey  ways  results,  food do n o t  their  clear  feed  fcund  in  by  examining  and  by  at  or  which  the  comparing  time known  the a c t u a l  diet.  Although  this  question  gave  somewhat  that  most f e e d i n g o c c u r r e d  of the  most s u r p r i s i n g  at  I t appears the  that  relatively  Estimates  of f e e d i n g t i m e  based  be  less  of the a c t u a l  estimates  based  on  different  digestion  in  findings  population  the e p i l i m n i o n , o r a t t h e  had  no  many l a r v a e high  prey  relatively  low  hypolimnion.  indicative the  vertical  herbivorous  depth  i n the  to  for  The  densities  found  the  with  time.  either  demonstrates  e u p h c t i c zone i n o r d e r  p r o p o r t i o n of the l a r v a l c r o p s a t any  readily  densities  occurred,  a t n i g h t . One  a large  in  i t was  herbivorous of  whether  determined  examining  This  distribution  given  1963).  distributions of  The  commonly  McLaren  near  depth.  the f o c d - r i c h  l a r v a e f e d was  epilimnion that  into  of  clearly  zooplankton,  1956,  where and  with  place  epilimnicn.  density  Chaoborus.  Eunice  that  migrate  fourth-instar  prey  in  mixed  highest  explanations  is  carnivorous,  was  of  well  gradient i n productivity  One  the  the  the f o o d  zooplankton  sharp  and  relatively  production takes  occurrence  times  of the  on  full  of fresh  crop  were  f e e d i n g time  prey  v a r i o u s prey  data  because  than  of  the  t y p e s . Thus,  no  30  diel but by  feeding  periodicity  a feeding  peak a t n i g h t  the o c c u r r e n c e  feeding  of f r e s h  periodicity  on  shows a c l e a r f e e d i n g  occurrence  when that  was prey  where  crops  during  the  digestion  day  i n the crops.  of  species  occurs  Feeding  of prey  capture  at  the  density.  The i n c r e a s e and  day  depth  depth  time t h a t  with  t h e downward m i g r a t i n g  the feeding  fourth-instar  larvae  probably  t o the  is  i n feeding  the  Knowing  prior  curves  f o r p. k e n a i  and p. t ^ r r e l l i 10 and  (Fedorenko  these prey  day d e p t h  feeding  at n i g h t .  night on  prey  the r e s u l t  o f slow  response  time.  Prey prey  place  larvae  at  overlap  curves  depth  i s most  likely  show f e e d i n g  100 p r e y  per l i t e r  of  old  distribution,  functional  to  occur.  response  saturation at respectively  d e n s i t i e s do not  of o l d f o u r t h - i n s t a r l a r v a e ,  must o c c u r  at  the  feeding  migrating  the f e e d i n g  prey d e n s i t i e s o f about  the  by  apparent  sampling  and t h e z o o p l a n k t o n  1973). S i n c e  occurs  fresh  kenai.  functional  old fourth-instar larvae  shown  a t 1800 h o u r s t a k e s  one c a n p r e d i c t t h e time t h a t f e e d i n g For  the  u n l i k e l y b e c a u s e o f low  t h e upward D.  1973).  and a r e f e e d i n g The  diel  individually  support  depths,  to the e p i l i m n i o n .  captured  taken  activity,  at d i f f e r e n t  is  Analysis  (Fedorenko  feeding  (0900-1500)  data,  October  t h e l a r v a e a r e i n the e p i l i m n i o n are r e s t r i c t e d  crop  i n d i c a t e d i n J u l y and  some prey  results.  percentage of f u l l  i n d i c a t e d by t h e f u l l  peak a t n i g h t  Data on t h e d e p t h prey  was  occur  one can i n f e r  A n a l y s i s of the l a r v a l  diet  at that  shows  31  this  to  be  less  in  proportion  Bosmina most  the  and  p.  5m  at  appear  to  take  5m d u r i n g p.  kenai  to  place  form  this  is  the  primarily  The  the  case,  while  old  below  and  ££±£ittatus in  this  a v a i l a b i l i t y .  with  larvae large  larvae  and  pupation 1973). wasn't old  have  amounts young  weight The  basis,  the  conditions.  to  would While  summer,  found  does  not  kenai,  distributed  below  spatially  with  the  p.  kenai  thermocline.  could  be  If  feeding  thermocline.  of  discussed  exposure  above  (1972)  and  i s of  food  only  due,  to  28  determine  the in  of  whether  amounts  given of  food  cycle  to  low  food  shown  that  rapidly Both tc  i n  late  the  if one  provided year  their  "heavy"  the  old  normal  (Fedorenko f a l l  and  one  appropriate  allow  of  l i f e  food  these  growth.  year  has  grew  and  growth  high  terminated  i f  two  1973).  larvae  days  larval  part,  very  physical  the  hypothesis  grow  year  was  pupate  that  this  the  determine  (Fedorenko  the  to  discuss  suggest  test  large  eaten  both  (dusk-dawn),  larvae  or  basis  pia£tomus  is  below  more  are  feeding  overlap  period  taken  prey, are  surface.  larvae  prey  the  of  after  the  the  potential of  abundant  biomass at  feed  numerical  On a  fourth-instar  experiment  possible  larvae  the  most  a  They  species  A field  On  summer.  Swift larvae  larvae  the  physiological effects  Fedorenko  the  two  migration  principal  gradients  seen  the  Since  biological  C-  abundance.  entirely  night.  the  fourth-instar  throughout  throughout  may  prey  times.  prey  the  old  throughout a l l  principal  The  t v r e l l i ,  frequently  above  the  case.  i t  year light  larvae  to  32  grow at  much f a s t e r t h a n  the differences i n i n situ  differences (1969,  in final  weight  i t i s i n t e r e s t i n g to lcok  g r o w t h among of the three  1970, 1971) were most p r o b a b l y  overall of  i n the f i e l d ,  food  1971  composition  than  levels. they  due  year-classes. year-classes to  The  studied  variations  in  P r e y d e n s i t i e s were h i g h e r  i n t h e summer  were  the  d i d not change.  in  1972,  although  species  33  Summary 1. diel  Fourth-instar  vertical 2.  3.  the  near  throughout  t h e summer.  exposes the l a r v a e t o a  wide  range  of  and p r e y d e n s i t i e s .  Because  L a k e , most night  migration  The m i g r a t i o n  temperatures  l a r v a e i n E u n i c e Lake u n d e r g o a r e g u l a r  of  feeding  the  zooplankton  distribution  by o l d f o u r t h - i n s t a r l a r v a e  the s u r f a c e .  However, p. k e n a i  takes  i n Eunice place  may be e a t e n  at  below  thermocline. 4.  The e n t i r e s p e c t r u m  vulnerable larvae  to  appear  proportion  to  predation to  feed  their  of prey by  on  old the  density;  species  i n E u n i c e Lake  fourth-instar various  p. kenai  prey  is  l a r v a e . The species  in  i s t h e main s o u r c e o f  biomass i n the d i e t .  5. its  L a r v a l growth  potential  Variations differences  i n E u n i c e Lake a p p e a r s t o be l o w e r  maximum  because  i n zooplankton density i n growth  among  of  low  probably  year-classes.  fcod  than  availability.  account  f o r the  34  IV.  ENERGETICS STUDIES  Introduction The the the  energy  equations total  is  C=P+R+F+U  intake  heat or  —  egesta  —  and  food  from  equations  available  C  not  environmental  much e f f e c t The  the  effects  Temperature,  time in  of  urine  biomass,  however,  is  i s converted  to  processes,  intake  the  material through  that  F  is  not  absorbed  ( p h y s i o l o g i c a l l y u s e f u l energy)  —  A l l the  study.  the  elements  Consumption  Excreta  and  (U)  from  light  encountered  is  P  R  food  or  —  or  separated  these  interval,  in l i f e  by  are by  these  light  two known  has  factors to  was  liquid  the  (C)  of  larvae not  these f c r old  data  not  estimated  most  is  variable  larvae.  were affect  The  relatively  been shown t o in  were  egesta.  migrating  physiological reaction rates of  by  gills  this  pressure,  factors  1971)  U were measured i n d i v i d u a l l y  a t m o s p h e r e s ) , and cn  part  1973). be  up  total  excreta.  change e x p e r i e n c e d (1-4  i s used  body as  and  (Fedorenko  Temperature,  increase  that  the  larvae i n  because i t c o u l d  small  —  l e s s the  except  fourth-instar  pressure  and  A is assimilation absorbed  a specified  —  p a r t of  U i s excreta  skin,  (Ricker  p a r t o f a s s i m i l a t i o n which  that  i s passed  i s stated  A=P + R where C i s c o n s u m p t i o n  during  (growth) that  that  animal  and  mechanical energy  absorbed,  the  of f o o d  production  respiration  is  b u d g e t o f an  have  invertebrates. not  examined.  physiological  35  reaction  rates,  temperature of  larvae.  Lawton  by  1970  on  was  was  measured  Any  ( P ) . The by  requires  swimming  involved.  implicitly  or  studies  i s not  the  Consumption process  which  efficiency,  the  successful,  is  Experiments  of  of  the  Most  appears  that  on  shown t c  be  for  and  C,  ration  digestion  Vlyroen  cost 1970)  an  only  (C) rate  this  was  of  of  high.  Recent  made t o  the  any  parameter are  assess  capture  equation.  study  that  larvae.  prey  captures  the  assumed,  trivittatus  attempted part  of  have s u g g e s t e d  e n e r g y budget  of  vertical  have  is  attempt  component  i n the  of  metabolic cost studies  this  important  to g u a n t i f y  of  about c o n s u m p t i o n  f o u r t h - i n s t a r C.  proportion an  loss  temperature  the  previous  1967,  i s the  directly,  1973  o v e r a l l energetics  a s s e s s m e n t of  old  effect  major e n e r g y  temperature  case. Therefore,  swimming c o s t  The  wide  (1973).  explicitly,  (Hutchinson  a  measured  (Fedorenko  information  e f f e c t of  an  the  changes  provide  consideration  migration  was  i n t e r a c t i o n of  Fedorenko  to  a s s i m i l a t i o n have been  temperature  measured t o  exposed  migration.  rate  represents  and  The  were  their  respiration  f o r A).  growth  the  larvae  (8-20°) d u r i n g  Consumption  and  this  the  r e s p i r a t i o n probably  unaffected  size  range  temperature  since the  and  Feeding  that of  included  are  feeding. in  this  section. The and  i n t e g r a t i o n o f a l l the  l o s s to  an  animal  f a c t o r s a f f e c t i n g energy  i s expressed  as  a change i n  the  gain  weight  36  of  the  density  animal.  In an a t t e m p t  and t e m p e r a t u r e  two  growth  used  to test The  the generalized  results  gain  budget  and  on t h e f e e d i n g results,  and l o s s ,  efficiency input  conducted were  migration.  s t u d i e s on t h e p a r a m e t e r s  were used,  data  I  o f prey  of these experiments  e q u a t i o n , on t h e swimming  as  the e f f e c t  model c f v e r t i c a l  of the f o l l o w i n g  energy  Chaoborus  on e n e r g y  e x p e r i m e n t s . The r e s u l t s  the  field  to g u a n t i f y  for  v e r t i c a l migration discussed  in  the  cost  of  migration,  conjunction general  in a later  of  model  section.  with of  37  Methods  Strike The  Efficiency,  strike  captures)  *  (contacts strike (D.  kenai)  >3.0mm times  efficiency,  1005?,  and  + captures)  at  (captures) /  contact  prey  (strikes  The  (D. r o s e a )  Experiments  o f t h e day w i t h 10°  Handling  efficiency,  sizes.  and c l a d o c e r a n s length.  Efficiency,  Time  + contacts +  (captures)  * 100$, were measured by w a t c h i n g  different  in  about  Contact  20-25  prey  were  varying  were  or f l u o r e s c e n t  0.6mm  of  room  water  at was  in  a time  larva;  strike was  definition  when  no  followed as  as  prey  by  A  in hitting successful  to  i n close  captures  binomial  into  200ml  was d e f i n e d a s a proximity to the movements  or h o l d i n g t h e prey ingestion.  A  o f a prey  Confidence  f o r n >30 were c a l c u l a t e d  the  For the  which  A c o n t a c t was d e f i n e d a s a  ingestion also.  strike  strike-like  were n e a r .  contacts  captured  approximation  prey.  excluded  thesuccessful  were s c o r e d proportion  200  movement a t a p r e y  which succeeded  not  defined  about  striking  occurred  and  t h e l a r v a e were p l a c e d i n d i v i d u a l l y  with  this  ccntacts,  being  t o twc p r e y  o v e r a p e r i o d o f 20 m i n u t e s t o one h o u r .  prey  water  definite  The l a r v a e were e x p o s e d  and t h e number o f s t r i k e s ,  recorded  smallest of  the experiments.  at  lighting. A l l  l a r v a e were s t a r v e d f o r between one and two days b e f o r e used  to  cut at various  l a r v a e i n 200-250ml  and i n c a n d e s c e n t  larvae  copepods  from  carried  /  distribution  item but  capture  item.  limits from  was  Captures for  the  t h e normal  (Snedecor  and  38  Cochran  1967)  confidence  and  limits  for  contact  was  the p o s t e r i o r possible tail  o f the head  whether  tabulated  the  directly  migration.  1956), a stopwatch,  the p r e y had  It  14-carbon  measuring was  nor  the  been  metabolic  quantity.  friction  of t h e c o s t  of v e r t i c a l  water  an upward f o r c e  has  the oxygen  necessary, therefore,  overcoming  I  over the d i s t a n c e migration.  method cost  the  passed was  head  or  i s the d e n s i t y  coefficient.  At  f=g(VDa-VDv)/v. experimentally trj.vit^atus  constant The  from larvae  the  rate  were  the l a r v a  plus  through  f  o f water, due is  Da  the  was  of  the of is  friction and  measured  fourth-instar weighted  o f t h e body  p i n to s i n k  of  tc gravity,  VDwg+fv=VEag  artificially  pin the length  cost  as an e s t i m a t e  coefficient  sinking  which  and  velocity,  friction  p i e c e s of i n s e c t i t took  body,  this  a downward f o r c e  velocity  the  suitable vertical  the  A body s i n k i n g  v  of  of  chose  o f t h e body, g i s t h e a c c e l e r a t i o n  the  was  t c approximate  the d e n s i t y  time  fully  ingested  migrated  o f VDwg+fv and  VDag where V i s the volume, Dw  The  from  c a p s u l e . I n most c a s e s i t  the p r e y had  w i t h some m e a s u r e a b l e  inserting  of  Coefficient  Neither  is  values  $  Friction  cost  (Crow  measured, u s i n g  first.  for  from  made t o the t i m e  margin  t c see  <30  of p r o p o r t i o n s  H a n d l i n g t i m e was time  n  through  by  cavity. 100cm  of  39  water was measured. The cavity the  and t h e l a r v a  measured  containing dorsal  cf  was a l l o w e d  100cm. O n l y  uppermost) larvae  and  measured known  trials  entirely  were used  was  discarded.  by w e i g h i n g  volume  of  The  water  ( h o r i z o n t a l and o f v. S i x  v and 6-7  measurements  i t  i t s natural  lost  parameters  VDa and VDw  containing  the  pin  (W1), and t h e water + l a r v a  displacement  ( W 3 ) . Thus  VDa=W2  acceleration  due t o g r a v i t y  body  t h e body o f t h e l a r v a  i n the c a l c u l a t i o n  before  the l a r v a  the  before reaching  position  t o measure  larva  within  t o s i n k 20cm  i n which  were used  v were made w i t h e a c h  shape  was  t h e p i n was i n i t s n a t u r a l  side  different  pin  and  were  (W2), a and p i n -  VDw= (W1+W2)-W3.  The  i s a constant.  Assimilation Assimilation £•  trivittatus  (D. r o s e a ) followed  larvae  and  that  Labelled Scenedesmus  efficiency  a  was  algae or  measured  copepod  of S o r o k i n  were  (D. k e n a i ) . The method  essentially  prepared  labelled  were  by  starting  ready  with  to hatch.  The newly  1  by  growing  in 1 liter  and  were grown  carrying hatched  added  to i t .  resuspended  that  of  medium  on t h e l a b e l l e d  embryos Da£hnia  cultures  of B r i s t o l ' s  *C-bicarbonate  centrifuged  Ba^hnia  females  f o r both  (1968).  Chlam_ydomonas  water.  fourth-instar cladcceran  42.5 uC o f  unchlorinated  old  a  with a p p r o x i m a t e l y algae  of  The in algae  were  almost  were a l l o w e d  t o grow  40  on  the  labelled  into  the l a b e l l e d  for  about  a  15,000 cpm labelled  Ten water, were and  individual.  prey a pH  o f about  9.  t h e water t h e y  At  assayed  for  containing  ingested  was  been  weights  For  consumed this  and  about single  in  200ml  day  the  taken  for  dissolved the  larvae  as:  and  (C0 -dpm 2  food,  organic  larvae  14-carbon  organic,  of  radioactive  amount of l a b e l l e d  of a l l the  was  food  experiment  e g e s t a (a p o r t i o n  to  ignored.  The  A=C-F/C  *100?o. S i n g l e p. dry  assayed  total  efficiency  relative  average  having  were carbon  recovered larval.  +  The  DOM-dpm  +  total-dpm.  of  liquid  The  was  Each  experiment  dissolved  2  feed  were f e d a  larvae  days.  ,  the  the sum  C0 ,  five  was  end  efficiency /  in  the  of  to  water c o n t a i n i n g u n l a b e l l e d  particulate,  Assimilation  basis,  had  taken as  assimilation  (A=C-F-U).  fresh  prey  put  placed into unchlorinated  f o r 3-5  the  particulate,  larval-dpm)  to  14-carbon.  allowed  Chaoborus l a r v a e  immediately  transferred  in  week. Diaj:tjomus were  produced  i t e m and  d i s h e s , each  fractions.  one  medium as c o p e p o d i t e s and  were i n c u b a t e d a t 15°  carbon  the  f o r about  week. These p r o c e d u r e s  per  water w i t h  algae  solid  egesta  formula  weight  also and  had  a  remainder  for assimilation k e n a i from  comparing  undigested  I assumed t h a t ,  of F)  (the  measured by  material on  negligible o f F)  efficiency  and  larvae  weight weight may  reduces  a p o p u l a t i o n with  were f e d t o f o u r t h - i n s t a r  a  be to  a known  which  were  41  allowed  to  egest  containing for  24  larvae  were  assimilated (weight of  was one  Two  ground and  glass one  on  using  collected. week a f t e r  by  filter 20,  a water The  young fall  and  and of  5.5ul one  dishes,  were h e l d  the  water  weighed.  of  at  15°  0.45u).  The  egested  each  filtered  (pore s i z e  old  amount  material)  1972  or the  a  /  10).  The  25°;  one  pressure with  a design  of  capacity  from  Dr.  respirometer to  the  chambers  respircmeter 2-3ml o f  young f o u r t h - i n s t a r l a r v a e ;  larvae  was  absorbed rates  temperatures  a  from  chambers c o n t a i n e d  paper. R e s p i r a t i o n  and  larvae  constant  used:  50ul  connected  The  two  using  were  with  flasks  fourth-instar  constructed  (Fig.  joints. old  20%  15,  of  of  bottom  respired  10,  and  (weight 1003.  laboratory  dioxide KOH  50°  *  water  filters  respirometers  (1968), and  round  at as  the  capacity  Klekowski's  water  rates in  respirometers.  were 5ml  dried  Five  Rates  measured  Klekowski  i n 200ml of  Millipore  taken  Respiration  measuring  material.  were removed  Ha  ccpepod)  Respiration  with  larvae  pre-weighed  filters  were  undigested  fed  h o u r s . The  through The  10  any  i n about  carbon  0.1ml  were measured  were m a i n t a i n e d  lake  of at  5,  within  1°  bath.  larvae All  were  held  respiration  capture.  T h e r e was  with  food  at  6°  after  being  measurements were done w i t h i n no  food  in  the  crops  of  one the  FIGURE  10  Constant pressure r e s p i r c m e t e r design. A. Detail o f t h e s c a l e t u b e and a d j u s t m e n t r o d . B. D e t a i l o f the sidearm and reaction f l a s k . C. View o f t h e entire apparatus. Legend: 1. Mercury level adjustment r o d , 2. Mercury, 3. S c a l e t u b e , 4. Index mark, 5. Opening from flasks tc the a t m o s p h e r e , 6. R e a c t i o n f l a s k , 7. F i l t e r p a p e r f o r carrying KOH, 8. C o n t r o l f l a s k , 9. E x p e r i m e n t a l f l a s k , 10. P l e x i g l a s s t a n d , 11. Water l e v e l d u r i n g o p e r a t i o n , (after Klekowski 1968).  42a  43  larvae in  used  the  i n the  f l a s k s a cne  before  hour  measurements  according hours.  to the  and  measurements  were  water, d r i e d  begun.  temperature were  every  few  but  50°,  calculated  per  and  was  the  period  15  were was  long  allowed  time three  ones.  larvae  varied and  short  were k i l l e d  milligram  temperature  30  After  consumption  per  placed  minutes during  w e i g h e d . Oxygen  at each  larvae  between  hours d u r i n g  i n d i v i d u a l and  Mean r e s p i r a t i o n r a t e s  the  Incubation  made e v e r y  completed  at  After  eguilibraticn  were  Measurements  incubations  was  experiments.  the  in  hot  at  dry  were f i t t e d  STP  weight. tc  the  equation Respiration where  a i s a constant,  b i s the  slope  against  In  ul  hr  mg  -1  of  dry  were  rates  of  measured  micro-Winkler  method  at  5,  for  reservoirs  connected  sides  stoppers (Fig.  saturated procedure with  11). with  was  water  and  with The  oxygen  8-10  weight  line  hr  - 1  of  rates  10,  in  them  - 1  of  the  larvae,  In  respiration  are  given  15,  water  used  at  and  20°  rate  in units  of  in ccoled  10ml  a  syringe  inserted ports  through in  incubations  to 6 ° . A  using  concentration.  sampling the  trivittatus  20°  oxygen  needles  experiment.  larvae  and  50ml f l a s k s w i t h by  and  .  Silastic-filled  used f o r each and  b  determining  were c a r r i e d o u t to  aW  young f o u r t h - i n s t a r C.  Incubations  rubber  dry  Respiration  ul i n d i v i d u a l  Respiration larvae  W i s the  regression  weight.  and  - 1  the  Rate =  The  flask  were added. A r u b b e r  was  the was  following filled  stepper  was  FIGURE 11 Incubation apparatus f o r micro-Winkler oxygen c o n s u m p t i o n measurements. L e g e n d : 1. 5 ml s y r i n g e , 2. S i l a s t i c - f i l l e d r u b b e r s t o p p e r , 3. 50 ml f l a s k , U. S i l a s t i c - f i l l e d s a m p l i n g p o r t .  44a  45  inserted barrel the  which was  so  displaced through  port  cut  the  replicates period  each)  depending  pushed  plunger  excluded port.  and  a b o u t 3ml  Water removed  during  for  final  the  syringe  was  two  flasks  of  from  sampling  with  into  the  water  were  the  flask  replaced  by  were  placed  at  measurements  concentrations  a  experimental  through  was  hours before  oxygen  were measured on  The  syringe  r e s e r v o i r . The  and  syringe.  inserted  temperature  Initial  the  was  port  syringe  into  water, a needle  sampling  sampling  experimental  began.  the  a i r was  the  the  water  with  and  that  water f r o m the  filled  sampling  barrel  displaced  6-24  hour  (three  incubation  temperature.  /  The  dissolved  following  way.  from  flask,  the  0.05ml  of  were  tip.  needle  displaced.  The  shaken and  stood  ml  liberate  1.2ml  the  iodine  with  thiosulphate After  was  end  so  the  a  incubation  this  100mg  the  was per  e a c h day larvae  consumption  at  made i n  0.2ml  cf  water  syringe  through  0.2ml  of  and  the  and  the  p u l l e d i n t o the titrated liter  were  to  solution  against  0.0005M dried  was  syringe  sample  at  was  syringe  p r e c i p i t a t e would  STP  the  alkaline-iodide-azide  sample  and  s u l p h u r i c a c i d was and  with  stoppered,  that  were  drawn i n t o the and  replaced  standardized  Oxygen  was  deep i n the  needle  5%  syringe  sulphate  was  on  the  sample  added  of  endpoint  weighed.  a  manganous  The  determinations  After rinsing  solutions  One  oxygen  was  settle.  syringe  to  the  starch  of  sodium  biiodate. 100°  c a l c u l a t e d as  and the  46  difference  i n oxygen c o n c e n t r a t i o n  measurements and  Growth  c o n v e r t e d t o u l mg  Experiment  Fourth-instar from  August  regimes  to  hundred and  C.  examine  trivittatus  by  the l a r v a e  at  and  was  (primarily  regimes p.  days  densities  a t a l l t i m e s . The regime  in  regime.  measurements  experiment.  Growth  initial  subsequent  and  was  p.  dry  and  The  20°,  fluctuating 16°  to  summer. The mixed  larvae  Eunice  t_yrelli,  an  Larvae  and  present at  the  weights.  The  control were  difference  high to a  fluctuating 12:12  was i m p o s s i b l e  removed the  Lake  Da_ph n i a )  approximately  during  for  experienced  20° t a n k s were e x p o s e d  periodically t a k e n as  5°  Two  change  during  Hore a c c u r a t e l i g h t available.  growth.  hours ( F i g .  incubators.  light:dark  the f a c i l i t i e s  on  for fcur  were f e d  5 ° and  temperature  (0400-2000),  f o r s i x weeks; e x c e s s f o o d was  a q u a r i a were e x p o s e d  weight  regimes.  changing  kenai,  temperature  in  three  of temperature  m i g r a t i n g i n the lake  light:dark  final  .  i n a q u a r i a at constant  e v e r y two  16:8  and  were f e d e x c e s s f o o d  a p p r o x i m a t e l y the temperature  a l l three temperature  zooplankton  - 1  under  8 ° f o r 16 h o u r s  (2200-0200),  was  1971  was  four  This  larvae  temperature  regime  1).  hour  -1  8-16°  temperature hours  12,  the e f f e c t  were h e l d  fluctuating  initial  I  17 t o O c t o b e r  larvae  between  for  dry  c o u r s e of the between  the  47  Growth  Experiment I I  Growth regimes  and  November in  experiments  seven  three  3  to  l i t e r  temperature for  16  to  5°  at  regime but  was  100  ,  prey  l a r v a  - 1  lake  as  5°,  20°  for  three  fluctuating 12:12  Eunice  and 600 -  1  d a y  -  1  prey  density. prey  densities before.  Two h u n d r e d  hours  ,  5°  The  three  20°  tanks Food  day  - 1  1  day  levels  prey  density  levels  were  maintained  the  required  - 1  ,  enough  level.  was  and 3  The  light  uncontrolled  were  of  mixed  no  prey,  prey  to  l a r v a  approximated by  was  to  0 -  1  the  sampling  plankton  Growth  5°  hours  and c o r r e s p o n d e d  middle  day and a d d i n g  5-20°  controlled  consisted  The  1  held  decreasing  was  was  prey  -  were  three  and  0.5  each  l a r v a  -  for  incubators.  food  from  regime  Light  and 20°  temperature  aquarium  Prey  up to  tc  1).  ran  fluctuating  (2200-0100), (Fig.  temperature  larvae  temperature  light:dark.  Lake.  prey  and  increasing  the  three  experiments  20°,  (0100-0300) in  using  The  The f l u c t u a t i n g  respectively,  remaining prey  at  usually from  day  aquaria  (0300-1900),  the  plankton  prey  1971.  light:dark  for  levels. 24,  two hours  16:8  repeated  November  hours  for  food  regimes.  (1900-2200),  were  the  bring  measured  48  Results  Strike  Efficiency,  Strike prey  size  Dajjhnia to  avoid  than  efficiency  increased  was  probably  the  The  away from upper  size  same, but  no  The  the s i z e s  efficiency  prey  the  c o p e p o d s p. size  The  time  increased  DajDhnia.  two  was  required  fcr  a t which  hypothesis between t h e  that two  species.  of  t h e r e was  —  ingest  the  data  likely rather  Cia£tomus size  range  two  prey  these  less  was  and  t h e same on a l l s i z e s  of  was  than  considerably higher  t h a n on  a  Da£hnia b u t  captured  cn  only  than  item  species  (Table  they  i n about  was  difference between were  prey  prey  ingested  were i n g e s t e d f a s t e r  generally  p r e y s p e c i e s and All  Danhnia  for  0.6irm  faster  variance no  limit  testing.  prey t e s t e d  manually  analysis  was  as  1mm.  Diajotomus  smallest  measured  were more  i n c r e a s e d f o r both  ingested  The  way  size  to  larvae  limit  t_yrelli  g r e a t e r than  size  large  virtually  p.  decreased  upper  these  size  for  Time  copepods i n t h i s  efficiency  k e n a i and  as p r e y  Larvae  be  was  types. Contact  when p r e y  could  available  Handling  efficiency  2.6mm. The  for testing.  both  each  contact  became t o e s m a l l t o be c a p t u r e d  Strike  A  Efficiency,  12).  and  at them. The  about  below  2) .  (Fig.  between 2.2  were a v a i l a b l e  was  and  o r push weakly  strike  types  Contact  used in  two  tc test  seconds. the  ingestion  the p r e y  transformed  than  sizes  null time  within  u s i n g the  In  FIGURE  12  Strike and contact success cf fourth-instar C. t r i v i t t a t u s l a r v a e as a f u n c t i o n o f p r e y size. Data a r e ireans ± 955? c o n f i d e n c e l i m i t s f o r s t r i k e s u c c e s s (Dap_hnia— s o l i d c i r c l e s and Dia^tcmus— open c i r c l e s ) and c o n t a c t s u c c e s s (Da_ghnia— sclid s q u a r e s and p i a p _ t o m u s — open s g u a r e s ) .  o  ro o  o  PERCENT  o o  oo o  o  -©-  Tl cn N  m  -B-  50  Table  2. Mean and s t a n d a r d  fourth-instar  larvae  species,  the  and  differences  P r e y Type  between  n  to  e r r o r o f the time r e q u i r e d f o r  ingest  different  analysis  of  s i z e s and  species.  Prey S i z e  variance  (mm)  Diaptomus  sizes  and  table  for  the  Ingestion  mean pap_hnia  prey  Time ( s e c )  mean  SE  28  1.0  24. 3  5.6  24  1.4  74. 2  10. 8  21  1.8  210.5  44. 1  16  1.0  5.0  0. 2  22  1.4  11.4  35  1.8  103.64  Analysis  of Variance  1. 1 28.0  Table  Source  d.f.  SSQ  Species  1  2. 98  2. 980  60,.92  <0.,001  Size  2  4. 62  2. 310  47.. 16  <0..001  2  0. 1 1  0. 055  1..13  Species Error  X Size  130  127. 50  MS  0. 049  F  p  0., 326  51  transformation  to c o r r e c t f o r unequal  difference  found  and  was  in ingestion  between s i z e s w i t h i n  significant  variances.  t i m e s between  each s p e c i e s  i n t e r a c t i o n between  A  (Table  s i z e and  significant  prey  2).  species  species  There on  was  no  ingestion  time.  Energy C c s t  cf V e r t i c a l  £ll§2£P.Ei! :  larvae  s  a considerable (Damant  increase density  their  depth in  will  density larvae  r a n g e by  1924).  particular  When  cause  for  Whatever  at  overcome  regulate  two is  of  In  depth,  swimming, i . e . by then g l i d i n g .  mechanism  i s used  f o r c e of  point  the  in  possible above,  migrate, a along  a an  to  g l i d e may  friction  —  a decrease  f l e x i n g and  to  at  and  mentioned  The  over  bladders  buoyant  equilibrium  addition  density air  neutrally  c a u s e i t to s i n k ,  changing  the  their  pairs  unstable  i t to r i s e .  r a p i d l y and  direction. least  larva  will  by  to  means of a  density  migrate  bodies  able  i t i s a t an  mechanism can  are  Migration  its  the  extending be  in  larva  any must  migration  path.  The the  energy  equation  (ergs),  f  required  E= ( f v s ) / ( e f f ) is  the  to the  the  movement  v e l o c i t y of and  where  friction  perpendicularly  (cm),  f o r the  e f f i s the  long  migration E  is  coefficient  axis  of  was  the  energy  f o r the  i t s body  (cm/sec), s i s the  metabolic  calculated  efficiency  required  larva  (gm/sec), distance (the  from  moving v  is  travelled  efficiency  of  52  converting  the  potential  Experimental with  the  friction  same  energy  values f o r v larva  coefficient  and  was  i n food were  tc k i n e t i c  similar  for different  between  larvae  between 0.0.and  energy).  1.0  trials  (Table 3). gm/sec  The  in  all  trials. High 1966), f (195)  values (1.0  were  estimate  the  calculation  13)  per  the  oxygen)  the  0.32  ul  Using day  i s less  Assimilation  a  (1.0  both  efficiency very  low  of  calculation  result:  oxygen  cost  than  and  low  Northcote  value  to  of  eff  produce a  high  x  of  for  3% of  of  10*  (E). T h i s  ergs.  4.89  x 10  - 3  Using  an  c a l per  ul  one  half  cf  metabolic  rate  of about  a  hour  - 1  complete  the d a i l y  - 1  the  at  24  10°,  migration  metabolic  daily ul Fig  (0.64  ul  rate.  Efficiency of carbon  assimilation  by  fourth-instar  l a r v a e i s shown f o r a c l a d o c e r a n  these  f o r the  one  efficiency prey day  v a l u e . T h e r e was  efficiencies  a  i n order  E = 6.6  factor  resting  (Table 4 ) . A s s i m i l a t i o n for  (20m), and  u l oxygen i n d i v i d u a l  efficiency  trivittatus  s  cm/sec, T e r a g u c h i  e n e r g e t i c c o s t of v e r t i c a l m i g r a t i o n  calculated  The  (0.33  conversion  =  migration. oxygen  i n the  yields  oxy-calorific cxygen, E  v  g m / s e c ) , and  used  of  of  types.  was  good  f o r copepods as  essentially  The  experiment  is  low the  mean  by  the  a copepod the  same  assimilaticn  result  agreement between  measured  and  of  one  assimilaticn  14-carbon  and  the  53  Table velocity  3.  Experimental  and c a l c u l a t e d  Trial  Sinking  measurements  friction  Velocity  niean + 1 S.  of  larval  sinking  coefficients.  Friction  Coefficient  D.  1.  8.76  + 0.29  0.39  2.  9.35  ± 0.46  0.42  3.  9.08  i 0.37  0.68  4.  8.14  ± 0.08  0.47  5.  8.41  ± 0.39  0.53  6.  9.13  + 0.52  0.84  54  Table  4.  fourth-instar values  C.  Carbon  assimilation  trivittatus  a r e means ± 95%  larvae  confidence  f e d on two  prey  Dap_hnia majgna  Type Cia£tomus  kenai  Radiocarbon 1 day  56.4  ± 14.8  3 day  67.4  ± 7.2  76.4  Weight 1 day  types.  limits.  Prey Method  efficiencies  66.9  ±  4.0  of The  55  percent  digested  methods.  Respiration  Weight-specific individual  oxygen larvae  13).  There  a  over  the  rate  suggestion  the  temperature vertical  the  with  temperature  at  5  and  p=.0218;  10°  and  i n  20°,  oxygen of  the  respiration  than  the  of  significantly and  10°  p=.0343;  The  25°,  old larvae  different  (t-test:  of  5°,  between  p=.1839;  also  5°, Both  the at the 10°,  15,  (Fig. rate  the diel  oxygen increased  than  the  p=.0327;  young  (Figs.  20,  old  measurements  rate  the  young  of  over  methods  respiration  larvae  and  individual  lower  of  )  )  their  micro-Winkler  p=.3214).  1  occur  larvae  (t-test:  -  1  weight-specific  during  and  consumption old  h r  1  -  individual  the  to  h r  - 1  temperature  the  significantly  Weight-specific that  the  -  plateaus  exposed  weight-specific  that  in  and i n These  measurements  Individual  than  plateau  are  but  were  mg  with  fourth-instar  14)  p=.3658;  increase  15°.  lower  15°,  a  range.  young  (Fig.  micro-respirometer  linearly  Weight-specific  of  (ul  (ul i n d i v i d u a l  10-15°  larvae  migration. rates  of  range  15-20°  range  consumption  sharp  increased  temperature  over  consumption  consumption  fourth-instar i s  oxygen  13  10°  showed  r  a  between  10  larvae  was  and  14).  larvae  was  higher  and  but  was n o t  two t y p e s p=.8307;  25° of  15°,  larvae p=.026;  at  5  20°,  p=.0458).  cxygen  consumption  of  both  old  and  young  56  FIGURE  13  Respiration rates of old fourth-instar larvae (1972 year-class) at d i f f e r e n t temperatures. The d a t a p o i n t s a r e means ± 95$ c o n f i d e n c e limits. »  FIGURE  14  Respiration rates of young f o u r t h - i n s t a r l a r v a e (1972 y e a r - c l a s s ) a t d i f f e r e n t temperatures. The data p o i n t s a r e means ± 95$ c o n f i d e n c e l i m i t s f o r measurements w i t h m i c r o - r e s p i r o m e t e r s (solid and open circles) and with t h e m i c r o - w i n k l e r method (Xs) .  57a  58  fourth-instar and  larvae  temperature  on  was  used  to determine the e f f e c t s  respiration  rate.  R = (R  is  oxygen  constants) metabolic with  consumption,  a straight  respiration oxygen 25°.  line,  (b).  consumption The  slopes  terms  of  the  respiration relating  is  the s l o p e  body  on  In d r y w e i g h t  weight,  between  body  regression  was  f o r 5,  dry  lines  weight  respiration  each  and  temperature  weight  10,  15,  and  fitted of  f o r In  20,  and  i n T a b l e 5.  The  weight-specific  more  variable  dry  weight.  are  be  calculated  relating  are  b are  i s the c o e f f i c i e n t  of these e q u a t i o n s are given  and  a and  o f R v e r s u s W can  of which  linear  regression  for  plot  A  individual  equations  The e q u a t i o n  b  W  A logarithmic  size  aW  d e f i n e s the r e l a t i o n s h i p rate.  of  than The  used i n the  those latter  simulation  model.  Growth The  Experiment  initial  regimes  --  end  o f 20  days  of  larvae  living  '71,  Sept.  ration.  was  larvae  larvae  more  run  2 0 ° , and  Growth was  t e m p e r a t u r e s , and  weight  somewhat  experiment  c o n s t a n t 5° and  an e x c e s s f e e d fluctuating  I  living  with  fluctuating  rapid  s l o w e s t a t 5°  fluctuating  larvae  temperature 7-15°  20°,  —  at  ( F i g . 15). At  the  living  i n the  temperatures ( F i g . 9,  a t 5 ° weighed  with  slower  a t 20° were more t h a n d o u b l e  than t h o s e i n t h e l a k e  ' 7 1 ) , and  at  o f t h e same y e a r - c l a s s  under  three  less  had C.  than  the lake, grown  trivittatus the  lake  59  Table  5.  Terms  In (R)=ln (a)+b (In (W)) oxygen  consumption  the  describing  regression  the  (R) and d r y w e i g h t  R= u l mg °C  of  n  -1  hour  - 1  equations:  relationship (W) .  and W=  In (a)  b  mg p of slope being  0.0  5  15  -1.053  -0.3700  0.204  10  16  -0.6577  -0.3127  0.999  15  10  -0.0859  -0.3552  0.014  20  12  0.0128  0.3407  0.046  25  12  0.3919  0.4020  0.019  R= u l i n d i v i d u a l °C  n  - 1  In(a)  hour  and W=  - 1  b  mg  p of slope being  0.0  5  15  -1.0530  0.6300  0.040  10  16  -0.6639  0.8851  0.003  15  10  -0.0859  0.6447  <0.001  20  12  0.0128  0.6593  0.001  25  12  0.3919  0.5979  0.002  between  60  FIGURE  15  L a r v a l growth during Growth Experiment I. The data points are mean larval dry weights ± 95% confidence limits after 21 and 45 d a y s a t the experimental temperatures.  61  population. living and  By t h e end o f t h e e x p e r i m e n t  a t 20° weighed  many  had  5°  growth  final  Under f l u c t u a t i n g  o f t h e one y e a r o l d l a r v a e  was e q u a l t o t h a t  l a k e . There larvae  more t h a n t h e two y e a r o l d  pupated.  was t w i c e t h a t  was  weight  the l a r v a e  lake  larvae  temperatures i n the l a k e ,  growth and  o f t h e one y e a r o l d l a r v a e  considerable  survived  (46 days)  mortality  at  20°,  to allow confidence l i m i t s  and  at  i n the  too  t o be p l a c e d  few  cn t h e  shown.  Growth E x p e r i m e n t I I  No  Food:  At (Fig.  5°  there  was  a  slow  1 6 ) . At t h e f l u c t u a t i n g  no l o s s  but continuous l o s s  and 2 0 ° t e m p e r a t u r e s  i n w e i g h t and p e r h a p s a s l i g h t  gain  i n weight there  was  i n weight over the  21 day e x p e r i m e n t a l p e r i o d .  High As  Food: in  the  under a l l t h r e e 16  and  larvae  9),  growth  experiment  temperature regimes  The  tripled  conditions  first  greatest  their  doubled  initial their  growth  than i n t h e occurred  weight; larvae weight,  weight  slightly.  Larvae i n the l a k e  during  the experimental period.  growth  and  greater  field  (Figs.  a t 20° where t h e  under  larvae  d i d not  was  fluctuating a t 5° g a i n e d  measureably  grow  62  FIGURE  16  Larval growth during Growth Experiment II. data points are mean larval dry weights ± c o n f i d e n c e l i m i t s a f t e r 13 and 21 days at experimental conditions.  The 95% the  63  Low  than  Food:  There  was  under  high  fluctuating their  some  growth  rations  (Fig.  temperature  i n i t i a l  weight  under  low  16).  Larvae  regimes during  grew  the  the  food  rations at  same  experiment.  the  amount, At  5°  but  less  20°  and  doubling  growth  was  slight.  The  amount  temperatures At two the  20°  the  amount  rations. null  food  growth  the  same  of  A two  way  and  ration  (Table  6)  show  effect  between  was that  not  was  in  their  considered  size  is  a  and  and  the  very  there  there  ration  5°  analysis  that  ration  at  whether  growth  hypothesis  temperature no  was  of  of is  at  ration  different variance no  fluctuating  was  was  used  interaction on  in  analysis.  highly  larval  significant  temperature  on  or  high.  between  effect the  low  these to  between  growth. The  test  The  results  interaction  growth.  64  Table ration  6.  Results  c f a two-way  analysis  and t e m p e r a t u r e a s main e f f e c t s  in  of variance  Growth  Experiment  II.  Source cf Variance  d . f . , Sum o f Mean Squares Square  Ration  1  Temperature  2  R X T  2  Error  27  Total  32  .155  .155  19.03  .C002  .682  83.47  <.0001  .175  .087  10.70  .C004  .221  .008  1.36  1.91  with  65  Discussion The  strike  inversely  these  and  drop  prey  size  instar and  two  rapidly  range  prey  which  can  by  zooplankton  are  size be  reported  eaten  by  a C.  njblaei  very  different  their  that  the  of  size  The and  the  similar  higher  a r e not  before  striking,  are  much  strike  contact  larvae  prey  C.  to  efficiency  f o r Daohnia) . 1.7mm  for  The  (>2.6mm) i n a vulnerable  system  that  can  prey assess  on on  c o p e p o d s and  once t h e  cladocerans  copepods suggest  prey  these  that  prey  i s contacted,  c a p t u r e of c o p e p o d s has  been  attributed  swimming  motion  1971).  show the same d i f f e r e n c e curve  The  strike  between  prey  i f l a r v a e are a b l e  to  efficiency types tc  the  types  copepods  efficient  efficiency  fact  manner  c l a d o c e r a n s . The  (Roth  are  ingest  than  contact  easily  tc  ingested  should  more  capsule  larvae  of  more  each  rather accurately.  efficiency  that  by  head  flavicans.  a b l e t o d i s c r i m i n a t e between but  discrete  handled  able  length  l a r v a e have a s e n s o r y  potential  are  Daohnia  response  The  (2.2-2.6mm  and  range  i n c r e a s e t o a peak  larval  and  expected,  size  trivittatus  maximum  to v e r y l a r g e  suggests  C.  large  l a r v a e respond  the  successfully of the  that  from  over  decreases.  larvae  guite  were, as  undoubtedly  Fourth-instar  that  (1970)  size  the s i z e  most C h a o b o r u s  zooplankton Eodson  prey  as  mouth-parts. than  to  efficiencies  i s determined  larger  contact e f f i c i e n c i e s  proportional  tested; then  and  more their curve  as does  the  differentiate  66  between  the  two  m o t i o n . T h i s was shape, and  prey  successful copepods  not  and  types  behavior The  cylindrical shaped  the  different  copepods  <1.0mm  i n l e n g t h are i n g e s t e d with of  in  their  reflected  decreasing  ingestion  faster  differences 1970). £•  than  than  size  these  of  contact  i s made. T h i s may  o f any  Every of  this  cost.  was  vertical If  this  with  therefore  cf l i t t l e  migration  would  not  result  (<3%  relative  The  types  is prey  and  were  copepcds same  (Roth  or  ease.  size.  1971,  Such  Sprules  mechanism i n  reject  prey  be a means o f r e j e c t i n g  after  unpalatable  to  the  made i n t h e c a l c u l a t i o n  of  the  energy  m i g r a t i o n t o p r o d u c e a maximum e s t i m a t e  negligible  calculated  accept  prey  size.  attempt  cost  to  ingested  times. Smaller  Swuste e t a l . (1972) r e p o r t e d a s e l e c t i o n operates  for that  all  prey  the  others  cf  in contact  and  two  prey  cladocerans by  suggestion  apparently egual  large  have been o b s e r v e d  £I§vicans t h a t  prey  of  curves  difference  prey  size,  determinants  more e a s i l y  respective ingestion  were i n g e s t e d more e a s i l y ingested  are  c l a d o c e r a n s . The  with  ease  Roth's  swimming  that  contact success  support  decreases  their  likely  c o n t a c t are the  success  relative  b a s i s of  I t i s more  after  cladocerans  irregularly  on  the case.  capture.  streamlined, than  prey  approximation  respect  to  the  consequence have  to  daily  to  the be  o f the d a i l y  daily  could  metabolic  be  shown  metabolic larva,  the  measured metabolic rate  and  to  be  cost,  and  cost  of  directly. rate)  the  cf  was  actual  The low  energy  67  cost  was p r o b a b l y  much  metabolic  efficiency  value  i n  used  energy  cost  downwards higher  actively, that  by  parallel  passively  change actual and  rising  l a r v a l  migration  i s  The agrees  cost  cost  be  to  organic  of  l i t t l e  body  a  the  of  on  i s  results  the  reported  migration  a  theoretical  i n  the  would  1% e f f i c i e n c y .  consequence i n  basis  food  to  a  f i l t e r  every  in  day.  rather  be  very  active  low.  i s  swimming  cost  of  He p o i n t e d  for  the  He f o u n d  the  assuming less  than  100$  than  0.5$  during out  that  organism  though  the  f r i c t i o n  100$,  Hutchinson  less  to  l o w . The  (1970)  oxidized  Even  sclely  calculated.  rate  feeding  than  bladders  copepods.  that  be  moving  by Vlymen  efficiency  somewhat  larvae  overcoming  metabolic  metabolic  body  of  for offset  metabclic  estimate  cost  basal  probably  assuming  high  metabolic  v e r t i c a l of  actual  of  be  be  a i r  might  combination  below  the  cost  might  accomplished  "the  1$  and  reguired  body  i s  the  upward  migration  the  the  The  calculated  might  tc  using  energy  probably  because  weight  the  the  energy  migration  probably  matter  migration  the  the  estimate  concluded  If  and  0.3$  efficiency; his  of  than  swim  increase  axis  change,  with  energy  this  lower  of  of  long  estimated  well  because  and s i n k i n g ,  i s  cost  due  density,  mechanism  density  metabolic  value.  higher  larvae  cost  i t .  calculated  would  f r i c t i o n  the to  this these  However,  a lower  perpendicularly by  If  the  the  was u n d o u b t e d l y  calculated  tc  than  calculation;  swimming.  somewhat  (eff)  considerably.  than  active  the  lower  a  (1967) of  the  a  50m  this  i s  eating  i t s  predator  like  68  Chaoborus e a t s r e l a t i v e l y migration  cost  o f 3%  infrequently,  of the d a i l y  (Fedcrenko,  1973),  metabolic cost  a  i s probably  negligible. Very  close  efficiencies  agreement  calculated  14-carbon  method and  on  34).  page  values are  was  found  u s i n g two  the f o r m u l a  This  The  here a g r e e  well  predators  (Lawton  invertebrate  carbon  with  those 1970,  groups  assimilation reported Monakov  found  increase in assimilation  study find  60%  magna.  feeding  rate, of  the  feed  food  directly  the  or c a l o r i f i c  efficiency  in  the  1968),  a wide r a n g e was  with of  (1968)  temperature temperature,  efficiency  in  his  Pjjrrhosoma. He  efficiency I t has  efficiency  with  been  but Lawton and  of  generally  Schindler  effect  did  which  suggested  content (1970) either  of  found ash  Pirrhosoma.  oxygen c o n s u m p t i o n  with temperature  calculated  invertebrate  i n c r e a s e s as c a l o r i c  assimilaticn  value i n  poikilotherms  h i g h as 95%.  were a s s i m i l a t e d .  efficiency  between  over  efficiency  no  defined  assimilation  other  d a m s e l f l y nymph  increases (Schindler  correlation  1972);  found  as  the  e f f i c i e n c i e s reported  on a s s i m i l a t i o n  difference  types  the  In  (1970)  predaceous  assimilation  content  o f t e n as  or diapause  that  no  and  Lawton  a significant  different  methods --  that  for  the a s s i m i l a t i o n  than  B.  assimilation  (symbols  indicates  greater  in  independent  A=C-F/C  agreement  the  p r o b a b l y good e s t i m a t e s o f t h e a c t u a l  efficiencies.  an  between  ( P r o s s e r and  generally  Brown  1961).  increases Jonasscn  69  (.1972)  reported  consumption  a  for  linear  C. f l a v i c a n s  temperature. R e s p i r a t i o n higher of  (0.7-7.8  0.3-0.8  hour  - 1  ul  young  their  Both  - 1  ,  young  response  hour  His larvae  larvae  tested.  ,  - 1  at  and s m a l l e r  old  range.  There  was  oxygen  consumption  ether  extends over t h e are  Regulation  poikilctherms  i§£i°dora.  Teal  middle  exposed  o f oxygen  (Moshiri  1959  in  demonstrate  consumption—temperature C, t r i v i t t a t u s  to during  no  regulatory  curve  t c be  consumption.  upper  temperatures diel  has been  ( O c a ) , A. W.  Further  apparent  oxygen  their  consumption  a crab  a  and  the  consumption  1969 i n t h e p r e d a c e o u s  comm., i n t h e s h r i m p N e o m y s i s ) . conclusively  that  cxygen  i n weight-specific  that  as  over the  their  temperature  young  increased  regulate  by 5 ° from  migration.  larvae  However, t h e r e i s a s u g g e s t i o n larvae  larvae  for  temperature increased  shifted  the  l a r v a e and  5-25°  fourth-instar  as  ul  than o l d f o u r t h - i n s t a r  in individual  that  (0.4-2.0  were a b o u t t h e same s i z e  f o r the plateau  plateau  increasing  i n h i s s t u d y were  study  reason  The  to  cxygen  h o u r - * , a t 7-24°) t h a n t h o s e  present  - 1  consumption  o v e r t h e 10-15°  individual  of the l a r v a e  the  and  fourth-instar  in  a t 5-25° f o r o l d f o u r t h - i n s t a r  larvae).  oxygen  temperatures old  in  fourth-instar  larvae.  rates  individual  fourth-instar  in  ul individual-*  C. t r i v i t t a t u s  individual  increase  vertical found  cladoceran  Knight,  pers.  study i s necessary plateau  of  old  in  to  i n the cxygen fourth-instar  larvae.  Temperature  is  the  environmental  factor  which  most  70  affects are  oxygen c o n s u m p t i o n ,  exposed  t o wide d i e l  of a s s i m i l a t e d metabolism of  this  energy  energy  making a d d i t i o n a l Regulators rate  energy  consumption  so  relatively mechanism animal  can  of  their  which  have  temperature  had  exposure  Teal  in  migrate to  many  Carey  affected  the  epipelagic  copepods  respired  day  depth  than  that  respiration  Perhaps  copepods  this  they d i d a t n i g h t .  oxygen cost  energy  saving  number  the time  the  of  these  to  diel  emphasis has  is  cn  prevented  sort.  that  temperature  rate  of  but  not  vertically  are l a r g e l y h e r b i v o r o u s .  Teal  temperature  of  (1971) f o u n d ,  m i g r a t i n g , predaceous depressing effect was  range)  cn  the  studies  l e s s a t t h e low  on oxygen c o n s u m p t i o n rate  that  constant  metabolic  and  by  reproduction.  adaptations  respiration  c o n s t a n t a t a l l t i m e s . The  temperature  such  found  magnitude  temperature  vertically  respiration  of v e r t i c a l l y  or  considering  evolve  (1967)  the  temperature  maintenance  90$  maintenance  essentially  wide  o f mechanisms o f t h i s  and  migrating,  metabolic  a  rising  fluctuations.  acclimatization  These  over  to  t o the a n i m a l  f o r growth  m a i n t a i n an  fcr  in  be a d v a n t a g e o u s  i s n o t more w i d e s p r e a d  groups  pressure  reduction  animals  S i n c e up  animal  c o n s t a n t . I t seems s t r a n g e t h a t  organisms  wider  effect that  any  migrating  changes.  t c an  available  o f oxygen c o n s u m p t i o n the  lost  would  ( a n i m a l s which  neutralize  was  be  1966),  cost  vertically  temperature  may  (Phillipson  and  offset  as p r e s s u r e i n c r e a s e d .  Teal  by  their  however, decapods  of d e c r e a s i n g an  increase i n  postulated  that a  71  constant  metabolic  rate  is  required  effective  predators  throughout  by  Chaoborus  larvae  night.  predators  whose  decreases. not  The  e f f e c t of  studied  temperature.  as  feeding  these  t e m p e r a t u r e s as  The  pressure  low  fits  oxygen  consumption  the  fourth-instar  the  and  young  larvae. of  The  of  between  general  larvae  lack  a temperature larvae  respiration  rate  wouldn't  temperature  10°.  The  from 5 t o  coefficient  poikilotherms  over  of  was  conjunction  feed  with  increases not  affect  readily  at  consumption  Brody for  (1945). the  smaller  and  dry  Individual  larger  young  fourth-instar  was  eld  old  greater  for  fourth-instar  in weight-specific respiration between 5 and  10°  may  be  i n oxygen c o n s u m p t i o n .  above  may  t e m p e r a t u r e . Thus t h e y  temperature  available.  t h a n f o r the  threshold found  and  migrating  probably  they  day  consumption  oxygen c o n s u m p t i o n  larvae  are  of  f o r the  increase  fourth-instar  would  oxygen  greater  than  o f an  are  pattern  was  in  remain  by  e f f e c t that  since  i f prey  weight-specific  fourth-instar their  4°  or  increases  as  oxygen  a pressure  fourth-instar larvae  young  result  as  on  tc  vertically  decreases  itself  larvae  relationship  weight  larvae,  by  presence of  metabolic rate in  rate  them  depth range,  also  pressure  either The  their  are  metabolic  for  10°  be  at  most o f a  phylogenetic  (b) and  is  Young  time  minimum  show a r e s p o n s e  respiration  the  the  at  and this  to a change  variable  ecological  in  in  groups  72  (Hemmingsen lie  between  are  within  value at  1960, .59  Huebner  and  the  10°  .89  rate  for  conjunction  with  a  between  5 and  in  the  young sharp  10° f o r o l d  Activity  fish  i n temperature  in  F r y 1971).  This  activity  increases  increased  the  oxygen and  remains  be  to  o v e r a wide r a n g e observed  to  move  typically  occasional effect  cxygen  activity  may  such of  the  individual  temperature i n  oxygen  ccnsumpticn  shown t o r e s p o n d  non-linearly  (Fisher  and  may  Sullivan produce  1958, an  apparent  consumption—temperature then  decreases 1953, and  as  cited  curve  if  temperature  is  i n Fry  activity  more t h a n  1971).  in  However, i n r e s p i r a t i o n the  cited  larvae  The  Chaoborus experiments were  never  they d i d i n h o l d i n g  tanks.  column  except  for  o r swimming  movements. A l t h o u g h some  be i n c l u d e d  i n the r e s p i r a t i o n whether  it  rates  would  bias  upward o r downward.  analysis  parameters  low  in  here, i t i s not at a l l c l e a r  Any  a  hang m o t i o n l e s s i n t h e water  consumption  elements  about  high  increase  temperatures,  sharp s t r i k i n g  of  reported  of  r e p o r t e d . The  that  temperature  studied.  and  at  (Schmein-Engberding between  of  consumption  larvae  non-linearity  relationship  They  result  has been  an i n c r e a s e  in  oxygen  here  larvae.  to  plateau  v a l u e s of b r e p o r t e d  cf values generally  was  respiration  The  for individual  range  (.89)  1973).  of the i n d i v i d u a l as  temperature  energy  budget  and  effects prey  of e n v i r o n m e n t a l density  equation ignores  the  on  the  complex  73  interaction  of such  parameters  change i n t h e i n d i v i d u a l examine t h e e f f e c t s The  first  fourth-instar  prey  densities  this  experienced The  growth  fourth-instar  by t h e e n e r g y b u d g e t  Metabolic  below. that  to e x p l o i t  high  rate  than i n the  temperature  regime  which  larvae  the  cost and  o f t h e s e two and  d e s i g n e d t o measure  temperature  trivittatus  on  the  larvae  (see p 3 4 ) . E g e s t a  during  the  (R)  varied  by  consumption Growth  (C)  (P) was  chosen  interactions  and  experiment. using  was  parameters because  physiological  energetic  as r e p r e s e n t e d  measured was  the  three  varied  by  as the i n d e x  i t reflects which  affect  a l l the  budget.  The  maintenance  in  the  and  F were z e r o and  during  C.  the prey d e n s i t y .  physical  energy  and  were not  regimes,  cf the e f f e c t the  size  was  e g u a t i o n C=P+R+F+U  energy  temperature changing  U)  to  conclusively  a much f a s t e r  experiment  budget  (F and  Attempts  lake.  cf r a t i o n  excreta  at  not t h e same as t h a t  interaction of  showed  reasons the f l u c t u a t i n g was  i n the  second  grow  energy  are discussed  l a r v a e have t h e p o t e n t i a l  and  experiment  experiment  net  time p e r i o d .  of these i n t e r a c t i o n s  lake. For t e c h n i c a l in  over a given  growth  young  i n d e t e r m i n i n g the  zero  energy  ration  cost  t c be  measured  t r e a t m e n t . S i n c e no f o o d was  P*R+U=0. The  the e x p e r i m e n t a l p e r i o d  the maintenance  was  metabolic cost  weight would for  loss  of  directly  provided, C the  larvae  be a minimum e s t i m a t e of each  temperature  regime  74  (-P=B+U). The R  assumed  use  that  This assumption weight  was  in  each  at  presence  o f an  designed  one  the  those  the  have grown probably  unfortunate.  of  R + U, the  i t  was  variables  t o examine. N e v e r t h e l e s s , are  not a f f e c t e d  be  by  the  regimes,  However,  low  no  food  source  and  very  low.  At  food  treatment  the  they  the  larvae The  cannibalism of  to  the  calculate  experiment  conclusions  inadequacy  If  did.  measure  impossible  the  into is  of f c o d ,  no  that  occur  there  amount of  With  i t  treatment.  more than low  in  temperatures.  partitioned  l a r v a e i n the  in  gain  Seme m o r t a l i t y d i d  not  of  of  treatment.  slight  o n l y have been  was  of  a  cannibalism.  could  in this  temperature  could  and  unknown but  value  consumption,  results  i t  as a measure  at f l u c t u a t i n g  temperature.  but  should  treatment  absolute  and  since  been a s i g n i f i c a n t  least,  treatment  consumption  at a l l three  than  had  no  a t 20°  temperatures less  ration  justified  that cannibalism  cannibalism  this  not  mortality"  grew much  in  was  occurred  three  20°,  was  treatment,  evidence  at  there  i n c r e a s e d with  "natural  all  zero  recorded  Cannibalism probably  of the  was  from  these  no  fcod  the  treatment.  The analyze  energy the  assimilaticn  budget  equation  conditions  necessary  efficiency  (A)  range i n these  experiments,  constant  can  and  growth t o o c c u r  be  C=P+R+F+U for  i s constant  (P p o s i t i v e ) ,  and  C must be  be  growth. over  ncn-assimilated  neglected,  can  the  to  Assuming temperature  material  C=P+R+U. In greater  used  than  (F)  is  order  for  R+U.  If  75  maintenance densities be  cost  at a given  directly  ration 5°  than  and  same  be  food  low  and  interrelated treatments  limiting  high  mechanisms  temperature These  physiological  rate  to  i n food  an i n c r e a s e  the  turnover rate  At  the  low  physiological high  ration.  increase gain. ration  size  function with  larvae  ration rate,  high and  a clear  and t e m p e r a t u r e  of temperature)  temperature  than  this  they  fed  could  below  resulted  5°  and  the grcwth maximum  not respond At  20°  were  higher.  their  maximum  than  larvae  two  i n these  consumption.  was l e s s  the  be  the  their  at  the  was t h e  to  feeding  that  were  at the  able  i n a greater  to  weight  interaction  between  the e f f e c t  of  on g r o w t h .  Maximum  ration  (a  apparently does  growth  Under  high  under  was  growth  ration  at a  temperature  larvae  and t h e i r  At the  may  and t h e m e t a b o l i c c o s t  the  sugar  and c o n s u m p t i o n  d e t e r m i n i n g growth  their  as  at  appear  size.  a  Thus,  where  There  by i n c r e a s i n g  of food  i s thus  were  blcod  was n o t t h e c a s e  and r a t i o n regimes  rates,  On  such  was g r e a t e r  regimes  must  (C).  temperature.  a t t h e low r a t i o n ;  consumption  There  with  |P)  processes  digestion  rations.  -- temperature  factor.  This  grcwth  consumption  at 2 0 ° , g r o w t h  temperature  control  fluctuating  rates,  low r a t i o n .  fluctuating  at  to  then  turnover i s faster  greater,  at a  regime,  etc., increase  temperatures,  t c be c o n s t a n t f o r a l l p r e y  temperature-dependent  interaction  rates,  potentially  temperature  basis,  predator-prey utilization  i s assumed  proportional  physiological  high  (R+U)  increases  metabolic rate,  more  so that  size  rapidly potential  76  growth cf  rate  metabolism  costs. of  increases  determined  loss  eguals  o c c u r s ; when OR+U,  by t h e i n t e r a c t i o n  at  level  maintenance the  amount  c f t e m p e r a t u r e and  The amount o f  by t h e b a l a n c e between rates  The m a i n t e n a n c e  when c o n s u m p t i o n  on c o n s u m p t i o n .  turnover  losses  weight  f  i s determined  prey d e n s i t y  food  i s reached  When C<R+U  growth  with temperature.  weight  the energy  gained  g a i n s from  the higher temperatures,  is  higher  and e n e r g y  due t o t h e h i g h e r m e t a b o l i c r a t e s a s s o c i a t e d  with  these  temperatures.  The  interaction  implications of  living the  high prey  differences  maximize  cost  non-migrants migrants,  experiments  even  can  are usually  of  exposed  results  demonstrate  f o r maximizing  utilize  Because  growth.  the  are  unable  t o them. to  digestion prey  Because  the temperature  are able  high  important  exploit  rate  faster a  growth  strategy  and  densities  distribution  cf  rates.  to  Larvae  t o h i g h e r prey d e n s i t i e s  in  that  by  when exposed  increased  has  migration.  larvae  a t high temperatures  and  and t h i s  imposed  to, migrating  between  growth.  temperature  of v e r t i c a l  constraints  densities  continuously  maintenance  best  rate  t h e y a r e exposed  utilize  and  f o r the e n e r g e t i c s  digestion  regime  o f food  to  prey, than These  o f no m i g r a t i o n i s  77  Summary 1. O l d f o u r t h - i n s t a r l a r v a e at  catching  ingesting prey  about  ingested  f a s t e r than  2.  The  covered small  relative  tested  was 2.6mm f o r c l a d o c e r a n s  The  regulate  r a p i d l y as (0.6mm), The  and  probably  size.  moving t h r o u g h  migration metabolic  r a t e s f o r both  linearly  with  was  oxygen c o n s u m p t i o n  over  a r e exposed  The  consumption  was t y p i c a l ;  decreased  as s i z e  increased  as s i z e  Larval  the d i s t a n c e  estimated  to  be  cost. f o r both  copepods  to  relationship  young and o l d f o u r t h - i n s t a r  temperature.  the 10-20° range  migration.  density.  of  were  was a b o u t 68$.  over  the l a r v a e  5.  o f t h e same  carbon a s s i m i l a t i o n e f f i c i e n c y  increased  plateau  cost  vertical  4. R e s p i r a t i o n larvae  cladocerans  t c the d a i l y  cladocerans  that  e f f i c i e n c y of  i t increased  t o t h e minimum s i z e  metabolic  by t h e d i e l  3.  a  after contacting  Their  inefficient  t h e same f o r c o p e p o d s . Copepods o f a l l s i z e s t e s t e d  ingested  and  item  decreased  maximum s i z e  relatively  b o t h c o p e p o d s and c l a d o c e r a n s .  a prey  size  were  may part  i n d i c a t e some a b i l i t y of the temperature  during  between  their body  weight-specific  increased,  The s u g g e s t i o n  diel size  oxygen  and i n d i v i d u a l oxygen  of to  range  vertical and oxygen  consumption consumption  increased.  growth  was a f u n c t i o n o f t e m p e r a t u r e  Temperature a f f e c t s  growth  through  and p r e y  i t s effect  cn  78  several through  physiological i t s effect  the  larvae  to  that  growth  was  on  rates; consumption  feed at t h e i r greater in  temperature  than  temperature  regime.  prey  in  and  t h u s on  affects the  maximum p o t e n t i a l .  larvae those  density  living  living  at  under  growth  ability  of  I t was  shown  constant  high  a  fluctuating  79  V.  SIMULATION  STUDIES  Introduction  Theories The value  on  the  various  of  Adaptive  Value  t h e o r i e s advanced  vertical  migration  M a u c h l i n e and  categories  previously  mentioned:  horizontal  transport,  social  energetics,  a combination  depths  well  Nevertheless, the  adaptive  reason  for  migration  availability The  below  a  prey  field  value  of  aid to  prey  day  escape  of  item)  behavior.  As  light  of v i s u a l  a refuge  from p r e d a t o r s  than  and  by  further  which  migrate. of  night.  Vertical  reducing  prey  providing refuges. which  i t  intensity  the  reactive  decrease  fcllcw  can  light  a s s o c i a t e d with  migration  cannot  at  primary  decreases  activity  Vertical  prey  the  by  i n p a r t by  intensity  rate,  a component  and by  six  effects.  their  (the volume w i t h i n  will  predators.  see  predaticn  i n prey  the  predators,  demographic  i s probably  rather  i s determined  into  many z o o p l a n k t e r s  predators,  a fish  temperatures  and  McLaren  reproductive  migration  from  visual  fall  adaptive by  from  of  undoubtedly  vertical by  They  control  t o which  the  been r e v i e w e d  escape  predators  s h r i n k s . A decrease  day-depth field  those  Migration  explain  (1969).  these,  can  escape from  reactive field  detect and  predators  descent  may  Fisher  of  to  have  (1963) and  Potential  of V e r t i c a l  may  low  the r e a c t i v e also the  provide  migration  80  because and  of  t h e r m o c l i n e s , low  chemical  easily their  gradients.  expose day  for vertical  Several migration  adaptive  value  the  the  toxic that  was  have  suggested  space  and  be a b l e The  zooplankton  productive  the  proposed  (Hardy  than  could  for  and  is  as at  Pearre  the  authors,  of the  from  main  1935).  and  to  remain  of  deep quite  these  evidence  Since  aids  patches  of  high  to d i s c r e t e  surface water;  this  (1956), in  the  at  the  randomly  in  would  their  have  to  migration.  most m i g r a t i o n p a t t e r n s s u g g e s t s  responding year  of  Hardy  which o c c u r  The  transport  patches.  transport  timing  effect  migrants.  i s no  i n them, m i g r a n t s  the e x t e n t and  to  Though  there  unexploited  vertical  areas  including  at patches  of  horizontal  Gunther  horizontal  to a r r i v e  a r e not the  (1959) , and  transport  effects  previously  nature  throughout  intake  of  to modify  regular  water  distribution  toxic  that  time  just  s e t of p r e d a t o r s  a v o i d dense p h y t o p l a n k t o n  order  physical  might  c o n s i d e r e d the v a l u e  advanced, s e v e r a l  "colonization"  other  avoidance  have been shown t o e x i s t ,  theory  In  different  horizontal  of  density  zooplankton  surface.  have  originally  effects  migration  predator  horizontal  avoidance  phytoplankton  a  or  migration.  in u t i l i z i n g in  was  that  theories  changes  to  zones,  M a n t e i f e l (1959a,b) , G i r s a  (1973) have s u g g e s t e d reason  However,  migrants  depth.  oxygen  patches.  that  However,  waters  are  uniformly  more  selection  for  increased  food  c o n c e i v a b l y have p r o d u c e d  s u r f a c e . T h i s advantage does not,  by. i t s e l f ,  a migration explain  to the  81  development  of  the  downward  movement  in  a  diel  vertical  migration. David  (1961)  • resulting highly  from  suggested  vertical  specialized  that  horizontal  migration prevents  s p e c i e s with  little  c h a n g e s i n the e n v i r o n m e n t .  T h i s occurs  "mixing"  provides  genetic of  of  zooplankton  recombination.  sexuality,  would  it  affect  vertically vertical before  migrate;  this  migration  of  b r e e d i n g . There  marine  copepods  speciation (McLaren mixing  1963).  David's  to  doesn't  that  group)  (Calanaus  this  vertical  produce  displays.  These  lack  which  apply  tc  they  emerge  non-migratory  are  more p r c n e  finmarchicus  time  the  the  time  scale  of  migration.  group) scale  tc  to  of  prevent physical  There  i s no  assumption.  (1962) s u g g e s t e d  at o t h e r  for  complete  cladocerans  t h e o r y assumes t h a t  without  s u r f a c e or  numbers and  horizontal  horizontal transport  evidence  the  cf to  chances  l a r v a e because  similis ones  almost  certainly  i s s h o r t e r than  t c support  evolved  the  adapt  f o r adequate g e n e t i c recombination  Wynne-Edwards has  because  those  is little  migratory  obtainable  evidence  theory  (Oithona  extreme s p e c i a t i o n mixing  to  that  Chaoborus  than  necessary  in  formation  additional  unlikely  recombination  the  capacity  Because o f t h e i r  seems  transport  depths  displays  that  aggregations i n order allow  to  vertical of  animals  carry  out  migration near  the  epideictic  the p o p u l a t i o n to asses i t s  regulate i t s reproduction rate  in  order  to  hold  82  its  density  evidence  at,  that  reproduction that  growth  food  and  or  20oplankters  and  (1970)  rather  concluded  that  pattern,  to food  latitudes.  This  being  production  productivity on  over  these  is  to  their  control  considerable  no  evidence  p r i m a r i l y dependent  the  on  considers  the  and  value  of  growth  at  to  of  time  feeding  nocturnal pressure,  a of  year  in  night  of  of  animal times low  temperate  length  (feeding  that  primary  year  has  vertical  value  would  at  which  stay  instead  of  in  the  spending  the  potential  role  proposed  another  theory  migration  based  as  peak  most the  p r o d u c t i v i t y . Neither  migration.  to occur  of  be  Kerfoct's  vertical  reproduction  i s assumed  depth  should  primary  feeding maximizes  e t a l . (1972) c r i t i c i s e d  all  adaptive  and  a  to changes i n the  Miller  (1963)  bioenergetic  o r i e n t a t i o n s t r a t e g i e s . He  his detractors considered  McLaren adaptive  two  a result  g r o u n d s t h a t an  i n the  of o r i e n t i n g  Animals o r i e n t i n g tc pressure  hours i n r e g i o n s  temperature  value  i n terms o f t h e  course  at  respond  region  nor  adaptive  orientation  is partially  occurs.  the  productive daylight  than  longest  to  pressure  from  i s lowest.  able  the  o r i e n t a t i o n to l i g h t  rather  exposure  alone;  r a t e s are  discussed  than t o  resulting  Kerfoot  (1963) c i t e d  reproduction  benefits  theory  able  optimum. T h e r e  temperature.  to l i g h t  less  are  r a t e ; McLaren  Kerfoot  time)  r e s t o r e i t t c , the  on  functions  when t h e  for  energetics. of  animal  of  the He  temperature is  at  the  83  surface.  H i s theory i s concerned  benefits result from  from  an a l t e r n a t i o n  of v e r t i c a l the  the p a r t i t i o n i n g proportion increase  of  of energy  increases  as  temperature  increases.  and  the  t h e energy the  energetic low  that  and  gain  difference Thus,  more a d v a n t a g e o u s  tc  migrate.  relationship rates;  his  Mauchline  and  pre-existing  assumptions.  and  about  but  migrants  potential  following general  benefits  benefits pattern  fortuitous  horizontal  population  to  light  intensity  derived  were of  exploit  do.  high  in  descent  may  day  transport new  preferences  may  and  and  (p 107).  assessment feeding  on  surface  there are a  species  number  migration.  The  analysis:  the  decrease enable  the  digesticn  his  depend  their  low  McLaren's  predation;  parts  phytoplankton patches; among  and  of  below  vertical  included  McLaren  i t becomes more  criticised  from  cnly  differential  respiration  ultimately  can  feeding  examined  The  temperatures  Criticisms  p r o d u c t i v i t y , these authors concluded that cf  rates  the  on  decreasing  (1969) a c c e p t e d M c L a r e n ' s  theories  Since  with  increases,  be c r i t i c a l l y  Fisher  t o growth  temperature  assumptions  between t e m p e r a t u r e  the t h e o r y w i l l  goes  depends  growth.  alternating  as t h e  day-depth  on  and  as a  resulting  temperatures  between  and  center  benefit  assimilation from  energetic  temperatures  decreases f a s t e r  surface  theory  cf  rate  low  respiration  energy  than d i g e s t i o n  that  between  to  available  predicted  Any  o f h i g h and  i f respiration  temperature  o f h i g h and  migration.  alternation  with the p o t e n t i a l  may  cf  a  different allow  the  84  partitioning  of  p r o d u c e s the  resources.  greatest  McLaren  possible  (1974) p r o p o s e d  migration  in  thermally  increase  cf  a  not  include  earlier  greater given  the  to  time  slower  period.  theory  and  is a  His  new  requires  more  rapid  with  maintained  specific  mortality 5)  the  assumptions  migrants the  3)  the  despite is  is  satisfied,  there  increased  mortality  by  increased  to  fecundity  will  produce  more eggs t h a n  the  marine  copepod  on  does  which  his  and  was  thus a  that  including  the  it is  not  assumptions  he  history  temperature;  on  2)  reproductive  stages  equilibrium. will  be  1)  final  fecundity periodicity 4)  than  age  on  When  in  which  development  larger size,  and  Empirical  minutus support  his  old  these  a p a r t i c u l a r set  r a t e s , etc.)  to  strategy  development;  young  a  require  assumptions:  non-migrants.  Pseudocalanus  of  mcdel  model,  life  prolonged due  by  his  five  near  (fecundities, mortality due  does not  prolonged  greater  rate  model  rate,  metabolic  required  conditions  offset  in  following  population  are  theory  of  upon  grcwth  vertical  the  metabolic  non-migrants;  function  size;  on  of  than i n non-migrants i n  model i s based the  migration  resources.  effect  waters  d e p e n d s . The  incorporate  negative  increases be  to  of  considerations  than of  vertical  m a r i n e c o p e p o d s . The  M c L a r e n ' s new  rate  f o r him  needed b e f o r e .  stages;  a  faster  grcwth  necessary  can  utilization  number of e g g s , i n m i g r a n t s  m i g r a n t s grow  size  of  theory  produce  view,  a model o f t h e  metabolic 1963)  their  stratified  population  (McLaren  required  In  time  of the is  migrants data  on  theory.  85  McLaren's demographic vertical  migration  dependent  on  is  not  model may  f o r some o r g a n i s m s .  t c be  very  stimulate  i n t e r e s t i n the  theory  the  The  field  and  designed  tc elucidate  effects and  of  experiments laboratory  the  a  certainly  life-history  strategy  migration.  with  (Sections  III  e f f e c t s of  computer  simulation  various  biological  will  it  trivittatus  and  temperature  migration  IV)  on  the  and  was  model o f  used  to  were major  larval by by  a  growth.  the  simulation  of  consideration  the  parameters,  The  results  vertical  examine  strategies, physical  suggested  experiments,  simulation  model  p a r a m e t e r s on  were  C.  a f f e c t i n g g r o w t h . These r e l a t i o n s h i p s were  into  The  of  parameters,  experiments  previously  processes  migration.  many  applicable. It  vertical  value  However, b e c a u s e i t i s  a p p l i c a t i o n of  laboratory  discussed  incorporated  adaptive  Model  larvae  energetic  widely  phenomenon o f  Simulation  The  the  a d e l i c a t e b a l a n c e among so  likely  to  explain  field  of  and  McLaren's  pred i c t i o n s .  The there  following  a demonstrable  migration nature  with  of  migration  "energy  natural  the  distribution  general  questions boost"  prey  interaction and  strategy,  vertical is  "best"  as  were a  examined:  result  distributions? between migration for  prey  of 2)  density  growth  is  vertical  what i s  strategy?  larval  1)  3) on  the and what an  86  energetics  basis?  Methods The  simulation  model  was  energy  balance of a v e r t i c a l l y  gains  from  feeding  were c a l c u l a t e d partitioning C=P+R+F+U except the  o v e r 20  (Ricker  detailed  description  of  their  the  II contains a l i s t i n g  running  the  All  budget  Appendix  model. Graphs  a  list  are  Appendix  model.  metabolism Energy equation  Davis  (1967)  change b e c a u s e I  of  in  the  the a  input  feeding  v a l u e s and used  this  o f t h e FORTRAN  simulations  of  of t y p i c a l  variables  included  was  contains  of parameter  o f t h e FORTRAN  definitions  daily energy  days.  Warren and  o f the g e n e r a l model and  a list  The to  f o r 30  the e n e r g y  units.  subroutines,  s o u r c e s , and  due  the  were m i s s i n g . Change i n w e i g h t  o f d a t a i n mass  digestion  model and  intervals  as m o d i f i e d by data  larva.  losses  t o e x p r e s s t h e net e n e r g y  data, flow diagrams  their  the energy  minute  1971)  where e m p i r i c a l  availability  migrating  i n the model f o l l o w e d  i n d e x used  and  and  designed to fellow  i n the  appendix.  programs used i n  were run cn an IBM  1130  computer.  Each larva and  simulation  a t 20m prey  empirical  from  setting  the  the t i m e e q u a l t o z e r o . The  densities  interpolated on  and  b e g i n s by  at  the  temperature  d a t a from  depth and  mid-summer  position water  o c c u p i e d by  prey d e n s i t y  of  the  temperature  the  larva  profiles  are  based  ( e x c e p t when t e m p e r a t u r e  cr  87  prey  density  pre-set  in  subsequent general  are  graphical  time  form  of  the  depth,  determined,  the  interval  form  intervals  appropriate  time  manipulated).  and t h e p o s i t i o n  i s determined  temperature,  a  the  crop. I f the crop i s f u l l only digestion  enters the feeding model  is  phase i s b y p a s s e d crop  has  been  formulation  crop  full  from to  is  the feeding  the  from  and  The weight  and  to  mimic  the  of the  o f t h e new  feeding of  number e a t e n  is  large is  bypassed the model  phase.  energy  The  food  in  process  g a i n e d from  next  time  position  energy  interval  in  change and  weight is  is  energy  is  begun  due  then  by t h e  of the l a r v a .  phase o f t h e model c a l c u l a t e s and s m a l l p r e y e a t e n stochastically  This  material  losses  digestion  The l a r v a l  the  pause a f t e r t h e  the energy  net  The  the f e e d i n g  digestive  there i s a digestive  and movement. the  phase  and t h e c r o p has been e m p t i e d .  movement.  the  to r e s p i r a t i o n  calculation  phase  once t h e c r o p i s f u l l  a set proportion  i n which  been  of f u l l n e s s o f  f o l l o w e d by t h e e g e s t i o n o f u n d i g e s t e d  respiration  incremented,  have  digestion  t h e c r o p . The model n e x t c a l c u l a t e s  calculated lost  so that  until  The  d u r i n g the c u r r e n t  on t h e d e g r e e  phase and t h e n  i s designed  larvae  r  depending  digested,  Jiil2l22 .31i*  c  and p r e y d e n s i t i e s  o c c u r s . I f t h e c r o p i s net f u l l ,  designed  is  of the l a r v a i n  The model e n t e r s a f e e d i n g  or  and  pattern  by i n t e r p o l a t i o n .  gain to the l a r v a  i s calculated. phase  migration  model i s shown i n F i g u r e 17. A f t e r t h e  energy  digestion  The  t h e number  per time  determined  interval.  from  a  and The  Poisson  88  FIGURE 17 Generalized f l o w d i a g r a m o f t h e s i m u l a t i o n model. The d i a g r a m r e p r e s e n t s t h e s e q u e n c e o f operations which o c c u r s d u r i n g one t i m e i n t e r v a l .  8 8a  TIME _—  f  DEPTH C A L C U L A T E  TEMPERATURE PREY  DENSITY  C A L C U L A T E  AMOUNT  EATEN  YES  V  C A L C U L A T E  AMOUNT  DIGESTED  'C A L C U L A T E RESPIRATION  COST  C A L C U L A T E  SWIMMING NO  1* CALCULATE ENERGY  NET  CHANG E  INCREMENT LARVAL WEIGHT  I N C R E M E NT  TIME  COST  89  distribution. density  The  mean  of the d i s t r i b u t i o n  according to the H o l l i n g  varies  disk equation  for  with  prey  two  prey  types: U= (ALPH 1 *BFUD)/ (1+ALPH1*BFUD*H1) + (ALPH2*SFUD*H2) for  large  p r e y and  U= (ALPH2*SFUD)/ (1 + ALPH1*BFUD*H1)+ (ALPH2*SFUD*H2) for  s m a l l prey,  ALPH 1  is  where U i s t h e mean o f a P o i s s o n  the  "catchability"  "catchability"  o f s m a l l prey,  SFUD  is  s m a l l prey  large  prey,  the  stochastic the  prey  large  prey,  BFUD i s t h e l a r g e  ALPH2 prey  for  small  i s the  density,  d e n s i t y , H1 i s t h e h a n d l i n g  and H2 i s t h e h a n d l i n g time element  rime f o r  prey.  The  i s i n t r o d u c e d t o make t h e f e e d i n g phase o f  model more c l o s e l y  £hl2^2£H§  of  distribution,  larvae.  imitate  Feeding  i t e m s , and t h e e x p e c t e d  the n a t u r a l  feeding pattern  cf  depends on random e n c o u n t e r s  with  number o f e n c o u n t e r s  time  i n cne  interval  i s s m a l l . My u s e o f t h e d i s k e q u a t i o n  i s not s t r i c t l y  correct  since  encounter  the  random  (ALPH1*BFUD and ALPH2*SFUD) This  formulation  physically Poisson  has  a  possible,  number  relative  would  element not t h e  permit  based  on  i s encountered.  t o t h e 20 minute t i m e maximum  probability potential calculating  of error prey  value.  These  getting from  is  the  mean  a larva  capture  rate  to eat f a s t e r  handling  time,  i f  However, h a n d l i n g t i m e intervals,  and  (U).  than i s a  large  i s short  and t h e c r o p  constraints,  rate  volume  the  low  a h i g h P o i s s o n number, mean t h a t t h e my  capture  use  of  i s very  the  random  element  s m a l l . The t o t a l  in  amount c f  90  food  i n the crop  total  food  eaten  fill  the crop  food  i n the crop  crop  and  the  digestible  t o t h e maximum  model b y p a s s e s  the feeding  cf  crop  observation  that  the  contents  which  fcod  i n the crop  i s increased  each t i m e  interval.  assimilation  The  not  The  This  the  amount  calculated  by  a  stored  digested  food  i n the crop  the  amount t o be d i g e s t e d  (68%)  when t h e  is  on t h e  a portion  The  during  amount  of of  variable  food  eaten i n  equal  every  tc  the  pool  a  time  The f o o d that  amount o f f o o d  is  digested  and from  are s e t to zero.  the  i s greater  than  The model w i l l  when t h i s  time  interval  t h e f e e d i n g phase i n t h a t  occurs.  interval  is  from  empirical  that  i s digested i s  used  in  later  i s subtracted  digestible  food.  frcm If  t h e amount a v a i l a b l e  the amount a v a i l a b l e i s d i g e s t e d  phase a g a i n  the  digested.  as a s e p a r a t e  during  rate data.  total  variables  of  i s based  of the t o t a l  model e n t e r e d  the  digesticn,  would  measured i n S e c t i o n IV.  The  food  been  again.  i s carried  proportion  calculations.  feeding  feed  occurs  egest  interpolation  temperature--digestion to  has  and e m p t y i n g  by a p r o p o r t i o n  efficiency  or  interval.  for  of food  d i g e s t i v e phase i s e n t e r e d  whether  added  then  the  phase i n s u b s e g u e n t  l a r v a e do n e t s e l e c t i v e l y and  interval  capacity  i s emptied. T h i s  filling  If  c a p a c i t y , t h e amount o f  i s s e t equal  the crop  phase.  i n a time  i t s maximum  portion of a c r o p - f u l l  crop  the feeding  ( l a r g e and s m a l l )  until  seguence  digestible  during  t o more t h a n  time i n t e r v a l s  This  i s updated  begin  and both to  enter  food the  91  Respiration considered from  and  movement a r e t h e s o u r c e s of e n e r g y  i n t h e model. R e s p i r a t o r y  energy  loss  loss  i s calculated  For  intermediate  the e q u a t i o n : R=aW  b  The  v a l u e s o f a and  b a r e from  Section  temperatures R i s i n t e r p o l a t e d . v  was  estimated in Section  respiratory  energy  energy  i s used  loss  The  net  is  IV, and  specific  to  mass u n i t s and  energy  and  of a migration  e s t i m a t e i s added  to the  i s m i g r a t i n g . The  total  i s calculated the t o t a l  as t h e  energy  difference  loss.  Stcred  f o o d minus a c o n s t a n t p e r c e n t a g e  dynamic a c t i o n . used  this  cost  calculations.  change  the d i g e s t e d  to  energy  when t h e l a r v a  in later  energy  between t h e s t o r e d energy  loss  The  IV.  The  net e n e r g y  loss  change i s c o n v e r t e d  to increment the l a r v a l  weight.  Results  Sensitivity A  number  sensitivity The  of  results  larval  growth  handling  time  (HI, H2)  the f o r m u l a t i o n little  were  t h e model t o c h a n g e s 18)  on  have  simulations  (Fig.  changes  because  of  effect  show was  had  tc  the  quite  variable.  little  the  assess  i n i t s parameter  that  effect  effect  of the d i s k on  dene  cn  of  of  values. parameter  Small changes larval  e q u a t i o n i s such  number  the  prey  in  grewth  that eaten.  they As  FIGURE  18  The e f f e c t s of changes i n the parameter v a l u e s of selected p a r a m e t e r s on l a r v a l growth. The l i n e s on e a c h graph a r e t h e r e s u l t s of simulations using the values associated with the l i n e s as i n p u t p a r a m e t e r v a l u e s f o r t h e model.  92 a  93  "catchability" small  prey  there  was  specific  varied,  e f f e c t on  values  on  larval  maximum  cf  WBF  of  proportion  of f c o d  relatively  large  proportion  directly  even  phase o f  small  g r o w t h . The  the  had  feeding  weight element  is  results  on  on  could  be  model. B e c a u s e  The  model i s r e l a t i v e l y  For  presented  prey  density,  and  this  reason  below  represent  large  large  in  compared some that  to  of  the  effect  cn  number in  stochastic  growth the  The  prey,  numbers used  by  a  effect  large  this  of  e f f e c t s of  had  larva.  captured  random  I believe  the  this  a f f e c t s the  e f f e c t of  low  effect  |AE)  the  a  have a  introduced  is  Changing  s i z e of  (RNI)  s e r i e s of  variability  to  l a r g e prey  number i n i t i a l i z e r  there  because  has  the  food  growth i s l e s s  growth  of  and small  any  assimilated  number e a t e n  model. The  held,  larval  (ALPH1) a l s o  the  Because  energy g a i n  number o f  a  of  amount o f  unlimited.  larval  a f f e c t s the prey  the  c r o p can  produce a v a r i a b l e p a t t e r n  temperature,  parameters.  the  s i z e was  effect  changing  ( F i g . 18). i n the  only  i t s e f f e c t on  that  phase o f t h e to  of  time i n t e r v a l .  which  crop  c h a n g e s i n the random  acts  eaten  the  p r e y e a t e n by  element  of  (SDA), t h e s e p a r a m e t e r s  weight  cf  size,  (WEF)  and  growth. W i t h i n  small  prey  food  large  their  number  large  g r o w t h . I t a f f e c t s the  feeding  cf  of  the  range  the  i f the  varied  because of  larval  i n any  i s constrained,  "catchability"  but,  g r o w t h . SDA  weight  i t would be  (ALPH2) was  the  for  which i s low  a  cn  prey  dynamic a c t i o n  digested,  than  small  eaten  little  reasonable  effect  of  and  final  stochastic the  effects  the  other  the q u a l i t a t i v e the  manipulated  94  variables  rather  than  Predictions and  variability  from t h e  every  day.  occur  in Eunice  days  i t  larvae. the  would Prey  day  have  If  consequences f o r the  at  the  surface.  use  vibration receptors would not  Zooplankton  may  during  the  day,  possibility. filled,  no  In  were p o s s i b l e be  the  to  and the  higher  see  but  there  and are  failed.  digested prey  the  than  until  to  the  predicted.  item  seems  that  i s assimilated  and  but  measured f o r f o u r t h - i n s t a r t o be  estimated  predator.  to  high  is  test  efforts  the  to  crop  cf  of  is  food  feeding  densities that  quantify that a l l  proportion  of  a  assimilation  trivittatus  energy c o s t  this  evidence  eguals the C.  larvae  amount o f  a reasonable representation  C h a o b o r u s l a r v a e . The  the  I have assumed  that  i s ultimately digested  day-night  once the  l a r v a at  i n computation  that  If continuous  There  which  Chaoborus  that  have  staying  predators  of  that  the  through  i t might  results  remains egested.  energy gain  ease  material  efficiency this  For  part  avoid no  of  animals  p r e y so  model I have assumed i s possible  of  ambush  the  Chaoborus e x h i b i t a d i g e s t i v e pause, it  constant true,  not  several  be  their on  over  to  net  to  does  energetics  energetics  expected  able  more f e e d i n g  digested,  might  be  be  this  the  However, C h a o b o r u s a r e  differences  that  assumed  on  were  to l o c a t e  assumptions  is  extended  i s assumed this  model.  several  evidence  a large effect  night.  cn  migration  i f migration  vulnerability  and  important  There i s l i t t l e  L a k e , but  i n t o the  model depend  functional relationships. Larval  occur  is  built  larvae;  digestion migration  in is  95.  assumed  to  probably  a n e g l i g i b l e source of e r r o r  amount of used  be  constant  energy  assumes  involved.  a  not  constant,  probably  low.  Some o f  respect  The  constant  probably  some a r e  with  to t e m p e r a t u r e . T h i s because  oxy-calorific  respiratory, but  the  the  parameter  model was  sensitive  (ALPH1, WBF,  was  measured  directly;  i t was  effects  of  Of  those  The  RQ  is  involved  is  were measured  discussed  and  above  to  and  AE),  only  estimated  from  laboratory  and  therefore  were done t o c h a r a c t e r i z e  temperature  Less emphasis  the  factor  ALPH1  experiments.  Experiments  the  conversion  values  which t h e  rate  small  variability  estimates.  strike  the  quotient.  reasonable  not  cf  is  was  placed  prey  cost  and  t e m p e r a t u r e , and effect  on  demonstrate  and  of  feeding  the  possible  to  accurate  parameter  quantification  cf  grcwth  (Section  IV).  between  part  form  of  of  the  analyze  pattern  are  that  temperature,  in detail  i n the  estimates growth  strategies,  but  and  fine  the  the  the  of  part  details model, a  effect migration  fcod, large  of  allow  a  and more  differences  r e s u l t s and  to  various  pattern  part  of cf  model i s a d e q u a t e  feeding  would of  feeding  N  and  model i s  Because  shown t o h a v e the  feeding  the  part.  b e n e f i t . However, u s i n g  food,  increase  the  metabolism  and  growth. I f e e l  growth. An  quantify  relationship  q u a l i t a t i v e d i f f e r e n c e s i n the  combinations  migration  the  than t h e  migration  larval  metabolism  The  estimates  model, i t i s not  energetic  on  density.  less rigorous  parameter  on  and  on  more exact  between  predictions  would  96  probably  The  be t h e same.  Effect  The  interaction  was  examined  with  various  density  in  first  migration  (Fig.  19)  upward  pattern  cr  s t r a t e g y on  n a t u r a l prey  densities,  of  was  and w i t h  simulation  migration is  grcwth  densities,  various  prey  experiments the prey  stayed  lake,  and  Growth under  these  food  stayed  i s triggered  triggered  the n a t u r a l Eunice  which  f o r Eunice  at  the  a p h y s i o l o g i c a l migration  t h e s u r f a c e and 16 h o u r s  larvae  varied.  i f the l a r v a  followed  migration  following  at  by  by an  a  empty  Lake m i g r a t i o n at  the  the  full  surface  pattern i n crop,  crop.  Larvae  pattern of 4  bottom  grew  t o p but more t h a n  and  hcurs  less  than  larvae  which  a t the b o t t o m .  The  second  s e t o f s i m u l a t i o n e x p e r i m e n t s compared  t h e s u r f a c e and f o l l o w i n g a p h y s i o l o g i c a l  natural  migration  from  zero  from  0  the  ways - - w i t h  set  was g r e a t e s t  which downward  stayed  and m i g r a t i o n  was s e t a t n a t u r a l summer v a l u e s  conditions  at  three  " s u r f a c e " prey  the  density  at  of food  profiles.  In  the  o f Food  pattern,  t o summer f i e l d  similar  as s u r f a c e prey  densities.  Prey  t c 300 e a c h o f l a r g e and s m a l l  s u r f a c e . No f o o d t o t h a t found  pattern  was p r o v i d e d  below  tc  the  densities varied  density  prey  staying  was  varied  p e r 100 l i t e r s  7m  i n t h e l a k e . The r e s u l t s  —  a  at  condition  ( F i g . 20)  again  FIGURE The  19  e f f e c t of m i g r a t i o n p a t t e r n on larval grcwth natural prey d e n s i t i e s . The l i n e s a r e r e s u l t s from s i m u l a t i o n s w i t h the m i g r a t i o n p a t t e r n s e t as labelled.  A-Physiological B-Surface C-Natural D-Bottom  98  FIGURE  20  The e f f e c t o f m i g r a t i o n p a t t e r n and surface prey density on l a r v a l g r o w t h . The d a t a p o i n t s a r e the f i n a l l a r v a l weights of s i n g l e s i m u l a t i o n s .  98  1.2 -I  O P h y s i o l o g ica I _  CT  J= -+—'  x  l.o-l  O  Natura S u rf a c e  _C D)  CD £ .8-  03 > ctf .6-  c  .— .4  o x  o  Sl 1  0  50  -1  100  Prey  1  1  1  150  200  250  Density  at  Surface  1 —  300  a  99  show  that  larvae  following  E u n i c e Lake grow l e s s t h a n migration  pattern  difference  between  patterns seldom  because  fills,  pattern the  and  the  experience  following  a  at the surface.  "stay-at-surface"  the  pattern  prey  larvae  following  t h e same c o n d i t i o n s  physiological  There  and  densities  found i n  was  little  physiological  examined the  the crop  physiological  as t h o s e  which s t a y a t  surface. In  food  the t h i r d  profile  available each  the  was  varied  size size  at  experiments  a t the s u r f a c e  A,B) t o s t a y i n g  day  depth  of s i m u l a t i o n s .  previous  profiles  tested  the  pattern  i n growth  patterns  with  but they  set  of  each  show a  maximizes  when f o o d  under  density i s best  variation  simulations  of  used prey  gradual  growth  from  i s abundant prey  the n a t u r a l  at the density Eunice  in this set  o f 200 a t t h e b o t t o m ,  the  i n terms of growth, but t h e  between t h e f o u r  stochastic  o f food  had 300  but i t i s not demonstrated  With a p r e y  the  i s low a t t h e day d e p t h { F i g .  maximum growth  pattern,  migration  differences within  amount  migration  which  a t t h e bottom  which p r o v i d e s  fcod,  and 50, 150, 200, and 250 o f  were  when f o o d  the  ( F i g . 21 D). T h e r e may be some c r i t i c a l  Lake m i g r a t i o n  natural  pattern  variable  food  The r e s u l t s a r e q u a l i t a t i v e ,  21  profile  increase  the s u r f a c e  i n the migration  staying  to  with  a t t h e bottom. The f o u r  previous  profile. shift  s e t of simulations  a t t h e day d e p t h . The f o u r  prey  each p r e y in  at  migration  larvae  or s t a y i n g the  the  in  there  migration the was  patterns  model. little  are  As i n t h e difference  100  FIGURE  21  The e f f e c t of m i g r a t i profile on l a r v a l from s i m u l a t i o n s with labeled (a, b, c, d ) . f o l l o w s : 300 o f e a c h 50 ( A ) , 150 (B) , 2 0 0 s i z e at the bottom.  o n p a t t e r n and prey density g r o w t h . The l i n e s are results the m i g r a t i o n p a t t e r n set as The p r e y d i s t r i b u t i o n i s as prey s i z e at the s u r f a c e , and (C) , a n d 2 5 0 (D) o f e a c h prey  100  (6UJ)  JllBlSAA  | B A J B ~]  a  101  between t h e " s t a y - a t - s u r f a c e " and p h y s i o l o g i c a l  The  Effect  The running the  o f Temperature  effect  of  simulation  natural  temperature  on  experiments with  migration  pattern,  following  growth  and  temperature  prey  various  The  constant  5, 10, 15, and 2 0 ° , and p r o f i l e s between s u r f a c e  was examined by  natural  profiles.  difference  profiles  and b c t t o m  9,  8,  profiles  7;  15, 14; e t c . ) .  were a l s o  pattern.  Ten  initializers  profiles  tested,  2,  surface growth  migration  difference  were  run  with  profile;  temperature.  between c o n s t a n t  were p o o l e d .  stayed  temperatures at the s u r f a c e  temperature patterns.  growth than  increased,  randomly  There  below  was much g r e a t e r  growth  was  was  migrated.  decreased  the little  with  1,  and bottom s o t h e s e  i s f o r constant  when t h e y  chosen  followed  t e m p e r a t u r e s and p r o f i l e s  The 5 ° p o i n t  migration  the mean growth  ( F i g . 22).  model wasn't s e t up t o h a n d l e t e m p e r a t u r e s surface  5, 10, 15, and 20°  At a l l t h e t e m p e r a t u r e  and 3° d i f f e r e n c e s between t h e s u r f a c e  results  surface  10, 9; 10, 9, 8;  was low when t h e l a r v a e  pattern  tested:  a 1, 2, and 3°  the " s t a y - a t - s u r f a c e "  f o r each t e m p e r a t u r e  against  temperature  temperatures a t  The c o n s t a n t  with  simulations  plotted  natural  tested  densities,  were  with  t e m p e r a t u r e s o f 10, 15, and 2 0 ° ( f o r example: 10,  patterns.  under  5° c n l y ( t h e 5°).  At a l l  when t h e l a r v a e As t h e both  surface migration  FIGURE  22  The effect of m i g r a t i o n p a t t e r n and t e m p e r a t u r e p r o f i l e cn l a r v a l g r o w t h . The d a t a p o i n t s f o r the surface m i g r a t i o n p a t t e r n ( s o l i d c i r c l e s ) and the n a t u r a l m i g r a t i o n p a t t e r n a t 5° (open c i r c l e ) are t h e mean f i n a l w e i g h t s of 10 s i m u l a t i o n s . The data points for the n a t u r a l m i g r a t i o n p a t t e r n a t 10, 15, and 20° ( s o l i d c i r c l e s ) a r e p o o l e d r e s u l t s of the four temperature profiles d e s c r i b e d i n the text.  102 a  2.2-  2.0-  1.8-  1.6-  1.4"  •Natural  o>1.2-  O  Surface  751.0H LL  .8-  1 .21  0  5  10  15  Surface Temperature  20  103  The  results  of the simulation  laboratory  growth  experiments  the l a r v a e  and  the  profile  studies.  temperature  encountered  experiments,  In  the  was  to  varied a  the  laboratory  situation  simulations  and t h o s e i n which  In  simulation  both  growth  experiments  surface  temperatures  profile  was v a r i e d s o t h a t  the  same  or  non-migrants.  (no m i g r a t i o n ) .  water  greater This  food  treatment  set  of simulations  only  II  for  the  When  the  migrating  grcwth  i n the s i m u l a t i o n  limited  at the s u r f a c e  were a t density  prey  larval  results  density  growth than  for  in  t o grow  feed  was  f o r t h e low  prey d e n s i t i e s  experiments  prey d e n s i t i e s .  and t h e  prey  larvae  f o r the high  was  ( F i g .20),  constant  were t o o low f o r t h e l a r v a e  larval  profile  food  the  "surface"  when t h e l a r v a e  the l a b o r a t o r y  results  to v a r i a b l e  ( F i g . 16)  ( F i g 21, C,D)  ( F i g . 1 6 ) . The s u r f a c e  simulation  reason  density  i t approached  column  matched  to match t h e l a b o r a t o r y  (  o f prey d e n s i t y  the  this  with v a r i a b l e s u r f a c e  was a f u n c t i o n  the  to  the prey  experiment  growth  throughout  analagous  grcwth  prey d e n s i t i e s  exposed  For  with  the t e m p e r a t u r e  In  were  and v a r i a b l e p r e y d e n s i t y . is  match  migration. larvae  well  laboratory  to c o n s t a n t  temperature  varied.  agree  were e x p o s e d  during  however,  experiments  this  enough  treatment;  was p r e y  density  104  Discussion A consideration migration in  order  diel the  suggests  whole  the  population,  migration  a  1) s t a y  pattern  is  ability  that  that  i t decreases  with  decreasing  The  patterns  f a s t e r than  and t h a t  pattern  is  the  are analyzed  i n terms  t o the  organism. patterns  temperature,  and a s s i m i l a t i o n r a t e s  the  that  1 9 6 7 ) . On an e n e r g e t i c s that  of  prey  vulnerability  water  near-surface  water.  In e i t h e r c a s e  be r e l a t i v e l y  and s e c o n d a r y  if  consumption  the  organism. At best,  and  staying  constant.  production  i s below  which  the  —  will  migration. do  not  in  reguired be slow  migrate  in  warm,  i n deep  cold,  fcod-rich,  maintenance  Staying  Many  a r e two c a s e s  staying  a r e low w i l l  the l e v e l  growth  no  basis there  must be c o n s i d e r e d  deep  primary  under  ever  energetic  v a r i e s with  digestion  food-poor,  will  is  a  The  gain  g r o u p s have r e p r e s e n t a t i v e s  of n o n - m i g r a t i o n  cost  that  2)  time.  simplest  (Hutchinson  i s synchronous  and b e n e f i t s o f t h e s e  respiration rate  temperature,  over  zooplankton  costs  They a r e ,  i n one p l a c e ,  asynchronously.  these  vertical  p h y s i o l o g i c a l s t a t e so t h a t  t o maximize n e t e n e r g y  t h e energy  have assumed  constant  migrating  of  patterns.  o f some s o r t t h a t  and 3)  of following  In c o n s i d e r i n g  is  basic  of the i n d i v i d u a l animal's  implications  I  pattern  population  of t h e i r  three  of i n c r e a s i n g complexity:  migration  control  of the p o t e n t i a l s t r a t e g i e s  metabclic water  result  in  where death  f o r maintenance of because  o f low f o o d  105  I  c o n s u m p t i o n . The  digestion  to  than  be  greater  occur.  Staying  problem. almost  at  the  the  and  level  prey  ( F i g s . 16  density Diel  (Cushing Fisher  1951,  in  and  Teraguchi  synchronously; modified regular  by diel  the  are  and  Nc  animal  following  migrate  down out  of  thus  decreasing  until  i t r e - a s c e n d s on  would  be  combinations  of  be  form  migration  the bad  These  time a r e  u s u a l l y assumed  the  for  cf  depth are  of  the  pattern  the  can  of  and  with  gut  they diel  advantageous  if  in  result  of  in  an  empty,  to n e a r l y  adjustable  better  is,  cycle. This since  a  periodically  its  feeding  be  physical  pattern  with  a  migrates  migrating  would  and  has  that  some  advantageous" combinations of t o be  nature  pattern  biological  predators An  in  maximize e n e r g y g a i n  next m i g r a t i o n  especially  others.  Above  Mauchline  one  animal  zone  probability  time and "more  An  sharp  than h e r b i v o r e s .  would  are  population  usually  food-rich  particularly  infreguently pattern  its  1966,  the  cannot  what the  the  density  widely  migration  of  is  pattern  a diel  prey  growth i s a f u n c t i o n  found  the  stimuli.  containing  matter  to  different  water.  Northcote  most  periodicity  migration  environment  gradients.  and  exogenous  growth  entirely  deep  have  20).  migrations  periodicity,  an  consumption  1969). C h a r a c t e r i s t i c a l l y  regular  an  than  of f o o d  vertical  presents  would  f o r any  d i g e s t i o n r a t e s and  higher  maintenance  assimilation rates  respiration rate  surface  Respiration  universally  and  zero  pattern feed  more  migration particular way depth  predation,  than and but*  106  McLaren  (1963) s u g g e s t s  The is  roost complex  they  are energetic  migration  envisaged  i s one t h a t  c o n t r o l l e d by t h e p h y s i o l o g i c a l s t a t e o f t h e a n i m a l .  a c o n t r o l mechanism o f t h i s  sort,  warm, f o o d - r i c h water and f e e d move  down  into  Energetically, animal  cool,  this  water  pattern  left  is  neither l e f t  i n deep water  evidence  that  been s u g g e s t e d possible that  easily  wculd  using  this  with  is  odds  energetic  adaptive  previous  from  therefore, to c r i t i c a l l y  general value  conclusions  of v e r t i c a l  to t r i g g e r  is  gut nor no  gccd  t u t i t has  (Pearre  1973).  been  periodicity  Each  and  an  occur.  presented that  i s most  (McLaren vertical  A  reported  asynchronously.  conclusion  above i s a surface  advantageous 1963)  on  migration.  examine M c L a r e n ' s  of McLaren's  migration  between  a full  There  seldom  pattern  theory  advantages r e s u l t i n g  necessary,  with  patterns  The  or p h y s i o l o g i c a l l y based  The  would  empty,  because t h e  mechanism  has s e l d o m  i t s own  energetics.  with  was  widespread,  would be m i g r a t i n g  pattern at  this  mechanism  and t h e n  alternation  chaetcgnaths  mass m i g r a t i o n  on  of  i s very  a n a l y s i s of the m i g r a t i o n  solely  i t s gut  at the surface  for  migrate  detectable  The based  that  the population  individual  use  mechanism  recently  reason  until  Using  move up i n t o  i t s g u t was f u l l  when i t s g u t i s empty.  this  could  i s t h e most a t t r a c t i v e  makes t h e most e f f i c i e n t  migration  an a n i m a l  until  warm and c o l d w a t e r . An a n i m a l  is  pattern  i n nature.  It i s theory.  (1963) t h e o r y  are presented  the  above  on t h e (page  107  83).  He  seen  concluded  that  i n zooplankton  (an  being  modified  the migration endogenous  This conclusion  the  energetics  of various  The  d i f f e r e n c e between i n McLaren's The  ignores  of  interaction  proper  advantage  rate  and  explicitly  faster  feeding"  can  assimilation  that  at  the  alsc  enough f o o d  his  the  which a r e  high  following:  a t the s u r f a c e ;  2)  and  r a t e s . He  theory  between  or r e s p i r a t i o n  to  temperature  assumption  out t h a t  on  the  and  low  1)  " a l l  respiration  rate  must  than  digestion  feed  guestion  during  i s invalid  not a l l o r g a n i s m s  surface.  many e u p h a u s i i d s  authors  consumption  3)  decrease and  r a t e s do.  been p o i n t e d  entirely  i s that i t  i n c r e a s i n g f u n c t i o n of temperature;  respect  McLaren's f i r s t has  occur  theory  respiration  of  alternating  rate i s constant with  abcve.  advantage  or i m p l i c i t l y ,  functioning  of  i s a monotonically  digestion  cf  the a n a l y s i s of  presented'  between f o o d  t e m p e r a t u r e s . These assumptions a r e necessary  capable  of energetic  McLaren's  digestion  makes s e v e r a l a s s u m p t i o n s ,  energetic  patterns  t h e two a n a l y s e s  dependent  t c the  i s a t odds w i t h  migration  criticism  t h e complex  critical  rhythmicity  commonly  assumptions.  general  temperature  most  by exogenous s t i m u l i ) i s e n e r g e t i c a l l y t h e most  advantageous.  lies  pattern  f o r two r e a s o n s . I t that  migrate  M a u c h l i n e and F i s h e r throughout  whether  the short  dark  their  grazers period  (1969) f o u n d  migration; are  feed  able  these  to f i l t e r  i n t h e summer t c meet  108  their feed  daily  irregularly  water "all  (Teal  and t o f e e d  1971, F e d o r e n k o  necessary feeding"  define. to  requirements. Several  It  can r e f e r  a maximum  consequences  for warm  cf  costly  widespread,  IV)  well  assumption  in  i s impossible to r a t i o n or  function  or  has  of temperature  move  the  1969).  vertically  If respiration  decreased, rate  with  ccld  up  rate  into  would  warm  of  suggested  tend  water.  this  rate  did  to  Although  type  would  gain  not  be  of  realized.  C r u s t a c e a d i d not d e c r e a s e a t the c o l d  vertically significant  migrating energy  phenomenon  predators,  loss.  as  of predaceous,  might and  not  metabolic (Section reported (Moshiri  temperature  a reduced metabclic  decapod  depth. T h i s  rate  from  that  day  respiration  decrease  showed  their  The  make i t  f o r C. t r i v i t t a t u s  not  the p o t e n t i a l energy  the  moving  water.  m i g r a t i n g c l a d o c e r a n , Le_ptodora  a t low t e m p e r a t u r e  is a  has i m p o r t a n t  associated into  rate  a d a p t a t i o n s to decrease t h e e f f e c t of  presence been  cost  downward  on r e s p i r a t i o n  tc  respiration  and f o r Neomysis ,(A. H. K n i g h t , p e r s . comm.) and  for  deep  The c o n c e p t o f  t o a maintenance  that  energetic  water  the  "regulation"  the  metabolic  temperature  less  by McLaren  and  ration.  increasing  high  1973, P e a r r e 1973).  equally  monotonically  presence  both a t the s u r f a c e  introduced  McLaren's i m p l i c i t  upward i n t o  p r e d a t o r s have been shown t o  well  Teal  (197 1)  mesopelagic  temperature  cf  be w i d e s p r e a d i n  i t could  represent  a  109  Any high  energetic  and  energy  low  temperatures  depends  to  respiration  and  assimilation decrease the  exist.  (Brett  conditions,  the  digestion  "boost"  that the  the  varies  the  a n a l y s i s of the  is  that  the  staying  rhythm  based  F o u r t h - i n s t a r C.  neither  of  these  consider  other,  strategy  at on  the  the  trivittatus  patterns.  non-energetic  of  into  grcwth  decrease  faster  is  by  and  or  one  pattern  McLaren.  vertical  maximizing  larvae  If  migration  surface  these  available  decreases.  filling  It  of  predicted  energetics  migration  cf  one  McLaren  Under  i s directed  not  by  Dnder  temperature  1973).  p h y s i o l o g i c a l one,  a  increase  growth.  with  r e s p i r a t i o n r a t e must  rate  will  partitioning  more e n e r g y  and  temperature,  predicted  most e f f i c i e n t  the  to  goes t o  the  physiological gut.  that  of  digestion  temperatures  Fedorenko  in  partitioning  respect  reasoning,  this  i s c l e a r that  gain  low  a l t e r n a t i o n of  If  temperature  From it  such  the  as  accepts is  1970,  temperatures,  the  with  energetic  f o r a change  to occur  low  than  'Higgs  the  growth.  of a v a i l a b l e energy the  on  However, d i g e s t i o n r a t e  and  energy  constant  i n r e s p i r a t i o n r a t e at  conditions  could  at  r a t e s are  proportion  these  b e n e f i t r e s u l t i n g from  migration  net  energy  following a  emptying  of  i n E u n i c e Lake  necessary  the  fellow  therefore  explanations  for their  these  might  to  migration  pattern.  The  diel  reflection  of  distribution the  diel  of  larvae  distribution  of  simply  their  prey.  be  a  This  110  explanation species kenai,  the  C.  made by  vertical  fourth-instar is  no  are found  zccplanktcn  above 5m.  most of  evidence  disease  or  the  the  Diajgtonius  biomass  of  i s opposite  to  larvae.  or  l a r v a e stayed  moribund  all  m i g r a t i o n which  experimental  that  i f these no  almost  s p e c i e s which makes up  hypothesis  study  since  trivittatus  makes a d i e l  abundant cf  by  prey  There the  unlikely  eaten  the d i e t , that  is  to s u p p o r t  parasites  might  i n warm water.  obviously  or d i s p u t e be  more  In t h r e e  years  larvae  were  parasitized  encountered. It  is  constant.  conceivable  A decrease  might be  expected  presence  of  larvae to  tc  and  t h e r e i s no decrease  hadn't  are b e t t e r  complete  Boulton  be  avoidance  vulnerability  occurred was  by  (Duhr  the  day  with  response  dawn. The  are  feed  apparent by  visicn  1955),  to  their the  a d j u s t i n g the  both  if  and  prey.  A  less  feeding  of c h a n g e s i n prey  day  ease,  make i t e n e r g e t i c a l l y  effect  able  on  their  day  the  Chacbcrus  throughout  able  light  might  examined by  Since  1967), and  to s t a y a t the s u r f a c e d u r i n g the  yet  not  able to detect  constant  l a r v a e are  c l a d o c e r a n s i n the  is  r e c e p t o r s r a t h e r than  darkness  should  vulnerability  during  during daylight.  ( H o r r i d g e and  trivittatus  apparent  in  attractive  in  vulnerability  vulnerability  vibration  d e t e c t prey  n i g h t . C.  copepods  use  prey  prey  prey  i f zooplankton  apparently  to c a p t u r e  and  prey  a Chaoborus l a r v a  detect their  ability  in  that  prey  d e n s i t y by  a  <  111  vulnerability  coefficient  (BVUL, SVUL) i n a few  The  of  simulations  results  these  vulnerability  must  night  the  to s h i f t  be  "stay-at-surface"  in  prey  in this  t o have p r o d u c e d  §!f=ricanus on  C.  larvae  restricted  to  fourth-instar apparatus  C.  is  length);  they  items;  they  a  are  feed  fourth-instar  C.  larvae  C.  trivittatus  larvae.  why  the  f o l l o w i n g two upward  migrants  Goldspink the  and  vertical  diet  are  Scott  surface  A change seems  theories  americanus seen i n  third  at  C.  a l l times,  of p o t e n t i a l prey than  are  Their  at  mouth  appear  and, be  prey  capture  gape,  antenna  capturing  restricted  diet  of  prey  than  than  to  account  of them  explains  their that  do  1973).  l e s s abundant  have been p r o p o s e d  out  large  (Fedorenko  numerically  down  is  to  larvae  also  o f C.  at  from  Fourth-instar  they  (1971) have s u g g e s t e d  migration  growth  pattern  length,  more  C.  larvae.  larvae.  a  move  than  however,  movement o f C h a o b o r u s . N e i t h e r should  day  pattern.  and  data,  range  trivittatus  americanus  for  the  efficient on  C.  The  near  (head  less  natural  migration  trivittatus  smaller  the  prey  system.  the  narrower  during  that  maximizing  trivittatus  and  showed  magnitude,  trivittatus  stay  morphological  the  this  between C.  fourth-instar  based  of  to  predator-prey  Competition unlikely  strategy  pattern  vulnerability  unlikely  times lower  migration  the  and  100  simulations.  food  source.  seme a s p e c t s  f l a v i c a n s i n Lochan  Dubh  of  agree  112  with  the e p i d e i c t i c  fourth-instar migrate about seems  18 months that  function Goldspink  downward  migration. that  sediments  Swift  i s high  and  fecundity  and  LaRcw  larvae  vertical  downward  tc  that t h i s  is  It  c a n have any far  in  causes  of the  (1970)  have  migrate.  migration  migration  emerge.  i n the hypolimnion  a t a l l depths i n Eunice  so i t seems u n l i k e l y  vertically  that  do n o t c o n s i d e r  (1958)  the  Lake  migration  low oxygen c o n c e n t r a t i o n  1972)  The  pupate  vertical  Scott  Hunt  a c c o u n t f o r t h e upward larvae.  they  would a f f e c t  stimulates  concentration and  their  and  ( 1 9 6 2 ) . T h i r d and  l a r v a e i n Eunice  before  that  advance.  suggested  c f Wynne-Edwards  C. t r i v i t t a t u s  unlikely  signalling  concept  of  Oxygen  Lake  (Fedorenko  explanation C.  or  can  trivittatus  not c o n s i d e r e d  in  these  studies.  Avoidance hypothesis patterns.  of  to  diurnal  explain  Welch  preyed  upon  very  (1956) f o u n d t h a t predation fish  were  suggested Corbett  on  the  as  the  in  Lake  by b e i n g  benthos.  during  Predator  t h e day  were  avoided  planktonic  when t h e  ( p e r s . comm.)  heavy f i s h  predation i n  hypolimnion  avoidance  above d i s c u s s i o n s u g g e s t s .  larvae  pond. MacDonald  Northccte  avoid  activity  Victoria  t h e day i n t h e a n o x i c  at night.  attractive  C. £uncti_pennis  i n a shallow  larvae  may  an  of n o c t u r n a l  and b e n t h i c  kannume  C. f l a v i c a n s  up t o f e e d  that  by f i s h  chaoborid  Borm_yrus  feeding that  at night  little  is  occurrence  showed  Lake by s p e n d i n g  migrating simple  by  the  (1968)  which were p l a n k t o n i c  predators  is  not  and so  Pope e t a l . (1973)  113  found  t h a t some C h a o b o r u s s p e c i e s  without some  fish,  (including  were p r e s e n t dusk are  larvae  in  reach  are v i s u a l  notonectids.  during  t h a n a b o u t 3-4m,  pressure these  them  persistance  previous  selective  behavior  pattern  of  larvae  a  neutral  i n the l a k e .  i n the lake.  2m and  probably  are  to They  unable  to  would e x e r t even  of by  little  i f the l a r v a e  n e v e r come c l o s e r to t h e s u r f a c e  i n Eunice  migration which  complex  i f  of the  trivittatus  L a k e may  pattern  adapted  i s now r e l a x e d  as  a  exogenous  diel in  be  such  a  behavior  nor a d v a n t a g e o u s , s e l e c t i o n  should  simply to  some  or absent.  migration crigin,  pattern act to  A  pattern, could  i n i t s e v o l u t i o n i n the face of relaxed  However,  fish  the n i g h t .  whether i t be endogenous o r  pressure.  of  t o escape d i u r n a l p r e d a t i o n  seen  pressure as  Chaobcrus  cause  C.  at  a r e known to be a b l e  on C. t r i v i t t a t u s  pattern  fish  t h e d a y . The downward m i g r a t i o n  even d u r i n g  migration  most  a r e no f i s h  abcut  However, n o t o n e c t i d s  not migrate;  conservative  that  deeper t h a t  whether  a proximal  and a r e abundant  might a l l o w  any p r e d a t i o n  The  there  predators  f i s h , and  I I I ) . Avoidance as  lakes  a r e most a c t i v e  fourth-instar  because  in  with  i n lakes  predators  of  larvae  C. t r i v i t t a t u s  C. t r i v i t t a t u s  the  Lake  unable t o forage  i n lakes  occurred  considered  pattern  Chaoborus  found  a r e t h e t i m e s o f day t h a t  be  Eunice  cnly  found  (LaRow 1969, S e c t i o n  cannot  Notonectids  did  C. t r i v i t t a t u s )  migration  capture  only  or not. C r e p u s c u l a r  migrating  vertical  if  were  and dawn; t h e s e  predation  are  some  were  be  selection i s neither  change i t .  1 14  It  a p p e a r s from  energetically at  the  the  be  the  migrate  migration  expected  to  unknown s e l e c t i v e larvae  in  Eunice  between  populations  with  no  migration a lake  pattern. high is  they  with Stahl  source  degradation with is  the  did  not  Within Forest the  the  which record a  species  adapted  the  are  one  and  of Eunice  represented  exchange  for  this  the  reasons  ether  provide so  behavior  a  that  i n those  the  gradual  in C,  a  C.  short  trivittatus not;  they  populations. B.  C.  Research  which c o n t a i n C h a o b o r u s include  ones  noticeable. It  these U.  lakes  associated  which d i d  Lake i n the  the  the  continuous  pattern  i s not  for in  than  mechanism  of  in a  population  behavior  patterns  several lakes  migration  a parental  tc lakes  of  an  vertical  of  pressure  is  diel  Pope e t a l . (1973) found  migration  miles  from  larvae  type  fish  would  population  favoring  is  trivittatus  enough  t h a t any  mechanism c o u l d  this  C.  of Chaoborus s p e c i e s  cf adults  contained  few  there  that  of s e l e c t i o n  t c study  Lake  observed  fast  pressure  h i g h l y adapted  Significantly,  lakes  pressure  on  the  is  lakes  of c o - o c c u r r e n c e  removal  impossible  study. in  of  there  (1966) s u g g e s t s  highly  i n Eunice  acting  maintains  selection  from. T h i s  of  is  i n nearby  chance d i s p e r s a l  emerged  that  that  remain  I t i s p o s s i b l e that there  recently derived  a high  frequency  the  be  Lake t o  physiological basis; i f this  persist.  selection  i s only  a  Lake t h a t  or  in  i t may  on  p a t t e r n observed  force  pattern,  lake  simulation s t u d i e s , that i t i s  advantageous f o r l a r v a e i n Eunice  s u r f a c e or  case,  not  l a b o r a t o r y and  flayicans  larvae; and  1 15  C.  trivittatus  lakes  without It  in lakes containing  is  clear  dielly  changing  day  a benthic Lake  from  C.  migrating  Eunice  field  data  trivittatus  with  length phase,  larvae  a migration and  the  i s cued  by  migration  is essentially  the  pattern  same as  the  most a d v a n t a g e o u s on  energetics  to  look  part  e l s e w h e r e f o r an migration  sufficient of  the  movement larvae  fish  existing  c.  of  which seems migration  most of  persistence  exposed  --  of  upward  must be  the  most  i n the  probable  avoidance surface  of  is  C. in due  to s t r o n g  trivittatus likely  trivittatus the to  face  periodic  selection  the  generally  the  with lack in  reported  appear  tc  be  necessary  adaptive  value  of  Near-surface  feeding  movement. The  critical  i s the  downward  waters. For  Chacbcrus  predation day.  —  particular  behavior  of  the  Lake  from  the  vertical  explanation  form  relaxed  immigration  the  especially  L a k e . The  in Eunice  for  None  explains  apparently  for this  are  trivittatus  does not  w a t e r s by  larvae of  o f C.  explanation  i n Eunice  for  shifts  Except f o r the  explained  t h e o r i e s , however, c o n v i n c i n g l y  migration  in  that  lake  basis, i t i s  food-rich surface  movement i s t h e  predation  the  which  the  in general,  pressure  explanation  explain  migration of  pattern  III)  Eunice  that  i n Chaoborus l a r v a e .  to  out  downward  trivittatus  which  light.  this  an  in  pattern  Chaoborus l a r v a e . Since  is  C.  (Section  for  vertical  and  fish.  fourth-instar  cf  fish  of  the  i s that i t s selection populations  pattern.  116  The not  young s t a g e s  m i g r a t e , but  (McLaren instar  C.  1972). they  1963,  the  as  surface  I t may  This  found.  food  shortages  more a b u n d a n t must  migrating be in  that  second  no  exception  (Fedorenko  and  Swift  live third  they  he  to g a i n  staying  habit  some p o i n t  may  attendant  high  involving  slower  energy  tc  migration Growth  rates  those of to  third spend  at  staying  risk.  the  one  of  when  more  they  would  still  be  best  and  fourth-instar larvae  l e s s time a t  trivittatus  the  surface  warm,  as  food  of is,  to a  vertically  the  It  may size  strategy  grcwth  with^  one  partitioning  cf  The  young,  an  to  physiological  were  the  case.  are  higher  than  larvae and  species  i s r e l a t e d to  i f this  young C.  i n the  advantage,  they are  of  some  the  increases  older.  as  from  development.  efficient  get  t o grow  where  shift  maximizing  cost  as  size  surface  less tolerant  Whatever  their  time  migrate.  zccplankton  migration As  the  to  refuge  surface  during  migrate. from  by  gradually  growth but  pattern  begin  staying  a size  the  vertical  metabolic  growth  at  they  that  shift  deep from  and  smaller  this  why  of m i g r a n t s  3m  young a n i m a l s a r e  resolve  species  with  facilitated  minimize  at  about instar  associated  that  commencement o f  those  appear  by  surface  and  in order  be  and  the  a d v a n t a g e o u s f o r young s t a g e s  would  I t may  near  do  1966). F i r s t  w a t e r s where many o f t h e  are  we  be  e n t i r e day  animals  Northcote  larvae  advantages  the  migrating  and  they reach  possible  predators.  spend  are  small  until  when s m a l l ? rapidly  rather  trivittatus  hatch  many v e r t i c a l l y  Teraguchi  These  What a r e  of  the they  latter get  larvae  cider.  117  Vertically fish,  migrating  have been  adaptive  largely  value  of  ignored  vertical  some p r o b l e m s when t h e s e them.  One s u c h  problem, t h a t  r a t e throughout  discussed  previously  adaptive  value  been c o n s i d e r e d juvenile  sockeye  thermoregulate Brett  subject high  sockeye Marion  lake.  during by  fish  of the maintenance of a  constant  and r e f u g e  gain.  as  McLaren's.  i n a cold  temperature  water  bioenergetic  patterns.  part  in  that  (1963)  however, he  Alternation  of  i n the h o r i z o n t a l movements  of  water a t t h e edge o f  s p r i n g i n the c e n t r e c f  regime experienced i s similar  to  by t h e s e  that  during  fish  experienced  their  vertical  conseguences of a l t e r n a t i o n of  and low t e m p e r a t u r e s a r e u n c l e a r ,  important  McLaren  fcraging  shallow  have  His conclusions are  can a l s o occur  i n warm  above  behavioura1ly  of food;  ration.  been  concludes  Unlike  i n B a b i n e Lake o r by z o o p l a n k t o n The  He  has  concerning  discussed  1971).  o f maximum  which f e e d  theories  i n B a b i n e l a k e , B.C.,  temperatures  The  ( T e a l 1971),  migration  (Brett  a h o r i z o n t a l migration  migrations. high  include  ( p e r s . comm.) i s s t u d y i n g  salmon Lake  to  a n a l y s i s of the r o l e  the case  low  Hyatt  extended  are  the m i g r a t i o n  t o t h e same c r i t i c i s m s  and  plane.  the  only  an  the  present  t o maximize e n e r g y  includes  considers  salmon  of  or  However, they  (Section I V ) . Various  fish  zooplankton  considerations  migration.  of v e r t i c a l  for  in  theories  metabolic  the  c a r n i v o r e s , whether  maintaining  but they  these  may  diverse  play  an  migration  118  The Lake the  a n a l y s i s of C h a o b o r u s v e r t i c a l  can  be  adaptive  viewed value  provocative  based  the  solely  Most  actively  them n e a r  any  above as  do  surface  the  the  to  effect  diel  M a u c h l i n e and  Fisher  single  can  theory  migration.  migrating  the  migration  two —  staying  mediated and  few,  advantage  presently  advantage.  i s an  derived  if  available  Such a t h e o r y  temperature distribution,  dependent and  the  seasonally  night  deeper  during  and  f o r the  from  are  one,  respiration of  the  adaptive  a variety  value  cf  of b e n e f i t s of  an  a l t e r n a t i o n of high  and  but  will have  places  i t is unlikely  to g r o u p . The the  that  possibility  pattern.  that  group  would  any,  pattern  there  attractive  a  at  migration  migration  account  from  follcw  (1969) p o i n t o u t ,  Rather,  energetic  temperatures  the  of  migration  at a l l ,  zooplankton  the  vertical  most a d a p t i v e  migrate  during  i n importance  is  not  mediated  which v a r y  low  leads  (1963)  establish  and  a n a l y s i s of  energetics  migrating  light  the  vertical  McLaren's  e n e r g e t i c s of v e r t i c a l l y  i n an  Eunice  consideration cf  properly  temperature  in  shown t o f o l l o w a p h y s i o l o g i c a l m i g r a t i o n  adjustable,  that  on  Some a n i m a l s  been  As  the  food  migration.  not  and  wider  or f o l l o w i n g a p h y s i o l o g i c a l l y  have  day.  does  discussed  surface  pattern.  vertical  on  Including  strategies  a model f o r the  between f o o d  interaction  animals.  of  theory  relationship this  as  migration  idea  nc a d e g u a t e  demonstrate tc  and  take  theory such  into  account  digestion rates,  irregular  feeding.  an  prey  119  Summary 1.  A review  vertical can  migration  account  alternation  should pattern  not  t h a t , on above  an  are  to  with  as  discussed.  With no  is  to  and  of by  subject  4.  the  maintain  concluded  loss  the  the  that  migration  than  on  this  from  respect  only,  animals  model of  the  confirmed  patterns  cited  pattern  existing  migration  pattern  pattern  i s probably by  populations  the  vertical  acting pattern  patterns basis in  Eunice  this  migration  Eunice  by  Lake  lakes  are  observed, i t  maintained  i n other  favoring  the  energetic  force  migration  pattern  and  an  vertical  to  assumptions  migration  larvae  obvious s e l e c t i v e the  of  the  most a d v a n t a g e o u s on  to s e l e c t i o n pressure  With  depend  advantage  theory.  trivittatus  migration  immigration  energetic  a p h y s i o l o g i c a l migration  two  growth  that  species.  i n Chaoborus l a r v a e  b a s i s , the  of  s i n g l e theory  energetics  or f o l l o w  d i f f e r e n c e s between t h e C.  value  i n a v a r i e t y of  i s shown t o  migration  McLaren's  suggested  any  maximize g r o w t h . A s i m u l a t i o n  vertical  fourth-instar  Lake  surface  energetics  The  cn  adaptive  A number o f b e n e f i t s have  migration  better for larval  associated 3.  migration.  (1963) t h e o r y  the  the  lack of  j u s t i f i e d . Considering  at  of  the  temperature  i n order  energetics  of  of  stay  confirms  for vertical  McLaren's  which a r e  e a r l y t h e o r i e s on  for vertical  been s u g g e s t e d 2.  of  slow  population which  migration  are  pattern.  i n general,  i t is  120  concluded  that the a d a p t i v e  group t o g r o u p . is  an  energy  t e m p e r a t u r e s . To energetics food  One  of gain  the  value  potential due  to  d a t e t h e r e has  of v e r t i c a l  availability.  of  migration  the  migration  benefits  from  alternating  been no  v a r i e s frcm  cohesive  high  migrating and  theory  on  low the  t h a t i n c l u d e s a d i s c u s s i o n of  121  LITERATURE  Berg,  CITED  K. 1937. 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In Methods the a s s e s s m e n t of f i s h p r o d u c t i o n i n f r e s h w a t e r s . I . P. Handbook No. 3. E l a c k w e l l , O x f o r d . 348 p.  for B.  Roth,  J. C. 1968. B e n t h i c and l i m n e t i c d i s t r i b u t i o n o f t h r e e Chaoborus s p e c i e s i n a s o u t h e r n Michigan lake (Diptera, C h a o b o r i d a e ) . L i m n o l . O c e a n o g r . 13: 242-249.  Roth,  J . C. 1971. The f c o d o f C h a o b o r u s , a p l a n k t o n predator, i n a s o u t h e r n M i c h i g a n L a k e . PhD. T h e s i s . University of Michigan.  Roth,  J. Bull.  Russell, the  C, and S. Parma. 1970. A Chaoborus E n t o m o l . Soc. Amer. 16: 100-110.  F. S. 1927. The s e a . B i o l . Rev.  bibliography.  v e r t i c a l d i s t r i b u t i o n of plankton Cambridge P h i l . Soc. 2: 213-262.  in  Schindler, E. W. 1968. F e e d i n g , a s s i m i l a t i o n and r e s p i r a t i o n rates cf Daphnia a<jna under various environmental c o n d i t i o n s and t h e i r r e l a t i o n t o p r o d u c t i o n e s t i m a t e s . J . Anim. E c o l . 37: 369-385. m  Schmein-Engberding, F. Knochenfische und F i s c h . 2: 125-155.  1953. ihre  Die V o r z u g s t e m p e r a t u r e n e i n i g e r physiologische Bedeutung. Z.  Sikorowa, A. 1968. The behavior of C h a o b o r u s L i c h t l a r v a e under u n f a v o r a b l e oxygen c o n d i t i o n s . Ekol. pol. Ser. A 16: 1-8. S i k o r o w a , A. 1973. belonging to  M o r p h o l o g y , b i o l o g y , and e c o l o g y o f s p e c i e s t h e genus C h a o b o r u s L i c h t e n s t e i n ( D i p t e r a ,  126  Chaobcridae) o c c u r r i n g i n Poland. summary]. Z e s z . nauk. ART Olszt. R y b a c t o S r o d l a d o w e 1:1-121.  [ i n Polish, English ( 1 0 5 ) . O c h r o n a Wed I  S n e d e c o r , G. W., and W. G. C o c h r a n . 1967. S t a t i s t i c a l 6 t h e d . Iowa S t a t e U n i v e r s i t y P r e s s . 593p. S o r o k i n , J u . I . 1968. The use o f C * nutrition of aquatic animals. L i m n o l . , M i t t . 16. 40p.  methods.  1  i n the study of the I n t . V e r . T h e c r . Angew.  S p r u l e s , W. G. 1970. The e f f e c t s o f and food competetion on communities o f high altitude P r i n c e t o n U n i v e r s i t y . 47p.  size-selective predation crustacean zcoplankton pends. PhD. Thesis.  S t a h l , J . E. 1966. C o e x i s t e n c e i n C h a o b o r u s and i t s e c o l o g i c a l s i g n i f i c a n c e . I n v e s t . I n d i a n a L a k e s and S t r e a m s 7:99-113. Swift, M. C., and A. Y. F e d o r e n k o . analysis o f the c r o p contents L i m n o l . O c e a n o g r . 18:795-798.  A r a p i d method f o r t h e o f Chaoborus larvae.  Swuste, H. F. J . , R. Cremer, and S. Parma. 1972. S e l e c t i v e predaton by l a r v a e o f Chaoborus flavicans (Diptera, Chaoboridae). I n t . V e r . T h e o r . Angew. L i m n o l . , V e r h . 18: in press. Teal,  J . M. 1959. R e s p i r a t i o n o f c r a b s i n G e o r g i a s a l t marshes and i t s r e l a t i o n t o t h e i r ecology. Physiol. Zcol. 32: 1-14.  Teal,  J. M. 1971. P r e s s u r e effects on t h e r e s p i r a t i o n o f v e r t i c a l l y m i g r a t i n g decapod Crustacea. Am. Zcol. 11: 571-576.  Teal,  J . M., and F. G. C a r e y . 1967. E f f e c t s c f p r e s s u r e and t e m p e r a t u r e on t h e r e s p i r a t i o n o f e u p h a u s i i d s . Deep-Sea Res.. 14: 725-733.  Teraguchi, M., and T. G. Northcote. 1966. Vertical d i s t r i b u t i o n and m i g r a t i o n o f C h a o b o r u s f l a v i c a n s larvae in C c r b e t t L a k e , B r i t i s h C o l u m b i a . L i m n o l . O c e a n o g r . 11: 164-176. Vlymen, W. J . 1970. E n e r g y e x p e n d i t u r e L i m n o l . O c e a n o g r . 15: 348-356.  of  swimming  copepods.  Warren, C. E . , and G. E. D a v i s . 1967. L a b o r a t o r y s t u d i e s cn the f e e d i n g , b i o e n e r g e t i c s , and growth o f f i s h . P. 175 t o 214. In S. C. G e r k i n g [ e d . ] The b i o l o g i c a l basis cf f r e s h w a t e r f i s h p r o d u c t i o n . B l a c k w e l l , O x f o r d . 495p.  127  Welch, H. E. 1968. E n e r g y f l o w t h r o u g h t h e major m a c r o s c o p i c components of an aquatic ecosystem. PhD. Thesis. U n i v e r s i t y o f G e o r g i a . 97p. Wood, K. G. 1956. E c o l o g y o f C h a o b o r u s ( D i p t e r a : C u l i c i d a e ) an O n t a r i o l a k e . E c o l o g y 37: 639-643.  in  Worthington, E. B., and C. K. Ricardo. 1936. Scientific r e s u l t s o f t h e Cambridge e x p e d i t i o n t o E a s t A f r i c a n L a k e s 1930-31. No. 17. The v e r t i c a l d i s t r i b u t i o n and movements of the plankton i n l a k e s R u d o l f , N a i v a s h a , Edward, and B u n y o n i . J . L i n n . Soc. London Z o o l . 40: 33-69. Wynne-Edwards, V. C. 1962. A n i m a l dispersal in s o c i a l b e h a v i o r . O l i v e r and Boyd, E d i n b u r g h .  relation 653 p.  to  128  APPENDIX I  Figure  Page  1.  Flow d i a g r a m s of s u b r o u t i n e s EATIT and DIGST.  129  2.  Flow d i a g r a m o f s u b r o u t i n e  130  3.  G r a p h s o f t h e i n p u t v a r i a b l e s f o r t h e model.  DOIT. . . . . . . . . . . . . . . . ...  Table 1. The the  131  Page meaning of t h e FORTEAN s i m u l a t i o n model  variables  2. The meaning, source, and value p a r a m e t e r s i n the s i m u l a t i o n model  used i n 132 of  the 134  129  FIGURE 1 Flow  diagrams of s u b r o u t i n e s  EATIT  and DIGST.  SUBROUTINE  EAT1T  SUBROUTINE  BFCTR =Y N T (TIME, TM, B V U D  AD = Y N T (TEMP, T M T U R ,  S F C T R = YNT (TIME, T M, B V U L ) BFUD = BFOOD * SFUD  DIGST  DP)  BFCTR  =SFOODxSFCTR  U=CALPHIXBFUD;/(I+(ALPHI>«BFUDXHI3+CALPH  2«S F U D * H 2;  Y E S  BFE=POIS(U) U=(ALPH2*SFUD)/  AD = FA  1+ F A L P H 1 * B F U D * H 1 ) + < A L P H 2 * S F U D * H 2 )  SFE=POIS(U) WBFE = WBF^BFE WSFE=  WSF*SFE  TFE = WBFE+  WSFE FPIG = AD VC=VC-AD FA= F A - A D  ^  v  R E T U R N J  d FA= FA + (0.68*TFE) STFE =S T F E + TFE  03  130  FIGURE 2 Flow d i a g r a m  of s u b r o u t i n e  DOIT.  130  II LG= I W - WO I PIG = 5FPIG II A 3 S = 0. FA = O. VC = 0.  moiro. STFE=0  TIME=0.  DEPTH= YNT (TIME. TIM. Z) TEMP = YNT (DEPTH; OT. T E M ) B F O O D = Y NT ( D E P T H , DF, BFUDE ) S F O O D = YNT (DEPTH. DF, SFUDE) R F E = O. S F E = 0.  YES  CALL  EAT IT  IF ( V C GE. VCMAX)  K= 1.30  IFLG=2  j  J = 1. 72  R R R L " EXP(A(L- l ) J « W » ' B ( L - l ) RHRH = G>:i'{A|l.|]*W<*B(L) RRR = R R R L + (RRRH-RRRL)*<T EMP-TMP(L-1)))/( XM P(L)-TMP(L- U)  RRR =EXP (A(l.))yWXXB(L) |  T = = RC = RRR 3. SC = 0. IF (T !M E .GE. 24. .AND. TIME .LT. 30. ) SC = .0-15 IF (TI M E .GE.42. .AND. TIME .LT. 48. ) SC = .0 45 RESP=(RC+ SCIKVVF ESTRD = FPIG - ( G D A * F P I G ) WG = E S T R D - H E S P V/ = V/ + WG TIME T I M E +1 e  OUTPUT  *  ROUTINES  a  131  FIGUBE 3 Graphs  o f the i n p u t  variables  f o r the  model.  131 a  132  Table simulation  Variable A AD BFCTR BFE BFOOD BFUD BFUDE BVUL DEPTH DP DT EASS ESTRD FA FPIG IFLG RESP RC RRR RRRH RRRL SC SFCTR SFE SFOOD SFUD SFUDE STFE SVUL TEH TEMP TFE TIM TIME TM TMTUR U  1. The meaning o f t h e FORTRAN  variables  used  i n the  model.  Meaning C o e f f i c i e n t i n the r e s p i r a t i o n r a t e c a l c u l a t i o n Weight o f f o o d d i g e s t e d p e r t i m e i n t e r v a l L a r g e prey a v a i l a b i l i t y c o e f f i c i e n t Number o f l a r g e p r e y e a t e n p e r time i n t e r v a l Large prey d e n s i t y A d j u s t e d l a r g e prey d e n s i t y Input d e n s i t y of l a r g e prey V u l n e r a b i l i t y c o e f f i c i e n t f o r l a r g e prey Depth Digestion rate Depth c o u n t e r f o r i n t e r p o l a t i o n Weight o f f o o d a s s i m i l a t e d per time i n t e r v a l Weight o f f o o d s t o r e d p e r t i m e i n t e r v a l Food a v a i l a b l e f o r a s s i m i l a t i o n Food p o o l i n t h e g u t F l a g f o r s w i t c h from f e e d i n g c y c l e t c d i g e s t i v e pause T o t a l weight c o s t p e r t i m e i n t e r v a l Respiration cost Respiration rate Upper i n t e r p o l a t i o n p o i n t i n t h e c a l c u l a t i o n o f ESR Lower i n t e r p o l a t i o n p o i n t i n t h e c a l c u l a t i o n o f RRR Swimming c o s t Small prey a v a i l a b i l i t y c o e f f i c i e n t Number o f s m a l l p r e y e a t e n per time i n t e r v a l Small prey d e n s i t y A d j u s t e d s m a l l prey d e n s i t y Input d e n s i t y f o r s m a l l prey Cumulative weight of f o o d eaten V u l n e r a b i l i t y c o e f f i c i e n t f o r s m a l l prey Temperature Temperature Weight o f a l l p r e y e a t e n p e r t i m e i n t e r v a l Time c o u n t e r f o r d e p t h i n t e r p o l a t i o n Time i n t e r v a l i n t h e s i m u l a t i o n Time c o u n t e r f o r t h e p r e y v u l n e r a b i l i t y i n t e r p o l a t i o n Temperature Mean o f t h e P o i s s o n d i s t r i b u t i o n i n EATIT  133  Variable VC W WBFE WG WSFE Z  Meaning Crop volume L a r v a l weight Weight o f l a r g e p r e y e a t e n p e r time G a i n i n w e i g h t p e r time i n t e r v a l Weight of s m a l l p r e y e a t e n p e r t i m e Depth  interval interval  134  Table in  2. The meaning, s o u r c e ,  and v a l u e o f t h e  parameters  t h e s i m u l a t i o n model.  Parameter  Units  Value  Source  Meaning  ALPH1  0.000128  Number p e r 100 l i t e r s per h o u r  Capture r a t e per u n i t l a r g e prey density during s e a r c h i n g time  Measured  ALPH2  0.000064  Number p e r 100 liters per hour  Capture r a t e per u n i t s m a l l prey density during s e a r c h i n g time  Measured  H1  0. 1  hours  H a n d l i n g time f o r l a r g e prey  S e c t i o n IV  H2  0. 30  hours  H a n d l i n g time f o r s m a l l prey  S e c t i o n IV  SDA  0.30  Specific action  Hypothetical  SEST  0.0015  mg  Initial stored  SFPG  0.0  mg  I n i t i a l food i n the gut  VCMAX  0. 16  mg  Maximum c r o p capacity  Measured  WBF  0.08  mg  Weight o f l a r g e prey  Measured  WF  0.00485  mg p e r minute  Conversion factor: oxygen consumed t o mg  Hargrave (1971)  WSF  0.006  mg  Weight o f s m a l l prey  Measured  WO  0. 15  mg  Initial  Hypothetical  dynamic weight  pool  weight  Hypothetical  Hypothetical  APPENDIX I I  FUNCTION YNT (TX,X,Y) DIMENSION X (20) , Y (20) 1=2 I F ( X ( I ) - T X ) 20,30,40 1=1+1  GO TC 19 YNT=Y (I) GO TO 50 YNT=Y ( 1 - 1 ) + ( (Y (I) -Y ( 1 - 1 ) ) * (TX-X (I-1) ) ) / (X (I) -X ( I - 1) ) RETURN END FUNCTION POIS (U) R=RANDV (0) XN=0. XNF=1. P = 0. E=EXP (-U) UN=1 P=P+UN*E/XNF IF(P.GF.R) GO TO 10 XN=XN+ 1. XNF=XNF*XN UN=UN*U GO TO 5 POIS=XN RETURN END THIS SUEROUTINE DRAWS A GRID FOR OUTPUT OF THE SIMULATION RESULTS. SUBROUTINE MOUT COMMON D1,SDA,WO,XMAX,YMAX,YMIN,TF,WF,SFPG,SEST,ALPH1 1,ALPH2,H1,H2,WBF,WSF,VCMAX,STFE,VC,FPIG,BFOOD,SFOOD,E 1 F E , S F E , FA, TEMP, TIME, Z (6) , TIM (6) , TEM (6) ,BFUDE(11) , SFUD 1E (11) ,RR (6) ,DP (6) , TMTUR (6) ,A (5) ,B (5) ,TMP (5) ,TM (6) , EVU 1L (6) ,SVUL (6) ,BFUD,SFUD, BFCTR,SFCTR,NPAR CALL CATSW (0,JQ) GO TC (3,4) ,JQ XSC = 6./XMAX YSC = 6./YMAX CALL SCALF (XSC,YSC,0.,0.) CALL FGRID (0,0.,0.,XMAX/30.,30) CALL FGRID (1,0.,0.,YMAX , 0)  x=o. Y=WO CALL FPLOT (-2,X,Y) IXMAX=XMAX DO UO I=1,IXMAX BEAD ( I ' l ) Y IF (Y-YMAX) 30,30,31 Y = YMAX IF (Y-YMIN) 33,34,34 Y = YMIN X=I CALL FPLOT (0,X,Y) CONTINUE CALL PENUP BETUBN END THIS SUBBOUTINE CONTAINS THE NECESSABY INSTRUCTIONS FOB MODIFYING THE INPUT PABAMETEBS. SUBROUTINE MMOD DIMENSION PAR (40) COMMON D1,SEA,WO,XMAX,YMAX,YMIN,TF,WF,SFPG,SEST,ALPH1 1,ALPH2 ,H1,H2,WBF,WSF,VCMAX,STFE,VC,FPIG,BFOOD,SFOOD,B 1FE,SFE,FA,TEMP,TIME,Z (6) , TIM (6) , TEM (6 ) , BFUDE (11) , SFUE 1E (11) ,RB (6) ,DP (6) , TMTUB (6) , A (5) , B (5) ,TMP (5) ,TM (6) , BVU 1L(6) ,SVUL(6) ,BFUD,SFUD,BFCTB,SFCTR,NPAB EQUIVALENCE (PAR(1),D1) M=6 TO CHANGE A PABAMETEB VALUE CALL E ATSW (1 , JQ) GO TO (1 1 ,20) , JQ WBITE (1,12) FORMAT (» ID/NEW VALUE') BEAD (M)IB,X PAR (ID)=X GO TC 10 TO CHANGE 'TIM' VALUES CALL EATSW(2,JQ) GO TO (21 ,30) , JQ WE IT E (1,22) FOBMAT ('NEW TIM VALUES') BEAD (M) (TIM (I) , 1=1,6) GO TO 20 TO CHANGE «Z' VALUES CALL D ATSW (3, JQ) GO TO (31,40) ,JQ WRITE(1,32) FOBMAT ('NEW Z VALUES') READ (M) (Z (I) ,1=1 ,6) GO TO 30 TO CHANGE 'TEM' VALUES CALL BATSW(4,JQ)  137  41 42  C... 50 51 52  C... 60 61 62  C... 70 71 72  C... 100 101 102  80 81 82  C... 90 91 92  C... 110 111 112  GO TO (41,50) ,JQ WRITE(1,42) FORM AT ('NEW TEM VALUES') READ (M) (TEM (I) ,1=1,20) GO TO 40 TO CHANGE 'EFUDE• VALUES CALL DATSW(5,JQ) GO TO (51 ,60) , JQ WRITE(1,52) FORMAT ('NEW LARGE FUDE VALUES') READ (M) (EFUDE(I) ,1=1,11) GO TO 50 TO CHANGE * SFUDE* VALUES CALL D ATSW (6, JQ) GO TC (61,70) ,JQ WRITE (1,62) FORMAT ('NEW SMALL FUDE VALUES') READ (M) (SFUDE (I) , 1 = 1 , 11) GO TO 60 TO CHANGE »A« VALUES CALL DATSW(7,JQ) GO TO (71, 100) , JQ WRITF(1,72) FORMAT ('NEW A VALUES') READ (M) (A (I) ,1=1 ,5) GO TO 70 TO CHANGE »B' VALUES CALL DATS W (9,JQ) GO TO (101 , 80) , JQ WRITE (1,102) FORMAT ('NEW B VALUES') READ (M) (B (I) ,1=1,5) GO TO 100 CALL DATSW (10,JQ) GO TO (81,90) ,JQ WRITE(1,82) FORMAT (' NEW DP VALUES') READ (M) (DP (I) ,1=1 ,6) GO TO 90 TO CHANGE *TM' VALUES CALL DATSW(11,JQ) GO TO (91 , 110) , JQ WRITE(1,92) FORMAT ('NEW TM VALUES') READ (M) (TM (I) , 1=1,6) GO TO 110 TO CHANGE 'BVUL' VALUES CALL DATSW (12,JQ) GO TO (1 1 1 , 120) , JQ WRITE(1,112) FORMAT ('NEW BVUL VALUES') READ (M) (BVUL (I) , 1=1,6)  138  C... 120 121 122 130  GO TC 120 TO CHANGE 'SVUL' VALUES CALL DATSW(13,JQ) GO TC (121,130) , JQ WRITE(1,122) FORMAT ('NEW SVUL VALUES') READ (M) (SVUL (I) , 1=1,6) GO TO 130 RETURN END  C... THIS SUBROUTINE CALCULATES THE NUMBER OF LARGE AND C... SMALL PREY EATEN PER TIME INTERVAL AND CALCULATES THE C. . .VOLUME OF THE CROP AFTER EATING. U IS THE CAPTURE RATE C... OF LARGE OR SMALL PREY CALCULATED FROM HCILING'S C... DISK EQUATION FOR TWO PREY TYPES. ALPH1 AND ALPH2 ARE C... CAPTURE RATES PER UNIT PREY DENSITY DURING SEARCH C... TIME. LFOOD AND SFOOD ARE THE PREY DENSITIES OF LARGE C... AND SMALL PREY. H1 AND H2 ARE HANDLING TIMES FOR LARGE C... AND SMALL PREY. WBF AND WSF ARE THE WEIGHTS OF LARGE C... AND SMALL PREY. POISS IS A FUNCTION WHICH GIVES THE C... NUMBERS OF LARGE AND SMALL PREY EATEN USING U AS THE C... MEAN OF A POISSON DISTRIBUTION AND A RANDOM NUMEER C... GENERATOR. SUBROUTINE EATIT COMMON D1,SDA,WO,XMAX,YMAX,YMIN,TF,WF,S FPG,S EST,ALPH1 1,ALPH2,H1,H2,WBF,WSF,VCMAX,STFE,VC,FPIG,EFCOD,SFOOE,E 1FE, SEE, FA, TEMP,TIME, Z (6) , TIM (6) , TEM (6) , BFUDE (1 1) , SFUD 1E(11) ,RR (6) ,DP (6) , TMTUR (6) , A (5) , B (5) ,TMP (5) ,TM (6) ,EVU 1L (6) ,SVUL (6) ,BFUD,SFUD, BFCTR,'SFCTR, NPAR BFCTR=YNT(TIME, TM, BVUL) BFUD=BFOOD*BFCTR SFCTR=YNT(TIME, TM, SVUL) SFUD=SFOOD*SFCTR U= (ALPH1*BFUD) / ( 1 + (ALPH1*BFUD*H1) + (ALPH2*SFUD*H2) ) BFE=POIS (U) U=(ALPH2*SFUD)/(1+ (ALPH1*BFUD*H1) + (ALPH2*SFUD*H2)) SFE=POIS (U) WBFE=WBF*BFE WSFE=WSF*SFE TFE=WBFE+WSFE IF (TFE.GT. (VCMAX-VC) ) TFE= (VCMAX-VC) VC=VC+TFE FA=FA+ (0.68*TFE) STFE=STFE+TFE RETURN END C... THIS SUBROUTINE CALCULATES THE AMOUNT DIGESTED FROM C... THE CROP DURING A TIME INTERVAL. SUBROUTINE DIGST COMMON D1,SDA,WO,XMAX,YMAX , YMIN,TF,WF,SFPG,SEST,ALPH1  1  39  1,ALPH2,H1,H2,WBF,WSF,VCMAX,STFE,VC ,FPIG,BFCOD,SFOOD,E 1 F E , S F E , F A , T E M P , T I M E , Z ( 6 ) , T I M ( 6 ) , T E M ( 6 ) , B F U D E ( 1 1) , S F U D 1 E ( 1 1) , B B (6) , D P ( 6 ) , T M T U R ( 6 ) , A ( 5 ) B ( 5 ) , T M P ( 5 ) , T M | 6 ) , B V U 1 L ( 6 ) , S V U L (6) , B F U D , S F U D , B F C T R , S F C T R , N P A B R  AD=YNT ( T E M P , T M T U R , DP) I F (AD.GT.FA) AD=FA FPIG= AE VC=VC-AD FA=FA-AD RETURN END C... C,..  C  C...  C... C... C...  400 510  T H I S SUBROUTINE DOES THE ACTUAL C A L C U L A T I O N S OF ENERGY G A I N S AND L O S S E S D U R I N G E A C H T I M E INTERVAL. SUBROUTINE DOIT (DF,DT, RTOT,H,ID) COMMON D1,SDA,WO,XMAX,YMAX,YMIN,TF,WF,SFPG,SEST,ALPH1 1,ALPH2 ,H1,H2,WBF,WSF,VCMAX,STFE,VC,FPIG,BFOOD,SFOOD,B 1 F E , S F E , F A , T E M P , T I M E , Z { 6 ) , T I M ( 6 ) , T E M (6),BFUDE ( 1 1 ) , S F U E 1 E ( 1 1 ) , R R ( 6 ) , D P ( 6 ) , T M T U R ( 6 ) , A ( 5 ) , B ( 5 ) , T M P ( 5 ) , TM ( 6 ) , B V U 1 L ( 6 ) , S V U L ( 6 ) , B F U D , S F U D , B F C T R ,S F C T R , NP A R INITIALIZE IFLG=1 NTEST-3 W=WO FPIG = SFPG ESTRE = SEST EASS =0. FA = 0. VC=0 . RTOT=0. STFE=0. LOOP AROUND T I M E I N T E R V A L S — 3 0 * 288 FIVE MINUTE INTERVALS ITEST=0 DO 2 0 0 K = 1 , 3 0 TIME=0. DO 105 J=1,72 DEPTH=YNT (TIME,TIM,Z) TEMP = YNT (DEPTH,DI,TEM) BFOOD= YNT ( D E P T H , D F , B F U D E ) SFOOC = YNT (DEPTH,DF,SFUDE) I F L G T R I G G E R S T H E P R O G R A M I N T O T H E F E E D I N G C Y C L E OR DIGESTIVE PAUSE (DIGESTIVE CYCLE ONLY). I T IS D E P E N D E N T ON T H E C R O P VOLUME. EFE=0. SFE=0. GO T O (400,510),IFLG CALL EATIT IF (VC.GE.VCMAX) IFLG=2 CALL DIGST I F ( F A . G T . O . ) GO T O 5 5 0 IFLG=1 VC=0.  >•  140  FA=0. C... ENERGY CALCULATIONS: ASSIMILATION, MAINTENANCE, C . . . STORAGE, GROWTH, AND RESPIRATION (RRR), 550 L=2 4 I F (TMP (L) -TEMP) 3,2,1 3 L=L+1 GO TO 4 2 RRR=EXP (A (L) ) *W**B (L) GO TC 5 1 RRRL=EXP (A (L-1))*W**B (L-1) RRRH=EXP (A (L) ) *W**B (L) RRR=RRRL+ ( (FRRH-RRRL) * (TEMP-TMP (L-1) ) ) / (TMP (L) -TMP (L- 1) ) GO TC 5 5 RC=RRR/3. SC=0.0 IF (TIME. GE. 24. .AND. TIME. LT. 30.) SC=.045 IF (TIME.GE. 42. .AND. TIME.LT. 48.) SC-.045 RESP= (RC+SC)*WF ESTR E= FPIG-(SDA*FPIG) WG= (ESTRD-RESP) W=W+WG TIME=TIME+1. CALL DATSW(15,JQ) GO TC (600,601) , JQ 600 WRITE(3,602) T1MB,DEPTH,TEMP,BFOOD,SFOOD,BFE,SFE,FPIG,FA, 1RRR, RESP, ESTRD, WG, W 60 2 FORMAT (1X,F11.0,9(1X,E10.'3)) WRITE (3,7 00) L,RRRL,BRRH,RRR, A (L) , B (L) ,TMP (L) ,TEMP 700 FORMAT (1X,11,7(5X,F1 0.4)) WRITE (3, 1000) VC,IFLG 1000 FORMAT (2X,»***', (F10.6) , » * * * » , 1 2 , ' * * * ' ) 601 CONTINUE RTOT=RTOT + RESP ITEST=ITEST+1 IF (MOE (ITEST,NTEST) .EQ.O) WRITE ( T I D ) W 105 CONTINUE 200 CONTINUE RETURN END  C... THIS IS THE MAINLINE PROGRAM WHERE ALL DATA INPUTS AND C... OUTPUTS ARE HANDLED. DIMENSION DT (20) , DF (11) ,PNAME (2) , PAR (40) COMMON D1,SDA,WO,XMAX,YMAX,YMIN,TF,WF,SFPG,SEST,ALPH1 1,ALPH2,H1,H2,WBF,WSF,VCMAX,STFE,VC,FPIG,BFOOD,SFOOD,B 1FE,SFE,FA,TEMP,TIME,Z (6) , TIM (6) , TE M (6 ) , BFUDE (1 1) ,SFUE 1E (11) ,RR (6) ,DP (6) , TMTUR (6) , A (5) , B (5) ,TMP (5) , TM (6) , BVU 11(6),SVUL(6),BFUD,SFUD,BFCTR,SFCTR,NPAR EQUIVALENCE (PAR(1),D1) DEFINE F I L E 1(730,2,U,ID) CALL P1130 M=6  READ IN PARAMETERS AND GRAPHS. READ (2,2) NPAR FORMAT (12) DO 120 1=1 , NPAR READ (2,104) K, PNANE,PAR(K) FORMAT (I3,7X,2A4,2X,F10.0) 104 WRITE(3,112) K, PNAME, PAR (K) FORMAT (3X,I2,1X,2A4,2X,E14.7) 112 CONTINUE 120 READ (2,100) (Z(I) ,1=1,6) READ (2,100) (TIM (I) ,1=1,6) READ (2,100) (TEM (I) ,1=1,20) READ (2,100) (DT(I) ,1=1,20) READ (2,100) (BFUDE (I) ,1= 1,11) READ (2,100) (SFUDE (I) ,1=1 , 11) READ (2,100) (DF(I),1=1,11) READ (2,100) (TMTUR (I) ,1=1 ,6) READ (2,100) (DP(I) ,1=1,6) READ (2, 100) (A(I),I=1,5) READ (2 ,100) (B (I) ,1=1,5) READ (2,100) (TMP (I) ,1=1,5) READ (2 ,100) (TM (I) ,1=1,6) READ (2,100) (BVUL (I) ,1=1 ,6) READ (2 ,100) (SVUL (I) ,1=1,6) 100 FORMAT (8F10.0) WRITE(3,602) Z WRITE(3,602) TIM WRITE(3,602) TEM WRITE(3,602) DT WRITE (3,602) BFUDE WRITE (3,602) SFUDE WRITE (3,602) DF WRITE (3,602) TMTUR WRITE (3,602) DP WRITE(3, 602) A WRITE (3,602) B WRITE (3,602) TMP WRITE(3,602) TM WRITE (3,602) BVUL WRITE (3,602) SVUL 800 PAUSE ID=1 READ (6, 333) C 333 FORMAT (F3.0) CALL RANDI (C) C...TO MODIFY INPUT CALL DATSW (8,JQ) GO TO (81 ,90) , JQ 81 CALL M MOD RTOT,W,ID) 90 CALL DOIT(DF,DT, WRITE (3,2000) W 2000 FORMAT (1X,'FINAL WEIGHT=',E14.7)  c..  142  P=W-WO RATIO= P/(P+RTOT) WRITE (3, 2001) RTOT ,P,RATIO 2001 FORMAT (30X,»RTOT = • , E 1 4 . 7 , 5 X , « P = ',E11.4,5X,'RATIO = », 1E14. 7) WRITE (3,3000) STFE 3000 FORMAT ( 5X,E12.5) CALL MOUT C,..TO MAKE ANOTHER RUN CALL DATSW (14,JQ) GO TO (800,801) , JQ 801 CALL EXIT 602 FORMAT (1X,10 (1X,F 10.4)) END EXECUTION TERMINATED T=5.40 DR=8  $SIG  

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