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UBC Theses and Dissertations

Growth and regulation of springtail populations, with special reference to predation by pseudoscorpions Johnson, Dan Lloyd 1980

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cl  GROWTH AND REGULATION OF SPRINGTAIL POPULATIONS, WITH S P E C I A L .REFERENCE TO PREDATION BY  PSEUDOSCORPIONS  by Dan L l o y d B.Sc,  Johnson  The U n i v e r s i t y o f S a s k a t c h e w a n ,  1978  A THESIS SUBMITTED I N PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER  OF SCIENCE in  THE FACULTY OF GRADUATE STUDIES (Department o f P l a n t S c i e n c e and The I n s t i t u t e  of Animal Resource Ecology)  We a c c e p t t h i s t h e s i s a s c o n f o r m i n g to the reguired  standard  THE UNIVERSITY OF B R I T I S H COLUMBIA (5}  Dan L l o y d J o h n s o n , 1980  In  presenting this  thesis  an a d v a n c e d d e g r e e a t the L i b r a r y I further for  agree  the U n i v e r s i t y  make  it  freely  written  thesis for  The  of  University  P  of  1  a  r  y  K  August 29,  c ,  British  1980  M  .  .  0  Columbia  requirements  for  I agree  r e f e r e n c e and copying of  this  that  not  for  that  study. thesis  t h e Head o f my D e p a r t m e n t  is understood  n  the  B r i t i s h Columbia,  by  financial gain shall  2075 W e s b r o o k P l a c e V a n c o u v e r , Canada V6T 1WS  Date  It  permission.  Department  of  that permission for extensive  representatives.  this  fulfilment of  available  s c h o l a r l y p u r p o s e s may be g r a n t e d  by h i s of  shall  in p a r t i a l  or  copying or p u b l i c a t i o n  be a l l o w e d w i t h o u t  my  ABSTRACT  The  effects  o f p r e d a t i o n by a p s e u d o s c o r p i o n ,  m i n i m u s , on g r o w i n g  p o p u l a t i o n s of s p r i n g t a i l s , F o l s o m i a  A n a l y s i s of i n d i v i d u a l s p r i n g t a i l  provided a technique  P r e d a t i o n r a t e s and  f o r determining  I t was  i n d i v i d u a l s and  t h a t t h i s p r e f e r e n c e may  of p r e y  dispersal,  predator  shown t h a t t h e p r e d a t o r s p r e f e r o l d e r  prey  r e s u l t i n higher  population dynamics, p o p u l a t i o n d i s t r i b u -  s p e c i e s c o m p o s i t i o n of the  c o m m u n i t y i n t h e s t u d y a r e a , s o i l m o i s t u r e and provided.  age.  juveniles.  B a s e l i n e d a t a on tions,  prey  t h e d e g r e e o f s i z e - s e l e c t i o n by t h e  were m e a s u r e d .  densities  Candida,  -  were s t u d i e d e x p e r i m e n t a l l y . growth over time  Apochthonius  microarthropod w e a t h e r were  TABLE OF CONTENT'S  ABSTRACT  i  L I S T OF TABLES  . . v i  L I S T OF FIGURES  . . . i x  ACKNOWLEDGEMENTS  xiii  INTRODUCTION General  i  1  Biology.....................................  4  CHAPTER ONE: A COMMUNITY SETTING FOR POPULATION STUDIES.... 8 Introduction  .....9  Methods Results  9 and D i s c u s s i o n . . . . .  11  D e n s i t i e s and d y n a m i c s . . ............................. 11 Distributions.  CHAPTER TWO:  ...........................13  POST-EMBRYONIC GROWTH OF THE COLLEMBOLANS,  FOLSOMIA CANDIDA AND XMXi±I.A G R I S E A, AT THREE TEMPERATURES ..r, Introduction. Methods Results  ...,i6 ... 17  . . . ... and D i s c u s s i o n . . . . . . . . . . . . . . .  L e n g t h a n d age  18 20 20  C o m p a r i s o n o f l e n g t h - a g e r e g r e s s i o n l i n e s . . . . . . . . . . . . 27 Tests of slopes:  do t h e g r o w t h p a r a m e t e r s d i f f e r ? . . . . 2 8  Tests of intercepts:  do t h e l e n g t h s a t h a t c h i n g differ?  30  Head w i d t h  30  L i n e a r and n o n - l i n e a r e f f e c t s o f t e m p e r a t u r e  34  Development  o f an a g i n g t e c h n i g u e  .......36  CHAPTER THREE: PREDATION OF AP0CHTH0NI0S M I N I M S (PSEUDOSCORPIONIDA: CHTHONIIDAE) ON FOLSOMIA (C0LLEM50L A: ISOTOMIDAE) . .  CANDIDA  I . . PREDATION AND S I Z E -  SELECTION  38  Introduction.•..........................................39 B i o l o g y o f t h e p r e y a n d p r e d a t o r . . . . . . . . . . . . . . . . . . . . . 41 F p l s o m i a Candida  41  A p o c h t h g n i u s minimus. Methods  ... 43 .  44  I . . P r e d a t i o n r a t e s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 II.  Size-selection..............  ...47  R e s u l t s and D i s c u s s i o n . .  43  I . . P r e d a t i o n r a t e s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 I I . . S i z e - s e l e c t i o n by t h e p r e d a t o r s . . . . . . . . . . .  CHAPTER  .57  FOUR: PREDATION OF APOCHTHONIUS MINIMUS  (PSEUDOSCORPIONIDA: CHTHONIIDAE) ON FOLSOMIA (COLLEM BOL A: ISOTOMIDAE).. PREY POPULATIONS  CANDIDA  I I . . EFFECTS OF PREDATION ON 64  Introduction............................................65 Methods.  ......66  R e s u l t s and D i s c u s s i o n .  ......68  V  Uncontrolled environmental  Interpretation  v a r i a b l e s . . . . . . . . . . . . . . . . . 68  of length-freguency  d i s t r i b u t i o n s . . . . . 70  SUMMARY  83  L I T ER AT UR E CITED.  ......85  APPENDIX A: C a l i b r a t i o n  of the Extractor  APPENDIX B: Abundance and D i s t r i b u t i o n Microarthropods Part  a t t h e UBC R e s e a r c h  102  of S o i l  F o r e s t , 1979  ... 104  I . . Population densities.  .104  P a r t I I . _ D i s t r i b u t i o n s . . . . . ........................... 120 APPENDIX C: S o i l  Moisture  APPENDIX D: R a i n f a l l Study S i t e During  a t t h e Study S i t e During  and D a i l y  Mean T e m p e r a t u r e s a t t h e  1979  APPENDIX E: O r t h o g o n a l  1979..135  .. 139  Contrast Coefficients  APPENDIX F: D i s p e r s a l o f F. C a n d i d a  142  ..........144  vi  L I S T OF TABLES  Table  1.  Regressions of ln(length)  a n d l n (age)  c o r r e s p o n d i n g t o F i g u r e s 5 and 6............... 25  Table  2a.. Slope comparisons  within  species f o r a l l pairs of  temperatures  T a b l e 2b.. S l o p e c o m p a r i s o n s  ..29  between s p e c i e s a t  each......29  temperature.  T a b l e 3a.  I n t e r c e p t comparisons  within species f o r a l l  p a i r s of temperatures........  T a b l e 3b.. I n t e r c e p t c o m p a r i s o n s  ...31  between s p e c i e s  31  Table 4a.  R e g r e s s i o n f o r F. C a n d i d a  T a b l e 4b.  R e g r e s s i o n f o r X. g r i s e a . . . . . . . . . . . .  ...35  Table  A n a l y s i s o f v a r i a n c e o f t h e number o f p r e y  eaten.  i n t h e f u n c t i o n a l response  ...51  5..  T a b l e 6..  Orthogonal tests)  35  experiment  c o n t r a s t s ( i n d i v i d u a l degree  o f freedom 52  711  Table  7.  Estimates  o f h a n d l i n g time  (a) f o r d i f f e r e n t  prey  (Th) and a t t a c k r a t e  s i z e and  treatments  Table  8.  Selectivity  temperature  ...................53  statistics  f o r l e n g t h c l a s s e s of prey. 60  Table  9.  D e s c r i p t i o n of the f i n a l of  Table  10.  populations  and  t h e c o n t a i n e r s a t t h e end o f t h e e x p e r i m e n t . . . 6 9  Relative frequencies different  sizes  (% o f t o t a l )  o f F. C a n d i d a  of the  i n t h e 16  populations..  Table  contents  75  B1.  Distribution  of Folsomia  sp  121  T a b l e B2.  Distribution  o f A f i o c h t h o n i u s minimus a d u l t s . . . . 122  Table  B3.  Distribution  o f Apochthonius  Table  B4.  Distribution  of Isotomids  minimus nymphs.... 123  other  than  F o l s o m i a . ..124  spp.  Table  B5. . D i s t r i b u t i o n  o f H y p o g a s t u r i d s . . . . . . . . . . . . . . . . . . 125  Table  B6. . D i s t r i b u t i o n  of Onychiurids  Tullbergia  sp.)  (other  than 126  viii  T a b l e B7. . D i s t r i b u t i o n o f T u l l b e r q i a  sp......  127  T a b l e B8.  D i s t r i b u t i o n of Entomobryids.  .128  T a b l e B9.  D i s t r i b u t i o n o f L e p i d o c y r t u s spp................  o f T o m o c e r u s spp  129  T a b l e B10._  Distribution  T a b l e B11..  D i s t r i b u t i o n o f Neanura  131  T a b l e B12.  D i s t r i b u t i o n of Sminthurids. .  132  T a b l e B13.  Distribution  133  T a b l e B14..  D i s t r i b u t i o n of Chilopods  of Mesostigmata  Table C I . . S o i l moisture a t t h r e e depths September cm  T a b l e C2.  Table E1..  1979.  134  f r o m May  Water l o s s i s f r o m  2.5  to cm  x  5.0  dia cores  1 36  Mean w e i g h t s o f s o i l s a m p l e s . 2.5  .....130  cm  x 5.0  Orthogonal  cm  Ml  dia cores  contrast  coefficients..  s a m p l e s were 138  .....143  ix  LIST OF FIGURES  Figure  1.  The harmony o f t h e p e d o s p h e r e  Figure  2a. R e p r e s e n t a t i v e collected (lengths  Figure  (lengths  Figure  springtails similar  i n the survey  i n the survey  s i m i l a r t o those  part of t h i s  5.  study  1-2 mm).  A high-gradient the  Figure  5  ...........6  3.. The U n i v e r s i t y o f B r i t i s h C o l u m b i a  4.  study  1-3 mm).....  F o r e s t , Maple R i d g e ,  Figure  t o those  part of t h i s  2b. More r e p r e s e n t a t i v e s p r i n g t a i l s collected  2  Research  B.C  10  Macfadyen e x t r a c t o r s i m i l a r t o  one u s e d i n t h i s  study.  12  Le.ngth-age r e l a t i o n s h i p s f o r F. C a n d i d a  reared  under t h r e e temperature regimes.......  Figure  6.  L e n g t h - a g e r e l a t i o n s h i p s f o r X. g r i s e a under t h r e e t e m p e r a t u r e r e g i m e s . . .  Figure  7.. The d e c r e a s e w i t h a g e i n t h e head w i d t h length (b)  r a t i o s of F..Candida  22  reared ......24  / body  (a) and X . . g r i s e a 33  X  Figure  8.. S c a n n i n g e l e c t r o n m i c r o g r a p h o f an A- m i n i m u s  adult  The h i n g e d ,  40  Figure  9.  s e r r a t e d c h e l i c e r a e o f A. minimus. ..45  Figure  10..Type I I f u n c t i o n a l r e s p o n s e c u r v e s t e m p e r a t u r e s and two p r e y  Figure  sizes  55  11. C h a n g e s i n t h e number e a t e n p e r 12 h o u r s changes i n prey  Figure  f o r t h e two  12. S i z e f r e q u e n c y  d e n s i t y , prey  s i z e and t i m e . . . . . 5 6  d i s t r i b u t i o n o f prey  a v a i l a b l e t o A. minimus and t h e p r e y  Figure  1 3 . . T a c t i l e setae  of the " p i n c e r "  with  population e a t e n . . . . . . 58  (palpal or chelal  hand) o f A. m i n i m u s  Figure  14. The l e n g t h - f r e q u e n c y populations  61  d i s t r i b u t i o n s of the four  that survived the predation  treatment  Figure  15. The l e n g t h - f r e q u e n c y  ................71  d i s t r i b u t i o n of the eight  control populations  Figure  B1. T o t a l C o l l e m b o l a  ..72  ,  ...105  xi  Figure  B2.  Folsomia  nivalis,  F. q u a d r i o c u l a t a ,  F. Candida  ....106  {Family I s o t o m i d a e )  Figure  B3.  Appchthonius  minimus,, a d u l t s  Figure  B4.  Apochthonius  minimus, nymphs.................. 108  Figure  B5..Isotomurus I*  Figure  palustris,  Isotoma  olivacea, I. viridis  B6. F a m i l y  Figure  Hypogastruridae.  Isotomidae)....  Includes  B7.,Onychiurus  flayescens, 0 . ghoreutes  Onychiuridae,  Hypoqastrura  H. y i r g o ,  Xenylla  B8. T u l l b e r g i a  Subfamily  sp.  (Family  armatus, (rare)  (Family  Onychiurinae)  Onychiuridae,  111  Subfamily  Tullbergiinae)  Figure  B9. Entomgbrya E.  ..112  guadralineata,  E.  comjoarata, E. i n t e r m e d i a  (Family  Figure  109  and X . . s p . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110  Lophognathella  Figure  trispinata,  (Family  pseudarmata, H . . v u l g a r i s , grisea  107  and E.  nivalis  Entomobryidae)  B10. L e p i d o c y r t u s (Family  multifasciata,  cinereus,  113  L . liqnorum  and L . s p .  E n t o m o b r y i d a e ) . . . . . . . . . . . . . . . . . . . . . . . . 114  xii  Figure  B11•  Tofflocerus e e l s u s ,  Entomobryidae,  T. s p .  (Family  Subfamily  Figure  B12. . Neanura  Figure  B13.  Figure  B14. . U n i d e n t i f i e d  mesostigmatid  Figure  B15.. U n i d e n t i f i e d  Chilopoda  Figure  D1.  Family  persimilis  Tomocerinae)  period,  (Family Neanuridae)  Sminthuridae  Rainfall  a t the study  D2.  Daily  Figure  F1.  The d i s p e r s a l  mites....-  ....118  (>2mm w i d t h ) . . .  site  mean t e m p e r a t u r e  tray  116  .....................117  May t o September,  Figure  115  119  during the sampling  1979  140  a t the study s i t e .  used  described  i n A p p e n d i x F.  141  i n the experiments  Figure  F2.  Dispersal  over  two h o u r s ;  Figure  F3.  Dispersal  o v e r two h o u r s ;  Figure  F4.  Dispersal  over t w e n t y - f o u r  (top v i e w ) . . . .  no f o o d i n a r e a  food i n area  hours;  1  145  1...148  149  nc f o o d . . . . . 1 5 0  ACKNOWLEDGEMENTS I am g r a t e f u l f o r D r . W.G. my m a s t e r ' s p r o g r a m .  Wellington's  H i s concern,  supervision  generosity  during  and p h i l o s o p h i c a l  g u i d a n c e were e s p e c i a l l y a p p r e c i a t e d . I  t h a n k D r . V.G. M a r s h a l l  f o r p r o v i d i n g me w i t h Dr.  A. C a r t e r  Dr.  G.W.  my o r i g i n a l s t o c k  k i n d l y leaned  me e x t r a c t i o n e q u i p m e n t .  spaced d e n s i t i e s i n Chapter Three. m i c r o g r a p h s i n t h e same c h a p t e r  D. H e n d e r s o n . . D r . E . J 3 . B e n e d i c t PhD.  provided  The  with Collembola  K. C h r i s t i a n s e n .  scanning  a r e t h e work o f a copy o f her  t h e s i s and o f f e r e d h e l p i n i d e n t i f y i n g  Assistance Dr.  o f F. C a n d i d a .  Eaton c a l c u l a t e d t h e c o n t r a s t c o e f f i c i e n t s f o r t h e  unegually electron  f o r h i s h e l p f u l s u g g e s t i o n s and  pseudoscorpions.  taxonomy was p r o v i d e d by  The w i l l i n g t e c h n i c a l a s s i s t a n c e o f S t e v e  G o r m i c a n was b o t h i n v a l u a b l e a n d e n j o y a b l e .  I am g r a t e f u l t o t h e  s t a f f o f t h e OBC R e s e a r c h F o r e s t f o r t h e i r f r i e n d l y permission  t o e s t a b l i s h a study  s e r v i c e and  site.  I e s p e c i a l l y want t o t h a n k my w i f e , C a t h y J o h n s o n , f o r h e r h e l p , encouragement and  understanding.  C o m p u t e r f u n d s were p r o v i d e d Dr. . W e l l i n g t o n Ecology. University  b y a NSERC g r a n t t o  a n d , i n p a r t , by t h e I n s t i t u t e  I was s u p p o r t e d of B r i t i s h  by a g r a n t  o f Animal Resource  t o Dr. W e l l i n g t o n , a  C o l u m b i a G r a d u a t e F e l l o w s h i p and a  Department o f P l a n t Science  Teaching A s s i s t a n t s h i p .  1  INTRODUCTION  F o r a t l e a s t a c e n t u r y , e n t o m o l o g i s t s h a v e been t r y i n g discover  what p r e v e n t s t h e u n l i m i t e d g r o w t h o f  populations.  I n more r e c e n t d e c a d e s  insect  t h e same g u e s t h a s  been  d i r e c t e d t o w a r d a l l manner of c r e a t u r e s t h a t i n h a b i t t h e f r o m mice  t o whales.  to  T h e o r i e s , a c r i m o n i o u s d e b a t e s and  earth, violent  c o n t r o v e r s i e s have e b b e d and f l o w e d o v e r t h e i m p o r t a n c e o f p a r a s i t i s m , p r e d a t i o n , weather, g e n e t i c feed-back polymorphism,  behavior, dispersal,  mechanisms,  food a v a i l a b i l i t y ,  pathogens,  c o m p e t i t i o n and a h o s t o f o t h e r f a c t o r s and i n t e r a c t i o n s t h e o r i e s a r e r e v i e w e d i n a r e a d a b l e way 1973 a n d P r i c e , even  1975).  by A n d r e w a r t h a  (the  and  With such a m u l t i t u d e of t h e o r i e s ,  Birch, and  g r e a t e r a c c u m u l a t i o n o f e v i d e n c e f o r we know n o t what, a  an new  i d e a seems t o be a l m o s t i m m e d i a t e l y c r u s h e d by t h e l o a d o f favorite  hypotheses t h a t has b u i l t  finding a relatively possibilities  untouched  up.  In such c i r c u m s t a n c e s ,  system t h a t o f f e r s i n t e r e s t i n g  seems an a l m o s t i m p o s s i b l e  dream.  N e v e r t h e l e s s , I b e l i e v e t h a t t h e system d e s c r i b e d here i s worth a second population predator assembled Appendix  look.  The b u l k o f t h i s t h e s i s c o n c e r n s t h e  r e l a t i o n s h i p s b e t w e e n a s p r i n g t a i l s p e c i e s and i t s  (Figure  1).  In the f o l l o w i n g  a community s e t t i n g B);  pages I h a v e : ( i )  f o r the study  ( C h a p t e r One  ( i i ) s t u d i e d the growth of i n d i v i d u a l  springtails  a n d i n so d o i n g d e v e l o p e d a t e c h n i q u e t o d e t e r m i n e t h e i r ( C h a p t e r Two); characterized  (iii)  quantitatively  and  and  ages  qualitatively  s i z e - s e l e c t i v e p r e d a t i o n o f the s p r i n g t a i l s  by  new  F i g u r e 1.  The harmony o f t h e p e d o s p h e r e .  T h i s s t u d y f o c u s e s on t h e r e l a t i o n s h i p b e t w e e n t h e s p r i n g t a i l ( p l a y i n g t h e oboe) and t h e p s e u d o s c o r p i o n ( o n c e l l o ) . (From S a t c h e . l l , 1 9 7 7 )  3  pseudo-scorpions  ( C h a p t e r T h r e e ) , and  (iv) experimentally  demonstrated the e f f e c t of t h i s predation populations confined Instead  on g r o w i n g  i n containers i n the f i e l d  of s l i p p i n g  springtail  (Chapter  i n t o a K e p l e r i a n d i s c o u r s e on  twist  and  t u r n o r e v e r y f a i l u r e and t r i u m p h o f my  shall  l e t the c h a p t e r s which f o l l o w  Four).  every  research,  speak f o r t h e m s e l v e s . .  I  4  General  Biology  S p r i n g t a i l s are s m a l l , wingless i n s e c t s (although they soon l o s e . t h i s t a x o n o m i c s t a t u s and that inhabit s o i l f r o m a few  and  litter..  hundred to  1/2  move i n t o t h e i r  N e a r l y any  m i l l i o n per  of m i t e s ,  pseudoscorpions,  Although overlooked  square meter of  they  occur  mainly  centipedes  and  reduced  open a i r .  fungi,  some i n s e c t  the i n t e n s i t y  variety  are  often  aversion to bright  i n the s o i l  of n a t u r a l s e l e c t i o n  that  larvaei  i n high d e n s i t i e s , Collembola  Their confinement  yield  soil  i n t u r n a r e f e d upon by a  b e c a u s e o f t h e i r c r y p t i c h a b i t s and  s u n l i g h t and has  Springtails  subclass)  ecosystem w i l l  s u r f a c e . . They f e e d on v a r i o u s m i c r o o r g a n i s m s , inhabit detritus..  own  may  on  and  litter  springtails.  They a r e s o m e t i m e s r e f e r r e d t o a s t h e most p r i m i t i v e i n s e c t since they c l o s e l y  resemble t h e i r  changed so  i n f a c t , t h a t a l l t h e y have t o show f o r n e a r l y  300  little,  Devonian ancestors.  order  m i l l i o n y e a r s o f e v o l u t i o n i s the a d d i t i o n of  segments  (Kuhnelt,  p h y s i o l o g y and  the c u t i c l e i s important interface  l,  advanced" i n s e c t s i n  morphology.  such  i t s qualities  r e l a t i v e r e s i s t a n c e or s u s c e p t i b i l i t y Except  One  difference in  because c u t i c l e i s t h e i n s e c t ' s  w i t h t h e e n v i r o n m e n t , and  onslaughts.  antennal  1961)..  S p r i n g t a i l s d i f f e r f r o m more development*  two  They h a v e  to  environmental  f o r t h e more h i g h l y e v o l v e d  s p r i n g t a i l s h a v e no t r a c h a e l s y s t e m and  determine  Sminthuridae,  t h e r e f o r e must  cutaneously.  T h i s t y p e o f r e s p i r a t i o n demands  permeability,  a h i g h s u r f a c e t o volume r a t i o , and  respire  cuticle an a b s e n c e  of  Figure 2a. Representative s p r i n g t a i l s s i m i l a r to those c o l l e c t e d i n the survey part of this study. (lengths 1 - 3 mm) a. )  Isotomurus p a l u s t r i s (Muller) 1776 ( i l l u s t r a t i o n from Folsom, 1937)  b. ) Isotoma andrei M i l l s , 193*1( I l l u s t r a t i o n from M i l l s ,  1934)  c. )  Isotoma v i r i d i s Bourlet, I839 ( " I l l u s t r a t i o n from Wade, 1954)  d. )  Entomobrya n i v a l i s (Linne) 1758 ( i l l u s t r a t i o n from Maynard, 1951)  e. ) Entomobrya comparata Folsom, 1919 ( i l l u s t r a t i o n from Folsom, 1919)  Figure 2b. More representative s p r i n g t a i l s s i m i l a r to those c o l l e c t e d i n the survey part of t h i s study, (lengths 1 - 2 mm) a. ) Onychiurus armatus Folsom, 1917 ( i l l u s t r a t i o n from Folsom,  1917)  b. ) Folsomia C a n d i d a Willem, 1902 [= F. f i m e t a r i a (Linnaeus)] ( i l l u s t r a t i o n from Wade, 195*0 c. ) Lepidiocyrtus cyaneus Tullberg, I87I ( i l l u s t r a t i o n from Maynard, 1951) d. )  Sminthurus purpurescens (MacGillivray) 1894 ( i l l u s t r a t i o n from Maynard, 1951)  e. ) B o u r l e t i e l l a r u s t i c a Maynard, 1951 ( i l l u s t r a t i o n from Maynard, 1951)  7  & - i m p e r m e a b l e e p i c u t i c l e and a n e a r a b s e n c e o f e x o c u t i c l e (Chapman,  1975).  To s u r v i v e , t h e r e f o r e s p r i n g t a i l s ' m u s t  surrounded  by h i g h h u m i d i t y .  Isotomidae  t o which  Many s p r i n g t a i l s  Folsomia Candida  belongs)  by a r e l a t i v e h u m i d i t y b e l o w 9 0 % a t n o r m a l (Bellinger,  1954).  They a r e a l s o k i l l e d  t e m p e r a t u r e s , e v e n when n e t w a t e r  be  (especially the are guickly  field  killed  temperatures  by m o d e r a t e l y  high  l o s s i s net a p p r e c i a b l e .  C o n s i d e r i n g t h e l a r g e numbers t h a t a r e l o s t t o p r e d a t i o n , t h e number t h a t p e r i s h d u r i n g t h e i r f r e g u e n t m o l t s , a n d t h e n a r r o w range  of environmental c o n d i t i o n s they can t o l e r a t e , i t i s  s u r p r i s i n g t h a t they s u r v i v e i n nature at a l l . . But they s u r v i v e , and w i t h g r e a t s u c c e s s .  I n a r e a s around  do  Vancouver, I  commonly f i n d  them a t d e n s i t i e s o f 5,000 t o 50,000 p e r m .  also flourish  i n harsh environments,  2  I s l a n d s and on m o u n t a i n t o p s , able to survive. and  the following  (Mani,  Arctic  where few a n i m a l s o f any k i n d a r e  A t 6800 m i n t h e H i m a l a y a s ,  m i t e s a r e common In  such as t h e High  They  only  springtails  1968)..  c h a p t e r s , o t h e r a s p e c t s and d e t a i l s o f  s p r i n g t a i l b i o l o g y and e c o l o g y  a r e d i s c u s s e d as r e g u i r e d .  CHAPTER  ONE  COMMUNITY SETTING FOR POPULATION  STUDIES.  9  INTRODUCTION  Since  little  i s known a b o u t t h e i n v e r t e b r a t e s i n t h e  community i n t h i s a r e a , s t u d y s u r v e y of relative provide  what s p e c i e s a r e seasonal  this  must be  present  during  and  importance i n the  background i n f o r m a t i o n  Research Forest, I monitored s o i l  prefaced how  with a  general  they change  community. f o r my  their  In order  study  soil  to  s i t e at the  microarthropod  UBC  populations  1979. .  Specific vegetation  and  f e a t u r e s of o t h e r  s i t e c h a r a c t e r i s t i c s , such  weather, are noted i n f o l l o w i n g chapters  as  where  relevant. .  METHODS Objectives:  t o c h a r a c t e r i z e the  community i n a n a t u r a l s i t e distributions create  and  and  soil  microarthropod  to guantify the d e n s i t i e s ,  d y n a m i c s of t h e  major s p e c i e s  a s e t t i n g i n which m e a n i n g f u l p o p u l a t i o n  i n order  to  studies could  be  developed. . The  site  with a corner (Mirb.)  i s a square c o n s i s t i n g of tree, i n a  Franco) p l a n t i n g  12 9'  X 9*  blocks,  19 59 D o u g l a s - f i r  (Pseudotsuqa  (Figure 3).  soil  The  each  menziesii  type i n the  area  is dystric brunisol. I  sampled the  site in a stratified  random s a m p l i n g p l a n .  On  THE  UNIVERSITY OF  BRITISH  COLUMBIA  RESEARCH FOREST MAPLE RIDGE,  F i g u r e  3.  B.C.  11  each  s a m p l i n g date t w e l v e c o r e s , each  consisting of three  were r e m o v e d . . S i x c o r e s were t a k e n f r o m site  and s i x f r o m t h e s o u t h e r n h a l f .  were d e t e r m i n e d  layers,  the n o r t h e r n h a l f  The  of the  p o s i t i o n s of the  cores  by a s e t o f random numbers c o m p u t e d f o r t h e  purpose. A t o t a l o f 36 2.5 s i x sampling dates.  X 5 cm  Data  soil  c o r e s was  from e a r l i e r  collected  sample d a t e s  d i s c a r d e d b e c a u s e o f c h a n g e s i n t e c h n i g u e and  The  and  c a l i b r a t i o n and o p e r a t i o n o f t h i s e x t r a c t o r  d e t a i l e d i n Appendix I identified and  were c h e c k e d  and  the e x t r a c t e d specimens  work.  The  corrected  C h r i s t i a n s e n , a well-known  of about  under a  1000  dissecting  specimens  where n e c e s s a r y by Dr.. K.. C o l l e m b o l a t a x o n o m i s t and  B e c a u s e o f an u n f o r e s e e n  dynamics  d e l a y i n t h e p u b l i c a t i o n of a  key t o t h e C o l l e m b o l a o f N o r t h A m e r i c a Dr..P. B e l l i n g e r ,  a l l the specimens  to species.  them i n t o c l a s s e s o f s e v e r a l s i m i l a r genus o r s u b f a m i l y .  The  ecologist.  DISCUSSION  D e n s i t i e s and  Dr. C h r i s t i a n s e n and  for  i d e n t i f i c a t i o n s o f some o f t h e s e  RESULTS AND  comprehensive  are  A.  prepared s l i d e s  f u r t h e r taxonomic  indentify  cooler  The  f o r s i x days i n a Macfadyen h i g h - g r a d i e n t e x t r a c t o r  (Figure 4 ) .  microscope  of  were  location..  c o r e s were t r a n s p o r t e d t o t h e l a b i n an i n s u l a t e d extracted  a t each  I was  by  not able to  Consequently,  I  grouped  s p e c i e s , u s u a l l y i n one  abundance of each  o f 11  such groups  of  12  a. b. c. d. e. f.  Upper surface of heater assembly; g. Chimney; h. Ceramic insulator for heating element; Lower surface of heater assembly; i. Supporting rail for sample rack; j. Sample of soil; k.  Bakelite cylinder containing soil; Sample rack containing twelve samples in circular holes staggered in two rows: Aluminium canister; Cold water bath in raised position; Cold water bath in lowered position.  Figure A h i g h - g r a d i e n t Macfadyen e x t r a c t o r s i m i l a r t o t h e one u s e d i n t h i s s t u d y . ( I l l u s t r a t i o n f r o m M a c f a d y e n , 1961.)  13  Collembola dates are  and  their  p r e d a t o r s at t h r e e depths  shown i n A p p e n d i x B,  these data  as an a p p e n d i x  m a j o r p a r t o f my this thesis.  F i g u r e s B1  and  s i x sampling  t o B14.  I include  because, although the survey  took  a  t i m e , i t does not c o n s t i t u t e a major p a r t o f  Surveys  have g e n e r a l l y l o w e r i n f e r e n c e v a l u e  than  experiments. Soil  moisture  was  c a l c u l a t e d f o r t h e 216  shown f o r t h e t h r e e d e p t h s Comparisons of these  d a t a and  the d e n s i t y histograms drought  of  1979  Collembola sampling  and  s i x dates i n Appendix  (Appendix  were p r e s e n t i n t h e  B)  ( F i g u r e B7) , and  Relatively  F o l s o m i a spp.  Neanura  d u r i n g t h e d r y p e r i o d , p r o b a b l y due heavy  C.  show t h e e f f e c t o f t h e  upper l a y e r a t the  d a t e . . Somes s p e c i e s , l i k e S  is  the weather data i n Appendix D w i t h  on t h e s o i l m i c r o f a u n a .  O l l l S k i i i i i J s PP«  s o i l s a m p l e s and  few  August 8 (Figure B2),  ( F i g u r e B12)  to vertical  summer  disappeared  m i g r a t i o n and/or  mortality. It  w o u l d o f c o u r s e be r i s k y t o b a s e e x t e n s i v e  i n t e r p r e t a t i o n s on mere c o r r e l a t i o n s b e t w e e n d e n s i t i e s and (e.g.  F i g u r e s B2, B3  (whether  significant  m o i s t u r e , o r p r e d a t o r and and  B4).  prey  not)  densities  These d a t a a r e , however,  background f o r the p o p u l a t i o n s t u d i e s t o  or  useful  follow.  Distribution Part in  the  of t h e problem  of i n t e r p r e t i n g data such  h i g h e s t i m a t e v a r i a n c e s caused  distributions.  by u n e v e n  I n order t o c h a r a c t e r i z e the  as t h e s e  spatial  spatial  lies  distributions B1 t o B14  o f t h e g r o u p s whose d e n s i t i e s a r e shown i n F i g u r e  (Appendix  B) , I i n c l u d e d mean v a r i a n c e r a t i o s  s p e c i e s g r o u p a t each d e p t h to  B14.  The  and  be  with a Poisson d i s t r i b u t i o n . inability  distribution. relatively  ratio  greater than  since  (1978) h a s  can  be  ~ ) ( with 2  f o r sample s i z e  2  ratios,  the type of d i s t r i b u t i o n  indicated  show s / x  p(  2  d a t a t o do  some c a s e s , a s  ( T a b l e s B2 and  B 3 ) , we  random d i s t r i b u t i o n indication  Elliot tests.  ( w i t h 11 d f )  Such d a t a a r e o f t e n f i t t e d  so w i t h a d e g u a t e  with Apochthonius may  and  but  to  show the  i n t h i s case  there  confidence. require great  m i n i m u s nymphs and  care.  adults  i n t e r p r e t a change f r o m c o n t a g i o u s  i n an e c o l o g i c a l s e n s e :  t h a t the animals  2  2  most o f t h e t a x o n - l e v e l - d a t e c o m b i n a t i o n s  distribution.  2  ( a t <*S. = .05) .  I n t e r p r e t a t i o n s of s p a t i a l d i s t r i b u t i o n s In  ~X  "X  A high  making t h e s e  values  ubiguitous negative binomial d i s t r i b u t i o n , a r e t o o few  X  n, i s an  distribution.  (1977) p r e s e n t s a u s e f u l g r a p h f o r g u i c k i y  a contagious  A  whereas a  \) d e g r e e s o f f r e e d o m . , A low  a c o n t a g i o u s , or aggregated,  expected,  is  i s thus a u s e f u l index.  indicates  As  of a random 2  a r e g u l a r , or uniform, d i s t r i b u t i o n .  t o B14  would  demonstrated t h a t s /x  indicates  B1  agreement  used i n t e s t s i n c o n j u n c t i o n w i t h n-1  2  to  index  1 i n d i c a t e s aggregation.  J ( s / x ) , where 0 =  Tables  of  1 indicates a regular distribution,  statistic  approximation  B1  i s a good  Agreement w i t h a P o i s s o n  i n d e p e n d e n t o f d e n s i t y and  l e s s than  i n Tables  used as a q u i c k t e s t  ~to r e j e c t t h e h y p o t h e s i s  Myers  ratio  This  date  s a m p l e mean t o s a m p l e v a r i a n c e r a t i o  of d i s p e r s i o n s i n c e i t can  i n d i c a t e an  each sampling  f o r each  i n t h i s case  a r e d i s p e r s i n g from o r i g i n a l  as  to  an  sibling  g r o u p s and " t h i n n i n g  o u t " as t h e y age.  However, a s G i l b e r t  (1973) makes c l e a r , t h e r e a r e many ways t o a r r i v e distribution.  Rather than  make u n s u p p o r t e d  present t h e s e data as background solid  ground  at a certain  i n f e r e n c e s here, I  i n f o r m a t i o n , and move t o more  i n t h e next three c h a p t e r s .  16  CHAPTER  TWO  POST-EMBRYONIC GROWTH OF THE COLLEMBOLANS, FOLSOMIA CANDIDA JLENILLA GRISEA, AT THREE TEMPERATURES  AND  17  INTRODUCTION  In  assessing factors affecting  t h e s i z e and c h a r a c t e r i s t i c s  o f an i n s e c t p o p u l a t i o n , i t i s o f t e n d e s i r a b l e t o know t h e age distribution.  This information i s p a r t i c u l a r l y  p o p u l a t i o n s have o v e r l a p p i n g g e n e r a t i o n s wished  (Southwood, 1978).  I  t o e s t a b l i s h r e l a t i o n s h i p s b e t w e e n a g e , s i z e and  temperature to  u s e f u l when  f o r two s p e c i e s o f C o l l e m b o l a  provide aging techniques  predictive  models.  u s e f u l i n other experiments  The two s p e c i e s , F o l s p m i a  and  X e n y l l a q r i s e a Axelson  and  litter  i n order and  C a n d i d a Willem  1902  1900, a r e common i n h a b i t a n t s o f s o i l  i n many p a r t s o f t h e w o r l d .  Accurate  age-grouping  i s always d i f f i c u l t  i m p o s s i b l e f o r many k i n d s o f i n s e c t s . estimates  (springtails)  However,  o f a g e c a n b e made f o r i n s e c t s , s u c h  which c o n t i n u e  t o grow a f t e r t h e y  ametabolous, monophasic l i f e number o f i n s t a r s  and o f t e n reliable as C o l l e m b o l a ,  become m a t u r e .  The  c y c l e of Collembola,  and t h e i r  large  (up t o 5 0 , C h r i s t i a n s e n , 1964) a l l o w s  comparison of dimensions  over  time  and, c o n s e q u e n t l y ,  offers a  method o f d e t e r m i n i n g a g e . Many l i f e be The  h i s t o r y p a r a m e t e r s o f i n s e c t s h a v e been shown t o  f u n c t i o n s o f temperature i n f l u e n c e of temperature  p e r i o d , and m o r t a l i t y  ( s e e , e . g . , M o r r i s and F u l t o n , on t h e f e c u n d i t y ,  1970).  developmental  o f F. C a n d i d a , f o r e x a m p l e , i s w e l l -  18  documented Butcher,  ( M a r s h a l l and K e v a n , 1962; G r e e n , 1 9 6 4 a ; S n i d e r and  1973; H u t s o n , 1 9 7 8 b ) .  The c l a s s i c s t u d y  of A g r e l l  (1949) d e a l t w i t h a l l o m e t r i c g r o w t h , number o f e c d y s e s , life  history  characteristics of related  g r o w t h o f i n d i v i d u a l s h a s been c o n c e r n e d development stadia) 1979)  1979)  (e.g., G i l b e r t e t a l . ,  or inherently nonlinear  time  f u n c t i o n s of temperatures  on t h e  f o r the various  1976; J o h n s o n e t a l . ,  (e.g.. B a i l e y ,  1978; T a y l o r a n d H a r c o u r t ,  Research  with the r a t e of  (the r e c i p r o c a l of developmental  as l i n e a r  Harcourt,  species.  and o t h e r  1976; Guppy a n d  1978; T a n i g o s h i and L o g a n ,  normally  experienced.  Recently,  m o d e l s f o r d e s c r i b i n g a n d p r e d i c t i n g t h i s r e l a t i o n s h i p h a v e been p r o d u c e d , n o t a b l y by S t i n n e r e t a l . , and  Curry  et a l . ,  1978.  1976;  S i m i l a r models o f t h e f u n c t i o n a l  r e l a t i o n s h i p of temperature h a v e been  1976; L o g a n e t a l . ,  with t h e growth of i n d i v i d u a l i n s e c t s  used i n s i m u l a t i o n models t o p r e d i c t t h e growth o f  p o p u l a t i o n s under f i e l d  c o n d i t i o n s ( e . g . Gage e t a l . , 1976;  Dover e t a l . , 1979; Herne and L u n d , 1 9 7 9 ) .  I designed  this  p o r t i o n o f my s t u d y t o s e r v e t h e d u a l p u r p o s e o f d e t e r m i n i n g growth r a t e s and d e v e l o p i n g interpretation  of other  an a g i n g t e c h n i g u e  t o be u s e d i n t h e  experiments.  METHODS F. C a n d i d a a n d X. g r i s e a were r e a r e d i n d i v i d u a l l y i n s m a l l vials  (2 cm X 4 cm) embedded i n p l a s t e r - f i l l e d  those  u s e d by M a r s h a l l and Kevan  different  temperature  regimes:  (1962),  trays similar to  maintained  i n three  12 h r s a t 6" C / 12 h r s a t 10° C;  19  12 h r s 140 c / 12 h r s 180 c, and  12 h r s 22<> c / 12 h r s 260  (These t r e a t m e n t s w i l l be r e f e r r e d 8°, 16°  and  t o by t h e i r  c _  mean t e m p e r a t u r e s ,  240 c , r e s p e c t i v e l y , t h r o u g h o u t t h i s c h a p t e r . )  The  r a n g e o f v a r i a t i o n o f t h e a i r t e m p e r a t u r e was < 0. 5° C i n t h e i n c u b a t o r s , b u t was  even l e s s i n t h e c o n t a i n e r s , s i n c e  t e m p e r a t u r e s were m o d e r a t e d  by m o i s t e n e d p l a s t e r b o t t o m s . .  f o r e a c h t r e a t m e n t were o b t a i n e d f r o m c u l t u r e s i n c u b a t o r s used i n t h e e x p e r i m e n t . maintenance  t h e X.  The  from i n d i v i d u a l s r e c e i v e d  grisea  stock o r i g i n a t e d  the University B.C.,  The  of r e l a t i v e h u m i d i t y near  normal s u r v i v a l of s p r i n g t a i l s . descended  cf B r i t i s h  e i g h t months  their Eggs  kept i n the  moist p l a s t e r  allowed  100%, a r e g u i r e m e n t f o r F. Candida  cultures  f r o m D r . V. G.  Marshall  with i n d i v i d u a l s c o l l e c t e d  C o l u m b i a Endowment L a n d s ,  and  from  Vancouver,  ( a b o u t 10 g e n e r a t i o n s ) b e f o r e t h e e x p e r i m e n t . .  Y e a s t , a minor component o f t h e n a t u r a l d i e t o f C o l l e m b o l a and commonly u s e d f o r r a i s i n g C o l l e m b o l a u n d e r l a b o r a t o r y (e.g..  U s h e r and S t o n e m a n , 1 9 7 7 ) , was  conditions  used i n powder f o r m  as  food. The  springtails  plexiglass vials  were r e a r e d i n d i v i d u a l l y  s i n c e Green  d i f f e r e n c e i n the growth F. - C a n d i d a .  i n stoppered  (1964b) f o u n d t h a t t h e r e was  r a t e s o f g r o u p e d and  no  isolated  F o u r t e e n v i a l s were u s e d f o r e a c h o f t h e s i x  species-temperature combinations.  The  body l e n g t h  (anterior  of  h e a d t o p o s t e r i o r o f a n a l segment) and h e a d w i d t h were m e a s u r e d each morning o f two  during the early  s t a g e s o f g r o w t h , and a t  intervals  t o f i v e d a y s t o w a r d s t h e end o f t h e s t u d y . . V i a l s i n w h i c h  individuals  d i e d were r e s t a r t e d  with the a d d i t i o n  of f r e s h  eggs;  c o n s e g u e n t l y the data c o l l e c t e d f o r each s p e c i e s - t e m p e r a t u r e  20  combination  represent f o r 75  were t a k e n  from  15 t o 31 i n d i v i d u a l s .  days.  RESULTS AND  DISCUSSION  L e n g t h and In age.  Measurements  Age  a l l c a s e s , the r a t e of growth d e c l i n e d g r a d u a l l y w i t h  The v a r i a n c e o f t h e l e n g t h s i n c r e a s e d w i t h a g e .  t r a n s f o r m a t i o n s of both  d e p e n d e n t and i n d e p e n d e n t v a r i a b l e s  y i e l d e d homogeneous  v a r i a n c e and a l l o w e d  estimated  linear regression.  by s i m p l e  used i s a l i n e a r i z e d  Log  p a r a m e t e r s t o be The r e g r e s s i o n  equation  f o r m o f t h e power f u n c t i o n :  b  l e n g t h = a (age)  where a = t h e mean body l e n g t h a t t i m e b = the estimated Least  squares f i t s  on t h e t i m e  growth  power  5 and 6 . .  The l e t t e r  i n Table  to oviposit.  The  1 with a s s o c i a t e d  estimates statistics.  The a c t u a l r a t e o f c h a n g e i n l e n g t h L a t a g i v e n age A i s :  dL/dA = abA Although  "m"  F i g u r e s i n d i c a t e s t h e age a t w h i c h  i n d i v i d u a l s become m a t u r e and b e g i n o f l n (a) and b a r e l i s t e d  and  parameter.  a r e shown i n F i g u r e s  s c a l e i n these  of hatching  b-1  power f u n c t i o n s a r e commonly  used t o d e s c r i b e  21  Figure  5-  L e n g t h - a g e r e l a t i o n s h i p s f o r F. C a n d i d a r e a r e d u n d e r t h r e e t e m p e r a t u r e r e g i m e s (mean t e m p e r a t u r e f o r e a c h c a s e i s shown). E a c h r e g r e s s i o n l i n e i s bounded b y t h e 99$ c o n f i d e n c e i n t e r v a l s f o r t h e e s t i m a t e d mean ln(length). The "m" i n d i c a t e s t h e a p p r o x i m a t e age a t w h i c h i n d i v i d u a l s became m a t u r e and b e g a n t o oviposit.  22  1500h  1  • 2  • 4  • 8  1  2  4  8  • 16  • • 32  64  32  64  <  16  1500F  1000  8  700h  AGE  (DAYS. L O G  E  SCALE)  23  Figure  6.  L e n g t h - a g e r e l a t i o n s h i p s f o r X. g r i s e a r e a r e d u n d e r t h r e e t e m p e r a t u r e r e g i m e s (mean t e m p e r a t u r e f o r e a c h c a s e i s shown). E a c h r e g r e s s i o n l i n e i s bounded by t h e 99$ c o n f i d e n c e i n t e r v a l s f o r t h e e s t i m a t e d mean ln(length). The "m" i n d i c a t e s t h e a p p r o x i m a t e age a t w h i c h i n d i v i d u a l s became m a t u r e and b e g a n t o oviposit.  1500 24  1000  700 500 400 300 1  2  4  8  16  32  64  1500  1000  1500  1000  8  AGE  (DAYS,  16  LOG  E  32  64  SCALE)  25  lable  1. B e g r e s s i o n s of l n ( l e n g t h ) to F i g u r e s 5 and 6 .  Species  Teap  (  C)  and l n ( a g e )  Begression  a, the s i z e  Eguation  F.  Candida  grisea  corresponding  a t ha'tch  8  ln  L=5.652 + . 118 ( l n A)  285  16  ln  L=5.853  •  .27 1  24°  ln  L=5.787  •  .288  8°  ln  L=5.682  •  16°  ln  L=5.487  •  24°  ln  L=5.629  p.  .613  <.0001  348 jx  .749  <-00 01  /i.  .749  <.0001  .098 ( l n 4)  294 ju.  .791  <.0001  .331 ( l n &)  242  . 880  <.0001  .275  278  . 77o  <.0001  ( l n A) (ln  (ln  4)  A)  326  JUL  26  r e l a t i v e r a t e s of growth of d i f f e r e n t studies  (Choudhuri  collembolan  and  body p a r t s i n a l l o m e t r i c  Bhattacharyya  s p e c i e s , and  Petersen  (1978) h a v e done t h i s  (1975) has  to d e s c r i b e the l e n g t h - d r y weight  used power f u n c t i o n s  r e l a t i o n s h i p s o f a number o f  C o l l e m b o l a ) , they are r a r e l y used t o d e s c r i b e a b s o l u t e over time  most c l a s s i c  g r o w t h and  N a i r , 1964).  W e l c h ' s work  a s i m p l e power f u n c t i o n was b e t w e e n h e i g h t and  age  construct orthogonal The  form.  s i z e s o f F.  Kevan  temperature  w i t h i n c r e a s i n g age  arrived (Table  data  morphological  g r o w t h and  two  cases  Milne  (1960)  a report  which are c o n s i s t e n t w i t h  A n a l y s i s o f M a r s h a l l ' s and  a t f r o m my  Kevan's  data  + . 232  ( l n (age) ) ,  a t 24°  C), s i m i l a r to  data taken at the  the  same  1) .  of G r e g o i r e - W i b o • s  (1974) s t u d y  development of F o l s o m i a  follow a similar  had  to  regression eguation,  growth curve  these  relationship  6 do n o t e x h i b i t  (1962) and  25 means f o r a n i m a l s r a i s e d  The  Davidson,  Welch u s e d t h i s e q u a t i o n  i n F i g u r e s 5 and  M a r s h a l l and  Candida  forms  i s an e x c e p t i o n i n w h i c h  used t o p r o v i d e a  l n ( l e n q t h ) = 5.80  ( f i t on  (1 970)  are  polynomials.  t h e r e s u l t s shewn h e r e . g i v e s the  (Medawar, 1945;  for children.  data i l l u s t r a t e d  logistic  growth  development e q u a t i o n s  of e x p o n e n t i a l or l o g i s t i c e q u a t i o n s 1944;  with a  pattern.  m o l t i n g of f i v e  J o o s e and  of  the  g u a d r i o c u l a t a appear Veltkamp  to  (1970) s t u d i e d t h e  l a r g e r s p e c i e s of C o l l e m b o l a .  Most o f  growth p a t t e r n s s i m i l a r t o the s p e c i e s I used, but tended  toward  a logistic  form.  in  27  Comparison o f length-age  regression  lines  T h e r e a r e a number o f ways i n w h i c h s l o p e s o f r e g r e s s i o n l i n e s may be c o m p a r e d .  Z a r (1974) s u g g e s t s  be c o m p a r e d w i t h t - t e s t s ,  t h a t two s l o p e s c a n  w h i l e more t h a n t w o s l o p e s may be  compared w i t h m u l t i p l e range t e s t s .  A better, but often  overlooked,  method o f c o m p a r i n g s l o p e s i n v o l v e s t h e u s e o f dummy  variables.  Cunia  and  Wasserman To  (1973),  K e r l i n g e r and Pedhazur  ( 1973)  (1974) d i s c u s s t h e d e t a i l s o f s i m i l a r  make t h e c o m p a r i s o n s by t h i s t e c h n i g u e ,  techniques.  t h e s i x data  were c o m b i n e d and s i x dummy v a r i a b l e s were c o n s t r u c t e d allowed  t e s t s o f t h e i n t e r c e p t s (1's f o r t h e d a t a  interest,  O's f o r a l l e t h e r s )  equation resulting  twelve  which  s e t of  observations f o r t h e data set o f  O's f o r a l l o t h e r s ) . (Cunia's  sets  a n d c o n s t r u c t i o n o f s i x new  i n d e p e n d e n t v a r i a b l e s ( l n (age) interest,  and Neter  Fitting  a multiple regression  (1973) " g i a n t s i z e r e g r e s s i o n " )  to the  v a r i a b l e s gave t h e r e s i d u a l sum o f s g u a r e s f o r  the s i x groups, together  with t h e i r  separate  s l o p e s and  intercepts. T h e s e new i n d e p e n d e n t be  (dummy) v a r i a b l e s a r e v e c t o r s t h a t c a n  added t o combine t h e s l o p e s  groups.  By c o m b i n i n g t h e v e c t o r s o f i n t e r e s t  corresponding fitting  o r i n t e r c e p t s o f t w o o r more (i.e.,  t o t h e slopes or i n t e r c e p t s being  a new m u l t i p l e r e g r e s s i o n e g u a t i o n  those  compared),  and o b t a i n i n g a new  r e s i d u a l sum o f s g u a r e s f o r c o m p a r i s o n w i t h t h e o r i g i n a l , then  test  whether t h e s l o p e s  (or i n t e r c e p t s ) a r e e q u a l ; i . e . ,  w h e t h e r t h e r e i s no s i g n i f i c a n t sguares.  we c a n  c h a n g e i n t h e r e s i d u a l sum o f  F o r e x a m p l e , t o t e s t f o r a d i f f e r e n c e among a l l s i x  slopes, I f i t :  28  1. ) l n ( l e n g t h ) = b„ X „ b  fcl  X  6  )  + b  X  I Z  *• b , X z  IZ  Z)  X  + b  3 z  + b 2  Z  + b  2 1  X  3  z  3l  X„  + b  + b  X  v t  V  l  X  vi  +b  S  X  5z  + b  I  f  l  s l  X , + s  + b«. X , 6 z  t  ( w i t h D1 r e s i d u a l d e g r e e s o f f r e e d o m )  2. ) l n ( l e n g t h ) = b„ X „ + b«  (X,  +  z  * b  Zl  X  t  l  + b, X , + b, X , + b 3  3  v  v  s i  X, + s  X  zz  +  X  3  Z  +  Xvz  +  X  F  •  i  X  6  l  )  ,  ( w i t h D2 r e s i d u a l d e g r e e s o f f r e e d o m ) where X „ , X intercepts;  X , a r e dummy v a r i a b l e s u s e d f o r t e s t s o f  l (  X  ) z  f c  ,  X  z  X  z  f e i  a r e t h e l n (age)  v a l u e s f o r each o f  t h e s i x g r o u p s a n d a r e used f o r c o m p a r i n g s l o p e s , and b' i s t h e common s l o p e . can  The s i g n i f i c a n c e o f t h e d i f f e r e n c e i n r e s i d u a l s  be d e t e r m i n e d by an F - t e s t  where  F = [ S S d i f f e r e n c e / (D2 - D1) ] / MS 1  with  (D2 - D1) and D1 d e g r e e s o f f r e e d o m .  easily any  be a p p l i e d t o m o d e r a t e l y l a r g e d a t a  reliable  This technigue can sets with the a i d of  m u l t i p l e r e g r e s s i o n package.  T e s t s o f s l o p e s : do t h e g r o w t h p a r a m e t e r s Using  t h e technique  differ?  d e s c r i b e d above, t h e s l o p e s  were  c o m p a r e d b e t w e e n t e m p e r a t u r e s f o r e a c h s p e c i e s and between species a t corresponding summarized i n Table  2.  temperatures.  The r e s u l t s a r e  F o r F. . . C a n d i d a t h e s l o p e s  f o r t h e groups  r e a r e d a t mean t e m p e r a t u r e s o f 16° a n d 20° C d i d n o t d i f f e r . Both v a l u e s  were s i g n i f i c a n t l y  l a r g e r than  t h e s l o p e f o r t h e 8«  2a.  Slope comparisons within s p e c i e s f o r a l l p a i r s o f temperatures.  Species  Comparison 0  F.  C a n d i d a  0  16  70.70  1, 58 9  <.0001  8°  vs  24°  9 1.62  1. 589  <.0001  VS  24°  0.98  1, 58 9  =.6756 (n.s.;  8  VS  16  111.78  1. 58 9  <.0001  8°  vs  24°  52. 18  1. 58»  <• 000 1  7.33  1. 58 a  =.0069  a  0  16  T a b l e 2b.  o  vs  0  24  S l o p e c o m p a r i s o n s betneen s p e c i e s a t each  Temperature  ill  temperatures 8° C  P  vs  0  qrisea  df  8  16  ?,  F  temperature.  df  4.01  1, 589  .0431  0.75  1, 589  .6106 (n. s.)  16°  C  11.32  1. 589  .0009  24°  C  0.44  1. 589  .5128 (n.s.)  (n.s.) = n o t s i g n i f i c a n t l y  different.  30  group.  The  l a r g e s t s l o p e f o r X.  t r e a t m e n t . . Those f o r t h e  8° and  smaller f o r t h i s species. C produced  different  f o r t h e two  Tests The  grisea 24°  occurred i n the  C treatments  16°  were  both  Between s p e c i e s , t h e t r e a t m e n t s  s l o p e s ; i . e . , the growth parameters  species i n that  of i n t e r c e p t s :  C  at  differed  regime.  do t h e l e n g t h s a t h a t c h i n g  differ?  i n t e r c e p t s f o r t h e r e g r e s s i o n e g u a t i o n s shown i n T a b l e 1  were c o m p a r e d w i t h t h e same m u l t i p l e r e g r e s s i o n t e c h n i g u e . . r e s u l t s i n Table tend to f o l l o w t h e two at  16»  3 show t h a t t h e  c, o r b e t w e e n hatching size  C,  comparable The  hatch  g r i s e a has i t s range.  r e l a t e d t o body l e n g t h and  for a l l six  (p <  species-temperature  (1951) p r e s e n t e d t h e  t o X. g r i s e a  age  o n l y c o m p a r a b l e work  h i s d a t a on head w i d t h and d e v e l o p i n g a t 24° C,  on  age,  show a  relationship.  ratio  increasing  for  width  Hypogastrurids that I could f i n d ; for a species similar  w h e r e a s X.  w i t h i n t h i s temperature  r e s i d u a l s unbiased) Britt  f u n c t i o n s of t e m p e r a t u r e  16° and  24°  The  hatch))  a maximum body l e n g t h a t  Head w i d t h i s l i n e a r l y  combinations..  (ln(size at  Candida has  Head  .001,  intercepts  opposite quadratic  s p e c i e s . . F.  minimal  16°  age  o f h e a d w i d t h t o body l e n g t h d e c r e a s e d (Figure 7).  with  T h i s r e l a t i o n s h i p i s common i n  v e r t e b r a t e s but i s not u s u a l l y  d i s c e r n a b l e i n i n s e c t s because of  their  metamorphosis.  d i s c r e t e d e v e l o p m e n t and  c o l l e m b o l a n s , t h i s c h a n g e seemed t o o c c u r  In  both  more s l o w l y a t  the  31  Table 3a.  I n t e r c e p t comparisons w i t h i n s p e c i e s f o r a l l p a i r s of teaperatures.  Species  Coaparison  Im C a n d i d a  df  16"  16.30  1. 589  =.0001  8°  vs  24°  7.8b  1, 589  =.0053  16°  vs  24°  1. 42  1, 589  =.2317 (n. s.)  8  vs  16  16. 57  1, 589  <.000 1  8°  vs  24°  1.29  1, 58 9  =.2557  16'  vs  24°  10. 17  1, 589  = .00 17  O  I n t e r c e p t c o a p a r i s o n s b e t ween s p e c i e s .  Teaperature  111  P  6* vs  O  t a b l e 3b.  F  temperatures 8- C  df  42. 16  1, 589  <.0001  0.40  1, 589  .5349 (n.s.)  16°  C  51.25  1. 589  <.0001  24°  C  10.53  'r  =.0014  (n.s.)  = not s i g n i f i c a n t l y  589  different.  32  Figure  7*  The d e c r e a s e w i t h age i n t h e h e a d w i d t h / b o d y l e n g t h r a t i o s o f F . C a n d i d a ( a ) and X« g r i s e a ( b ) . A l t h o u g h p h y s i o l o g i c a l time i s n o t a p u r e l y l i n e a r f u n c t i o n o f t e m p e r a t u r e and c h r o n o l o g i c a l t i m e , age i s r e p r e s e n t e d h e r e b y d e g r e e - d a y s t o make t h e r e s u l t s more c o m p a r a b l e . The r e g r e s s i o n equations are: : HW/BL = . 2 9 8 6  F o r F. C a n d i d a SE  For  =  .03635  X. g r i s e a  r  2  .185  : HW/BL = . 3 6 3 2  SE = .03284  r  2  .400  - .01l62(ln p < .0001 -  .02363(ln  p <  .0001  Degdays)  n = 234 Degdays) n = 244  .45  .35  4"" # •  •  • ••  l  •  •«  •"•iter* •* 4»l •  *  •  •  •  .  •••  • ; • • • •'  ..  .  •••••••• 1  •  • • • •  , I.  .15 400  AGE  800  1200  1600  (degree-days)  .45  .35  .25 • »L:P***  • •••••• 11 •  •  • •  .15  —i  ——i  400  AGE  800  1  1200  (degree-days)  1—  1600  34  lowest  t e m p e r a t u r e , a s m i g h t be e x p e c t e d .  significant  temperature.  f i n d i n g s o f M a r s h a l l and six instars  Kevan  30 d a y s i n age)  unaccounted  f o r by age  E r r o r s o f measurement may  of a c t i v i t y  o f some  L i n e a r and The  the  range  within  t e m p e r a t u r e , and addition the  head  and  of  high  temperature  n o n - l i n e a r over  These t e m p e r a t u r e s a r e  X. g r i s e a  M u l t i p l e r e g r e s s i o n s were p e r f o r m e d  o f l n (age) and  after  temperature  well  species.  f o r each  non-linear effects  be  has i t s m a x i m a l  s l o w e r r a t e s of growth  of these  swelling  i s low a t 8° C a n d a p p e a r s t o  a p p r o a c h i n g a maximum a t 20" C.  effects  of  1 show t h a t t h e e f f e c t  F. C a n d i d a ' s r a t e o f g r o w t h  significance  of the s m a l l s i z e  n o r m a l l y e x p e r i e n c e d by b o t h  C, and  to  amount  individuals.  of temperatures t e s t e d .  16°  large  a l s o be h i g h e r f o r t h e  r a t e of these i n s e c t s i s c l e a r l y  the range  r a t e near  The  i s p r o b a b l y due  non-linear effects  r e s u l t s i n Table  on t h e g r o w t h  a t 8°  and  24°  growth C. .  species to test  of temperature.  temperature, the g u a d r a t i c e f f e c t  t h e i r i n t e r a c t i o n s a r e shown i n T a b l e 4.  of these a s p e c t s of temperature  the  Linear of In  t o l n (age), temperature, the sguare of t e m p e r a t u r e ,  interaction  the  o f F. Candida  p r o t h o r a x b e f o r e , d u r i n g and  w i d t h s t h a n f o r body l e n g t h s , b e c a u s e degree  the  o b s e r v a t i o n s on  a r e shown i n F i g u r e 7..  and s h r i n k a g e o f t h e head and ecdysis.  (1962) ; t h e i r  support  the  i s a constant.  Least sguares f i t s variability  T h e s e d a t a do n o t  (up t o a b o u t  suggest t h a t the r a t i o  of  highly  d i f f e r e n c e i n t h e r e l a t i o n s h i p o c c u r r e d between  s p e c i e s a t any  first  However, no  with ln(age)  and are  35  T a b l e 4a.  Begression  f o r F.  Candida  3  1B l e n g t h = f ( l n (age), t e a p , F = 496.7  Coefficient  intercept l a (age) teaperatare tenp* ( l n (age)) X t e n p (In (age) ) X temp  1  Begression  F = 380.5  Standard  5.18630 -.17188 .07484 -.00208 .04476 -.00 107  Error  . 171830 .062567 .025644 .000815 .008729 .000267  p p p p p p  < = = = < =  .000 I .0063 .0040 .0113 .0001 .0001  f o r £. qrisea  l n l e n g t h = f ( l n (age) , ( l n ( a g e ) ) l n (age) X t e a p )  teap, teap  , ln(age)  X teap,  p < .0001 2.  Hultiple B  = . 8977  Tariable intercept l n (age) (ln(age)) teaperature teap (In (age)) x t e a p (In (age)) X teap. 2  SE= . 16774  , 8775  Tariable  z  l n (age) X tenp )  p < .0001  Hultiple B  T a b l e 4b.  *  t e a p , l n (age) X tenp,  Coefficient 5.93560 -.37772 -.04402 -.03069 -.00092 .05271 -.00 134  SE= . 16774 Standard . 115810 .051463 .005788 .016905 .000514 .007885 .000239  Error  P  < < <  .000 1 P .000 1 P . 0001 P P = . 0706 P = .074 1 . 0001 P .000 1 P  < <  36  s i g n i f i c a n t terms temperature linear  and  i n the regression equations.  on c o l l e m b o l a n g r o w t h t h u s a p p e a r s non-linear effects  which  may  The  to i n c l u d e  vary with  r a p i d growth  of  whenever p e r i o d s o f  t e m p e r a t u r e and h u m i d i t y o c c u r r e d .  would  both  temperature  a l l o w t h e s e c o l l e m b o l a n s t o undergo  disproportionately  environments,  of  age.  Under n a t u r a l c o n d i t i o n s , n o n - l i n e a r e f f e c t s changes would  influence  growth  In l e s s  favorable  favorable  w c u l d be r e t a r d e d and t h e o n s e t o f m a t u r i t y  be d e l a y e d u n t i l c o n d i t i o n s became more c o n d u c i v e t o  reproduction.  D e v e l o p m e n t o f an a g i n g t e c h n i g u e The  r e g r e s s i o n s a b o v e were p e r f o r m e d  the changes i n post-embryonic i s o l a t e and model.,  illustrate  r a t e o v e r t i m e and  t e s t the e f f e c t s of s p e c i f i c terms  i n the  to  growth  I t i s p o s s i b l e t o use t h e same d a t a t o p r e d i c t age  length.  Some r e s e a r c h e r s and  regressions involving  l e v e l s as i s p o s s i b l e  from  s t a t i s t i c i a n s have o b j e c t e d t o  independent  s a m p l i n g o r measurement e r r o r  (1974)  growth  i n order to  v a r i a b l e s that are subject to  ( i . e . , not f i x e d  at  specified  i n many e x p e r i m e n t a l s i t u a t i o n s ) .  f o r i n s t a n c e recommends " i n v e r s e  Zar  p r e d i c t i o n " i n which  a  r e g r e s s i o n e q u a t i o n and i t s p r e c i s i o n e s t i m a t e s a r e r e a r r a n g e d t o predict would  X from  Y, a l t h o u g h i t seems t o me  n o t be l e a s t s q u a r e s e s t i m a t e s .  objection  t o "dependent"  and  The  that such e s t i m a t e s reason f o r the  "independent" v a r i a b l e s that  h a v e a s s o c i a t e d random e r r o r s i s t h a t t h e s l o p e b  ;  is  both  37  underestimated is  because the d i v i s o r  i n c r e a s e d by t h e g u a n t i t y  independent v a r i a b l e .  used t o c a l c u l a t e t h e s l o p e  (n-1) Ox,-  , where X,- i s t h e  The f l a w i n t h e a r g u m e n t i s t h e u n d e r l y i n g  a s s u m p t i o n t h a t we a r e t r y i n g  to find  an e s t i m a t e  of the t r u e  f u n c t i o n a l r e l a t i o n s h i p b e t w e e n two v a r i a b l e s when we p e r f o r m regression.  Regression  p u r p o s e , however. prediction  techniques  Regression  are not designed  eguations  independent v a r i a b l e Future  values  will  i n c l u d e random  for this  a r e meant t o f a c i l i t a t e  and i n t e r p o l a t i o n o n l y . . As G i l b e r t  i n a c t u a l p r a c t i c e i t does n o t m a t t e r  a  (1973) p o i n t s o u t ,  i f the observations of the  e r r o r s of  measurement.  i n c l u d e t h e same e r r o r s and h e n c e t h e  p r e d i c t i v e v a l u e of t h e r e g r e s s i o n i s not changed. I  reversed the regressions discussed i n t h i s  used t h e r e s u l t i n g age o f F . . C a n d i d a  chapter  and  s l o p e and i n t e r c e p t e s t i m a t e s t o e s t i m a t e t h e individuals  i n o t h e r work  F o u r a s w e l l a s a number o f s i m u l a t i o n s ) .  ( C h a p t e r s T h r e e and Although  my l a t e r  work  d o e s n o t depend on p r e c i s e e s t i m a t e s o f a g e , t h e d a t a  presented  in  two  t h i s chapter  collembolans,  not o n l y d e s c r i b e t h e growth o f these  but a l l o w r e l a t i v e l y  s e e n i n F i g u r e s 5 and  6.  p r e c i s e p r e d i c t i o n a s c a n be  CHAPTER  PREDATION OF APOCHTHONIUS  THREE  MINIMUS  CHTHONIIDAE) ON FOLSOMIA CANDIDA I..  PREDATION RATE AND  (PSEUDOSCORPIONIDA:  {COLLEMBOLA: ISOTOMIDAE) SIZE-SELECTION  39  INTRODUCTION  Apochthonius length  1.9  - 2.3  leaf l i t t e r , western  (Figure 8).  mm)  bark  British  Collembola  minimus  (Schuster  1966)  i s a small (adult  h e t e r o s p h y r o n i d p s e u d o s c o r p i on common i n  and  bryophytes  of a v a r i e t y of f o r e s t s  C o l u m b i a , W a s h i n g t o n and  Pseudoscorpions (springtails)  t h e c a s e f o r A.  collected  f r o m my  (Benedict,  ( W e y g o l d t , 1969) .  m i n i m u s ; o f n e a r l y 150  This i s individuals  s t u d y s i t e n e a r l y a l l f e d on I s o t o m i d  Entomobryid Collembola  1978)  o f t h i s t y p e a r e known t o p r e f e r  as f o o d  certainly  Oregon  of  w h i l e none a c c e p t e d  f o o d o f any  and other  kind. A. site;  minimus i s found  up  in relatively  t o s e v e r a l hundred per m  h i g h d e n s i t i e s a t my  i s not  2  t h e most common o f t h r e e p s e u d o s c o r p i o n site leaf  litter  ( o n l y a few  h a v e been c o l l e c t e d along  f r o m my  with mesostigmatid  uncommon.  I t i s by f a r  s p e c i e s I found  s p e c i m e n s o f t h e o t h e r two study s i t e ) .  These  in  species  of  s p r i n g t a i l s i n the area.  Weygoldt  "pseudoscorpions  r e g u l a t e t h e d e n s i t i e s of s m a l l  animals,  especially Collembola".  that collembolan treatment, t h i s case  by O l i v i e r and  factors limiting questions  Edwards et a l . .  a p p a r e n t l y , they suggest,  c o l l e m b o l a n d e n s i t i e s and reported  (1969) s t a t e s t h a t  densities significantly  m i t e s , were r e d u c e d .  because t h e i r  how  the  found DDT  increases i n  As p a r t o f a s t u d y  of s p r i n g t a i l s ,  edaphic  predators, in  i n predator d e n s i t i e s  Ryke ( 1 9 6 9 ) .  were of i n t e r e s t t o me:  (1967)  i n c r e a s e d under  S i m i l a r concomitant  decreases  the d e n s i t i e s  the  pseudoscorpions,  m i t e s , are the major p r e d a t o r s  probably  study  were of  following  many s p r i n g t a i l s m i g h t  the  Figure  8.  Scanning  electron  o f a n A. minimus a d u l t .  micrograph  (Mag.: 57  X)  41  pseudoscorpions and  e a t , what f a c t o r s i n f l u e n c e t h e p r e d a t i o n r a t e s  what a r e t h e e f f e c t s o f t h i s  p o p u l a t i o n s under c o n t r o l l e d g u e s t i o n s and  p r e d a t i o n on t h e  field  conditions?  i t s a s s o c i a t e d hypotheses  growth  The  last  of  prey  of  these  a r e examined i n t h e  next  chapter. .  Biology  o f t h e P r e y and  Little as Muchmore  Predator  i s known a b o u t  the l i v e s  (1973) p o i n t s o u t , t h e i r  i n o f f e n s i v e n e s s t o man however, have caught  of pseudoscorpions retiring  habits  make them " i n v i s i b l e " . .  of h a b i t a t s .  and  Springtails,  the i n t e r e s t of a r e l a t i v e l y  r e s e a r c h e r s , i n p a r t because of t h e i r  l a r g e number o f  high natural d e n s i t i e s  presence  i n a wide range  nivalis,  F o l s o m i a Candida, F p l s o m i a q u a d r i o c u l a t a and  I n my  study s i t e ,  Folsomia  The 2.0  mm)  and  Fplsomia  other  s i m i l a r I s o t o m i d s o c c u r a t d e n s i t i e s as h i g h as 30,000, commonly 5000 t o 10,000, p e r  because,  and  m. 2  Candida  springtail cryptic  between l i t t e r  apterygote and  F. C a n d i d a i s f o u n d f o r e s t s and  used i n t h i s  soil  study i s a s m a l l  (Figure  2b)  t h a t i n h a b i t s moist  p a r t i c l e s i n a v a r i e t y of  throughout  ( l e n g t h 0.2  E u r o p e and  spaces  ecosystems.  North America  g r a s s l a n d s , wherever t h e h i g h r e l a t i v e  -  in  humidity  and  42  fungal and  food i t requires  has  an  periodic  moults  clawed  legs  of  fourth  life  throughout  and  history  and  and  (1977) and  Butcher (1978b)..  (1973),  and  contacted  (1964a,b),  ventrum  and  experiments  Milne  Snider  with  this  (1970) , Usher  (1975) and  the  Snider  Usher  the b e h a v i o r of the prey, I noted t h a t  by t h e s e n s o r y  F. Candida u s u a l l y r u n s continuing  feeding  effects  the  setae of a pseudoscorpion 1 t c 20  or r e s t i n g .  mm,  et a l .  and  of such c o n t a c t l a s t  same sequence  that  palpal  o n l y a few  seconds,  collembolan  w h i l e s e a r c h i n g f o r food or a moister r e s t i n g  culture  litter  p o t s or i n t a c t o f emergency  locomotion  furcula  with the tenaculum,  muscles  and  then r e l e a s i n g  as a means o f c h a n g i n g conditions  than  and  away f r o m soil  samples  manubrial  the f u r c u l a )  i n e s c a p i n g from p r e d a t o r s .  and jostles  place.  i s rare. locking  and  My  to  This the  abdominal  seems t o be  in relation  the  predators i n arenas,  ( a c c o m p l i s h e d by  tensing  position  hand,  i s very b r i e f ;  o c c u r s when one  "springing"  when  s e e m i n g l y a t random, b e f o r e  T h i s response  o b s e r v a t i o n s show t h a t  method  the  {1977).  Regarding  another  Hider  It is  o b s e r v a t i o n s on  Christiansen  which  with s i x  from  Gregoire-Wibo  Ecological  (1971), T o r n e  follow  arising  Detailed  (1962), G r e e n  by  Usher  in  Candida have been made by  s p e c i e s have been c o n d u c t e d  apparent  seguence  up t o 30 i n s t a r s . ,  (furcula)  o f F.  Kevan  (1974),  produce  segment.  biolcgy  Hutson  life  spring  abdominal  S n i d e r and  Stoneman  species i s parthenogenetic,  f o r locomotion i s eguipped  a short  (1960), M a r s h a l l and (1971),  The  ametabolous-monophasic developmental  s o f t-bo.died, b l i n d ,  the  occur.  employed  physical  more  43  Apochthonius  minimus  A. m i n i m u s a d u l t s a r e a c t i v e i n my s t u d y s i t e March t o O c t o b e r . and  on t h e f o r e s t f l o o r  almost  litter.  logs.  vertical  from  a l l cases found  Reproduction  my s o i l  and l i t t e r  extractions  selection  A similar  t h e summer  (Appendix  B:  p a t t e r n i n occurrence of Chthgnius (1970).  the C h t h o n i o i d e a .  the a c t o f f e e d i n g i n C h t h o n i u s what I h a v e o b s e r v e d f o r prey  H i s d e s c r i p t i o n of  ischnochelus i s nearly  f o r A. m i n i m u s .  A. m i n i m u s  identical  actively  ( m a i n l y by t o u c h ; i t i s d o u b t f u l t h a t i t s f o u r  ocelli  a r e image-forming)  timid,  c a u t i o u s approach  but r e t a i n s i t s c h a r a c t e r i s t i c a l l y e v e n when p r e y i s e n c o u n t e r e d .  p r e d a t o r s o f t e n r u n backward i n a t y p i c a l escape c o n t a c t prey or another  predator.  a c h i e v e d t h e prey i s g u i c k i y pinched transferred  period,  (1951) h a s d e s c r i b e d t h e f e e d i n g b e h a v i o r o f s e v e r a l  pseudoscorpions, including  they f i r s t  and  by t h e p s e u d o s c o r p i o n s .  i s c h n o c h e l e s h a s been r e p o r t e d by J o n e s Gilbert  were  d i d n o t show  p r o b a b l y i s n o t r e s t r i c t e d t o one b r i e f  F i g u r e s B3 and B 4 ) .  The  i n t h e t o p few c e n t i m e t e r s o f s o i l  s i n c e nymphs a r e p r e s e n t t h r o u g h o u t  hunts  migrations within the top  S a m p l e s c o l l e c t e d a t 3 a.mi. and a t 3 p.m.  d i f f e r e n c e s i n depth  to  I t i s doubtful that the  a s some s p r i n g t a i l s a r e b e l i e v e d t o do.  i« linims i n d i v i d u a l s in  daily  layer  p i e c e s o f d e t r i t u s , t w i g s a n d moss  o r on f a l l e n  perform  5 - 15 cm o f s o i l ,  late  They a r e f o u n d p r i m a r i l y i n t h e l i t t e r  a l s o a r e common i n l a r g e r  pseudoscorpions  from  attempt  The when  When c a p t u r e i s  w i t h t h e p e d i p a l p s and  to the powerful chelicerae.  The c a p t o r t h e n moves t o  a g u i e t s p o t w h e r e , w i t h t h e c h e l i c e r a e a l o n e , i t k i l l s a n d chews  44  the  prey.. During feeding,  but  often  its  own s e r r a t e d ,  g r a s p and chew i n d e p e n d e n t l y , movable s e c t i o n  macerated, the l i g u i d digestive cuticle  i s discarded A guick  a lengthy  jointly  s i n c e each c h e l i c e r a has  (Figure  ingested,  by s c r a p i n g defecation  rest period  9).  After the food i s  and t h e r e m a i n i n g  and w i p i n g  and c l e a n i n g  follow.  hours s l o w l y e x p l o r i n g before  t h e m o u t h p a r t s on t h e of the mouthparts,  The p r e d a t o r  may s p e n d  making a n o t h e r c a p t u r e .  t h i s p e r i o d , i t i s common f o r t h e p r e d a t o r vulnerable  hold the prey,  portion, i n c l u d i n g the pseudoscorpion's  j u i c e s , i s apparently  substrate.. and  the c h e l i c e r a e  prey i n d i v i d u a l , touch i t ,  several  During  t o approach a  a n d t h e n move on w i t h o u t  attacking. S u r p r i s i n g l y , there Chthoniid muscorum  have been no s t u d i e s  pseudoscorpions. (Leach),  springtails  of predation  The l a r g e r p s e u d o s c o r p i o n ,  Neobisium  h a s a t t r a c t e d some a t t e n t i o n as a p r e d a t o r  ( S i m o n , 1966, 1 9 6 9 ) . . E r n s t i n g and J o o s e  e x p e r i m e n t e d w i t h N. muscorum and o t h e r  predators  springtails,  of i n d i r e c t  that this  by  a n d s u g g e s t e d on t h e b a s i s  (1974)  of l a r g e r observations  p s e u d o s c o r p i o n might a c c o u n t f o r a s i g n i f i c a n t  of t h e m o r t a l i t y of these  of  portion  collembolans.  METHODS  I. Objectives: described  Predation  Rates  t o g u a n t i f y t h e f u n c t i o n a l r e s p o n s e (as  by H o l l i n g , 1959) o f A. m i n i m u s t o F. C a n d i d a p r e y and  Figure  9.  The h i n g e d ,  serrated  chelicerae  of A. minimus.  The c h e l i c e r a e  a r e much l a r g e r  and more p o w e r f u l  portion  to  scorpions.  size)  than those  (Magnification:  of 120  of  this (in  other X)  species pro-  pseudo-  46  to  t e s t t h e h y p o t h e s i s t h a t t h i s r e l a t i o n s h i p does not change  w i t h p r e y s i z e or w i t h ambient A d u l t A. to  anus;  minimus  p a l p a l hand  (body l e n g t h (pincer)  from l a r g e bags of l i t t e r Hylocomium s p l e n d e n s fir  0.7  l o n g ) were  and  Research  18 cm )  The a r e n a s  (40 t o 1 ) . . The  were 150 ml Each  The  plastic  specimen 1.0  p l a s t e r o f p a r i s mixed  water.  -  1.5  with  was a m i x t u r e o f  2  animal  w h i c h p r o v i d e s a d a r k s u b s t r a t e w i t h a pH o f 5.5  distilled  sex  i n hunger  p o t had a f l o o r  charcoal i n turn  f l o o r was  site  Individual  guts t o reduce v a r i a b i l i t y  of t e c h n i c a l  2  ( H a t s o n , 1 9 7 8 a ) . . The with  Douglas-  hemlock  Forest.  p a r t s powdered a c t i v a t e d c h a r c o a l t o 3 p a r t s powdered  wet,  (primarily  t o s e p a r a t e a r e n a s and a l l o w e d  (pots) with screw-top l i d s .  charcoal,  aspirated  western  o f t h e p r e d a t o r s were n o t d e t e r m i n e d .  before the experiment.  charcoal  chelicerae  (Eaf.y Sarg.) ] c o l l e c t e d from t h e s t u d y  24 h o u r s t o e v a c u a t e t h e i r  (area  from  f e a t h e r moss  (Mirb.) Franco)  p s e u d o s c o r p i o n s were t r a n s f e r r e d  deep  mm  mm  and h a l f n e e d l e s f r o m  t h e . U n i v e r s i t y of B r i t i s h Columbia  vials  - 2.4  [roughly half  (Pseudotsuga m e n z i e s i i  and e x a c t age  cm  1.9 - 0.8  (Hedw.) BSG.)  (Tsucja h e t e r o p h y l l a at  temperature.  -  6.0  k e p t s a t u r a t e d , b u t not  visibly  A b o u t 10 washed D o u g l a s - f i r  needles  were a d d e d t o e a c h p o t t o p r o v i d e a more n a t u r a l e n v i r o n m e n t a l texture. Prey d e n s i t y , temperature, prey s i z e  and t i m e  were  manipulated t o c h a r a c t e r i z e the f u n c t i o n a l response. densities  were 2, 4,  P r e y were c l a s s i f i e d (1.0 - 1.2 posterior  mm  8,  12 and  as " s m a l l "  20 i n d i v i d u a l s p e r (0.5 - 0.7  mm  Prey  18 c m  l o n g ) and  area.  2  "large"  l o n g ) w i t h l e n g t h s m e a s u r e d from t h e mouth t o t h e  of the anal  segment.  T h e s e l e n g t h c l a s s e s were  used  47  instead moults  o f s t a d i a b e c a u s e o f F. Candida's a m e t a b o l o u s occur f r e q u e n t l y  ( e v e r y 4-10 days) t h r o u g h o u t  growth: life,  a l t h o u g h t h e g e n e r a l body p l a n d o e s n o t change m a r k e d l y f i r s t i n s t a r to the last all  F. C a n d i d a  o b t a i n e d from  (see Chapter  and  d e s c r i b e d here  stock laboratory cultures.  enclosed  were  The p o t s were  divided  i n c u b a t o r s , one a t a c o n s t a n t  t h e o t h e r a t a c o n s t a n t 16° C, a n d t h e e x p e r i m e n t  o u t i n c o n t i n u o u s dim l i g h t . .  Q°C  was c a r r i e d  S i n c e t h e p r e d a t o r s and p r e y  were  i n t i g h t l y c o v e r e d p o t s , t h e r e was no need t o c o n s i d e r  "incubator effects" sequence e f f e c t no  Two).  f o r the experiments  e q u a l l y b e t w e e n two i d e n t i c a l  from t h e  individual  o t h e r than t e m p e r a t u r e .  and t o a c c o u n t  To a v o i d a t r e a t m e n t  for variability  among p r e d a t o r s ,  p s e u d o s c o r p i o n was s u b j e c t e d t o more t h a n one  d e n s i t y - s i z e - t e m p e r a t u r e combination d u r i n g t h e course of the experiment.  T h e r e were f o u r p s e u d o s c o r p i o n s p e r t r e a t m e n t  combination. . In a l l , incubator.  80 p s e u d o s c o r p i o n s  were used  i n 80 p o t s , 40 p e r  The measured v a r i a b l e was t h e number o f o f f e r e d  t h a t were e a t e n by i n d i v i d u a l p s e u d o s c o r p i o n s ; recorded every replaced.  pseudoscorpions to ensure  t h i s number was  12 h o u r s , when t h e p r e y t h a t had b e e n e a t e n  The e x p e r i m e n t  was t e r m i n a t e d a f t e r  were o b s e r v e d  prey  48 h o u r s .  were The  f o r 3 days f o l l o w i n g t h e experiment  t h a t none s u f f e r e d a n y o b v i o u s i l l  e f f e c t s or dramatic  changes i n b e h a v i o r .  II..  Size-selection  O b j e c t i v e s : t o estimate the p r o b a b i l i t y of capture of the  48  different  s i z e c l a s s e s o f p r e y and  to t e s t the hypothesis that  these p r o b a b i l i t i e s are equal. . 4-  m i n i m u s a d u l t s were c o l l e c t e d  experiment  on f u n c t i o n a l r e s p o n s e .  as d e s c r i b e d f o r the  Three  similarly-sized  adults  were i n t r o d u c e d t o e a c h o f 2 p o t s o f t h e t y p e d e s c r i b e d a b o v e . After  24 h o u r s , a p o p u l a t i o n c o n s i s t i n g o f a l l s t a g e s o f  ( i n c l u d i n g e g g s ) was  added t o e a c h  a l l o w e d 6 h o u r s t o become f a m i l i a r conditioning period  was  pot.  The  prey  p r e d a t o r s were  w i t h the prey a v a i l a b l e .  r e q u i r e d because of the p o s s i b i l i t y  s t a r v e d p s e u d o s c o r p i o n s might  f e e d on p r e y t h a t t h e y w o u l d  normally prefer.  a l s o allowed the  This period  pseudoscorpions to adjust to t h e i r activity  d u r i n g the f o l l o w i n g  48 h o u r s  was  classes with the f o l l o w i n g  0.4,  0.6,  0.7,  0.8,  0.9,  1.0,  n o t e d and t h e l e n g t h s At t h e end  RESULTS AND  I. Table  48  grouped  1.2,  1.3,  1.4  and  1.5  0.3, mm.  were n o t r e p l a c e d .  DISCUSSION  P r e d a t i o n Rates  5 shows t h e r e s u l t s  number o f p r e y e a t e n .  of  mean body l e n g t h s : 0.2,  1.1,  Prey eaten d u r i n g the experiment  not  A l l predatory  h o u r s , t h e r e m a i n i n g p r e y were c o u n t e d , m e a s u r e d , and into size  that  timid  surroundings.  o f c a p t u r e d i n d i v i d u a l s were a l s o r e c o r d e d .  0.5,  This  o f an a n a l y s i s o f v a r i a n c e o f  S e l e c t e d main e f f e c t s and  interactions  are  49  shown i n T a b l e  6, w i t h i n d i v i d u a l  degree of freedom t e s t s of  d i f f e r e n c e s i n f u n c t i o n a l response Figure  10 shows f i t s  of the observations  four periods f o r i l l u s t r a t i o n ) (Holling,  means and  shapes. {pooled over t h e  to Boiling's disc  eguation  1961),  Na = aTN / 1 + aThN  where  Na = number  attacked  a = attack rate T = total  time  Th = h a n d l i n g  available  time  N = prey d e n s i t y . I  found  t h a t e s t i m a t i n g a and Th by f i t t i n g  the eguation  Na/N = aT - aThNa  with simple l i n e a r  l e a s t sguares  o c c a s i o n a l l y unreasonable lower  r e g r e s s i o n g a v e u n r e l i a b l e and  estimates.  More r e a l i s t i c  v a l u e s and  s t a n d a r d e r r o r s o f e s t i m a t e were o b t a i n e d by n o n - l i n e a r  l e a s t sguares  fits.  For s i m p l i c i t y , the Michaelis-Menton  Na = cN / d '+ N  where  c = t h e maximum eaten  = T/Th  (asymptotic)  number  form,  50  d = the h a l f s a t u r a t i o n d e n s i t y = (2  T = t o t a l time N = prey was  used  f o r these  days i n t h i s c a s e ) ,  density,  fits.  E s t i m a t e s o f h a n d l i n g t i m e and temperatures  and two  attack rate f o r the  t y p e s of p r e y a r e shown i n T a b l e  B o t h h a n d l i n g t i m e and  the higher temperature. d e n s i t y i s not merely B o t h t h e l i n e a r and  a linear  The  curves are a l l t y p i c a l  {Appendix  no  was  (1980) who  The  o n l y weakly  a l t e r e d by t e m p e r a t u r e  found t h a t f u n c t i o n a l response  have a r i s e n merely  parameters  16°  C are  the range  Higher  or l o w e r t e m p e r a t u r e s might a l t e r  time.  P r e l i m i n a r y r e s u l t s f r o m an e a r l i e r e x p e r i m e n t  not i n c l u d e d  by h u n t i n g  well  pseudoscorpions.  a t t a c k r a t e and h a n d l i n g not  s u g g e s t t h a t b o t h a t t a c k r a t e and h a n d l i n g  t i m e a r e l o w e r a t 24<> C t h a n a t 8 o r was  and  This difference i n  b e c a u s e 8 and  normally encountered  ( T a b l e 5;  (1978)  within  here i n f a c t  on  d i f f e r e n c e i n number e a t e n a s a  seemed t o be s e n s i t i v e t o t e m p e r a t u r e . .  reported  little  h i g h l y s i g n i f i c a n t e f f e c t of t e m p e r a t u r e  response..  of s i z e  r e s u l t s may  Type I I  E contains the.contrast  T a b l e 6b) . . T h i s r e s u l t i s u n l i k e t h o s e o f Thompson Everson  6a.  used).  T h e r e was  function  i n c r e a s e i s shown i n T a b l e  h i g h e r o r d e r components account f o r  o r none o f t h e v a r i a t i o n  functional  a t t a c k r a t e a r e somewhat h i g h e r a t  g u a d r a t i c components of o r t h o g o n a l c o n t r a s t  responses;  coefficients  larger  Evidence t h a t the response to prey  tests are highly s i g n i f i c a n t . . functional  two  7..  H a n d l i n g t i m e i s h i g h e r and a t t a c k r a t e l o w e r f o r t h e prey.  1/aTh  i n t h i s experiment  16° c . . A 2 4 ° because of the  C  treatment  unnaturally  T a b l e 5-  A n a l y s i s o f v a r i a n c e o f t h e number o f p r e y eaten i n the f u n c t i o n a l response experiment. Analysis  Source  df  of  variance SS  Numbers e a t e n MS  F  2  Temperature  1  0.050  0.050  0.061  0.8168  Prey  size  1  56.113  56.113  68.447  < 0.0001  Size  X Temp  1  0 .200  0 .200  0 .244  0.6323  Density  4  35.519  8.880  10.832  < 0.0001  Dens X Temp  4  10.294  2.573  3.139  0.0261  Dens X S i z e  4  12.981  3.245  3.959  0.0086  Dens X Temp X Sz  4  5.956  1.489  1.722  0.1569  60  51.875  0.865  Pseudoscorpions Time ( h r s )  3  104.463  34.821  35.790  < 0.0001  Time X Temp  3  2.575  0.858  0.882  0.4515  Time X Dens  12  10.381  0 .865  0.889  0.5597  Time X S i z e  3  25.662  8.554  8.792  < 0.0001  12  10.956  0.913  0.938  0.5104  Time X Tmp X Sz  3  1.725  0.575  0.591  0.6217  Time X Den X Sz  12  I8.369  1.531  1.573  0.1024  Tm X D X S X Tmp  12  17.744  1.479  1.520  0.1200  Residual  180  175.126  0.973  Total  319  539-998  Time X Tmp X Den  52  Table  6. O r t h o g o n a l  BOUTce  c o n t r a s t s <i  ividual  degree  of freedom  tests)  1/  of v a r i a t i o n  a. ) P r e y  Density Linear  component  Quadratic Cubic  component  Higher b. ) D e n s i t y  component  order  components  X Temperature  4  10.270  0. 0001  1  29.115  < 0 0001  1  11. 357  1  0. 400  0 5293  1  0.212  0.6469  4  2.977  0.0261  1  5. 392  0 0236  1  2. 230  0 1406  1  3. 636  0. 0613  1  0. 650  0. 4234]  4  3. 754  0. 0083  1  5. 049  0 02S3  1  6. 412  0. 0140  1  2. 565  0. 1145  1  0. 987  0. 3244  4  35 790  < 0. 0001  1  B4.182  < 0.0001  1  20.557  0.0007  1  2. 631  0 1065  4  B. 792  < 0 0001  1  24.177  0 0007  1  0 463  0. 4973  1  1. 737  O.  0  0013  Differences in: LineaT  components  Quadratic Cubic  components  Higr.er c. > D e n s i t y  order  X Prey  D i f f e r e n c es Linear  Cubic  Size in:  components  components  Higr.er-  order  components  ) Time Linear  component  Quadratic Higher e  components  components  Quadratic  d  components  ) Time  component  order  X Prey  components  Size  D i f fe f e r, c e s i n : Linear  components  Quedr-etic Higher  1 /  components  order  components  1B92  F o r m a i n e f f e c t s <parts a a n d d) p ( t h e p r o b a b i l i t y o f ar, F-value the  as l a r g e  contribution  response.  indicates  significance  of t h e  by a component to t h e s h a p e of t h e f u n c t i o n a l  For i n t e r a c t i o n s  significance ac t i on.  or l a r g e r )  (parts  b,c a n d e ) , p i n d i c a t e s  o f t h e change i n a component due t o t h e i n t e r —  Table  7.  Estimates for  different  Each of  of handling time  estimate  20  prey  size  i s based  (Th) a n d  and on  attack  temperature  4 measurements  rate  (a)  treatments. taken  on  each  pseudoscorpions.  TEHPEfiATOBE 16° C  8°C  Th body  a 1.0 £M1  =  . 45  1  Th =  .59  = .38  1  a =  .47  = . 14  i  Th =  .24  = .68  1  length -  1. 2  mm  SIZE Th body  length a  0.5  -  0.7  am  a = 1.72  54  h i g h m o r t a l i t y o f t h e b o t h t h e p r e d a t o r and p r e y a t  this  temperature. Of t h e f o u r main e f f e c t s s t u d i e d i n t h e e x p e r i m e n t , s i z e accounted  f o r most o f t h e  v a r i a b i l i t y i n g r o s s numbers  eaten, suggesting that a well-defined size distribution Thompson  may  f u n c t i o n a l response  This effect  was  results  of i n d i v i d u a l  (p=0.0 1 1 7 ) . saturation  (shapes)  The  (p=0.Q245).  of the curves a l s o  (T/Th) and a t t a c k r a t e  s m a l l animals are required  linear  components the  The  differ  t o the higher  (a) f o r s m a l l p r e y .  to s a t i s f y the predators  they are attacked at a higher  prey  t o s m a l l p r e y and  T h e s e d i f f e r e n c e s a r e m a i n l y due level  Figure  6c.  t o l a r g e prey d i f f e r  q u a d r a t i c components  Lawton  d e g r e e o f f r e e d o m t e s t s on  of the f u n c t i o n a l response  f u n c t i o n a l response  and  by  glauca.  s i z e r e l a t i o n s h i p s a r e shown i n T a b l e (overall rises)  to prey  shown i n d e t a i l  (1975) f o r I s c h n u r a e l e q a n s and by M c A r d l e  (1979) f o r N o t o n e c t a The  exist.  prey  1  needs,  More and  rate.  10 r e p r e s e n t s t h e c u m u l a t i v e number o f c a p t u r e s  over  a 4 8 - h o u r p e r i o d . . T h e r e were, h o w e v e r , s t r o n g d i f f e r e n c e s i n t h e f u n c t i o n a l responses of i n d i v i d u a l changes through  48 h o u r s  p r e y d e n s i t i e s and t h a t each  predators over time.  The  i n t h e numbers o f p r e y e a t e n f o r t h e 5  2 p r e y s i z e s a r e shown i n F i g u r e 11.  p s e u d o s c o r p i o n was  s u b j e c t e d t o o n l y one  Recall  combination  of  t h e t e m p e r a t u r e - d e n s i t y - s i z e t r e a t m e n t s b u t t h a t a l l were observed over the f o u r time i n t e r v a l s . c a p t u r e s were r e l a t i v e l y of  F i g u r e 11 shows t h a t  high d u r i n g the f i r s t  12 h o u r s f o r most  the treatment combinations.. W i t h i n the f i r s t  24 t o 36  hours.  F i g u r e 10. Type I I f u n c t i o n a l r e s p o n s e c u r v e s f o r t h e two t e m p e r a t u r e s and two p r e y s i z e s . E s t i m a t e s o f the d i s c e q u a t i o n parameters are shown i n T a b l e 7.  Prey number eaten (l.0-1.2mm  prey)  4  5  density  8  12  4 3 2 1  ol  j  .  t  *  12  24  36  48  number eaten (0.5-0.7mm  prey)  12  24  36  48  Time  12  24  36  period  48  12  24  36  48  (hours)  F i g u r e 1 1 . Changes i n t h e number e a t e n p e r 12 h o u r s w i t h changes i n p r e y d e n s i t y , p r e y s i z e and t i m e . S t a n d a r d e r r o r b a r s a r e shown. E a c h p o i n t i s t h e mean o f 8 o b s e r v a t i o n s ( o n 8 d i f f e r e n t p r e d a t o r s ) .  57  t h e number o f c a p t u r e s p e r 12 h o u r s i n most c a s e s l e v e l l e d a minimum. . A number o f p s e u d o s c o r p i o n s  were o b s e r v e d  o f f at  for further  p e r i o d s up t o 84 h o u r s , b u t i n no c a s e was any d r a m a t i c i n c r e a s e or  decrease i n captures observed  where two p s e u d o s c o r p i o n s container strong  walls).  linear  were drowned i n c o n d e n s a t i o n on t h e  (p < 0.0001) and g u a d r a t i c (p=0.0008)  had p r e v i o u s l y  (except  I n g e n e r a l , t h e c h a n g e w i t h t i m e had v e r y  w i t h no s i g n i f i c a n t  relationship  i n the l a t e r i n t e r v a l s  h i g h e r degree t r e n d s  components  (p=0.1121; T a b l e 6 d ) .  hypothesized that temperature  s h o u l d change  because of expected changes i n a c t i v i t y ,  I  this  metabolism  and n u t r i t i o n a l n e e d s of t h e p r e d a t o r , b u t t h i s d o e s n o t seem t o have happened size, in  (Time X T e m p e r a t u r e i n t e r a c t i o n ,  however, d i d cause a s i g n i f i c a n t  (p=0.0007)  c a p t u r e s o v e r t i m e , a s was e x p e c t e d .  first  Table 5). linear  Prey change  The c h a n g e f r o m t h e  1 2 - h o u r p e r i o d t o t h e l a s t was g r e a t e r f o r s m a l l p r e y ,  suggesting that the pseudoscorpions  "adjust" to eating smaller  prey. .  II.. The r e s u l t s  Size-selection  by t h e P r e d a t o r s .  o f t h e two r u n s o f t h e s i z e - s e l e c t i o n  were v e r y s i m i l a r , so t h e d a t a were p o o l e d .  During the period  a l l o w e d , t h e p s e u d o s c o r p i o n s a t e 26 o f t h e 221 p r e y (Figure  12).  As i n o t h e r e x p e r i m e n t s  experiment  available  n o t r e p o r t e d h e r e , none o f  t h e p r e y e g g s were e a t e n , e v e n when h u n d r e d s were o f f e r e d . data suggest a strong preference f o r prey i n d i v i d u a l s in length.  I showed  i n the f u n c t i o n a l  The  a r o u n d 1 mm  response experiments  A. m i n i m u s d i d n o t r e f u s e t h e s m a l l e r p r e y when no c h o i c e  that  was  58  •y  .1 .2  .3  .4  .5  .6  .7 .8 .9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0  length  class  (mm)  F i g u r e 12. Size frequency d i s t r i b u t i o n of prey population a v a i l a b l e to A. minimus and t h e p r e y e a t e n .  59  available. Selection  The  e q u a t i o n s of Manly  Experiments  estimate s e l e c t i v i t y  (1973,  f o r Type  (without prey replacement) statistics.  The  Two  were used  to  p r o b a b i l i t y , J5c , t h a t a  p r e y i n d i v i d u a l from the i t h s i z e c l a s s had  1974)  would  have b e e n  t h e r e been an e q u a l number o f i n d i v i d u a l s i n e a c h  selected  class i s  shown i n T a b l e 8. . S i n c e A.  minimus uses i t s l a r g e p a l p a l c l a w s t o " p i n c h " t h e  p r e y on t h e abdomen o r p r o t h o r a x , and  g u i c k l y t r a n s f e r them t o  the c h e l i c e r a e , i t i s u n l i k e l y  that the preferred  determined  t h a t c a n be g r a s p e d  by t h e maximum s i z e  as i n the mantid Holling  Hierpdula crassa (Holling,  e t a l . , 1976).  l i m i t e d by t h e a b i l i t y macerate  which  first  of the s m a l l e r c h e l i c e r a e t o h o l d  manner  s i z e a t t h e moment when t h e d e c i s i o n  c a p t u r e i s made.  I believe that a hunting  measures prey s i z e  t h u s c o u l d be  with the long t a c t i l e (see F i g u r e 1 3 ) .  suggested  a c t i v i t y , and  t h a t t h e r e may  pseudoscorpion  s e t a e on  spp.  prey,  the  A decision to attack  b a s e d on p r e y s i z e , p r e d a t o r h u n g e r ,  minimus r e f u s e s t o eat O n y c h i u r u s  s i z e , shape,  to  t h e n , as i t r e a c h e s f o r t h e  o t h e r i n f o r m a t i o n , s u c h a s t e x t u r e or s m e l l .  and  perhaps  (I have noted  (Collembola) of  c o l o r t o F . , C a n d i d a . . Weygoldt  that  similar (1969)  be an o l f a c t o r y r e c e p t o r on t h e t i p o f  t h e p a l p a l f i n g e r s and a t a s t e r e c e p t o r n e a r t h e p r e o r a l which  and  I have observed i t b e i n g used t o " f e e l " p r e y , t h a t i t i s  dorsum o f t h e p a l p a l hand  A.  also  I suspect t h a t t h e s i z e of prey i s  d e t e c t s p r e y movement and  roughly  see  foreleg  g i v e n t h e m o r p h o l o g y o f t h e p a l p a l hand and t h e  used t o e s t i m a t e prey attempt  196 4;  by t h e  i t s o t h a t body f l u i d s c a n be drawn o f f . . But i t i s a l s o  possible, in  prey s i z e i s  allow pseudoscorpions to recognize the unpalatable  cavity  Table S. s e l e c t i v i t y s t a t i s t i c s foe length classes o£ prey. 2 . /  Class  pooled lenqth  L  e.  £i  classes  1  0.2  ,0.3  21  0  21  0.00 0 0  2  0.4  ,0.5  42  0  42  0.0000  3  0.6  ,0.7  60  1  59  0.0176  4  0.8  ,0.9  35  6  29  0. 1963  5  1.0  ,1.1  43  16  27  0.4858  20  5  15  0.3003  6  1.2, 1.3, 1.4,1.5  (1973) &  2./ HAH L Y s 1  -  \  i s c a l c u l a t e d as  log ( / KI /J^logU:, / AJ  where  Ci  kc = the nuaber of prey of c l a s s i i n i t i a l l y available e; = the number of prey of c l a s s i eaten r = the number of prey remaining (  K = t o t a l nuaber of s i z e c l a s s e s = 6  Figure (palpal  13. or  Tactile  setae  on  c h e l a l hand) o f A.  (Magnification:  210  X)  the  "pincer  minimus.  62  Onychiurids.) The  s i z e of prey t h a t i s p r e f e r r e d  predator's  lifetime.  suggest t o  me t h a t  mm)  usually prefer  proportionately  Casual observations  these smaller  smaller,  change over a o f A . . m i n i m u s nymphs  s i z e d predators  s m a l l e r , though not  necessarily  the  feeding  r e s p o n s e of  p s e u d o s c o r p i o n N e o b i s i u m muscorum i s i n i t i a t e d prey..  S i m i l a r l y , the  show t h a t  observations  movement o f c o l l e m b o l a n  d e t e c t i o n , p u r s u i t and biguttatus ecdysis,  F..  the  predation  risk  attack  not  carabid beetle  of r e l a t i v e by t h e  beetle.  the  influenced Say.  The  predation  by t h e  movement b y t h e  prey's i n s t a r .  The  predator  I is  was  individuals sucessfully in later  defensive  movements were t o o  do n o t  believe that  a direct function  C a n d i d a had  (and  other  and  species  l e v e l s of  Podius  maculiyentris  more a c t i v e was  (Dyar),  larvae  a t t r a c t e d by  the  unable t o attack i n s t a r s because  the  their  vigorous.  s i z e - s e l e c t i v e predation  of prey a c t i v i t y .  d i f f e r e n c e s i n a c t i v i t y among o l d and o l d e r F.  relative  ( E r n s t i n g et a l . ,  p e n t a t o m i d bug,  movements o f s m a l l a c t i v e l a r v a e b u t active  The  Malacosoma c a l i f o r n i c u m p l u y i a l e  conseguences of  changed w i t h  such a s  (1970) f o u n d t h a t a c t i v i t y  Wellington  tent c a t e r p i l l a r ,  Notiophilus  d e p e n d s on t h e r a t i o of a c t i v e  w e l l as on r e l a t i v e d e n s i t i e s  1977).. Iwao and  the  their  inactivity,  i n a c t i v e i n d i v i d u a l s of a p a r t i c u l a r species present) as  by movement o f  prey i s necessary'for  detected  of p r e y s p e c i e s  the  o f E r n s t i n g e t a l . . (1977)  by t h e  During periods  prey are  ( l e n g t h < 1.5  F. C a n d i d a .  (1976) n o t e d t h a t  Goddard  may  a tendency to  I have not  by  A..minimus  s e e n any  great  young i n d i v i d u a l s , a l t h o u g h  disperse  f a r t h e r than  the  63  younger ins-tars i n separate F)..  Sudden b u r s t s o f p r e y  circumstances  d i s p e r s a l experiments activity  among i t s p r e y  t o capture  i n which t h e p r e d a t o r  moving p r e y .  own p r e d a t o r s , p a r t i c u l a r l y  The  experiments  A. m i n i m u s w i l l  and J o n e s  pseudoscorpions.)  on f u n c t i o n a l r e s p o n s e  demonstrate t h a t  f e e d on s m a l l F. C a n d i d a i f no a d u l t p r e y i s  a v a i l a b l e , b u t t h e s a t u r a t i o n number o f p r e y e a t e n rate are consistently  higher f o r s m a l l prey.  c h o o s e among v a r i o u s s i z e s defined these  When A. m i n i m u s can  of prey, however, i t d i s p l a y s a w e l l -  c l a s s e s (see Chapter  lationship)  represent  d i f f e r e n t age c l a s s e s w i t h  different preference f o r  p r e y h a s s i g n i f i c a n t e f f e c t s on t h e s t r u c t u r e and  a t t r i b u t e s of a n a t u r a l population. suggest  Additional observations  t h a t A. m i n i m u s h a s t h e same t y p e  of s i z e  preference  f e e d i n g on L e p i d o c y r t u s s p . _and I s o t o m a s p p . , o t h e r in  my s t u d y  site.  Because of t h e i r  g r o w t h and d e v e l o p m e n t a l be  Because  Two f o r t h e a g e - l e n g t h r e -  reproductive r a t e s , I telieve that the predator's larger  and t h e a t t a c k  p r e f e r e n c e f o r m i d - s i z e t o l a r g e F. C a n d i d a .  size  movements by  (Pseudoscorpions  centipedes;  (1975) a l s o d o c u m e n t s s p i d e r p r e d a t i o n on  behavior,  makes no  Sometimes, i n f a c t ,  t h e p r e y l e a d t o f l i g h t by t h e p s e u d o s c o r p i o n s . have t h e i r  i n some  s t i m u l a t e A. m i n i m u s t o b e g i n s e a r c h i n g  b u t t h e r e a r e many e n c o u n t e r s attempt  (see Appendix  particularly  selective chapter.  peculiar  springtails  post-embryonic  p a t t e r n , a l l s p r i n g t a i l p o p u l a t i o n s may  vulnerable t o the r a m i f y i n g e f f e c t s of s i z e -  predation.  when  I i n v e s t i g a t e these e f f e c t s  i n t h e next  CHAPTER POUR  PREDATION OF APOCHTHONIUS MINIMUS CHTHONIIDAE) ON FOLSOMIA CANDIDA II.  (PSEUDOSCORPIONIDA:  (COLLEMBOLA: ISOTOMIDAE)  EFFECTS OF PREDATION ON PREY POPULATIONS  65  INTRODUCTION  When age o r s i z e c l a s s e s a r e e a s y t o d i s t i n g u i s h w i t h i n a population, numerical for  i n v e s t i g a t o r s can study  t h e s t r u c t u r a l as w e l l as t h e  consequences of s e l e c t i v e predation  whole c o m m u n i t i e s .  F o r example, Paine  f o r populations  (1976) d e s c r i b e d  situation  i n which l a r g e r mussels escaped p r e d a t i o n  Galbraith  (1967) f o u n d t h a t s i z e - s e l e c t i v e p r e d a t i o n  p e r c h e l i m i n a t e d one l a r g e s p e c i e s d i s t r i b u t i o n s of others and  B r o o k s and Dodson  larger  species  (1965) r e p o r t e d  of Cladocera,  with  s e l e c t e d w i t h i n each s p e c i e s . s u r v i v a l time predation  by t r o u t and  Brooks  a predator  size  (1968)  preference f o r  l a r g e r i n d i v i d u a l s being  Brooks  (1968) f o u n d t h a t  prey  was i n v e r s e l y p r o p o r t i o n a l t o p r e y l e n g t h , s o t h a t  pressure  towards s p e c i e s  shifted  with  demonstrated t h a t selection  classes.  a  by s t a r f i s h .  o f D a p h n i a and s h i f t e d  t o the smaller  or  the species  composition  s m a l l e r body s i z e .  zooplankton  Dodson  of the prey  (1974)  associations are subject t o size-  a t b o t h ends o f t h e s i z e spectrum, and d i s c u s s e d t h e  community c o n s e g u e n c e s .  Addicott  (1974) showed how t h e p r o t o z o a n  communities of p i t c h e r plants a r e a l t e r e d i n r e l a t i o n t o t h e distribution  and d e n s i t y  of predatory  mosquito l a r v a e .  most o f t h e s e s t u d i e s have been c o n c e r n e d w i t h  Although  predation-related  changes i n c o m m u n i t i e s , t h e e f f e c t s o f s e l e c t i v e p r e d a t i o n populations on  may be as d r a m a t i c .  I t h i n k t h a t one r e a s o n  t h e e f f e c t s of s i z e - s e l e c t i v e p r e d a t i o n  has so o f t e n  communities r a t h e r that s i n g l e - s p e c i e s populations p r e y t y p e s and s i z e s  ( i . e . species  d i s t i n g u i s h i n communities.  on research  concerned  may be t h a t  o r genera) a r e e a s i e r t o  66  Assessing  these  more d i f f i c u l t  when age  indistinguishable, and  their  s t r u c t u r a l c o n s e q u e n c e s o f p r e d a t i o n may or s i z e c l a s s e s are  or a p p a r e n t l y  be  superficially  unrelated.  Among t h e i n s e c t s  n e a r r e l a t i v e s s u c h a s s e s s m e n t s have i n most c a s e s  restricted  t o the  LeCato, 1978;  predator  ( e . g . B e d d i n g t o n and  Eveleigh, 1979)..  however, the C o l l e m b o l a ,  because of t h e i r  predation..  p o p u l a t i o n consequences of  I have used t h e p r e f e r e n c e  of the  predation.  to assess My  o f p r e d a t i o n c o u l d be  significantly  guality  populations.  of s p r i n g t a i l  structural  as  pseudoscorpion, Candida  the p o p u l a t i o n conseguences of  more i m m e d i a t e g o a l was  growth  selective  A p o c h t o n i u s minimus, f o r c e r t a i n s i z e s of Folsomia (Collembola)  insects,  p e c u l i a r form of  provide exceptional opportunities f o r assessing the w e l l as t h e n u m e r i c a l  1976;  Free,  I n c o n s t r a s t t o most  been  selective  to determine i f t h i s  a f f e c t i n g the  size  sort  and  METHODS O b j e c t i v e s : t o q u a n t i f y t h e e f f e c t s o f p r e d a t i o n on and  age  the  hypothesis  prey  (size)  s t r u c t u r e o f F . . c a n d i d a p o p u l a t i o n s and  growth  to  test  t h a t the presence of predators r e s u l t s i n reduced  numbers. A simple  performed  experiment with a completely  i n which the only treatment  was  o f a d u l t A.  minimus.  s i t e at the  UBC  to k i l l  desicate a l l microarthropods.  and  grams o f t h i s  the presence or  L i t t e r from the f o r e s t f l o o r  R e s e a r c h F o r e s t was  litter  randomized design  d r i e d at 600  were added t o e a c h o f  absence  of the  study  c f o r 48  hours  Approximately 16  was  plastic  8  pipe  to  10  67  containers 16°  (I.D.  C f o r one  (ranging from  5 cm;  day. 1.0  -  length  10 cm),  m o i s t e n e d , and  Ten  a d u l t s f r o m F.  1.2  mm  i n length)  Candida  The  laboratory  16 c o n t a i n e r s  had  no  The  p s e u d o s c o r p i o n s had  study  predators  site  and  and  laboratory  and  at  stock  were added t o e a c h o f  c o n t a i n e r s . . (F. C a n d i d a i s p a r t h e n o g e n e t i c m a l e s e x i s t e d i n my  incubated  I suspect  the  that  no  populations.)  were r a n d o m l y d i v i d e d i n t o  8 r e c e i v e d 3 a d u l t A.  groups: 8  m i n i m u s per  been c o l l e c t e d t h e day  stored i n incubators  two  before  container. at  t h a t mimicked the  the  field  environment. The plastic  c o n t a i n e r s were c o v e r e d  mesh h e l d by s n a p - o n r i n g s and  Preliminary f i e l d  t r i a l s and  m i c r o s c o p e showed t h a t n o t escape through in  at b o t h ends w i t h  the  mesh.  observations  and  centimeter  covered  The  containers  E v e r y two  with l e a f l i t t e r  o f t h e i r s u r f a c e was  randomly assigned  i n a 2m  X 2m  weeks t h e c o n t a i n e r s  of d r y i n g .  46  Temperatures at the  days  were g u i c k l y t r a n s p o r t e d  study  site,  until  only the  exposed. area  on  their  uppermost  T h e i r p o s i t i o n s were  s h a d e d by  4 corner  trees..  were c h e c k e d f o r damage and litter  surface  danger  were m o n i t o r e d floor.  {enough t i m e f o r a b o u t 3 g e n e r a t i o n s  of t h e  prey)  the  insulated cooler.  were r e t r i e v e d and  returned  There they  p r e v i o u s l y c a l i b r a t e d Macfadyen  Candida  laid  forest  containers  F.  could  the  the  w h i c h had  tape.  under a d i s s e c t i n g  w i t h a 7-day t h e r m o g r a p h i n a s h a d e d s c r e e n After  with  e v e n n e w l y h a t c h e d F. C a n d i d a  a humid, i n s u l a t e d c o o l e r t o the  sides,  sealed  54-micron  t o the  laboratory i n  were e x t r a c t e d w i t h  (1961) h i g h - g r a d i e n t  a measured e x t r a c t i o n e f f i c i e n c y (discussed below).  on  The  of  springtails  ~  96% and  a extractor for  68  p s e u d o s c o r p i o n s were e x t r a c t e d picric  o v e r a 6-day p e r i o d i n t o  a c i d , c o u n t e d , and m e a s u r e d .  i n t o n i n e t e e n 0.1-mm s i z e c l a s s e s  I grouped  (measured  the  cold  springtails  f r o m t h e mouth t o t h e  p o s t e r i o r t i p o f t h e a n a l segment) o v e r t h e r a n g e , 0.2  - 2.0  The  after  cylinders  drying  a t 70°  were w e i g h e d  b e f o r e e x t r a c t i o n and a g a i n  mm.  C i n order t o estimate moisture content of the  litter.  RESULTS AND  DISCUSSION  Uncontrolled Environmental Air  t e m p e r a t u r e s and r a i n f a l l  s t u d y a r e a by t h e UBC D.  The  Research  23.5° C d u r i n g t h e e x p e r i m e n t .  week were 14. 1 + 0.48,  The  range  20°  C ) , s i n c e t h e s t u d y s i t e was  consistently  0.5  was  179.6  differ  14.5  to  not extreme  (between  The  middle  + 0.27° c. 10  and  temperature  not c o n t i n u o u s l y monitored, but  R a i n f a l l d u r i n g the experiment  to a total  o f 15.6  cm.  + 14.35.  at  was  Mean m o i s t u r e and  soil  was  (176.2 + 2 2 . 4 ) .  (183.0 + 19.5)  light,  ( w a t e r l o s s as a  i n the c o n t a i n e r s  Per cent moisture at c o l l e c t i o n  between t h e 8 t r e a t m e n t  containers  and  w e l l shaded.  p e r c e n t of dry weight) of the l i t t e r was  Appendix  - 1.0" C c o o l e r t h a n t h e s u r f a c e t e m p e r a t u r e  whenever c h e c k e d . amounting  f r o m 8.5  i n t e r v a l s f o r the f i r s t ,  16. 1 + 0.46  of s u r f a c e temperature  was  s u r f a c e ranged  my  Means and s t a n d a r d e r r o r s o f t h e  s u r f a c e t e m p e r a t u r e a t t h r e e hour  a d e p t h o f 5 cm  d a t a r e c o r d e d 1 km f r o m  F o r e s t S t a f f a r e shown i n  temperatures of the l i t t e r  and l a s t  Variables  and  time d i d not  the 8 c o n t r o l  M o i s t u r e c o n t e n t of t h e s o i l  and  Table  9.  D e s c r i p t i o n o f t h e f i n a l p o p u l a t i o n s and c o n t e n t s c o n t a i n e r s a t t h e end of t h e e x p e r i a e n t .  F.  Container "H»ber  Control  Per cent Moisture  Total iaaatures .no,. K . 7 5 an)  o f the  Candida  adults (>.75aa)  Bean l e n g t h .(variance!  aedian length  remaining ijredatati.  populations:  1  66.67  136  48  88  2  162.50  202  94  3  196.00  86  4  2 16.67  5  . 845  (.070)  . 872  108  .816  (.123)  .779  23  63  .987  (.096)  . 998  91  12  79  .986  (.042)  . 985  198.33  132  67  65  .817  (.120)  .710  6  164. 81  438  170  268  .843  (.06 1)  . 881  7  206.25  6  0  6  1.23  (.016)  1.22  8  252.94  243  133  110  . 743  (. 100)  . 683  .780  (.058)  .758  Populations  with  predators:  9  283. 54  371  179  192  10  109. 14  0  0  0  1 1  215.63  215  10 1  114  .821  (.081)  .77*  2  12  203.77  440  193  247  .827  (.078)  .803  3  13  198.55  0  0  0  (  Extinct )  0  IV  125.61  0  0  0  (  Extinct )  0  15  177.05  0  0  0  ( Extinct )  1  16  115. 63  20 6  143  63  ( Extinct )  .664  (.065)  3 1  .596  3  70  litter  p l a y s an i m p o r t a n t  Collembola 1977).  p o p u l a t i o n s and  In t h i s experiment,  were n e i t h e r l a r g e n o r composition, Moisture, in  role  Table  i n the  survival  communities  (Verhoef,  o r mean body l e n g t h a t c o l l e c t i o n and  mean and  length-frequency  p o p u l a t i o n s t h a t s u r v i v e d the c o n t r o l populations  Normally,  can 40th  moisture  size,  time  (p >  0.3).  median l e n g t h s a r e  shown  Distributions  d i s t r i b u t i o n s of  predation treatment  ( F i g u r e 15)  expected  t e n d e d t o be  t o be n e a r l y c o n t i n u o u s , most o f t h e i r  i n s t a r according  distributions  to Snider,  lives  1971).  shown h e r e i s a r e s u l t  populations  the  ( F i g u r e 14)  populations  because the i n s e c t s (from  The  the  6th t o  b i m o d a l form of  of t h e f a c t t h a t  t h e d i s t r i b u t i o n s shown h e r e t h e r e f o r e must i n c l u d e a t  least  wave o f  the o r i g i n a l a d u l t s , t h e i r  j u v e n i l e s t o hatch  the  the Most  last  were composed e n t i r e l y  the  of a d u l t s .  three generations:  and  bimodal.  s i z e - f r e g u e n c y d i s t r i b u t i o n s of Collembola  l a y eggs through  starting  Ernsting,  9. .  Several of the  c o u l d be  1977;  c o r r e l a t e d with population  population size,  s t r u c t u r e of  however, the d i f f e r e n c e s i n  I n t e r p r e t a t i o n of Length-Frequency  of the  and  of  o f f s p r i n g , and  before the f i e l d c o n t a i n e r s  the were  returned t o the l a b o r a t o r y . T h e r e was  great v a r i a b i l i t y  i n d i v i d u a l s p e r c o n t a i n e r , as  i n t h e t o t a l number o f  m i g h t be  expected  when t h e  experimental  u n i t s are c o n f i n e d , growing p o p u l a t i o n s .  v a r i a n c e may  be  changes i n t h e i r Mertz,  1969);  due  toz  own  (2) t h e  (1) t h e  This  s e n s i t i v i t y of p o p u l a t i o n s  s t r u c t u r e or q u a l i t y treatments,  high to  (as w i t h T r i b o l i u m ,  [as with the  variabilities  in  71  40,  .0  0) 3 U 0)  n —  r .1  J  .«  —i , , , , .4  .6  M  .7  »  .• 1.0 i.l  1J l » 1.4 l » t.  (  1.7 l.« i t  length  2.0  class  .1  J a  4  .»  •  ,T  .1  t 1.0 1.1 1.1 1.3 14 IS  1.C 1.7 1.1 l.t  (mm)  F i g u r e 14. The l e n g t h - f r e q u e n c y d i s t r i b u t i o n s o f the f o u r p o p u l a t i o n s t h a t s u r v i v e d the p r e d a t i o n treatment.  1.0  I 3 C  9)  <*-  J  J l  10;  V« VI  1*  1.T  VI  VI  1.0  J  •*  •*  length class F i g u r e 15The l e n g t h - f r e q u e n c y the e i g h t c o n t r o l p o p u l a t i o n s .  •*  •*  -•  J  *  1*  VI  VI  1.3  1.4  1.5  VI  1.?  (mm) distributions  of  1.8  1.9  2.0  73  s i z e and  yield  Slobodkin  and  e x a m i n e d by Richman  exploitation  Hoppenheit  - 440  individuals..  environmental  (1975) ]; o r  (3)  differences  final  population size  T h e r e was  scarcely  ranged  any  I t i s possible that  undetected  i n f l u e n c e s or f u n g a l growth a f f e c t e d the  fecundity  and  following  analyses accordingly take t h i s p o s s i b i l i t y  account,  (197 1) ,  rates.  r e p r o d u c t i o n i n c o n t a i n e r #7. adverse  Usher e t a l .  i n f l u e n c e s or undetected  I n a l l b u t c o n t a i n e r #7, b e t w e e n 86  (1955),  (1956) and  uncontrolled environmental in  Watt  s u r v i v a l of the s p r i n g t a i l s i n t h i s c o n t a i n e r .  by i n c l u d i n g  and t h e n  The  into  e x c l u d i n g #7.  I take  this  a p p r o a c h t o be c o n s e r v a t i v e .  I n c l u s i o n o f #7  i n the  analyses  would s t r e n g t h e n  d i f f e r e n c e s and  favor  the observed  my  interpretation. The  presence  probability eight)  of the pseudoscorpions  of s u r v i v a l o f t h e  of t h e s e  populations.  p o p u l a t i o n s became e x t i n c t  cases, the pseudoscorpions of the  prey  markedly a f f e c t e d t h e  probably  (Table  Four  9). . In  managed t o f i n d  o r i g i n a l s p r i n g t a i l s before they  their  could reproduce.  among t h e (Figures  l a r g e s t of the s u r v i v i n g 14 and  c l a s s e s ) do  The  Although  the t o t a l  not d i f f e r s i g n i f i c a n t l y  c o n t r o l groups immmatures  15)..  collembolan  (0.1  But  the  with  t h e s e f o u r were populations  numbers  (ignoring size  between t h e t r e a t m e n t  < p < 0.2) , t h e numbers o f  these  In  p o p u l a t i o n s t h a t s u r v i v e d along  p r e d a t o r s p r o d u c e d an u n e x p e c t e d r e s u l t :  of  most o r a l l  c o n t r a s t , none o f t h e e i g h t c o n t r o l s became e x t i n c t . other four experimental  (out  and  surviving  do.  f i n d i n g s o f M a r s h a l l and  Kevan  (1962), S n i d e r  (1971),  74  Snider  and  begins  o v i p o s i t i o n i n the  vary from although and vary  Butcher  0.7  (1973) and  - 0.8  mm  [ M a r s h a l l and  Hutson  The  immatures than  container  6th i n s t a r ,  i n l e n g t h and Kevan  pH  f o r l e n g t h c l a s s e s 0.2  included).  s u g g e s t t h a t F.  and  t o 0.7  are about  16 - 21 days o l d ,  ( 1 9 6 2 ) , S n i d e r and  Butcher  at f i r s t  genetics]. mm  Table  ( i m m a t u r e s ) and  0.8  t o 2.0  must be members o f t h e  l a b p o p u l a t i o n s as those  is  "immatures" i n each  most r e c e n t g e n e r a t i o n ,  l e n g t h s of F. C a n d i d a  used i n t h i s  Two).. F i g u r e  5 shows t h e  age-length  Although  f e c u n d i t y and  l o n g e v i t y may  be  10. (from t h e  experiment)  t h r e e f l u c t u a t i n g t e m p e r a t u r e s w i t h means o f 8, (Chapter  this  Relative  f r e q u e n c i e s o f t h e s i z e c l a s s e s a r e shown i n T a b l e p r e v i o u s l y recorded  mm  h a v e more  t h e c o n t r o l s (p=0.048; o r p=0.03 i f #7 m a j o r i t y of the  may  9 shows t o t a l s  populations s u r v i v i n g predation  Since the  (1973),  oviposition  d i f f e r e n c e , though not l a r g e , i s worth n o t i n g .  I  Candida  when i n d i v i d u a l s u s u a l l y  (1978) h a v e shown t h a t age  with temperature,  (adults)..  myself  over  75  16 and  same days at  24°  C  relationship.  overestimated  i n such  l a b o r a t o r y s t u d i e s , subseguent c o n f i r m a t o r y i n v e s t i g a t i o n s with another  p o p u l a t i o n suggest t h a t the  age-length  t h i s species i s , i n fact, r e l a t i v e l y  inflexible,  r e l a t i o n s h i p shown i n F i g u r e 5 s h o u l d r a t e s of i n d i v i d u a l s t h e r e can  be no  adequately  so t h a t  d o u b t t h a t s i z e i s a f u n c t i o n o f age  Some a r t h r o p o d  age  and  for  the  represent  u n d e r n a t u r a l c o n d i t i o n s . . I n any  size classes represent  growth  case, that  c l a s s e s , t h o u g h not e x a c t l y .  p o p u l a t i o n s h a v e been shown t o a d j u s t mean  l e n g t h and  weight i n r e l a t i o n  Peters  Barbosa, 1977). . Hoppenheit  and  relationship  to population d e n s i t y (1976) has  (reviewed  by  shown t h a t mean  Table  10.  Relative frequencies  (S o f t o t a l )  s i z e s o f t t S S S i i S a i n t h e 16  of the d i f f e r e n t  populations.  Container No.  S I Z E CLASS ( :0.2  0. 3 —  0.4  0.5  0.6  0.7  0.8  0. 9  1. 1  1. 2  1. 3  1.4  1.5  1.6  1.7  ---  1  0.0  0.7  4.4  14.0  10.3  5.9  11.0  2  0.0  5.0  9.4.  16.8  8.4  6.9  8.9  3  0.0  0. 0  0.0  5.8  17.4  3.5  9.3  4  0.0  0. 0  0.0  1. 1  3.3  8.8  9.9  20. 9  5  0.0  3.0  10.6  15.2  12.9  9. 1  9. 1  6.8  6  0.0  0.0  2.7  12.6  9.4  14.2  13.7  12.3  7  "0.0  0.0  0.0  0.0  0.0  0.0  0.0  8  0.0  3.7  17.3  18. 1  6.2  9.5  9  0.0  1.9  8.4  17.0  10  1.0  5. 1  14. 0  i. a —  1. 1 —  —  7.  19. 1  10.3  5. 1  2. 2  1.5  0.7  0. 7  0.0  0. 0  0. 0  0. 0  8.4  10. 9  7.9  6. 4  4.0  3. 0  1.0  1.0  0.5  0. 5  0. 5  0.5  7.0  14.0  11.6  9. 3  8. 1  5.8  7.0  0. 0  0. 0  1.2  0. 0  0. 0  16.5  18.7  16. 5  .1. 3  0. 0  0.0  0. 0  0.0  n.  n  1. 1  0. 0  6.8  6. 1  3.0  0. 8  0. 0  0. 0  0. 0  O.n  1. 1  0.0  0. 2  0.0  0. 0  0. 0  0.0  0.0  0. 0  0.0  0. 0  0. 0  n. o  5. 3  5. 3  6. 1  13.0  9. 8  7. 3  3. 7  0.0  16. 7  0.0  33. 3  33. 3  16.7  10. 7  7.8  7.0  9.9  2. 5  3. 7  1.2  0.8  0.8  0.8  0. 0  n. f)  0. n  15.9  15.9  12. 4  11.3  6. 7  1.9  2. 2  0. 3  (1. 3  0. 3  0.3  0. 3  0. 0  o. n  { E x t i net )  1 1  0.0  1. 4  4.2  12.6  18.6  10.2  7.9  10. 7  13.0  7. 0  6.5  5.6  0.9  0.0  0.5  0.5  0.5  0. 0  o. n  12  0.5  3.0  3.2  10.7  13.9  12.7  8.6  12. 3  14. 3  6. a  7.7  3. 6  1.4  0.9  0. 2  0.0  0. 0  0. 2  n. o  16.0  15.5  17.0  12.1  8.3  2.9  2. 9  1. 5  1.5  0. 0  0.0  0..5  0.5  0.5  o. n  0.0  13  ( Extinct  14  ( Extinct )  15  ( Extinct  16  0.0  5.8  )  ) 15.0  n  76  w e i g h t and  length  mean p o p u l a t i o n  o f a d u l t c o p e p o d s may  d e n s i t y , but  Green  be  i n v e r s e l y r e l a t e d to  (1964b) f o u n d no  b e t w e e n t h e r a t e o f d e v e l o p m e n t o f i s o l a t e d F. i n d i v i d u a l s and the  s p r i n g t a i l s i n a l l 16 c o n f i n e d  r a t e , and not  t h o s e i n mass c u l t u r e s .  that the  i n c l u d e any  final  density-induced  One  experimental  at the  end  of the  all  of these populations  (0.2  p r e v i o u s l y d o m i n a n t age  Macfadyen high  Folsomia  - 0.4  10 a d u l t s , and d i d not  mm  s m a l l number o f i n length)  (1973, 1979)  (Although  he  m u l t i p l y i n g by  individuals in  6.)  discovery  that  e x t r a c t o r i s low  that  (Dapson,  the  1971;  be efficiency  f o r very  small  larger size classes  of  w e l l w i t h t h i s eguipment, Takeda  o f c l a s s e s < 0.5  mm  had  t o be  corrected  S i m i l a r f i n d i n g s have been r e p o r t e d  Petersen  (1978) f o r a v a r i e t y o f s p r i n g t a i l s p e c i e s .  m i g h t be  argued t h a t the  young F.  Candida i n my  a l s o h a v e been u n d e r e s t i m a t e d d u r i n g s o , however, a l l of t h e p o p u l a t i o n s a f f e c t e d and  vary  losing a  young m a t u r e d  could estimate  octoculata reasonably  the  the  merely i m p l i e s  were e i t h e r d e c l i n i n g or  gradient  do  experiment.  c l a s s as the  found t h a t h i s e s t i m a t e s by  same  In f a c t ,  A l t e r n a t i v e l y , t h i s s m a l l number m i g h t  by T a k e d a ' s  springtails.  with  surviving populations  younger c l a s s e s  of the  that  such changes, s i n c e I s t a r t e d  populations  the  explained  grew a t t h e  changes i n l e n g t h .  might a l s o argue that the  Tanner, 1978).  I t h e r e f o r e assume  populations  have p r e v e n t e d  d e n s i t i e s of the  appreciably  Candida  f r e g u e n c y d i s t r i b u t i o n s of t h e i r l e n g t h s  method I u s e d s h o u l d each of the  difference  should  t h e e f f e c t s of p r e d a t i o n  Thus i t  experiment  extraction.  If this  have b e e n  by  might were  similarly  w o u l d n o t h a v e been  o b s c u r e d by a c o n f o u n d i n g e f f i c i e n c y e f f e c t .  The  differences in  77  t h e numbers o f i m m a t u r e s shown i n T a b l e s and  9 and 10 a n d F i g u r e s  15 t h e r e f o r e must r e f l e c t a r e a l d i f f e r e n c e b e t w e e n t h e  treatment  and t h e c o n t r o l g r o u p s , so t h e y  have n o t been  P r e l i m i n a r y e x p e r i m e n t s by U s h e r e t a l . F.  C a n d i d a p o p u l a t i o n s i n 15.7 c m  first  and then  stabilized  individuals,  probably  This finding  roughly  cultures in  14  i n 18 c m  2  after  c u l t u r e v i a l s grew r a p i d l y a t  2  a g r e e s w i t h my o b s e r v a t i o n s o f F. C a n d i d a  pots.. I suspect  that the confined  c o n t a i n e r s used i n my  {discussed  which suggest t h a t p o p u l a t i o n s  exploited.  that  10-15 weeks, a t 700 - 1300  were a t o r n e a r s i m i l a r l i m i t s .  imposed l i m i t s  (1971) showed  b e c a u s e o f c o m p e t i t i o n f o r s p a c e and f o o d .  the larger, l i t t e r - f i l l e d  t h e o r e t i c a l grounds  adjusted.  populations  experiment  T h e r e a r e e m p i r i c a l and by W a t t , 1968 a n d E m l e n , which a r e near  may i n c r e a s e t h e i r  1977)  environmentally  p r o d u c t i v i t y i f they a r e  The m a g n i t u d e o f a n y s u c h i n c r e a s e i n p r o d u c t i v i t y  would d e p e n d o n t h e r a t e o f e x p l o i t a t i o n a n d t h e age d i s t r i b u t i o n of the s u r v i v o r s .  I n e f f e c t , t h e degree t o which  e x p l o i t a t i o n might reduce c o m p e t i t i o n , together and  type  the a d d i t i o n a l  w i t h t h e number  of i n d i v i d u a l s s u r v i v i n g density-independent  mortality,  w o u l d s e t t h e new p r o d u c t i o n r a t e . In  such s i t u a t i o n s , the type o f i n d i v i d u a l which s u r v i v e s t o  reproduce i s as important attention  a s t h e number.  (1969) h a s drawn  t o t h e c o r r e s p o n d e n c e b e t w e e n methods w h i c h use  b e h a v i o r a l and p h y s i o l o g i c a l t y p e s guality  Mertz  t o determine  population  ( W e l l i n g t o n , 1964) and methods w h i c h a n a l y z e and  c a t e g o r i z e i n s e c t p o p u l a t i o n s a c c o r d i n g t o age-groups. types  of study  Both  a r e c o n c e r n e d w i t h p o p u l a t i o n g u a l i t y and w i t h t h e  c o n t r i b u t i o n s of d i f f e r e n t types of i n d i v i d u a l s t o the  78  performance of the t o t a l behavioral different  a g e s may  as i m p o r t a n t  outbreaks.  45 -  135  rates at  days o l d are  Thus i f a p r e d a t o r group the  population  end  density. My  springtails  i n the containers  populations,  t o the  The  a higher^  suggest that the  of t h e  rather than  of the  t h a t are  size-structure.  Watt  standing  populations  c r o p of  in a  larger pressures,  confined  environmental  limit.  l a r g e r i n d i v i d u a l s , more  the  mean age  (as e v i d e n c e d  populations  by  decreased i n  controls.  a c t u a l dynamics of e x p l o i t e d p o p u l a t i o n s  from c a l c u l a t e d values  eat  on b e e t l e s  i m m a t u r e members of t h e  experimental  mean age  are  preventing  were e x e r t i n g c o m p a r a b l e  i m m a t u r e s were a b l e t o s u r v i v e , and  relation  most e f f e c t i v e i n  pseudoscorpions ate the  mean l e n g t h )  example, t h e r e  which d i f f e r e n t a d u l t s  a l l o f w h i c h were n e a r t h e i r  Thus when t h e  For  fed p r e f e r e n t i a l l y  data  or i n d i r e c t , on t h e  of  C e r t a i n l y , p r o d u c t i v i t y would  increase.  the  shown t h a t  p h y s i o l o g i c a l and  r e s u l t m i g h t be  temporarily  direct  as  d i f f e r e n c e s between i n s t a r s .  eggs; b e e t l e s  lower,  be  d i f f e r e n c e s i n the  t h i s age  M e r t z has  d i f f e r e n c e s among T r i b o l i u m c a s t a n e u m a d u l t s  reproductive striking  population.  obtained  (1955) m e a s u r e d t h e of the  flour  by  differs  i g n o r i n g age-  greatly and  p r o d u c t i v i t y and beetle  Tribolium  confusum a t d i f f e r e n t r a t e s of e x p l o i t a t i o n of d i f f e r e n t s t a d i a , and  found  which o n l y  that the  age  the  optimum y i e l d  a s m a l l number o f a d u l t s were l e f t b e h i n d .  such a g e - r e l a t e d greatly  regimen producing  f a c t o r s , the  f r o m t h a t p r e d i c t e d by  composition  o f a d u l t s was  maximum s u s t a i n e d a logistic  yield  equation.  t h a t would u l t i m a t e l y p r o d u c e t h e one  f r o m w h i c h a d u l t s were i n i t i a l l y  was  one  in  Because  of  differed In f a c t ,  the  maximum number absent.  79  Nicholson of  (1955) o b s e r v e d a s i m i l a r  r e s p o n s e a f t e r removing 99%  the a d u l t b l o w f l i e s from h i s e x p e r i m e n t a l  Slobodkin  and Eichman  population.  ,(1956) a l s o f o u n d t h a t a g e s t r u c t u r e  i n f l u e n c e d the response of e x p l o i t e d populations pulicaria.  In short, before  of p o p u l a t i o n s structure after the  And  o f Daphnia  the e f f e c t s of f u r t h e r e x p l o i t a t i o n  c a n be g a u g e d , one must know t h e e f f e c t s o f age  on p r o d u c t i v i t y , and t h e p r o b a b l e age d i s t r i b u t i o n  harvest  ( W a t t , 1 9 5 5 ) . . A. .minimus p r e y s upon F. C a n d i d a i n  0.7 - 1.3 mm r a n g e when t h e s e i n d i v i d u a l s a r e a v a i l a b l e  (Chapter Three).  The e f f e c t s o f t h i s s i z e - s e l e c t i v e p r e d a t i o n  the  p r o d u c t i v i t y o f t h e s u r v i v o r s t h u s w i l l depend on t h e  and  reproductive  on  value  on  behavior  o f t h i s e x p l o i t e d age c l a s s a s w e l l a s  any d e n s i t y - r e l a t e d c h a n g e s i n f e c u n d i t y . Green  Candida  (1964a) f o u n d t h a t l a b o r a t o r y p o p u l a t i o n s  attained their  i n d i v i d u a l neared  maximum  fecundity  of  Folsomia  when a v a i l a b l e s p a c e p e r  1.2 cm .. R e d u c e d f e c u n d i t y a t h i g h e r 2  densities  was due t o : (1) t h e c o m p l e t e i n h i b i t i o n o f o v i p o s i t i o n by some individuals; by  (2) a g e n e r a l  reduction  o t h e r s , a n d (3) a r e d u c t i o n  Green s u g g e s t e d t h a t " j o s t l i n g "  i n t h e number o f e g g s  i n the duration and g e n e r a l  laid  of o v i p o s i t i o n . .  interference  with  o v i p o s i t i o n among c r o w d e d a d u l t s were c o n t r i b u t i n g f a c t o r s . A l t h o u g h t h e number o f F. C a n d i d a w i t h o v a r i e s  reduced-in  was t h e same i n dense and l e s s d e n s e p o p u l a t i o n s , proportion sparser  size  a greater  o f i n d i v i d u a l s were c a p a b l e o f o v i p o s i t i n g i n t h e  populations  ( j u d g i n g by t h e a p p e a r a n c e o f t h e g e n i t a l  aperture)..  Cannibalism  was e q u a l l y h i g h  populations  i n Green's experiments.  cannibalism  u s u a l l y approached  i n dense and l e s s d e n s e  Average l o s s e s t o  2 eggs p e r a n i m a l p e r day ( u s u a l l y  80  11 - 18% o f t h e t o t a l  number o f e g g s ) .  G r e e n was a l s o a b l e t o show t h a t c r o w d i n g conditioning  during early  o f t h e s u b s t r a t e , c o m p e t i t i o n f o r f o o d , and  competition f o r o v i p o s i t i o n s i t e s d i d not s i g n i f i c a n t l y fecundity. pattern to  (Fujita,  1954) i n w h i c h f e c u n d i t y i s m a x i m a l a t some l o w  intermediate density.  ("Drosophila  type")  ("intermediate important  e x h i b i t t h i s type of p a t t e r n  monotonic d e c r e a s i n g f u n c t i o n of d e n s i t y o r an e f f e c t a t h i g h d e n s i t y o n l y  type";  Watt, 1960).  Aggregation  h a s been shown t o  i n t h e e c d y s i s and s u b s e q u e n t r e p r o d u c t i o n o f  reproducing  Nagelkerke,  [ I t i s n o t c l e a r t o me why a  i n s e c t should  instead of a simple  sexually  affect  H i s d a t a on f e c u n d i t y v e r s u s d e n s i t y show an " A l l e e "  parthenogenetic  be  life,  1979).  species of Collembola Perhaps aggregation  o v i p o s i t i o n i n parthenogenetic The p o s s i b i l i t y  (Verhoef  and  could stimulate  s p e c i e s as w e l l . ]  o f an A l l e e e f f e c t on f e c u n d i t y o f f e r s an  a l t e r n a t i v e e x p l a n a t i o n o f the e x t i n c t i o n s , as w e l l as t h e relatively  l a r g e p o p u l a t i o n s , t h a t o c c u r r e d i n my  containers. £• - C a n d i d a  I f p r e d a t i o n by A. m i n i m u s on t h e o r i g i n a l a d u l t s i n these c o n t a i n e r s h e l d the prey  0.5 i n d i v i d u a l s p e r c m stages  2  numbers below  ( c f . Green's data) d u r i n g t h e  initial  o f p o p u l a t i o n g r o w t h , f e c u n d i t y would d r o p b e l o w t h e  recovery the other  l e v e l , and s u c h  2  surviving  p o p u l a t i o n s w o u l d become e x t i n c t .  hand, s l i g h t l y h i g h e r d e n s i t i e s  i n d i v i d u a l s p e r cm )  occur  On  ( e g u i v a l e n t t o 0.5 - 2  w o u l d a l l o w much h i g h e r f e c u n d i t y i n t h e  t r e a t e d p o p u l a t i o n s than  t h e greater crowding  unchecked c o n t r o l p o p u l a t i o n s would p e r m i t . did  experimental  i n the experimental  I f such  i n the  an e f f e c t  p o p u l a t i o n s , t h e mean l e n g t h o f  81  their  i n d i v i d u a l s w o u l d be r e d u c e d by t h e s e c o n d o r t h i r d  generation  b e c a u s e o f t h e l a r g e r number o f j u v e n i l e s t h o s e  populations  would t h e n c o n t a i n .  ( I n f a c t , as l o n g  fewer a d u l t s i n the experimental during  the f i r s t  obtained, end to  two g e n e r a t i o n s ,  generations.)  our r e s u l t s , i t s u n d e r l y i n g  t h i s result could  Since  i t c a n be t e s t e d f u r t h e r .  0.784 mm  still  be by t h e  s c e n a r i o c o u l d have l e d should  n o t be r e j e c t e d  The mean l e n g t h o f t h e  (n=1232, SD=0. 3 0 0 ) ,  eight c o n t r o l populations  this  hypothesis  s p r i n g t a i l s i n the four populations only  were  containers than i n the c o n t r o l s  even i f t h e numbers o f a d u l t s were n e a r l y e g u a l  of the three  until  as t h e r e  that survived predation  was  whereas t h e i n d i v i d u a l s i n t h e  had a mean l e n g t h o f 0.839 mm  SD=.279; s e e a l s o T a b l e 1 ) . The d i f f e r e n c e i s h i g h l y (p < 0.001) w h e t h e r o r n o t c o n t a i n e r  #7 i s i n c l u d e d  (n=1334,  significant  ( i f excluded,  t h e mean l e n g t h o f t h e c o n t r o l s i s r e d u c e d t o 0.837 b e c a u s e #7 consisted  of adults only).  U s h e r e t a l . . (1971) p e r f o r m e d a s e r i e s o f r e m o v a l experiments t o t e s t t h e hypotheses that p r o d u c t i v i t y of F.  Candida p o p u l a t i o n s  exploitation,  would i n c r e a s e  with i n c r e a s i n g  that selective exploitation  would r e s u l t  i n higher  p r o d u c t i v i t y t h a n n o n - s e l e c t i v e e x p l o i t a t i o n , and t h a t t h e availability  of food  would change t h e r e l a t i o n s h i p of  productivity  to exploitation.  They f o u n d t h a t , i n g e n e r a l ,  e x p l o i t a t i o n increased production although  because r e p r o d u c t i o n  d i f f e r e n c e s among s t a n d i n g  e x p l o i t a t i o n were n o t s i g n i f i c a n t .  crops  at different rates of  Increasing the proportion of  a d u l t s removed f r o m one- t o t w o - t h i r d s e v e r y both the numerical  increased,  and b i o m a s s p r o d u c t i o n  t w o weeks i n c r e a s e d  by 150%..  ( I f t h e same  82  i n c r e a s e i n e x p l o i t a t i o n r a t e was a p p l i e d n o n - s e l e c t i v e l y t o t h e total  population,  numerical  biomass p r o d u c t i o n Relatively shorter  high  10.5%.)  recorded  barriers to  when more o f t h e o l d e r i n d i v i d u a l s were  As n o t e d e a r l i e r , t h i s l a t t e r high  by 50% and  r a t e s of e x p l o i t a t i o n a l s o r e s u l t e d i n  were r e l a x e d  the r e l a t i v e l y lengths  increased only  increased  mean body l e n g t h , b e c a u s e t h e c o m p e t i t i v e  reproduction removed.  production  response might e x p l a i n  numbers o f a n i m a l s and t h e r e d u c e d  i n my e x p e r i m e n t a l  mean  populations. . Selective  e x p l o i t a t i o n o f t h e a d u l t s by t h e p s e u d o s c o r p i o n s would be followed  by i n c r e a s e d  among t h e r e m a i n i n g not  fecundity  springtails.  ( o r egg and j u v e n i l e s u r v i v a l ) A l t h o u g h such p o p u l a t i o n s  c h a n g e much n u m e r i c a l l y , a t t h e end o f 46 d a y s t h e y  have t h e l a r g e number o f j u v e n i l e s and t h e s h o r t t h a t were d e s c r i b e d  above..  mean  might  would  lengths  83  SUMMARY  In Chapter  One,  I discussed the d i s t r i b u t i o n  and  abundance  of m i c r o a r t h r o p o d s , m a i n l y C o l l e m b o l a , i n a s i t e i n t h e  UBC  Research F o r e s t . I s e t o u t t o measure t h e e f f e c t s o f p r e d a t i o n on populations.  I n o r d e r t o do t h i s I n e e d e d a t e c h n i g u e f o r  d e t e r m i n i n g t h e age accomplished  of i n d i v i d u a l s p r i n g t a i l s .  i n C h a p t e r Two  of s p r i n g t a i l s )  the predaceous  where i t was  pseudoscorpion, Apochthonius  and  prey s i z e  Temperature s l i g h t l y  sizes  and  was  ( f o r two  species of  age.  Three, I i n v e s t i g a t e d the f u n c t i o n a l response  of t h e s p r i n g t a i l , F o l s o m i a Candida, as  the r i s e  shown  This  t h a t l e n g t h i n c r e a s e s a s a power f u n c t i o n  In Chapter  temperature  springtail  minimus, t o  altered the o v e r a l l r i s e  shape of the response  density  w e l l as t h e e f f e c t s  on h a n d l i n g t i m e and  of  of  attack rate. i n response.  d i f f e r e d f o r t h e two  Both  prey  used. The  c h a n g e s i n number o f p r e y e a t e n o v e r a 4 8 - h o u r  were a l s o e x a m i n e d , a n d t h e a t t a c k and ik- m i n i m u s were d e s c r i b e d and predation experiments. F..Candida, 0.8 range,  0.2  The  - 1.5  - 1.2  The mm  period  f e e d i n g behavior of  discussed i n relation  pseudoscorpion  to the  preferred  young  adult  i n l e n g t h , when o f f e r e d p r e y i n t h e  mm..  experiment  described i n Chapter  preference the pseudoscorpion, s i z e s of the s p r i n g t a i l ,  Four  utilized  the  A. m i n i m u s , d i s p l a y s f o r c e r t a i n  F. Candida, i n o r d e r t o a s s e s s t h e  p o p u l a t i o n conseguences of t h i s s e l e c t i v e  predation.  Although  84  predation  drove h a l f o f t h e t r e a t e d c o l l e m b o l a n  populations to  e x t i n c t i o n , • t h e p o p u l a t i o n s w h i c h s u r v i v e d were n o t r e d u c e d i n s i z e a n d were i n f a c t due t o s i g n i f i c a n t l y first  l a r g e r than  most o f t h e c o n t r o l  l a r g e r numbers o f i m m a t u r e s . .  two t o t h r e e weeks o f t h e e x p e r i m e n t ,  a p p a r e n t l y f e d mainly  on t h e o r i g i n a l  populations  During t h e  the predators  a d u l t s and t h e l a r g e r  i n d i v i d u a l s o f t h e second g e n e r a t i o n , t h u s i n c r e a s i n g a v a i l a b l e space and i m p r o v i n g reproduction. significant experimental  t h e prey's  The r e s u l t i n g  decrease  demographic s h i f t  p o p u l a t i o n s w i t h o u t any accompanying  i n the significant  f e c u n d i t y o f F. C a n d i d a , a c t i n g i n  w i t h t h e e f f e c t s o f s i z e - s e l e c t i v e p r e d a t i o n , may l e a d t o  a variety  of p o p u l a t i o n conseguences.  predation  may c a u s e i n c r e a s e d p r o d u c t i o n w i t h d e c r e a s e d  size,  I n some  and no d r a s t i c c h a n g e i n s t a n d i n g c r o p .  circumstances,  a l o c a l p o p u l a t i o n may become e x t i n c t .  r e s u l t s should  f u r t h e r our understanding  of establishment  litter  patches  These  of the sporadic record  a n d g r o w t h d i s p l a y e d by s p r i n g t a i l  the s m a l l , moist  mean  In d i f f e r e n t  circumstances,  in  f o r the  numbers.. Some e f f e c t s o f d e n s i t y , f o o d ,  a g e - s t r u c t u r e on t h e t o t a l  concert  accounts  i n mean l e n g t h t h a t o c c u r r e d  change i n t h e i r t o t a l and  chances f o r s u c c e s s f u l  where t h e y t e n d  populations t o aggregate.  85  LITERATURE CITED  Addicott,  J . F.  1974.  experimental  P r e d a t i o n and p r e y community s t r u c t u r e : an  study  of the e f f e c t  o f m o s q u i t o l a r v a e on t h e  p r o t o z o a n communities of p i t c h e r p l a n t s . . E c o l o g y  55: 475-  492. .  Agrell,  I . . 1949. . S t u d i e s on t h e p o s t - e m b r y o n i c d e v e l o p m e n t  Collemboles.  Arkiv. For Zool.  A n d r e w a r t h a , H. G. ecology. Wittier  B a i l e y , C.  G.  and L. C. B i r c h .  41A:1~35.  1973. . The  I n : The H i s t o r y o f E n t o m o l o g y , and C.  development  h i s t o r y of i n s e c t R. F. S m i t h ,  N. S m i t h , e d s . A n n u a l R e v i e w s , P a l o  1976. T e m p e r a t u r e  of  effects  on  i n Mamestra c o n f i q u r a t a  T..E.  Alto.  non-diapause (Lepidoptera:  N o c t u i d a e ) . . C a n . . E n t . . 1 0 8:1339-1344..  B e d d i n g t o n , J . R. and C. predator-prey  Bellinger,  A. F r e e .  interactions.  1S76. Theor.  P. F. .1954. S t u d i e s o f s o i l  reference to the Collembola. No. , 583. .  Age s t r u c t u r e e f f e c t s i n PODUI.  Biol.  fauna with  Conn. Acjric. .  9:15-24..  special EXJD.  Stn.  Bull.  86  Benedict,  E. M.  1978. A b i o g e o g r a p h i c a l s t u d y o f c u r r e n t l y  identified western  Block,  W.  Oregon p s e u d o s c o r p i o n s  Oregon forms.  w i t h an e m p h a s i s on  PhD. t h e s i s , P o r t l a n d .  1966. Some c h a r a c t e r i s t i c s  of t h e Macfadyen h i g h  g r a d i e n t e x t r a c t o r f o r s o i l micro-arthropods. Oikos  Britt,  N. W.  1951. O b s e r v a t i o n s on t h e l i f e  Collembolan  A c h o r u t e s a r m a t u s . Am.  17:1-9.  h i s t o r y of t h e  Micro..Soc.  Trans.  70: 119-132.  Brooks,  J . L.  1968. The e f f e c t s o f p r e y s i z e s e l e c t i o n by l a k e  planktivores.  S y s t e m . Z o o l . 17: 273-291.  B r o o k s , J . L..and S. I . Dodson.  1965. P r e d a t i o n , body s i z e  c o m p o s i t i o n of p l a n k t o n . . S c i e n c e  Chapman, R. F.  and  150:28-35..  1975. The i n s e c t s , s t r u c t u r e and  function.  A m e r i c a n E l s e v i e r Pub* Co., I n c . •a  Choudhuri,  D.  K. and B h a t t a c h a r y y a , B.  embryonic growth i n L o b e l i a 1966  1978. On t h e r a t e o f p o s t -  (Lobelia) m a x i l l a r i s  ( C o l l e m b o l a : I n s e c t a ) . Rev. E c o l . B i o l .  Yosii,  S o l 15: 537-  549.  Christiansen,  K.  9:147-178.  1964.  Bionomics  o f C o l l e m b o l a . Ann. Rev. E n t .  87  Christiansen, and  Cunia,  K.  1970,  Experimental  s t u d i e s on  the  d i s p e r s i o n of C o l l e m b o l a . , P e d q b i q l o g i a  T..1973. Dummy v a r i a b l e s and regression analysis.  Nash,  uses i n  I n : I n t e r n a t i o n a l U n i o n of  Nancy, France  (eds.)  10:180-198.,  some o f t h e i r  l ^ s e a r c h Organizations, Proceedings Meeting,  aggregation  ; T.  Forest  of t h e June  C u n i a , K. K u u s e l a  .1973  and  A.  J..  V o l . 1:1-146.  C u r r y , G..L., E..M..Feldman and  K..C.  Smith..1978._  A stochcastic  m o d e l o f a t e m p e r a t u r e - d e p e n d e n t p o p u l a t i o n . Theor._Po£. Biol.  13:197-213.  D a p s o n , R.W.  1971.  d i f f e r e n t age  Davidson,  J..1944.  Q u a n t i t a t i v e comparison of p o p u l a t i o n s s t r u c t u r e s . Ann.  On  Z o o l . F e n n i c i 8:75-79..  the r e l a t i o n s h i p  between t e m p e r a t u r e  t h e r a t e of development of i n s e c t s a t c o n s t a n t J.  Anim. E c o l .  D o d s o n , S.  e x p e r i m e n t a l t e s t o f the  temperature..  c o m p e t i t i o n and size-efficiency  predation:  an  hypothesis.  55:605-613..  Dover M..J., B.  A. C r o f t , S.  M..Welch and  R. L._Tummala..197 9..  B i o l o g i c a l c o n t r o l of Panonychus ulmi chidae)  and  13:26-38.  I . . 1974. . ZooplanJcton  Ecology  with  by  Amblyseius  apple: a predator-prey  fallacis  (Acarina:  Tetrany-  (Acarina: Phytoseiidae)  m o d e l . E n v i r o n . E n t . . 8: 282-292.  on  88  E d w a r d s , C. .A., E. B. . D e n n i s and D. W..Empson..1967. P e s t i c i d e s and  the s o i l  field.  Elliot,  Ann.  fauna: a £ D l .  e f f e c t s o f a l d r i n and DDT i n an a r a b l e  Biol.  60:11-22  J . M. 1 9 7 7 . . S t a t i s t i c a l ana l y s i s  i n v e r t e b r a t e s . Freshwater  o f samples of b e n t h i e  Biological Association Scientific  P u b l i c a t i o n No. .25. _ 160 pp.  E m l e n , J..M. 1 9 7 7 . . E c o l o g y : an e v o l u t i o n a r y a p p r o a c h .  Addison-  W e s l e y P u b l . C o . , R e a d i n g , Mass.  E r n s t i n g , G. 1977. A s p e c t s collembolan  prey  o f p r e d a t i o n and t h e c o e x i s t e n c e o f  s p e c i e s . I n : S o i l o r g a n i s m s as components  of ecosystems, E c o l . . B u l l .  Ernsting,  G. and E..N..G..Joose.  25:478-480. S t o c k h o l m .  1974..Predation  of surface dwelling Collembola. labelled  prey.  Pedobioloqia  E r n s t i n g , G., J . M. M a r q u e n i e of behavior Ml*  Eveleigh,  Icol.  with r a d i o - i s o t o p e  14:222-231.  and C. N. de  and p r e d a t i o n r i s k Biol.  A study  Vries..1977._Aspects  o f two s p r i n g t a i l  species of p h y t o s e i i d mites  Toronto,  Toronto.  behavior  o f two  (Acarina: Phytoseiidae)  r e f e r e n c e t o t h e i r responses t o prey and p r e y  species.  S o l 14: 27-30.  E. S. 1979. S t u d i e s on t h e p r e d a t o r y  density  o n two s p e c i e s  distribution.  density,  with  predator  PhD T h e s i s , U n i v e r s i t y o f  89  Everson,  P. .1980. The r e l a t i v e  activity  °f P h y t o s e i u l u s p e r s i m i l i s  and f u n c t i o n a l r e s p o n s e  {Acarina: Phytoseiidae)  Tetranychus u r t i c a e {Acarina: Tetranychidae):  and  the e f f e c t of  t e m p e r a t u r e . .Can. _Ent. .112: 17-24. .  F o l s o m , J . .W. . 1917. . N o r t h  American C o l l e m b o l o u s  subfamily Onychi uridae.. Proc.  F o l s o m , J . W. . 1919.  i n s e c t s of the  U.S. N a t . Museum 53: 6 3 7 - 6 5 9 .  Report of t h e Canadian A r c t i c  Expedition  1913-18..Volume I I I : I n s e c t s . . F a r t A: C o l l e m b o l a . t o t h e King^s  F o l s o m , J . W.  Most E x c e l l e n t M a j e s t y ,  1937. N e a r c t i c C o l l e m b o l a  Printer  O t t a w a . .27 pp. .  of s p r i n g t a i l s ,  of t h e  f a m i l y I s o t o m i d a e . . 0 . S . . N a t . .Museum B u l l . .168: 144-460.  Fujita,  H. . 1954.  An i n t e r p r e t a t i o n  population density effect Ecology  o f t h e changes i n t y p e  of t h e  upon t h e o v i p o s i t i o n r a t e . .  35: 253-257.  Gage, S. H., M. K. . M u k e r j i and R. .L. . R a n d e l l . . 1976. . A p r e d i c t i v e model f o r s e a s o n a l in  Saskatchewan  occurence of three grasshopper  (Orthoptera:  species  A c r i d i d a e ) . Can. E n t . 108:245-  253.  Galbraith,  M. G. 1967. S i z e - s e l e c t i v e p r e d a t i o n on D a p h n i a by  rainbow t r o u t and y e l l o w 10.  perch.  Trans.  Am. F i s h .  Soc. 96:1-  90  Gilbert,  N. 19 73. B i o m e t r i c a l  I n t e r p r e t a t i o n . Clarendon P r e s s ,  Oxford.  Gilbert,  N., A. P. . G u t i e r r e z , B. D. F r a z e r and R.'. E. _ J o n e s . . 1976.  Ecological relationships.  G i l b e r t , 0. false  1951..Observations  W.  H. F r e e m a n , San  Francisco.  on t h e f e e d i n g o f some  scorpions. Proc. Zool.  British  Soc. L o n d . 1 2 1 : 5 4 7 - 5 5 5 . .  G o d d a r d , S. J . 1976. F e e d i n g i n N e p b i s i u m  muscorum  (Arachnida: Pseudoscorpiones) . B u l l .  Brit,  (Leach)  a r a c h n o l . .Soc.  3:232-234. .  G r e e n , C..D..1964a. Candida  The l i f e  history  (Willem) v a r d i s t i n c t a  and f e c u n d i t y o f F o l s o m i a (Bagnall) (Collembola:  I s o t o m i d a e ) . P r o c . .R. E n t . S o c . L o n d .  G r e e n , C. . D. . 1964b. .The e f f e c t F o l s o m i a Candida  (A) 39: 125-128. .  o f c r o w d i n g upon t h e f e c u n d i t y  (Willem) v a r d i s t i n c t a  of  (Bagnall). Ent.  EX£..A££l..7:6 2-70..  G r e g o i r e - W i b o , C.  1974. B i o l e c o l o g i e de F o l s o m i a q u a d r i q c u l a t a  ( I n s e c t a : C o l l e m b o l a ) . P e d p b i o l o g i a 14:199-207.  G r e g o i r e - W i b o , C. and R. M. S n i d e r . 1977. .The i n t r i n s i c natural  increase:  rate of  i t s i n t e r e s t t o e c o l o g y and i t s  a p p l i c a t i o n t o v a r i o u s s p e c i e s of C o l l e m b o l a . I n : S o i l organisms  as c o m p o n e n t s o f e c o s y s t e m s , E c o l . . B u l l . . 2 5 : 4 4 2 - 4  91  Suppy  , J . .C. .and D. . G. . H a r c o u r t •  1978. E f f e c t s o f t e m p e r a t u r e on  development o f t h e immature s t a g e s b e e t l e . Quiema melanopus Ent.  of the cereal  leaf  { C o l e o p t e r a : C h r y s o m e l i d a e ) . Can.  110:257-263.  H e m e , D. C. and C. . T..Lund..1979. . S i m u l a t i o n m o d e l o f E u r o p e a n red  mite p o p u l a t i o n dynamics developed f o r a mini-computer.  Can. E n t . 111:499-507.  H o l l i n g , C. S. 1959. The c o m p o n e n t s o f p r e d a t i o n a s r e v e a l e d by a study  o f s m a l l mammal p r e d a t i o n o f t h e E u r o p e a n s a w f l y .  C a n . E n t . 9 1 : 29 3-320.  H o l l i n g , C..S. . 1961. P r i n c i p l e s o f i n s e c t p r e d a t i o n . Ann,  gey.  E n t . .6: 163-182.  H o l l i n g , C. S. 1964. The a n a l y s i s o f c o m p l e x p o p u l a t i o n processes.  Can. - E n t . . 96: 335-347. .  H o l l i n g , C . S . , R. L. Dunbrack s i z e and p r e y s i z e : Hierodula  and L. M. D i l l . . 1 9 7 6 . . P r e d a t o r  presumed r e l a t i o n s h i p i n t h e m a n t i d  c o a r c t a t a S a u s s u r e . C a n . J . Z o o l . 54: 1760-1764. .  H o p p e n h e i t , M. 1975. On t h e d y n a m i c s o f e x p l o i t e d p o p u l a t i o n s o f Tisbe bolothurine density, Meer.  (Copepoda, H a r p a c t i c o i d a ) . I I . P o p u l a t i o n  age d i s t r i b u t i o n ,  27:377-395.  growth and y i e l d . . H e l g . . W i s s . .  92  H o p p e n h e i t , M..1976. On t h e d y n a m i c s o f e x p l o i t e d p o p u l a t i o n s Tisbe  bolothuriae  Reproduction, time.  Helq.  H u t s o n , B. R.  (Copepoda, H a r p a c t i c o d a ) . I I I .  sex r a t i o , W i s s . Meer.  1978a..Effects  charcoal  method  Pedobio1oaia  of  r a t e o f d e v e l o p m e n t and  survival  28:109-137.  of v a r i a t i o n s of the p l a s t e r -  on a c o l l e m b o l a n ,  Folsomia  Candida.  18:138-144..  H u t s o n , B. R. . 1 9 7 8 b . . I n f l u e n c e o f pH, t e m p e r a t u r e and s a l i n i t y the  f e c u n d i t y and l o n g e v i t y o f f o u r  P§42bi2i°aia  species  of  on  Collembola.  18: 163-179.  Iwao, S. .and W. G. W e l l i n g t o n . _ 1970. The i n f l u e n c e o f b e h a v i o r a l d i f f e r e n c e s among t e n t - c a t e r p i l l a r pentatomid bug..Can.,J..Zool.  J o h n s o n , E. F.  l a r v a e on p r e d a t i o n  by a  48:896-898..  , R. T r o t t i e r and J . E. L a i n g . . 1 9 7 8 . D e g r e e - d a y  r e l a t i o n s h i p s t o the development of blancardella  (Lepidoptera:  Lithqcolletis  Gracillariidae).  Can. E n t .  111:1177-1184.  J o n e s , P. E.  1970. The o c c u r r e n c e  (Hermann) coppice  of Chthqnius  (Chelonethi: chthoniidae)  leaf  litter.  Bull.  Brit,  ischnocheles  i n two t y p e s  arachnol.  Soc.  of  hazel  1:77-79.  Jones,  P.. E. _ 1975.  N o t e s on t h e p r e d a t o r s  pseudoscorpions.  Joose,  E.  N. G.  moulting  and and  Bull.  E.  N.  a r a c h n o 1.  V e l t k a m p . 1970.  and  prey  LeCato,  W.  G.  1961.  s p e c i e s of  Neth. J . Z o o l .  response  1976.  An  J . W o l l k i n d , S. C.  W i n s t o n , New  York.  London.  of red f l o u r  o f c i g a r e t t e b e e t l e s and  D.  surface  20:315-328.  S o i l b i o l o g y . Faber S Faber,  beetles to  the r o l e of p r e d a t i o n i n  p o p u l a t i o n r e g u l a t i o n . E n v i r o n . Ent.  L o g a n , J . A.,  growth,  E. . J . P e d h a z u r . .1973. M u l t i p l e r e g r e s s i o n i n  L. . 1 9 7 8 . . F u n c t i o n a l  density  British  Soc. .3:104-105.  b e h a v i o r a l r e s e a r c h . H o l t , R i n e h a r t and  Kuhnelt,  of  Some a s p e c t s o f  reproduction i n five  dwelling Collembola.  K e r l i n g e r , F.  Brit,  and  7:77-80.  Hoyt and  L..K._Tanigoshi.  a n a l y t i c model f o r d e s c r i p t i o n o f  temperature  d e p e n d e n t r a t e phenomena i n a r t h r o p o d s . . E n v i r o n .  Ent.  5:1 133-1 140. .  M a c F a d y e n , A. . 196 1. . I m p r o v e d f u n n e l t y p e e x t r a c t o r s f o r arthropods.  M a c f a d y e n , A.  J . Anim. E c o l .  1962.  Zoology,, London.  P.  W.  30:171-184.  C o n t r o l of humidity  extractors for soil  soil  arthropods.  M u r p h y , e d . , pp.  i n three  funnel-type  I n : Progress  in  Soil  158-168. . B u t t e r w o r t h s ,  94  M a n i , M.  S.  1968.  insects.  E c o l o g y and  B..F.J.  1973.  N. . V. , P u b l i s h e r s , The  A linear  B..F.  J . 1974.  V.,G.  and  Hague.  A model f o r c e r t a i n t y p e s o f  D. K.  McE.  Schmitschek,  Pgpul. , Ecol.,14:137-150..  experiments..Res..Popul.Ecol.  Marshall,  altitude  model f o r f r e g u e n c y - d e p e n d e n t  s e l e c t i o n by p r e d a t o r s . Res.  Manly,  of high  Volume 4 o f S e r i e s E n t o m o l o g i c a , E.  e d . . Dr. . W. . J u n k  Manly,  bioqeography  selection  14:137-150..  Kevan.  1962.  Preliminary  o b s e r v a t i o n s on t h e b i o l o g y o f F o l s o m i a C a n d i d a 1902  ( C o l l e m b o l a : I s o t o m i d a e ) . Can. . E n t . . 94: 575-586. .  M a y n a r d , E. A. .1951..A Monograph o f t h e C o l l e m b o l a o r i n s e c t s o f New Ithaca.  339  springtail  Y o r k S t a t e . C o m s t o c k P u b l i s h i n g Co.,  Inc;.,  pp.  M c A r d l e , B..H., and J . H. predator-instar Ecol.  Willem,  Lawton.  1979.  E f f e c t s of p r e y - s i z e  on t h e p r e d a t i o n o f D a p h n i a  and  by N o t p n e c t a .  E n t o m o l . .4:267-275. .  Medawar, P. B. on g r o w t h  1945.  S i z e , shape and age.  Pp..157-187 i n : E s s a y s  and form..W..E. L e G r o s C l a r k and P. B.  (Eds.). Clarenden Press, Oxford.  Medawar  95  Mertz,  D. B. 1 9 6 9 . A g e - d i s t r i b u t i o n and a b u n d a n c e i n p o p u l a t i o n s of f l o u r  beetles. I . Experimental  s t u d i e s . Ecol..Mpnggr.  3 9:1-31.  Mills,  H. . B. .1934. A Monograph o f t h e C o l l e m b o l a C o l l e g i a t e P r e s s , Ames, Iowa.  Milne,  S. . 1960.  S t u d i e s on t h e l i f e  o f Iowa.  143 pp.  histories  of various species  o f a r t h r o p l e o n e C o l l e m b o l a . . P r o c . .. R . . E n t . .Soc. .Lond. . (A.) 35:  133- 140.  M o r r i s , R. F. and W. C. F u l t o n . 1970. M o d e l s f o r t h e d e v e l o p m e n t and  survival  and  h u m i d i t y . .Mem. . E n t . _ Soc.  Muchmore, W..B.  of Hyphantria  cunea i n r e l a t i o n  temperature  Can. ..No. .70. .  1973..Ecology o f pseudoscorpions:  Proc. Jst S o i l  to  Microcomm. C o n f . , S y r a c u s e ,  a review. I n : N.Y.,  pp..121-  127.  M y e r s , J . 1978. S e l e c t i n g a m e a s u r e o f d i s p e r s i o n . E n v i r o n . E n t o m o l . 7:619-6 21.  Nair,  K. R. 1964. The f i t t i n g  of growth curves..Pp.  119-132 i n :  S t a t i s t i c s a n d m a t h e m a t i c i n b i o l o g y . .0..Kempthorne, T. A. B a n c r o f t , J . W. . Gowen a n d J . .L. . L u s h , C o l l e g e P r e s s , Ames.  (eds.)  Iowa S t a t e  96  N e t e r , J . _ a n d wm. Wasserman. . 1974. A_g£lied l i n e a r models. . R i c h a r d  Nicholson,  D. . I r w i n , I n c . , Homewood, 1 1 1 .  A. J . 1954. C o m p e n s a t o r y r e a c t i o n s o f p o p u l a t i o n s  s t r e s s e s , and t h e i r e v o l u t i o n a r y Zool.  Olivier,P.  Paine,  s i g n i f i c a n c e . Aust. J .  G. and P. A. J . Ryke. 1969. The i n f l u e n c e o f p r a c t i c e s on t h e c o m p o s i t i o n o f s o i l  Collembola populations.  Pedobiglggia  R..T. . 1976. . S i z e - l i m i t e d p r e d a t i o n :  Acari  9:277-281.  an o b s e r v a t i o n a l a n d  experimental  approach with t h e M y t i l u s - P i s a s t e r  interaction.  Ecology  Peters,  57:858-873.  T..M.  and P. B a r b o s a . _ 1 9 7 7 . . I n f l u e n c e o f p o p u l a t i o n  density  on s i z e , f e c u n d i t y , a n d d e v e l o p m e n t a l r a t e o f  i n s e c t s i n c u l t u r e . Ann..Rev.  Petersen,  to  2: 1-8.  citricultural and  statistical  H. 1975. E s t i m a t i o n  Entomol.  22:431-450.  o f d r y w e i g h t , f r e s h weight and  c a l o r i f i c content of various  Collembolan  species.  £ed o b i o 1 o q i a 15: 222-243..  Petersen,  H. '1978. Some p r o p e r t i e s  o f two  high-gradient  e x t r a c t o r s f o r s o i l m i c r o a r t h r o p o d s , and an a t t e m p t t o evaluate  t h e i r e x t r a c t i o n e f f i c i e n c y . Natura  Jutlandica  20:95-122.  97  Price,  P. . W. _ 1 9 7 5 . . I n s e c t e c o l o g y . J o h n 514  Wiley & Sons,  New  York.  pp.  Satchell,  J . E.  Closing  1977.  Earthworms - t h e trombones o f the grave.  presidential  address. I n : S o i l organisms  components of ecosystems,  Ecol.  Bull.  as  25: 598-603. _  Stockholm.  S i m o n , H.. R..1966. Der (Leach)  S i m o n , H..R.  Pseudoskorpionide Neobisium  a l s Collembolenfeind. Inst.  .1969. Der  seine Stellung  Mosskorpion  F u r N a t u r s c h . ,8 ( 3 ) . .  Neobisium  im O k o s y s t e m . M i t t .  muscorum  Pgllichia  S l o b o d k i n , L. B. and S. R i c h m a n . .1956. The fixed  effect  (Leach)  und  3:149-159..  of removal  p e r c e n t a g e s o f t h e newborn on s i z e and  p o p u l a t i o n s o f Dap_hnia p _ u l i c a r i a  muscorum  of  variability in  (Forbes) . .Limnol. Oceanoq.  1:209-237.  S n i d e r , R. .1971. L a b o r a t o r y o b s e r v a t i o n s on t h e b i o l o g y Folsomia Candida Ecol-  S n i d e r , R.  Biol*  (Collembola: Isotomidae) .  Rev.  S o l . 10:103-124.  M. .and J . .W. . B u t c h e r . 1973. . The  Folsomia Candida to  (Willem)  of  (Willem)  life  history  (Collembola: Isotomidae)  t e m p e r a t u r e . G r e a t L a k e s E n t . 6:97-106.  of relative  98  Southwood,  T. R . E .  Halsted  1978. E c o l o g i c a l methods.  P r e s s , New  Second  edition.  York.  S t i n n e r , R. .E., A. .P. G u t i e r r e z and G..D. . B u t l e r . . 1 9 7 4 . . A n a l g o r i t h m f o r temperature-dependent growth r a t e Can..Ent.  simulation.  106:519-524..  S t i n n e r , R. E., G. D. . B u t l e r , J r . , J . S. B a c h l e l e r  and C.  Tuttle.  1975. S i m u l a t i o n o f t e m p e r a t u r e - d e p e n d e n t d e v e l o p m e n t i n p o p u l a t i o n d y n a m i c s m o d e l s . Can.  T a k e d a , H.  1973. A p r e l i m i n a r y  Ent.  s t u d y on c o l l e m b o l a n  i n a pine f o r e s t . Ees.,Popul. Ecol.  T a k e d a , H.  1979. On t h e e x t r a c t i o n  MacFadyen's  107:1167-1174.  15:  populations  76-89.  p r o c e s s and e f f i c i e n c y  high gradient extractor. Pedobiologia  of 19:106-  1 12.  T a n i g o s h i , L. K. and J . A. L o g a n .  1979. T e t r a n y c h i d  development  under v a r i a b l e t e m p e r a t u r e r e g i m e s . Recent Advances  In  A c a r o l . . 1 : 165-175..  T a n n e r , J . T.  1978. G u i d e t o t h e s t u d y  U n i v . Tennessee  T a y l o r , R.  G. and D.  Press,  of a n i m a l p o p u l a t i o n s .  Knoxville.  G. H a r c o u r t .  1978. E f f e c t s o f t e m p e r a t u r e on  d e v e l o p m e n t a l r a t e of t h e immature s t a g e s of asparagi  Crigceris  ( C o l e o p t e r a : C h r y s o m e l i d a e ) . Can..Ent.  110:57-62.  99  Thompson, D. J . 1975..Towards a more r e a l i s t i c  predator-prey  model i n c o r p o r a t i n g a g e - s t r u c t u r e : t h e e f f e c t s o f s i z e and p r e y Ischnura  s i z e on t h e p r e d a t i o n o f Dajahnia  predator  magna by  e l e g a n s . . J . Anim. E c o l . .44: 907-916. .  Thompson, D. J . 1978. Towards a p r e d a t o r - p r e y  model: the e f f e c t  o f t e m p e r a t u r e on t h e f u n c t i o n a l r e s p o n s e a n d l i f e of l a r v a e of the d a m s e l f l y , Ischnura Ecol.  47:  J . Anim.  757-767..  T o r n e , E . . v o n . 1974. E x p e r i m e n t e l l e D e u t u n g e n von z o o t i s c h e n Pedobiologia  U s h e r , M..B.  elegans.  history  Motivation  Aggregationen  systemokologischer  im Boden.  14: 324-338.  and C. F. Stoneman.  1977. F o l s o m i a  C a n d i d a - an  i d e a l organism f o r population s t u d i e s i n the l a b o r a t o r y . . J . Biol.  Educ.  11:83-90.  U s h e r , M. B. and H i d e r , M. . 1975. . S t u d i e s on p o p u l a t i o n s o f Folsomia  Candida  aggregation.  {Insecta: Collembola.:  Pedobiologia  15:276-283.  U s h e r , M..E., B. C. L o n g s t a f f and on p o p u l a t i o n s The  of Folsomia  D..R..Southall..1971..Studies Candida  p r o d u c t i v i t y of populations  exploitation..Oecologia  causes of  (Insecta:  i n relation  7:68-79..  Collembola). t o food  and  100  Verhoef,  H. A. 1 9 7 7 . . S o i l  coexisting  ecological  significance  Stockholm.  1977. F o r m a t i o n  of aggregations  and  i n Collembola.  31:215-226.  Wade, L. E. 1954. The C o l l e m b o l a British  o r g a n i s m s a s components o f  B u l l . .25:480-482.  H. A. and C . J . N a g e l k e r k e .  Oecologia  and t h e p o p u l a t i o n d y n a m i c s o f  collembola. I n : S o i l  ecosystems, Ecol.  Verhoef,  moisture  o f t h e Vancouver r e g i o n of  C o l u m b i a . . M. A. . T h e s i s .  University  of British  Columbia, Vancouver.  W a t t , K. E. F. 1955. S t u d i e s on p o p u l a t i o n p r o d u c t i v i t y . a p p r o a c h e s t o t h e optimum y i e l d T r i b o l i u m confusum. E c o l .  I . Three  problem i n p o p u l a t i o n s o f  Mpngr..25:269-290..  W a t t , K.,E. F. 1960. The e f f e c t o f p o p u l a t i o n d e n s i t y on f e c u n d i t y i n i n s e c t s . C a n . E n t . 92: 674-6 95. .  W a t t , K. .E. .F. 1968. . E c o l o g y Hill,  New  and r e s o u r c e  management.  McGraw-  York.  W e l c h , Q. B. 1970. F i t t i n g  growth and r e s e a r c h  data.  Growth  34:293-312.  W e l l i n g t o n , W. G. unstable  1964. Q u a l i t a t i v e  changes i n p o p u l a t i o n s i n  e n v i r o n m e n t s . Can. E n t . 96:436-451.  101  Zar,  J . H. . 1974.  Biostatistical  Englewood C l i f f s ,  N.  J. .  analysis..Prentice-Hall,  Inc.,  102  APPENDIX A  Calibration  The  Macfadyen h i g h - g r a d i e n t  collection  of  since  Macfadyen similar  the  mid  extractors  1960's.  In a d d i t i o n . Block  patterns  of  Petersen To as  m i t e s and for s o i l  a factorial  and  by  were t h e  right,  Takeda  moistened allowed  Macfadyen  the  identical  by  He  estimated  Block  emergence the  extraction  were e s t i m a t e d  and  10%  ( t h a t had  of Collembola  and  (?)  extraction block  (Hypogastrura (Linne) ,  1958;  type of e x t r a c t i o n  fluid  methylene blue s o l u t i o n ) . rows i n the  extractor.  s p r i n g t a i l species  10  lab  They were added 70  A f t e r a 6-day e x t r a c t i o n to  Blocks Six  ( a l l from  p r e v i o u s l y been d r i e d a t  (with temperature i n c r e a s i n g 5  one  a randomized complete  center  hours to adjust.  by  (1979).  W i l l e m , 1902)  acid or  left  described  (1962) and  monitored the  were u s e d i n e a c h t r e a t m e n t .  cores  two  e x t r a c t o r was  Onychiurus f i m e t a r i u s  i n d i v i d u a l s of each of the populations)  study i s nearly  e x t r a c t o r t h a t I used, I ran  1841;  picric  used i n  m i t e s as a g r o u p a t 76%. . E x t r a c t i o n  f a c t o r s were s p e c i e s  Folsomia Candida  (saturated  (1 966)  experiment with  §£Si|t.a ( N i c o l e t )  4)  t e m p e r a t u r e c h a r a c t e r i s t i c s of  Collembola.  c a l i b r a t e the  The  (Figure  f o r a number o f C o l l e m b o l a s p e c i e s  (1978) and  design..  The  were d e t a i l e d by  (1966).  efficiencies  extractor  h a v e b e e n u s e d i n a l a r g e number o f s i m i l a r  (196 1 ) . . H u m i d i t y and  efficiency  Extractor  microarthropods i n t h i s  to e x t r a c t o r s t h a t studies  of the  C per  day)  the  C)  to  and period  extracted  103  i n s e c t s were c o u n t e d .  A n a l y s i s of t h e  showed t h a t p o s i t i o n i n t h e species-fluid S p e c i e s was  extractor, extraction fluid  i n t e r a c t i o n d i d not  the  only  highly significant  lower e f f i c i e n c y f o r the  than f o r the  two  e f f i c i e n c y , with  ±  2.7%  F.  Candida  96.3%  +  1.5%  95.4%  +  1.4%  fimetarius  i n Chapter Four, these estimates  c o m p a r i s o n s made and only  (p<.00 1)  84.3%  (1979).  methods of h a n d l i n g  included  sighted  armata  t h a n t h o s e o f Takeda the  colored,  H.  discussed  and  The  was standard  are  higher  d i f f e r e n c e i s p r o b a b l y due  preparing  t o t h e age  a d u l t s i n my  of y o u n g e r  the  of the  cores,  t e s t , whereas Takeda  (1973,  litter,  coring.  a b o u t 95%) In  e x a m p l e , i n some p r a i r i e  soils.  r a n g e d f r o m 5 - 20%,  I h a v e no  but  and  loosely-packed  however, compression i s not  estimate.  of  I  1979) higher  springtails.  e m p i r i c a l l y t o be  compression during  to  t o the types  insects involved..  Other f a c t o r s i n measuring e f f i c i e n c y are (estimated  a  H..armata  f o u n d t h a t e x t r a c t i o n e f f i c i e n c y o f a d u l t s i s o f t e n much than that  and  o  follows:  0.  As  (p<.0001) f a c t o r and  unpigmented, b l i n d s p e c i e s  E s t i m a t e s of r e t r i e v a l  e r r o r s , were as  type  have s i g n i f i c a n t e f f e c t s . .  consistently  indicated.  percentage r e t r i e v e d  as  great  counting  losses  due  to  forest soil a problem as,  I suspect that coring way  accuracy  o f m a k i n g an  and for  losses  exact  APPENDIX B Abundance and  distribution  microarthropods Forest  Part  site,  I.  at  the  UBC  of  soil  Research  1979.  Population  densities.  20. 000  IS. 000 01 +1  £  10.OO0  +  111  a cc UJ  r 9000  15  May  5  June  26  j  u  n  e  17  J u l y  T o t a l Collembola Figure Bl  8  August  8  September  JOOO  Figure B2  O  ON  400  300  Ul  cn  +1  r tc Ul  a cc Ul ca E  100  •113. 3  "1.7  15 May  5 June  t'1.7  2 6 June  17 J u l y  Apochthonius minimus, adults Figure  B3  8 August  8  September  o  Hi  in +1  300 Ct  UJ a. ±1:11  cc UJ  200 •  100  J>  *5b. 2  15 May  5 June  26 J u n e  17 J u l y  8 August  8  September  Apochthonius minimus, nymphs Figure Bk  o oo  2h  June  17  July  Isotomurus p a l u s t r i s . Isotoma I. o l i y a c e a ( ? ) , I. v i r i d i s Isotomidae) Figure B5  8  August  8  September  trispinata, (Family O  15 May  5 June  26 June  17 J u l y  8 August  Family Hypogastruridae. Includes Hypogastrura pseudarmata, H. v u l g a r i s , H. v i r g o , X e n y l l a g r i s e a and X- sp. Figure B 6  8  September  1*33 750 •  ca +i  r UJ a. ct LU  ca E 250  +  15  May  5  June  26 J u n e  17 J u l y  8 August  Onychiurus flavescens. 0. armatus, Lophognathella choreutes (rare) (Family Onychiuridae, Subfamily Onychiurinae Figure  B7  8  September  8000  T u l l b e r g i a sp. (Family Onychiuridae, Subfamily T u l l b e r g i i n a e ) Figure B8  300  Entomobrya quadralineata. E. m u l t i f a s c i a t a , E. comparata, E. intermedia and E. n i v a l i s TFamily Entomobryidae) Figure B9  1500  LU  ±355  01  +1 1000  +  cc  Ul EL  CC 111 •2  soo  •  156 • 97  11 30  3  + 168  M 7 9  |:«3-3  15  May  5  June  26  June  17  July  B August  Lepidocyrtus cinereus, L. lignorum and L. sp. CFamily Entomobryidae) Figure BIO  8  September  130  LU  •65.  11  3  +1  100 cc  SB.?. 3  LU a  De ul  cc  £ 5 2  90 +  • 41  15  May  7  •41. 7  June  26  June  17 J u l y  8 August  8. S e p t e m b e r  Tomocerus celsus, T. sp. (Family Entomobryidae, Subfamily Tomocerinae) Figure B l l  0\  NUMBER PER M  9TT  2  t+ SE)  , 55  JOO •  Ul  01 +1  01  E  CC LU CL CC LU  2  100 •  15 May  5 June  26 J u n e  17 J u l y  Family Sminthuridae Figure  B13  8 August  8 S ep t e m b e r  •U06  3000  UJ Ul  tl  0J  2000  CC Ul a  ct ui 03 E  3  z  100O  15 May  5 June  2& J u n e  17 J u l y  8 August  8  September  U n i d e n t i f i e d mesostigmatid mites Figure Blk  Co  130  APPENDIX B Abundance and  distribution  m i c r o a r t h r o p o d s a t the Forest  Part  site,  1979.  II.  Spatial  UBC  of  soil  Research  distribution.  Table B l . Date  15  5  May  June  Distribution  Depth  0.2.5  s /  a  Distribution  2 . 5 - 5 . 0 cm  30.96  5.0-7.5  13-34  146.61  contagious  0-2.5  cm/  0-2.5  contagious contagious  cm  5 . 0 - 7 . 5 cm June  8.34  ^ =SSx/ x  91.73 340.50  cm  2 . 5 - 5 . 0 cm  26  X  o f Folsomia sp.  3.0 2.31  33-0  contagious  25.43  contagious  -  -  cm  2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm 17  July  0-2.5  cm  2 . 5 - 5 . 0 cm 3-0  ' 33-0  contagious  1 .0  11.0  random  4.02  44.22  contagious  2 . 5 - 5 . 0 cm  4.88  53-65  contagious  5 . 0 - 7 . 5 cm  5 .0^4-  55.^5  contagious  5.O-7.5 cm 8 August  0-2.5  cm  2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm 8  Sept.  0-2.5  cm  122  Table B2. Date 15 May  D i s t r i b u t i o n o f A p o c h t h o n i u s minimus a d u l t s  Depth  s*/  x  K~=SSx/ x  Distribution  0 . 2 . 5 cm 2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm  5 June  26 June  0 - 2 . 5 cm 2 . 5 - 5 . 0 cm  1.00  11 .00  random  5 . 0 - 7 . 5 cm  1 .00  11 .00  random  0 - 2 . 5 cm  1.00  11 .00  random  2 . 5 - 5 . 0 cm  1 .00  11 .00  random  1.00  11 .00  random •  0 - 2 . 5 cm  1 .00  random  2 . 5 - 5 . 0 cm  2.00  11.00 22.00  contagious  1.55  17.00  random  5.O-7.5 cm 17  July  0 - 2 . 5 cm 2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm  8 August  5.O-7.5 cm 8 Sept.  0 - 2 . 5 cm 2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm  T a b l e B3Date  15 May  Distribution Depth  o f A p o c h t h o n i u s minimus nymphs  ^ =SSx/ x  Distribution  13.00  143.01  contagious  1.00  11.00  random  0.91 6.00  10 .00  random  66.00  contagious  1.27  14.00  random  0.91  10.00  random  1.64  18.00  random  sV  x  2  0 . 2 . 5 cm 2 . 5 - 5 - 0 cm 5 . 0 - 7 . 5 cm  5 June  0 - 2 . 5 cm 2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm  26 J u n e  0 - 2 . 5 cm 2 . 5 - 5 - 0 cm 5 . 0 - 7 - 5 cm  17 J u l y  0 - 2 . 5 cm 2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm  8  August  0 - 2 . 5 cm 2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm  8  Sept.  0 - 2 . 5 cm 2 . 5 - 5 . 0 cm 5 . 0 - 7 - 5 cm  124  Table B4. Date 15 May  5 June  26 June  D i s t r i b u t i o n o f I s o t o m i d s o t h e r t h a n F o l s o m i a spp. Distribution  15.21  167.31  contagious  2 . 5 - 5 . 0 cm  3.60  39.63  contagious  5.O-7.5 cm'  3.52  38.77  contagious  9.24  contagious  0 . 2 . 5 cm  0 - 2 . 5 cm  8 Sept.  X  2  2 . 5 - 5 . 0 cm  22.34  5 . 0 - 7 . 5 cm  10.96  120.5^  contagious  0 - 2 . 5 cm  19.12  210.35 87.24  contagious  55.00  contagious  351.53 686.50 52.00  contagious  5 . 0 - 7 . 5 cm  8 August  S /  101.67 245.76  2 . 5 - 5 . 0 cm  17 J u l y  2. , _  9f =SSx/ x  Depth  7.93 5.00  contagious  contagious  2 . 5 - 5 . 0 cm  31.96 62.41  5 . 0 - 7 . 5 cm  ^•73  0 - 2 . 5 cm  103.88  2 . 5 - 5 . 0 cm  9.44 3.64  40.05  contagious contagious  5 . 0 - 7 . 5 cm  5-89  64.75  contagious  0 - 2 . 5 cm  12.31  135-37  contagious  2 . 5 - 5 . 0 cm  8.21  contagious  5 . 0 - 7 . 5 cm  10 .24  90.35 112.60  0 - 2 . 5 cm  contagious contagious  contagious  125  T a b l e B5.  Date  15 May  5 June  26 J u n e  17  July  8 August  Distribution  Depth  0.2.5  ^ =SSx/ x 2  Distribution  95.58  contagious  2 . 5 - 5 . 0 cm  9.9^  contagious  5 - 0 - 7 . 5 cm  5.42  109.30 59.60  0-2.5  contagious  43.34  contagious  2 . 5 - 5 . 0 cm  3-9^ 12.91  142.00  contagious  5 . 0 - 7 . 5 cm  12.67  139.33  contagious  3.64  40.00  contagious  2 . 5 - 5 . 0 cm  1.73  19.00  contagious  5 . 0 - 7 . 5 cm  1.55  17.00  random  11.00  random  2 . 5 - 5 . 0 cm  1 .00 7.22  79.^6  contagious  5.O-7.5 cm  3.62  39.80  contagious  0.91  10.00  random  1.73 2.36  19.00  random  26.00  contagious  41.50 68.74  contagious  2 . 5 - 5 . 0 cm  3.77 6.25  5 . 0 - 7 . 5 cm  3.26  35-80  contagious  0-2.5  0-2.5  0-2.5  cm  cm  cm  cm  5 . 0 - 7 . 5 cm Sept.  X  8.69  cm  2 . 5 - 5 . 0 cm  8  s /  of Hypogasturids  0 - 2 . 5 cm  contagious  Table B 6 .  D i s t r i b u t i o n of Onychiurids  Date  15  5  May  June  Depth  0.2.5  s /  X  (other than T u l l b e r g i a nC* s s x /  44.00  contagious  2 . 5 - 5 . 0 cm  2.00  22.00  contagious  5 . 0 - 7 . 5 cm  11.16  122.80  contagious  3.00  33.00  contagious  -  -  -  -  -  -  —  —  0-2.5  cm  5.O-7.5 cm June  0-2.5  cm  2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm 17  July  0-2.5  cm  2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm 8 August  0-2.5  cm  2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm 8  Sept.  Distribution  4.00  cm  2 . 5 - 5 . 0 cm  26  sp.  0-2.5  cm  2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm  127  Table B 7 . Date 15 May  D i s t r i b u t i o n o f T u l l b e r g i a sp.  Depth 0 . 2 . 5 cm 2 . 5 - 5 . 0 cm 5 . 0 - 7 - 5 cm  5 June  0 - 2 . 5 cm 2 . 5 - 5 . 0 cm 5.O-7.5 cm  26 June  17  July  8 August  X  5-98  ^*=SSx/ x 62.72  Distribution  11.09 8.23  122.00  contagious contagious  90.55  contagious  3.03 4.94 4.02  33.37 5^-36 44.18  contagious contagious contagious  5.14  56.55  0 - 2 . 5 cm 2 . 5 - 5 . 0 cm  13.18  5 . 0 - 7 . 5 cm  8.63  145.00 94.94  contagious contagious contagious  0 - 2 . 5 cm 2 . 5 - 5 . 0 cm 5.O-7.5 cm  7.91 8.91 10 .21  87.03 97-98 112.28  contagious contagious contagious  0 - 2 . 5 cm 2 . 5 - 5 . 0 cm  -  -  -  5 . 0 - 7 . 5 cm 8 Sept.  s /  0 - 2 . 5 cm 2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm  11 .87 17.01  130.54 187.17  contagious contagious  32.93 14.70  362.24  contagious  161.69 161.63  contagious contagious  14.69  128  Table Date 15 May  5 June  26  June  B8.  Distribution  Depth 0.2.5  s"/ x  cm  -  5.0-7.5  cm/  -  2.5-5.0  cm  5.0-7.5  cm  0 - 2 . 5 cm 5 . 0 - 7 . 5 cm  July  8 August  1.00  -  11.00  -  random  -  0 - 2 . 5 cm  0.91  10.00  random  2 . 5 - 5 . 0 cm  1.00  11 .00  random  5 . O - 7 . 5 cm  1 .00  11.00  random  0 - 2 . 5 cm  0 .64  7.00  random  2 . 5 - 5 . 0 cm  1.27  14.00  random  -  -  5 . 0 - 7 . 5 cm 8 Sept.  Distribution  cm  2 . 5 - 5 . 0 cm  17  SSx/ x  cm  2.5-5.0  0-2.5  o f Entomobryids  -  0 - 2 . 5 cm  1 .00  11.00  random  2 . 5 - 5 . 0 cm  1 .00  11.00  random  5 . 0 - 7 . 5 cm  2.00  22.00  contagious  129  T a b l e B9.  Date  15 May  Distribution  Depth  June  8 August  8  Sept.  Distribution  1.55 1 .00  17.00  random  11 .00  random  . 4.06  44.60  contagious  2 . 5 - 5 . 0 cm  0.91  10.00  random  5 . 0 - 7 . 5 cm  0.91  10.00  random  2.60  28.57  contagious  1.39 2.00  15.26  random  22.00  contagious  0 - 2 . 5 cm 2 . 5 - 5 . 0 cm  1 .70  5 . 0 - 7 . 5 cm  3.00  18.727 31.00 33-00  1 .08  11.86  random  2 . 5 - 5 . 0 cm  2.00  22.00  contagious  5.O-7.5 cm  -  -  2.36  26.00  contagious  2 . 5 - 5 . 0 cm  3.20  35.80  contagious  5 . 0 - 7 . 5 cm  3.09  34.00  contagious  0-2.5  0-2.5  cm  cm  5 . 0 - 7 . 5 cm July  a  contagious  2 . 5 - 5 . 0 cm  17  -# =SSx/ x  22.14  cm  5 . 0 - 7 . 5 cm  26  X  2.01  0.2.5  2 . 5 - 5 . 0 cm  5 June  s /  o f L e p i d o c y r t u s spp.  0-2.5  0-2.5  cm  cm  2.82  random contagious contagious  -  130  T a b l e BIO.  Date  15  Distribution  Depth  s / x  "X - S S x / x  1.00  11.00  random  0 - 2 . 5 cm  1.00  11.00  random  2 . 5 - 5 . 0 cm  2.00  22.00  contagious  2.91  31.96  contagious  1.00  11.00  random  0.82  9.00  random  0.2.5  May  o f Tomocerus s p p .  Distribution  cm  2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm 5  June  0 - 2 . 5 cm 2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm  26  June  5 . 0 - 7 . 5 cm 17  July  0  0-2.5  cm  2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm 8 August  0-2.5  cm  2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm 8 Sept.  0-2.5  cm  2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm  131  Table B l l . Date  15 May  Depth  Distribution  sV  x  o f Neanura  ^ =SSx/ x 2  Distribution  0 . 2 . 5 cm 2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm  5  June  0 - 2 . 5 cm 2 . 5 - 5 . 0 cm  26 J une  July  8  Sept.  11.00  random  0 - 2 . 5 cm  -  -  -  -  -  -  0 - 2 . 5 cm 2 . 5 - 5 . 0 cm 5.O-7.5 cm  8 Augus t  random  5 . 0 - 7 . 5 cm  2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm 17  io.oo  0.91 1.00  1 .00  11.00  •-  -  -  -  random  0 - 2 . 5 cm  1 .00  11 .00  random  2 . 5 - 5 . 0 cm 5.O-7.5 cm  8.04  88.41  contagious  1.55  17.00  random  0 - 2 . 5 cm  -  2 . 5 - 5 . 0 cm  9.05 4.00  5 . 0 - 7 . 5 cm  -  99.50 44.00  contagious contagious  132  T a b l e B12. Date  15 May  Depth  Distribution s /  x  0 . 2 . 5 cm  3-57  2 . 5 - 5 . 0 cm  of Sminthurids  2 >C = S S x / x  Distribution contagious  4.18  39-29 46.00  2.82  31.00  contagious  contagious  5 . 0 - 7 . 5 cm 5  June  0 - 2 . 5 cm 2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm  26  June  0 - 2 . 5 cm 2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm  .82  9.00  random  17  July  0 - 2 . 5 cm 2 . 5 - 5 . 0 cm 5 . 0 - 7 - 5 cm  0.91  10.00  random  4.15  45.66  contagious  8 Augus t  0 - 2 . 5 cm 2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm  8  Sept.  0 - 2 . 5 cm 2 . 5 - 5 . 0 cm 5 . 0 - 7 - 5 cm  T a b l e B13Date 15  May  5 June  26  17  June  July  8 August  8 Sept.  Distribution  Depth  S  /  X  o f Mesostigmata ^ =SSx/ x 2  Distribution  0.2.5 cm 2.5-5.0 cm 5.0-7.5 cm  4.43  48.77  contagious  7.21  79-33  contagious  -  -  -  0-2.5 cm 2.5-5.0 cm  3.30  36.29  contagious  3.31  contagious  5.O-7.5  7.00  36.40 77-00  contagious  3.74  41.12  contagious  7.52  82.71  contagious  3.58  39.3^  contagious  5.29  58.24  contagious  2.79  30  .7^  contagious  9.16  100  .71  contagious  22.00 69.64 47.00  contagious contagious  42.13  contagious  22.14 11.00  contagious  cm  0-2.5 cm 2.5-5.0 cm 5.0-7.5 cm 0-2.5 cm 2.5-5.0 cm 5.0-7.5 cm 0-2.5 cm 2.5-5.0 cm 5.0-7.5 cm  4.27  0-2.5 cm 2.5-5.0 cm 5.0-7.5 cm  3.83 2.01 1.00  2.00 6-33  contagious  random  Table  Date  15 May  Bl4.  Depth  0.2.5  Distribution  sV  x  of Chilopoda  ^*=SSx/ x  Distribution  cm  2 . 5 - 5 . 0 cm  0.82  9.00  random  1.00  11.00  random  0.91 1.00  10.00  random  11 .00  random  1.00  11.00  random  1.00  11.00  random  1 .00  11.00  random  5 . 0 - 7 . 5 cm' 5  June  0-2.5  cm  2 . 5 - 5 . 0 cm 5.O-7.5 cm 26  June  0-2.5  cm  2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm 17  July  0-2.5  cm  2 . 5 - 5 . 0 cm 5 . 0 - 7 - 5 cm 8 August  0-2.5  cm  2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm 8  Sept.  0-2.5  cm  2 . 5 - 5 . 0 cm 5 . 0 - 7 . 5 cm  135  APPENDIX C S o i l moisture  a t the s t u d y  site  during  1979.  136  Table C I . S o i l m o i s t u r e a t t h r e e d e p t h s f r o m May t o S e p t e m b e r 1979W a t e r l o s s i s f r o m 2 . 5 cm x 5 ' 0 cm d i a c o r e s . Moisture i s calculated as / w a t e r l o s s weightN . \dry s o i l weight / 1  0  Q  Variable  26  Mean  SE  n  loss  0 - 2 . 5 cm 2.5 - 5-0 cm 5 . 0 - 7 . 5 cm  8.88g 13-89g 15.57g  0.93g 0.91g 0.84g  12 12 12  Moisture (as $ o f d r y weight)  0 - 2.5 cm 2.5 - 5 . 0 cm 5 . 0 - 7 . 5 cm  78.67% 9.78$ 70.73% 9.65$ 72.89/2 14.84$  12 12 12  Water  loss  0 - 2.5 cm 2.5 - 5 . 0 cm 5 . 0 - 7-5 cm  12.56g 15-21g 13-66g  1.60g 2.25g 1.15s  12 12 12  Moisture (as $ o f d r y weight)  0 - 2 . 5 cm 2.5 - 5 . 0 cm 5.0 - 7 . 5 cm  85.92$ 52.78$ 35.90f*  9.26$ 9.22$ 3.00$  12 12 12  Water  loss  0 - 2 . 5 cm 2.5 - 5-0 cm 5 . 0 - 7-5 cm  7-33g 10.76g 11.20g  1.03g 0.96g 1.29g  12 12 12  Moisture (as $ o f d r y weight)  0 - 2 . 5 cm 2.5 - 5 . 0 cm 5 . 0 - 7 . 5 cm  73.75$ 11.91$ 46.61$ 6.43$ 40.23$ 6.87$  12 12 12  Water  5  Level  June  June  137  Table C l continued  Variable 17  Mean  SE  n  July Water  loss  Moisture (as % of d r y weight)  8  Level  0 - 2.5 2.5 - 5.0 5-0 - 7.5  cm cm cm  5-63g 8.19g 9-3^g  0.8lg 1.12g 0.87g  12 12 12  0 - 2.5 2.5 - 5.0 5.0 - 7-5  cm cm cm  50.27% 33-33% 38.81%  6.44% 5.42% 7.46%  12 12 12  0 - 2.5 2.5 - 5.0 5.0 - 7.5  cm cm cm  1.66g 4.52g 5.27g  0.21g o.33g o.50g  12 12 12  0 - 2.5 2.5 - 5.0 5.0 - 7.5  cm cm cm  13-78% 18.37% 20.54%  1.32% 1.84% 2.41%  12 12 12  0 - 2.5 2.5 - 5.0 5.0 - 7.5  cm cm cm  13-56g 11.19g 8.69g  1.12g l-59g 1.34g  12 12 12  0 - 2.5 2.5 - 5.0 5.0 - 7.5  cm cm cm  153.22% 49.81% 37.30%  17.63% 11.01% 6.60%  12 12 12  August Water  loss  Moisture (as % of d r y weight)  8 September Water  loss  Moisture (as % of dry weight)  138  Table C2. Mean w e i g h t s o f s o i l s a m p l e s . A l l samples were 2 . 5 cm x 5-0 cm d i a c o r e s . Level Dry s o i l weight ( a l l dates)  0 - 2.5 2.5 - 5-0 5.0 - 7.5  Mean cm cm cm  13.68g 26.90g 30.91g  SE  1.02g 1.33g l.50g  n  72 72 72  APPENDIX D Rainfall at  and  d a i l y mean  the s t u d y s i t e  during  temperatures 1979.  -»»•  35  ~ 30h  30  E E  28 20 or a.  181-  18 10  it l  8  • is  I May  26  June  17  July  6  August  S  Soot  Figure D l . R a i n f a l l at the study s i t e during the sampling period, May to September, 1979-  O  141  Figure  D2.  D a i l y mean t e m p e r a t u r e [ a p p r o x i m a t e d by ( d a i l y maximum + d a i l y minimum)/2] a t the s t u d y s i t e . The b l a c k l i n e i s a p o l y n o m i a l used t o r e p r e s e n t the degreeday a c c u m u l a t i o n t r e n d o v e r t h e p e r i o d .  142  APPENDIX E  Orthogonal  When t r e a t m e n t s  Contrast  Coefficients  are e g u a l l y spaced,  contrasts coefficients listed  standard  i n most b i o m e t r i c s t e x t b o o k s  used.. However, because o f the need f o r r e a l i s t i c ratios  and  precision  f o r enough m e a s u r e m e n t s t o a c h i e v e and  better allocation  parameters are changing treatments  orthogonal can  be  predator-prey  acceptable  o f e f f o r t i n t h e r a n g e s where  rapidly,  equally-spaced  density  a r e n o t o f t e n e m p l o y e d i n most f u n c t i o n a l  response  e x p e r i m e n t s. Coefficients  f o r the d e n s i t y t r e a t m e n t s  functional  response  experiment  T a b l e E1._  Standard  coefficients  periods.  (Chapter  used i n  my  T h r e e ) a r e shown b e l o w i n  were u s e d f o r t h e  egually-spaced  143  o  Source  of  v a n a t i on MEAN'S  ii  X2  M.  *3  *1  X6  11  ii  IB  13  3  -7  -27  981  1221  -986  *2  >U.o  COEFFICIENTS': Prey  density  -is  -13  -3  7  CL. 1  Qaadvat i c  1059  155 - 9 S i - i 2 2 1  99S  Cubic  -505  511  531  -6B2  145  64  -135  120  -54  5  Linear-  -IB  -13  -3  7  27  Quadratic  1059  1 55 - 9 6 1 - 1 2 2 1  9 8 8 - 1059 -155  Cub i c  -505  51 i  531  -682  145  505  -531  682  -145  64  --135  120  -54  5  -64  135 - 1 2 0  54  -5  The  rest  Dansitu  The  y  Six*  rest  Table E l .  Orthogonal contrast  coefficients.  144  APPENDIX  Dispersal In Chapter  Four,  size-selective C a n d i d a ..  o f F.  Candida  I d i s c u s s e d f a c t o r s w h i c h may  p r e d a t i o n by t h e  I noted  F.  pseudoscorpion  that the general a c t i v i t y  A.  The  possibility existed,  move a b o u t v a r i e d w i t h age did not..  I designed  o f F.  between  hypotheses t h a t d i s t a n c e t r a v e l l e d  Candida age  however, t h a t the tendency  ( s i z e ) even though g e n e r a l  the f o l l o w i n g  n o t a f u n c t i o n of age  minimus on F. .  level  i n d i v i d u a l s d i d not appear t o vary s i g n i f i c a n t l y classes.  influence  experiments  to  activity  to t e s t  the  by F. Candida i n d i v i d u a l s i s  or t h e p r e s e n c e  of  feed.  METHODS P o p u l a t i o n s of F. C a n d i d a were r a i s e d f o r s e v e r a l months and stable  age  allowed  distribution.  i n 18 c m  c u l t u r e pots  2  t o a t t a i n some s e m b l a n c e o f a  Random s a m p l e s f r o m s e v e r a l p o p u l a t i o n s  were c o m b i n e d t o p r o d u c e t h e t h r e e p o p u l a t i o n s u s e d i n t h e following one  experiments.  week b e f o r e  p o p u l a t i o n was t o t h e one the t r a y limit  The  starting  p o p u l a t i o n s were k e p t  the experiments.  t r a n s f e r r e d to area  shown i n F i g u r e F1.  into  5 areas.  The  t r a v e l t o one-way movement.  t h e same m o i s t e n e d  1 of a d i s p e r s a l t r a y  The  cm)  divided  s u b s t r a t e of the t r a y s described in  Two.  A t t h e s t a r t o f e a c h r u n , t h e p o p u l a t i o n was  begin  d i s p e r s i n g from  1.  7.5  a  similar  of t h e g l a s s w a l l s h e l p e d  c h a r c o a l - p l a s t e r mixture  area  for  I n each experiment,  G l a s s p l a t e s (4 X  angles  together  allowed  to was  Chapter to  After a s p e c i f i e d p e r i o d , the  F i g u r e F l . The d i s p e r s a l t r a y used i n the experiments d e s c r i b e d i n A p p e n d i x F. ( t o p view)  146  s p r i n g t a i l s were k i l l e d  with 95% e t h a n o l  measured t o t h e n e a r e s t  0.1  and t h e i r  lengths  were  mm.  RESULTS Experiment  1:  Two-hour p e r i o d ; no It  c a n be c l e a r l y  food.  seen i n F i g u r e  F2 t h a t t h e l a r g e r  (older)  i n d i v i d u a l s h a d a t e n d e n c y t o t r a v e l f a r t h e r (p < . 0 0 0 1 ) . A l l i n d i v i d u a l s i n area remaining  i n area  Experiment  5 a r e > 0.8 mm  1 a r e < 1.0  i n length while  most o f t h o s e  mm.  2:  Two-hour p e r i o d ; w i t h  food..  The p r e s e n c e o f a b o u t 20 g r a i n s o f y e a s t  i n area  1 seems t o  h a v e c h a n g e d t h e t e n d e n c y o f t h e o l d e r a n i m a l s t o move (p < .001).  The d i s t r i b u t i o n s o f a n i m a l s i n a r e a s 2 t o 5 ( F i g u r e F3)  are s i m i l a r , although  overall  d i f f e r e n c e s are strong  due t o t h e l a r g e number o f v e r y  small insects l e f t  (p < .000 1)  behind i n area  1.  Experiment  3:  T w e n t y - f o u r h o u r p e r i o d ; no Again, is  highly  food.  t h e e f f e c t o f l e n g t h on d i s t a n c e t r a v e l e d  significant  (p < . 0 0 0 1 ) .  I t seems t h a t  ( F i g u r e F4)  the extended  147  period  d i d not change the b a s i c p a t t e r n  The  e f f e c t i s accentuated  0.9  to  1.5  mm  classes.  apparent  i n Figure  F2..  by t h e l a r g e r number o f a n i m a l s i n t h e  .1  .2  .3  .4  .5  .6  .7  .8  length  .8  1.0  class  Starting  Figure  F2.  1.1  1.2  1.3  1.4  1.5  1.6  1.7  1.8  1.9.  2.0  (mm)  population  Dispersal  over  two h o u r s ; no f o o d i n a r e a 1.  .1  .2  .3  .4  .5  .8  .7  length  .8  .9  1.0  1.1  1.2  class  D i s t r i b u t i o n a t end  1.3  1.4  1.5  1.9  1.7  1.8  19  (mm)  of 2  hours  2.0  r~i  n-i  _•= .1 .2 .3 .4 .5  .9  .7 .8 .9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0  length  class  (mm)  Starting population F i g u r e F3. two  Dispersal  over  hours; with food i n area  1.  .2 ' .3 ' .4' .6 length  Distribution  .9'  r' .a' .9  1.0 1.1  class  a t end  1.2  1» 14 V S  1-8 1.7 1.8 1.9 2.0  (mm)  of 2  hours.  1  10  .1 .2 .3 .4 .5  r-n  mm  .6  .7 .8 .9 1.0 1.1 1.2 1.3 1.4 1.5 1.8 1.7 1.8 1.9 2.0  Starting population F i g u r e F4. twenty-four  hoursj  Dispersal no  over H " T h  food.  .1  .2  .3  .4 .5 .6 .7 .8 .9 1.0 1.1 12 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 length  Distribution  class  a t end  (mm)  o f 24  hours.  

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