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UBC Theses and Dissertations

A study of some factors influencing the orientation behaviour of the ambrosia bettle Trypodendron lineatum… Chan, Vernon Bruce 1967

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A STUDY OF SOME FACTORS INFLUENCING THE ORIENTATION BEHAVIOUR OF THE AMBROSIA BEETLE TRYPODENDRON LINEATUM (OLIVIER) (COLEOPTERA: SGOLYTIDAE)  by  VERNON BRUCE CHAN B.Sc,  U n i v e r s i t y o f V i c t o r i a , 1964  A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF  Master o f S c i e n c e i n t h e Department of Zoology  We a c c e p t t h i s t h e s i s a s conforming required  t o the  standard  THE UNIVERSITY OF BRITISH COLUMBIA June,  1967  In  presenting  for that  this  an a d v a n c e d  degree  the L i b r a r y  study. thesis  thesis at  in p a r t i a l the  s h a l l make  University  it  I f u r t h e r agree that  fulfilment of  freely  of  British  available  for  the  requirements  Columbia,  I  reference  and  permission for extensive  copying of  for  scholarly  p u r p o s e s may be g r a n t e d by t h e Head o f my  Department  o r by h i s  representatives.  or p u b l i c a t i o n of w i t h o u t my w r i t t e n  Department  this  thesis  for  permission.  of  The U n i v e r s i t y o f B r i t i s h V a n c o u v e r 8, C a n a d a  Columbia  It  is understood that  financial  gain  shall  not  be  agree  this  copying allowed  ii  ABSTRACT  The  b e h a v i o u r o f t h e ambrosia b e e t l e Trypodendron l l n e a t u m ( O l i v i e r )  has  been c o n s i d e r e d  i n respect  t o i l l u m i n a t i o n , body m o i s t u r e and h o s t f a c t o r s .  The  i n v e s t i g a t i o n was designed t o study p o t e n t i a l uses o f t h i s i n s e c t as a  t e s t i n s t r u m e n t f o r c h e m i c a l s t u d i e s o f h o s t wood a t t r a c t a n t s .  A  preliminary  study o f h o s t a t t r a c t a n t s was a l s o conducted u s i n g a newly-proposed b i o a s s a y technique. Monochromatic l i g h t a t t h e wavelength 543 m i l l i m i c r o n s was found t o be the  s o l e peak o f s t i m u l a t i o n t o t h i s i n s e c t i n t h e v i s i b l e spectrum.  displayed  Beetles  a p o s i t i v e p h o t i c response by w a l k i n g toward t h e source o f l i g h t .  A decrease i n s e n s i t i v i t y occurred  on e i t h e r s i d e o f t h i s peak, and i n t h e  l o n g e r wavelengths t h e s e n s i t i v i t y t o l i g h t d i m i n i s h e d  a t 735  millimicrons.  E v i d e n c e t o date i n d i c a t e d a second peak o f s e n s i t i v i t y i n t h e u l t r a v i o l e t r e g i o n o f t h e spectrum; t h e l a t t e r a p p e a r i n g t o be much g r e a t e r i n t h e v i s i b l e spectrum.  t h a n t h e peak  The i n t e n s i t y o f any wavelength was a l s o found t o be  a l i m i t i n g f a c t o r i n a f f e c t i n g b e e t l e r e s p o n s e , a l t h o u g h i n t h e l o n g e r wavelengths  t h e s e n s i t i v i t y appeared t o be a f u n c t i o n o f wavelength a l o n e .  Monochromatic l i g h t a s a standard has been proposed f o r f u t u r e techniques t o a c t i n opposition t o be e f f e c t i v e i n s i m u l a t i n g •Green  1  t o odour s t i m u l i .  Red i l l u m i n a t i o n was found  darkness t o T. l i n e a t u m .  u n a t t r a c t i v e sapwood shavings o f D o u g l a s - f i r a f t e r placement  under oxygen d e f i c i e n t c o n d i t i o n s  became a t t r a c t i v e t o T. l i n e a t u m .  a t t r a c t i v e n e s s , was i n d i c a t e d i n wood p l a c e d under a n a e r o b i o s i s hours.  bioassay  Beyond 30 hours, l i t t l e  s i g n o f a t t r a c t a n t s was n o t e d .  f o r 20 t o 26 C o n t r o l wood  s e r i e s d i d not undergo any t r a n s i t i o n , t h i s l e a d i n g t o t h e c o n c l u s i o n s i g n i f i c a n t change o c c u r r e d The  Maximum  that a  i n wood a s a r e s u l t o f t h e a n a e r o b i c t r e a t m e n t .  i m p l i c a t i o n s o f t h i s r e s u l t have been d i s c u s s e d .  The s u c c e s s f u l use o f  iii wood shavings has made possible further studies on the nature of origin of attractants. The use of the anemotactic behaviour of beetles of both sexes to an airstream carrying host odour was found to be a highly efficient technique of analysis.  The role of greater quantities of light in attracting insects away  from a source of olfactory stimulation became increasingly apparent from this study. Moisture loss of the insect apparently did not alter their response to white light.  iv ACKNOWLEDGMENTS The author wishes to express his deep gratitude to Dr. Kenneth Graham, for his many helpful suggestions and for his endless encouragement throughout the conduct and preparation of this thesis. Special acknowledgment i s extended to Dr. G. G. E. Scudder for his reading of the manuscript and for the use of various pieces of laboratory equipment, and to Miss D. Lee for her endless patience and typing skills during the preparation of this thesis.  Thanks are also extended to Dr. J. T,  McFadden for his suggestions on the statistical analyses. This study was conducted with the aid of grants to Dr. K. Graham from the National Research Council of Canada. Special financial assistance i s gratefully acknowledged from the University of British Columbia (student laboratory assistantships), Later Chemicals Co., Ltd., and the British Columbia Loggers' Association.  Acknowledgement i s also extended to the  Department of Zoology, University of British Columbia, for the use of laboratory space and f a c i l i t i e s .  V  TABLE OF CONTENTS Page INTRODUCTION  1  MATERIALS AND METHODS  5  1.  The e x p e r i m e n t a l i n s e c t :  its  s o u r c e and method o f h a n d l i n g . . .  2.  Study o f r e s p o n s e s t o monochromatic l i g h t  6  (a)  Source o f l i g h t  6  (b)  C o n d i t i o n s o f wavelength and i n t e n s i t y  8  i  V a r y i n g wavelengths  ii  V a r y i n g b o t h wavelength and i n t e n s i t y  Study o f t h e e f f e c t  3.  at a constant i n t e n s i t y  10 11  o f water l o s s on p h o t i c r e s p o n s e . . .  12  (a)  Dehydration of beetles  12  (b)  Testing of photic response.  13  The e f f e c t  4.  of subjecting  ' g r e e n ' wood t o a n a e r o b i c  conditions  •  15  (a)  P r e p a r a t i o n o f the wood  15  (b)  Bioassay techniques  20  EXPERIMENTAL RESULTS 1.  29  Study o f r e s p o n s e s t o monochromatic l i g h t  29  (a)  V a r y i n g wavelengths a t a c o n s t a n t i n t e n s i t y  29  (b)  V a r y i n g b o t h wavelength and i n t e n s i t y  33  Z.  Study o f t h e e f f e c t  3.  The e f f e c t  o f water l o s s on p h o t i c r e s p o n s e . .  of subjecting  36  ' g r e e n ' wood t o a n a e r o b i c  DISCUSSION I  5  52  The e f f e c t s  of various p h y s i c a l f a c t o r s  on the' r e s p o n s e s  o f Trypodendron l i n e a t u m ( O l i v i e r ) 1«  MODOClirOni£L"biC Xi§[lltja  a.  » « # o 0 « a < t 0 0 0 0 * » « o 0 0 o o o © 0 0 f l 0 O 0 o i > 0 0 o « 0 « 0 o  G e n e r a l COI1S— d@I*8>i/_L0nS o  » 0 0 « o 0 0 0 « 0 0 0 0 0 0 0 » 0 0 0 0 0 0 0 0 « 0 0 0 » » »  52 $2 52  vi  TABLE OF CONTENTS ( c o n t i n u e d ) Page b. 2.  II  New i n f o r m a t i o n f o r t h e b i o a s s a y t e c h n i q u e  56  Water l o s s v e r s u s p h o t i c r e s p o n s e s and i t s i m p l i c a t i o n s t o the bioassay technique  58  The m o d i f i c a t i o n and b i o a s s a y o f 'green' wood u s i n g t h e newly-proposed t e c h n i q u e o f a n a l y s i s .  •••  60  1.  The wood f a c t o r s  60  2.  The b i o a s s a y t e c h n i q u e  66  CONCLUS TONS • • • « * « » « » « * e « « * o « o » o o 0 » « « e « « « e » « o o « » 0 « « o « * » « « « « o « « « « « « * * * * * « LITERATURE C I T E D • • • « « « o o o « o « « o « « « « APPENDICES  ••••••«•••••••«••••••••••••••«••  ^9 71 77  vii LIST OF TABLES T a b l e No. 1.  Summarized r e s u l t s  Page o f b e e t l e responses t o v a r i o u s  wavelengths  o f monochromatic l i g h t a t an e q u a l i n t e n s i t y  30  2.  Summarized s t a t i s t i c s o f p o s i t i v e p h o t i c r e s p o n s e s o f T r y p o dendron a d u l t s t o v a r i o u s wavelengths o f monochromatic l i g h t  3.  V a r i a n c e a n a l y s i s r e s u l t s t e s t e d a t the 5% l e v e l o f s i g n i f i cance showing the d i f f e r e n c e s i n p o s i t i v e p h o t i c r e s p o n s e s between wavelengths  4.  5.  6.  7.  t e s t e d a t an e q u a l i n t e n s i t y  T a b l e o f v a l u e s from the monochromator c a l i b r a t i o n graphs (appendix 2) showing t h e percentage o f p o s i t i v e p h o t i c r e s p o n s e s f o r 10 per cent i n t e r v a l s r a n g i n g from 0 t o 60 per cent (appendix l ) and the c o r r e s p o n d i n g r e q u i r e d energy output o f monochromatic l i g h t f o r the wavelengths t e s t e d  35  Comparison o f the s u r v i v a l times o f t h e two groups o f b e e t l e s , one i n the 'humid environment' ( c o n t r o l ) and the o t h e r on t h e ' d r y ' environment as measured a t t h e e a r l i e s t time a f t e r d e a t h .  37  Comparison o f weight l o s s e s by Trypodendron i n t h e ' d r y ' and ' h u m i d ' environments, the f i n a l f i g u r e was r e c o r d e d a t the e a r l i e s t p o s s i b l e measurement a f t e r death  37  Summarized i n d i v i d u a l comparisons o f d i f f e r e n c e s i n p h o t i c responses w i t h water l o s s f o r t h e ' r e f r a c t o r y ' and ' r e a c t i o n ' times as d i s p l a y e d by a d u l t Trypodendron t o white l i g h t a t t h e \% l e v e l o f s i g n i f i c a n c e . . . . . .  8.  9.  ...................  T a b u l a t e d r e s u l t s o f t h e v a r i o u s p h o t i c responses o f a d u l t Trypodendron t o white l i g h t w i t h i n c r e a s i n g water l o s s  39 40  Summarized d a t a o f r e s p o n s e s from b i o a s s a y t e s t s o f wood samples s u b j e c t e d t o v a r y i n g times under a n a e r o b i c c o n d i t i o n s . Responses a r e computed as percentages i n 4 hour i n t e r v a l s f o r the three d i f f e r e n t l i g h t i n g s i t u a t i o n s  10.  34  •  Summarized d a t a and response percentages o f Trypodendron a d u l t s t e s t e d t o v a r i o u s wood samples and c o n t r o l s . . . . . .  47 50  viii LIST OF ILLUSTRATIONS F i g u r e No. 1.  Page  Shimadzu spectrophotometer Model QV-50 used as a source o f monochromatic l i g h t t o t e s t t h e e f f e c t s o f v a r i o u s wavelengths and i n t e n s i t i e s on the p h o t i c responses o f f l i g h t - i n e x p e r i e n c e d T, lineatum adults  2a,  Apparatus used f o r s t u d y i n g t h e p h o t i c responses o f T ,  lineatum  a d u l t s t o monochromatic l i g h t 2b.  9  Monochromatic l i g h t e x i t h o l e p l a c e d i n p o s i t i o n t o p r o j e c t a beam o f l i g h t a c r o s s the t e s t arena s u r f a c e . . . . .  9  3.  B e e t l e - l a d e n aluminum c o n t a i n e r s p l a c e d i n one o f t h e two P e t r i d i s h environments. P l a s t i c s c r e e n was p l a c e d beneath t h e c o n t a i n e r s t o prevent any c o n t a c t w i t h the f i l t e r paper ( e i t h e r  L.  Apparatus used t o t e s t the p h o t i c responses o f f l i g h t - i n e x p e r ienced T . lineatum t o white l i g h t f o l l o w i n g varying periods of desiccation. The R e i c h e r t i l l u m i n a t o r w i t h the Bausch and Lomb heat f i l t e r was used as t h e source o f l i g h t . . . . .  5.  Double samples o f wood c h i p s i n 250 m l . Erlenmeyer placed i n the  6.  7.  8a.  8b.  'anaerobic'  10.  L4  flasks  chamber.  18  ' A e r o b i c ' c o n t r o l s e r i e s o f wood c h i p s i n 250 m l .  Erlenmeyer  f l a s k s and p l a c e d i n t o a l a r g e p l a s t i c bag and s e a l e d  19  Apparatus used f o r the b i o a s s a y o f wood u s i n g monochromatic l i g h t (735 mu), t h i s s i m u l a t i n g darkness t o T„ l i n e a t u m . Wood f a c t o r s were p r e s e n t e d i n double s e r i e s v i a a f i n e g l a s s n o z z l e l o c a t e d a t t h e r i g h t o f the t e s t a r e n a . . . . .  23  B e e t l e s p o s i t i o n e d on e n t o m o l o g i c a l cardboard p o i n t s w i t h g l u e by the pronotum. As a p r e c a u t i o n a g a i n s t water l o s s , p o i n t s were mounted over a medium o f water  24-  Female T . l i n e a t u m a d u l t mounted f o r c a p t i v e Specimen i s seen r e t r a c t i n g  9.  7  i t s wings a f t e r  flight-exercise. flight,...  Apparatus used t o t e s t wood i n the ' o p p o s i n g ' l i g h t s i t u a t i o n . The R e i c h e r t i l l u m i n a t o r w i t h a Bausch and Lomb heat f i l t e r was used t o produce a broad d i f f u s e beam o f l i g h t . The same apparatus as d e s c r i b e d f o r t h e ' d a r k ' s i t u a t i o n was used t o Apparatus used t o t e s t wood w i t h t h e overhead c e i l i n g l i g h t s produced by f o u r f l o u r e s c e n t lamps l o c a t e d about 2 meters above the t e s t stage. The apparatus f o r t h e p r e s e n t a t i o n o f wood f a c t o r s was the same as t h a t d e s c r i b e d f o r t h e ' d a r k ' and  ZL  ix  LIST OF ILLUSTRATIONS ( c o n t i n u e d ) F i g u r e No. 11.  12.  13.  14.  15.  16.  17.  Page  Graphs o f t o t a l l e d p o s i t i v e and near p o s i t i v e (?<•) responses o f Trypodendron t o v a r i o u s wavelengths o f monochromatic l i g h t a t an e q u a l i n t e n s i t y  31  Graphs o f t h e c u m u l a t i v e percentage weight l o s s e s o f i n d i v i d u a l Trypodendron a d u l t s w i t h i n c r e a s e d exposure time i n t h e two environments. a . d e s i c c a t e d group ( d r y environment) b. n o n - d e s i c c a t e d group (humid environment)  38  L i n e t r a c i n g s o f paths t a k e n by two f l i g h t - i n e x p e r i e n c e d female Trypodendron a d u l t s t o w h i t e l i g h t w h i l e b e i n g s u b j e c t e d to varying periods of d e s i c c a t i o n . a . Responses o f a b e e t l e from t h e d e s i c c a t e d group. b. Responses o f a b e e t l e from t h e n o n - d e s i c c a t e d group  41  L i n e t r a c i n g s o f t h e paths t a k e n by two f l i g h t - e x p e r i e n c e d female Trypodendron a d u l t s i n t h e t h r e e d i f f e r e n t l i g h t i n g s i t u a t i o n s and t e s t e d t o v a r i o u s t y p e s o f wood. a . a t t r a c t i v e D o u g l a s - f i r sapwood c o n t r o l b. ' a n a e r o b i c ' sample (23.5 h o u r s ) c. ' a e r o b i c ' c o n t r o l (23.5 hours) d. a i r only e. 'green' c o n t r o l f. a t t r a c t i v e Douglas-fir c o n t r o l again....  43  L i n e t r a c i n g s o f t h e paths t a k e n by two male and one female f l i g h t - e x p e r i e n c e d Trypodendron a d u l t s t e s t e d i n t h e 'dark' and 'opposing' l i g h t s i t u a t i o n s . Wood f a c t o r s i n c l u d e ? a . a t t r a c t i v e D o u g l a s - f i r sapwood c o n t r o l b. ' a n a e r o b i c ' sample (21 h o u r s ) c. ' a e r o b i c ' c o n t r o l (21 h o u r s ) . . . . . ...........  44  P o i n t graph o f t o t a l l e d percentage p o s i t i v e and near p o s i t i v e (?+•) r e s p o n s e s t o wood shavings p l a c e d under a n a e r o b i c c o n d i t i o n s f o r v a r y i n g p e r i o d s (2 t o 46.5 h o u r s ) . T h r e e s e t s o f p o i n t s have been i n c l u d e d f o r the t h r e e d i f f e r e n t l i g h t i n g s i t u a t i o n s ( d a r k , opposing, overhead)  46  Frequency histograms o f t o t a l l e d percentage p o s i t i v e and near p o s i t i v e r e s p o n s e s o f Trypodendron t o ' a n a e r o b i c ' samples d i v i d e d i n t o 4 hour treatment c l a s s e s and t e s t e d under t h e three l i g h t i n g situations % a . b e e t l e s t e s t e d I n 'dark' b. b e e t l e s t e s t e d i n 'overhead' l i g h t s i t u a t i o n c. b e e t l e s t e s t e d i n 'opposing' l i g h t s i t u a t i o n . . . . . . . . . . . . .  48  1  INTRODUCTION  The  o r i e n t a t i o n r e a c t i o n s o f t h e ambrosia b e e t l e Trypodendron  lineatum  ( O l i v i e r ) a r e a s u b j e c t o f c o n s i d e r a b l e i n t e r e s t and importance t o i n v e s t i g a t o r s o f t h i s i n s e c t , as w e l l as t o s t u d e n t s  o f S c o l y t i d behaviour i n general.  I t i s d e s i r e d t o understand t h e f a c t o r s and b e h a v i o u r a l mechanisms which i n f l u e n c e t h i s s p e c i e s i n i t s d i s c o v e r y o f host i d e n t i t y and s t a t e o f m o r b i d i t y . c o n t r i b u t e t o an understanding  l o g s b o t h as t o taxonomic  A. thorough knowledge o f t h e s u b j e c t  o f important  will  f e a t u r e s o f t h e ecology and host  r e l a t i o n s o f t h i s i n s e c t , as w e l l as p r o v i d e  information f o r using the beetles  as b i o a s s a y  of chemical a t t r a c t a n t s or  instruments  i n t h e f u r t h e r study  repellents. Considerable  i n f o r m a t i o n has been gained  on t h i s  s u b j e c t by v a r i o u s  i n v e s t i g a t o r s working i n both f i e l d and l a b o r a t o r y , but some important remain t o be e x p l o r e d .  aspects  I t i s known t h a t t h e f o l l o w i n g f a c t o r s i n f l u e n c e t h e  r e a c t i o n s o f T. lineatum  i n r e s p e c t t o host t r e e f a c t o r s :  the p h y s i o l o g i c a l  s t a t e o f t h e i n s e c t , p r e - c o n d i t i o n i n g o f t h e i n s e c t , host t r e e f a c t o r s , and p h y s i c a l f a c t o r s o f t h e environment a t t h e moment o f o b s e r v a t i o n . The p h o t i c responses a r e among t h e most c o m p e l l i n g behaviour  and ecology  o f T. lineatum.  f a c t o r s i n the  A photonegative behaviour e v i d e n t l y  causes t h e newly-emerged a d u l t s i n summer t o seek shade and e n t e r a l o n g dormancy i n t h e s o i l  (Dyer and Kinghorn, 1961).  I n s p r i n g , temperature  a c t i v a t i o n and a p h o t o p o s i t i v e response cause emergence and d i s p e r s a l . p h o t o p o s i t i v e response i s however m o d i f i e d by ambient temperature,  The  such  t h a t a maximum p r o p o r t i o n o f a p o p u l a t i o n sample becomes p h o t o p o s i t i v e a t about 26 t o 28 degrees C e n t i g r a d e .  T h e r e a f t e r a p h o t o n e g a t i v e response  appears u n t i l a l l i n d i v i d u a l s a v o i d t h e l i g h t a t AO degrees (Francia,  1965).  Centigrade  The p h o t o p o s i t i v e response tends t o o v e r r i d e a l a t e n t  c a p a c i t y t o respond t o host f a c t o r s u n t i l f l i g h t has o c c u r r e d  (Graham, 1959).  2  The s w a l l o w i ng o f a i r d u r i n g f l i g h t  (Chapman, 1956) e v i d e n t l y i s t h e  i n i t i a t i n g mechanism f o r t h e change o f r e l a t i v e response t h r e s h o l d s t o odour and l i g h t  (Graham, 1961).  As l i t t l e as f i v e minutes o f f l i g h t may be  s u f f i c i e n t t o change t h e responses i n a t l e a s t some i n d i v i d u a l s ( F r a n c i a , The mechanism by which t h e swallowed such ( F r a n c i a ,  1965).  a i r a c t s i s e v i d e n t l y not p r e s s u r e as  1965).  Now t h a t t h e importance o f t h e p h o t i c response i s b e t t e r understood, i t i s p o s s i b l e t o study o l f a c t o r y responses i n T. l i n e a t u m w i t h o u t i n t e r f e r e n c e from p h o t i c e f f e c t s .  O l f a c t o r y t e s t s r e q u i r e e i t h e r t h a t t h e b e e t l e s be  p r e - c o n d i t i o n e d by f l i g h t  so t h a t they c a n respond t o odour even i n t h e  presence o f l i g h t , o r t h a t t h e b e e t l e s be p l a c e d i n t o t a l darkness d u r i n g an o l f a c t o r y t e s t , o r t h a t o b s e r v a t i o n s be c a r r i e d out under a wavelength o f l i g h t which i s i n v i s i b l e t o t h e b e e t l e , y e t v i s i b l e t o t h e human o b s e r v e r . V a r i o u s c r i t e r i a o f response have been d e v i s e d .  One i s m a n i f e s t i n t h e  b e e t l e s b o r i n g i n t o wood c o n t a i n i n g i n h e r e n t o r a p p l i e d (Graham and Werner, 1956).  attractants  Another i s m a n i f e s t i n an up-wind anemotactic  response which i s prompted by t h e presence o f odour i n t h e a i r stream ( F r a n c i a , 1965).  A t h i r d i s m a n i f e s t i n t h e tendency o f t h e b e e t l e s t o  retain their position within a  substratum f i e l d  o f odour.  In t e s t s employing p r e - f l o w n b e e t l e s , a beam o f l i g h t p r o v i d e s a c r i t i c a l t e s t o f t h e apparent response t o odour. i n e f f e c t i v e , a photopositive r e a c t i o n i s manifest.  I f odour i s absent o r Therefore a l i g h t  source  i s no l o n g e r an o b s t a c l e t o t h e o l f a c t o r y study but a u s e f u l f a c t o r i n i t . The s t u d i e s o f p h o t i c responses o f t h i s i n s e c t and i t s o l f a c t o r y responses i n t h e presence o f a l i g h t source have h e r e t o f o r e depended on an arbitrarily  chosen i l l u m i n a t i o n standard.  The e f f e c t o f l i g h t on p h o t i c  responses a l o n e i s known o n l y i n g e n e r a l terms, and t h e r e remains t o be  3  determined  the e f f e c t o f wavelength and i n t e n s i t y .  Knowledge of t h i s k i n d  w i l l be not o n l y of s c i e n t i f i c i n t e r e s t , but w i l l permit the d e f i n i t i o n o f r e f e r e n c e s t a n d a r d s i n the b i o a s s a y o f host a t t r a c t a n t s . o f the o b j e c t i v e s of the p r e s e n t i n v e s t i g a t i o n was responses t o l i g h t o f d i f f e r e n t wavelengths and  and Werner they f a i l e d  (1956),  intensities.  may  i n T.  lineatum  E a r l i e r o b s e r v a t i o n s by Graham  u s i n g t h e s e b e e t l e s i n darkened a r e n a t e s t s ,  showed t h a t  t o d i s p l a y t h e i r u s u a l a g g r e g a t i v e t e n d e n c i e s about odour  sources when t h e humidity was moisture  loss.  one  t h e study o f p h o t i c  Another q u e s t i o n c o n c e r n i n g o r i e n t a t i o n responses p e r t a i n s t o the e f f e c t s of m o i s t u r e  Accordingly,  very low.  The  general v i t a l  l o s s were known from work o f N i j o l t and  s u r v i v e l o s s e s o f between 1 0 and  2 5 per cent.  Chapman  limits for  (I964).  T.  lineatum  Since orientation studies  sometimes expose the b e e t l e s t o moderate l a b o r a t o r y h u m i d i t i e s o f about 50%  R.H.  f o r up t o s i x hours,  loss within v i t a l  i t was  important  l i m i t s a f f e c t s responses  t o know i f t o t a l  t o l i g h t and  moisture  odour.  Another problem i n the study of f a c t o r s i n f l u e n c i n g t h e responses ambrosia  b e e t l e s t o t h e i r host t r e e s concerns  chemical a t t r a c t a n t s .  Graham  (1962)  the nature and  of  o r i g i n of the  had demonstrated t h a t f r e s h sapwood  s u b j e c t e d t o a n a e r o b i c c o n d i t i o n s f o r 2 4 hours becomes a t t r a c t i v e t o T. lineatum. whereas t h e u s u a l span of time r e q u i r e d f o r a t t r a c t i v e n e s s t o develop i n a l o g may  be weeks or months.  F r e s h sapwood kept under a e r o b i c  c o n d i t i o n s f o r 2 4 hours remained u n a t t r a c t i v e . The d i s c o v e r y o f e f f e c t s o f a n a e r o b i o s i s on sapwood i s s i g n i f i c a n t f o r s t u d i e s aimed a t both u n d e r s t a n d i n g and formation process.  c o n t r o l l i n g the  attractant-  The a d o p t i o n o f an a c c e l e r a t i n g p r o c e s s a f f o r d s an  o p p o r t u n i t y of speeding up the s e a r c h f o r m e t a b o l i c i n h i b i t o r s attractant  formation.  of  The t i m e f a c t o r r e q u i r e d f o r the c h e m i c a l changes  under a n a e r o b i c c o n d i t i o n s was remains t o be d i s c o v e r e d detectable  change, and  T h i s problem was  how how  known only  on an e m p i r i c a l b a s i s .  It  l o n g a p e r i o d i s r e q u i r e d t o produce a long i s required  t o produce a maximum change  thus another o b j e c t i v e of the  study.  MATERIALS AND METHODS  1.  The e x p e r i m e n t a l Experimental  ( O l i v i e r ) , gathered  insects  i t s source and method o f h a n d l i n g .  i n s e c t s were t h e ambrosia b e e t l e Trypodendron l i n e a t u m from t h e i r o v e r w i n t e r i n g q u a r t e r s i n f o r e s t d u f f and  under t h e bark o f o l d D o u g l a s - f i r t r e e s near Cowichan Lake on Vancouver I s l a n d , B r i t i s h Columbia i n e a r l y A p r i l o f 1965, j u s t p r i o r t o t h e i r normal emergence and a t t a c k .  The b e e t l e s c o n t a i n e d i n bark and f o r e s t l i t t e r  s t o r e d i n f i v e g a l l o n metal at  were  U.S. army water cans and p l a c e d i n a r e f r i g e r a t o r  a temperature o f 0-5 degrees C e n t i g r a d e .  Some o f t h e s e b e e t l e s were  a d u l t s t h a t had s u r v i v e d t h e p r e v i o u s seasons a t t a c k , but t h e m a j o r i t y were newly-developed a d u l t s t h a t had never undergone any a t t a c k on host  breeding  material. Whenever t e s t specimens were r e q u i r e d , a h a n d f u l o f b e e t l e - c o n t a i n i n g medium was p l a c e d i n a s h a l l o w pan and f l o a t e d over warm water a t a temperature o f a p p r o x i m a t e l y  30 degrees C e n t i g r a d e .  B e e t l e s on warming up  emerged t o t h e s u r f a c e o f t h e d u f f , from which t h e y were immediately to  removed  s t a n d a r d 5 i n c h P e t r i d i s h e s c o n t a i n i n g a p i e c e o f moistened f i l t e r  u n t i l t h e y were r e q u i r e d f o r t e s t i n g .  paper,  Extreme c a r e was taken i n h a n d l i n g  b e e t l e s since mutilated i n d i v i d u a l s a r e u n s u i t a b l e f o r t e s t s o f behaviour. Those w i t h e i t h e r broken o r amputated l e g s showed d i f f i c u l t y i n w a l k i n g , i n many cases r o l l i n g over and moving t h e i r l e g s f r a n t i c a l l y i n an unsuccessful attempt t o r e c o v e r a s t a n d i n g p o s i t i o n .  Gara  (1963) has s t a t e d t h a t t h e  l o s s o f a n antenna can a l s o r e n d e r an i n d i v i d u a l u n s u i t a b l e f o r t e s t purposes s i n c e t h e s e s t r u c t u r e s c o n t a i n many o f t h e sensory organs n e c e s s a r y f o r insect orientation.  He has c o r r e l a t e d a 50 p e r cent r e d u c t i o n i n performance  w i t h t h e l o s s o f a n antenna.  6 2.  Study (a.)  o f responses Source  t o monochromatic  light,  of l i g h t .  T h i s phase o f t h e p r e s e n t study was t o i n v e s t i g a t e t h e e f f e c t s o f v a r y i n g wavelengths and i n t e n s i t i e s o f monochromatic l i g h t on the p h o t i c responses  o f Trypodendron.  Shimadzu Spectrophotometer  The source o f t h i s  l i g h t was s u p p l i e d by a  Model QV-50 ( F i g . 1 ) .  T h i s i n s t r u m e n t was  equipped w i t h a hydrogen d i s c h a r g e lamp as w e l l as a t u n g s t e n lamp, t h e l a t t e r h a v i n g a n output rangingfrom 350 t o 1200 m i l l i m i c r o n s . lamp was d e s i g n e d t o produce  The hydrogen d i s c h a r g e  an output beyond 350 mu i n t o t h e s h o r t e r  wavelengths o f t h e u l t r a v i o l e t .  P r e l i m i n a r y t e s t s i n d i c a t e d t h a t t h e output  i n t o t h e s h o r t e r wavelengths o f t h e u l t r a v i o l e t w i t h t h e hydrogen lamp were not s u f f i c i e n t f o r t h e experiments  a t hand.  t h e r e f o r e l i m i t e d t o t h e wavelengths produced  T e s t s d e s c r i b e d h e r e a f t e r were by t h e t u n g s t e n f i l a m e n t ,  namely 299 t o 880 m i l l i m i c r o n s . * Designated wavelengths were o b t a i n e d by a simple t u r n o f a c a l i b r a t e d d i a l , t h e l i g h t produced  b e i n g emitted through a one i n c h diameter h o l e a t  one end o f t h e instrument housing.  The i n t e n s i t y o f l i g h t was c o n t r o l l e d by  v a r y i n g the width of the c o l l i m a t o r s l i t  i n t h e spectrophotometer."'"  The q u a n t i t y o f l i g h t emitted was measured by means o f t h e p h o t o m u l t i p l i e r l o c a t e d i n a s e p a r a t e h o u s i n g u n i t next t o t h e l i g h t e m i s s i o n h o l e .  * .values appear t o be 'odd' because t h e spectrophotometer a f t e r t h i s experimental s e r i e s t  This  was r e c a l i b r a t e d  Expanding t h e c o l l i m a t o r s l i t not o n l y changes t h e q u a n t i t y o f l i g h t e m i t t e d but a l s o t h e q u a l i t y , s i n c e expanding t h e s l i t a l l o w s a l a r g e r a r e a o f t h e s p e c t r a l band t o be emitted, t h e r e b y i n c r e a s i n g t h e i n t e n s i t y . T h i s however would a l s o tend t o i n c r e a s e t h e ' f r i n g e ' wavelengths. Most experiments however, u t i l i z e d v e r y s m a l l s l i t widths thereby i n c r e a s i n g ' greatly the 'purity' of the transmitted l i g h t .  Figure 1.  Shimadzu spectrophotometer Model QV-50 used as a source of monochromatic light to test the effects of various wavelengths and intensities on the photic responses of flight-inexperienced T. lineatum adults.  8 photometer c o u l d e a s i l y be removed from t h e remainder when r e q u i r e d .  o f t h e instrument  I t d i d not however g i v e r e a d i n g s i n the standard  measurement u n i t s s i n c e i t was not o r i g i n a l l y designed r a t h e r i n u n i t s o f a percentage  light  f o r such a study, but  transmission/absorption of l i g h t .  however was found t o s u f f i c e f o r t h e purposes  This value  o f t h e p r e s e n t study,  t h a t was r e q u i r e d was a s t a n d a r d f o r which t o measure t h e energy  since a l l  emission of  t h e v a r i o u s t e s t wavelengths and t h e i r c o r r e s p o n d i n g i n t e n s i t i e s .  An  approximate s t a n d a r d l i g h t measure was o b t a i n e d by u s e of a P h o t o v o l t photometer Model 200.  Most i n t e n s i t i e s were e s t i m a t e d t o range between a  minimum o f 0.02 f o o t - c a n d l e s and a maximum o f 6.00 f o o t - c a n d l e s .  (b)  C o n d i t i o n s o f wavelength and i n t e n s i t y . F o r t h e purposes  o f t e s t i n g , a l l p h o t o c e l l s were removed  o b s t r u c t i n g t h e p a t h o f t h e beam o f l i g h t c a l i b r a t e d spectrophotometer.  from  emitted by t h e p r e v i o u s l y  T h i s beam was p r o j e c t e d a c r o s s a l e v e l  p l a t f o r m , t h e l a t t e r covered w i t h a p i e c e o f white 8£" x 11" w r i t i n g t h i s s e r v i n g as a s u b s t r a t e on  set-up  approximately Preliminary  o f t h e monochromator i n d i c a t e d t h a t  and c o n t r a c t i n g o f the s l i t  beam o f monochromatic l i g h t . and  t h e w i d t h o f t h e beam was  w h i l e a t i t s d i s t a l edge i t was a p p r o x i m a t e l y 32.0 mm.  t e s t i n g w i t h the c o l l i m a t o r s l i t expanding  paper;  which the e x p e r i m e n t a l b e e t l e s c o u l d meander.  At t h e p r o x i m a l edge o f t h e paper, 12.0 mm.,  arena  d i d not a l t e r t h e dimensions  of the  F i g u r e s 2a and b i l l u s t r a t e t h e apparatus  used.  T e s t e were conducted  on f l i g h t - i n e x p e r i e n c e d beetle's by p l a c i n g an  i n d i v i d u a l specimen i n t h e c e n t r e o f the t e s t f i e l d w i t h i t s head f a c i n g towards t h e source o f monochromatic l i g h t . darkened room.  However, a n opposing white  A l l t e s t s were conducted light  source was pla'aed i n  in a  Fig.  2a.  Fig.  2b.  Apparatus used f o r s t u d y i n g t h e p h o t i c responses o f T. l i n e a t u m a d u l t s t o monochromatic l i g h t . The beam o f l i g h t was p r o j e c t e d a c r o s s t h e t e s t arena from t h e l e f t . During re-alignment p e r i o d s t h e t e s t f i e l d was i l l u m i n a t e d by t h e opposing R e i c h e r t i l l u m i n a t o r w i t h t h e Bausch and Lomb heat f i l t e r i n t e r p o s e d .  Monochromatic l i g h t e x i t h o l e p l a c e d i n p o s i t i o n t o p r o j e c t a beam o f l i g h t a c r o s s t h e t e s t a r e n a s u r f a c e . The c e n t r a l s t a r t i n g p o i n t o f t h e arena i s marked w i t h a c r o s s (+).  10  o p p o s i t i o n t o t h e source o f monochromatic  l i g h t , t h i s serving to illuminate  the t e s t f i e l d during the b e e t l e r e - a l i g n i n g periods.  Responses  of beetles  were merely r e c o r d e d a s e i t h e r p o s i t i v e o r n e g a t i v e ; p o s i t i v e r e s p o n s e s b e i n g t h o s e i n which i n d i v i d u a l s walked towards t h e source o f monochromatic e i t h e r d i r e c t l y o r i n d i r e c t l y from t h e i r s t a r t i n g p o s i t i o n .  light,  N e g a t i v e responses  were t h o s e i n which b e e t l e s showed no tendency t o o r i e n t towards t h e l i g h t and d i s p l a y e d o t h e r w i s e random movements. Two s e p a r a t e methods were adopted i n t h i s study t o t e s t t h e e f f e c t s o f t h e v a r i o u s wavelengths and t h e i r r e s p e c t i v e i  intensities.  V a r y i n g wavelengths a t a c o n s t a n t i n t e n s i t y .  The f i r s t was t h e s i m p l e r o f t h e two methods, i t i n v o l v i n g o n l y 9 d i f f e r e n t wavelengths  (34-8 mu t o 735 mu), a l l a t a s i m i l a r i n t e n s i t y .  r e s p o n s e s o f b e e t l e s a t t h e c o n s t a n t i n t e n s i t y would t h e r e f o r e depend 'stimulative efficiency  1  o f each i n d i v i d u a l wavelength.  The on t h e  A measure o f t h e  a t t r a c t i v e n e s s o f each wavelength c o u l d t h e r e f o r e be expressed as a p e r c e n t a g e o f t h e p o s i t i v e responses e x h i b i t e d by t h e t o t a l complement o f t e s t the h i g h e r t h e percentage t h e g r e a t e r t h e ' s t i m u l a t i v e  beetles;  efficiency'.  In t h i s s e r i e s , 29 f l i g h t - i n e x p e r i e n c e d Trypodendron a d u l t s were t e s t e d , o f which 20 were f e m a l e s .  Each i n d i v i d u a l was g i v e n 10 t r i a l s t o each  wavelength b u t some however were not t e s t e d t o a l l  o f t h e 9 wavelengths.  Also  7 females and 7 males were d i s c a r d e d because they showed no apparent c a p a c i t y t o respond a t a l l  t o any wavelength o f monochromatic  light.  Chapman (1955b)  has d e s c r i b e d s i m i l a r i n s e c t s i n an a p p a r e n t l y normal p o p u l a t i o n which showed no i n c l i n a t i o n t o respond l i k e t h e m a j o r i t y o f t h e i n d i v i d u a l s .  Results a r e  t h e r e f o r e from a sample p o p u l a t i o n o f i n d i v i d u a l s showing a t l e a s t some a c t i v e c a p a c i t y t o respond t o t h e monochromatic insects i n the light-adapted  state.  light.  They a r e a l s o c o n f i n e d t o  11 ii  V a r y i n g both wavelength and i n t e n s i t y .  The second method o f t e s t i n g was somewhat more c o m p l i c a t e d than t h e f i r s t , but was s i m i l a r t o i t i n many r e s p e c t s .  Some a d d i t i o n a l  wavelengths  were t e s t e d t h i s time t o g e t h e r w i t h t h o s e p r e v i o u s l y d e s c r i b e d , there'by g r e a t l y expanding t h e e x p e r i m e n t a l s p e c t r a l range.  A l s o , i n t e n s i t i e s over a  wide and v a r i e d range were t e s t e d on t h e b e e t l e s , which were examined s i n g l y under p e d e s t r i a n s i t u a t i o n s . wavelengths  tested  In t h i s s c h e d u l e o f events f o r each o f t h e  (299 t o 880 mu), t h e i n t e n s i t y was manipulated such t h a t  t e s t b e e t l e s responded p o s i t i v e l y t o t h e monochromatic l i g h t a p p r o x i m a t e l y 80 t o 100 per cent o f t h e time a t t h e minimum i n t e n s i t y which gave maximum response w h i l e a t t h e lowest i n t e n s i t y t h e r e was no f u r t h e r p o s i t i v e response (Appendix.1).  T h i s lowest maximum i n t e n s i t y would t h e r e f o r e be t h e l i m i t i n g  threshold o f the insects} t h i s threshold varying with the 'stimulative e f f i c i e n c y ' o f t h e wavelength.  The r e s u l t s o f t h i s t e s t i n g procedure would  t h e r e f o r e y i e l d a d i r e c t p o s i t i v e c o r r e l a t i o n between b e e t l e response and intensity. By u s i n g a graph o f p r e v i o u s l y c a l i b r a t e d energy output r e a d i n g s f o r each wavelength  examined (Appendix 2 ) , i t was p o s s i b l e t o d i r e c t l y f i n d t h e  q u a n t i t y o f energy n e c e s s a r y t o produce any percentage o f p o s i t i v e r e s p o n s e s . F o r t h e purpose o f t h i s i n v e s t i g a t i o n , 7 percentages o f p o s i t i v e response were a n a l y z e d f o r each o f t h e wavelengths;  t h e s e r a n g i n g from a zero  p e r c e n t a g e ( t h r e s h o l d ) t o a n approximate 60 p e r cent p o s i t i v e p o i n t , w i t h i n t e r m e d i a t e v a l u e s a t 10 p e r cent i n t e r v a l s  (Table 4 ) .  R e s u l t a n t energy  output v a l u e s a t each o f t h e response l e v e l s were expected t o v a r y a c c o r d i n g t o t h e ' s t i m u l a t i v e e f f i c i e n c y ' o f each wavelength. equal percentage p o s i t i v e response l e v e l , wavelengths  That i s t o say, a t an with a higher  ' s t i m u l a t i v e e f f i c i e n c y ' would r e q u i r e l e s s energy ( l i g h t ) t o i n v o k e a p o s i t i v e  12 r e s p o n s e than those wavelengths having a lower ' s t i m u l a t i v e e f f i c i e n c y ' .  3.  Study o f t h e e f f e c t o f water l o s s on p h o t i c response, (a) Dehydration The  of beetles.  experiment t o examine t h e e f f e c t s o f water l o s s on t h e p h o t i c  r e s p o n s e s o f Trypodendron was conducted o n l y w i t h newly-emerged diapaused i n d i v i d u a l s , thereby being f l i g h t - i n e x p e r i e n c e d . was adopted f o r t h i s p a r t i c u l a r study  post-  This  precaution  s i n c e v a r i a t i o n s i n p h o t i c responses  a r e known t o occur a s a r e s u l t o f t h e a d d i t i o n a l f a c t o r o f f l i g h t - e x e r c i s e ( F r a n c i a , 1965). F o r weighing t h e b e e t l e s , s m a l l aluminum f o i l c o n t a i n e r s 1.5 cm. i n diameter and 1.5 cm. i n h e i g h t were c o n s t r u c t e d . perforated with  Each was  s m a l l p i n h o l e s near i t s base and a l s o equipped w i t h a  t i g h t - f i t t i n g l i d , a l s o o f aluminum f o i l .  Containers  were f i r s t weighed on  a M e t t l e r Microgrammatic B a l a n c e Model M5 w i t h an a c c u r a c y range o f _ 0.002 mg.  Beetle-laden  i n the o p t i c a l  B e e t l e s o f both sexes were p l a c e d i n d i v i d u a l l y i n each  c o n t a i n e r and t h e accompanying l i d a t t a c h e d escape.  approximately  so a s t o prevent  any p o s s i b l e  c o n t a i n e r s and l i d s were a g a i n weighed, thus  e s t a b l i s h i n g a weight f o r each b e e t l e .  A s i m i l a r procedure has been  d e s c r i b e d by N i j o l t and Chapman (1964.) i n t h e i r d r i n k i n g experiments  with  Trypodendron. Two 5 i n c h P e t r i p l a t e s w i t h l i d s were then used t o house t h e b e e t l e - l a d e n containers. was l e f t d r y .  One p l a t e c o n t a i n e d a p i e c e o f moistened f i l t e r w h i l e t h e o t h e r Three p i e c e s o f 0.3 cm. mesh p l a s t i c s c r e e n i n g were t h e n  p l a c e d over t h e f i l t e r papers t o prevent  any c o n t a c t by t h e aluminum  c o n t a i n e r s when these were added t o t h e P e t r i d i s h e s container represented  ( F i g . 3 ) . The d r y  a normal d e s i c c a t i o n chamber but t h i s time u s i n g  room temperatures and h u m i d i t i e s .  only  The moistened c o n t a i n e r served a s a c o n t r o l .  13 Both groups were then p l a c e d i n t o a darkened c o n t a i n e r and  left  f o r an  alloted period of time a f t e r w h i c h b e e t l e s were again re-weighed and t e s t e d t o the w h i t e l i g h t . (b)  T e s t i n g o f p h o t i c response.  after weighing, each beetle was t e s t e d for p h o t i c responses  Immediately to white l i g h t .  Again the a r e n a - t y p e s i t u a t i o n was  R e i c h e r t microscope i l l u m i n a t o r Model 'Lux resistor. any  An output s e t t i n g o f 3.0  amperes was  t h e r m a l s i d e - e f f e c t s a Bausch  (Fig.  4).  A Photovolt  and  operating  through a v a r i a b l e  adopted, and  Lomb heat f i l t e r was  a l s o to avoid interposed  photometer measuring, t h e output o f the lamp showed i t  14 f o o t - c a n d l e s a t the c e n t r e o f t h e t e s t f i e l d .  t o be a p p r o x i m a t e l y were a l l o w e d  FNI'  used a l o n g w i t h a  8 individual trials,  towards t h e source o f l i g h t .  Beetles  each commencing w i t h a b e e t l e a l i g n e d  Responses were recorded  l i n e made by a p e n c i l f o l l o w i n g a p p r o x i m a t e l y 4.0  cm.  using a t h i n p e n c i l behind the b e e t l e .  Mot o n l y was t h e path o f b e e t l e s recorded from the c e n t r a l s t a r t i n g p o i n t but a l s o the time r e q u i r e d f o r each  beetle t o walk t o the n e a r e s t edge  of the test s u r f a c e . In a d d i t i o n t o measuring was  included.  T h i s was  this ' r e a c t i o n ' time, a second time measure  designated  the  ' r e f r a c t o r y ' p e r i o d and  was  the  d u r a t i o n o f time between p l a c i n g a b e e t l e on the c e n t r a l s t a r t i n g p o i n t  the commencement of the ' r e a c t i o n ' time. time  The  importance  to  of s t u d y i n g t h i s  i s quickly realized when i t i s c o n s i d e r e d t h a t i n t e r n a l changes o f t h e  insect can be demonstrated merely from s t u d y i n g i t s r e s p o n s e s to v a r i o u s external factors.  Water l o s s by the i n s e c t may  movements o f the appendages i n response t o D u r i n g the normally  had  appear i n the form o f slower  light.  ' r e f r a c t o r y ' p e r i o d a b e e t l e when p l a c e d on the t e s t  surface  I t s l e g s t i g h t l y f o l d e d a g a i n s t the body, the antennae were  u  Fig.  3.  B e e t l e - l a d e n c o n t a i n e r s p l a c e d i n one o f the two P e t r i d i s h environments. P l a s t i c s c r e e n was p l a c e d beneath the c o n t a i n e r s t o prevent any c o n t a c t w i t h the f i l t e r paper ( e i t h e r wet or dry). Three o f the l i d s have been removed from the c a p s u l e s t o show the b e e t l e s .  Fig.  L.  Apparatus used t o t e s t the p h o t i c responses o f f l i g h t - i n e x p e r i e n c e d T. l i n e a t u m t o white l i g h t f o l l o w i n g v a r y i n g p e r i o d s o f desiccation. The R e i c h e r t I l l u m i n a t o r w i t h the Bausch and Lomb heat f i l t e r was used as the source of l i g h t .  h e l d t i g h t l y a g a i n s t the head, and at  t h i s time.  Gradually  the e n t i r e i n s e c t appeared  the antennae began t o v i b r a t e s t r o n g l y .  r o c k i n g s i d e movements o f t h e e n t i r e i n s e c t soon f o l l o w e d , the gradual  u n f o l d i n g o f the l e g s beneath.  t o i t s f e e t and  began t o walk.  the s e n s o r y antennae c o n t i n u e d  R e s u l t s were a n a l y z e d responses to l i g h t . b e e t l e , one times.  f o r the  continued  experiment.  s l i g h t l y h i g h e r than the p o s t e r i o r , w h i l e  returned  to i t s appropriate  variance analyses  changes had  occurred  i n the  were performed f o r each  the other f o r the  'reaction'  Trypodendron specimens were used f o r t h i s  In some cases however, a b e e t l e had  more than once, t h e r e f o r e no v a r i a n c e a n a l y s e s groups o f t r i a l s  environment  u n t i l a l l the b e e t l e s e v e n t u a l l y d i e d .  ' r e f r a c t o r y ' p e r i o d s and  In a l l , f o u r t e e n  to  Then t h e i n s e c t r o s e q u i c k l y  t o show whether o r not any A l s o two  t h i s being due  to v i b r a t e a c t i v e l y .  A f t e r t e s t i n g , each b e e t l e was t h i s procedure was  Slight  When r e a c t i n g t o the l i g h t , t h e a n t e r i o r  p o r t i o n o f the body became e l e v a t e d  and  motionless  c o u l d be performed.  t h e number o f times each was  died before  i t was  tested  o f the d i f f e r e n c e s between  However, f o r the r e m a i n i n g b e e t l e s ,  subjected  t o i t s s e r i e s o f t r i a l s v a r i e d from  2 t o 7, depending on the s u r v i v a l time o f each.  Variance  analyses  could  t h e r e f o r e be attempted; t h e s e showing e i t h e r s i g n i f i c a n t or n o n - s i g n i f i c a n t d i f f e r e n c e s f o r the groups o f t r i a l s  f o r eaeh b e e t l e .  comparisons f o r each group o f t r i a l s by method o f Tukey's w.  Individual  each b e e t l e were then made u s i n g  These r e s u l t s were t e s t e d a t the 1% l e v e l  the  of  significance.  4.  The (a) The  e f f e c t of subjecting Preparation  'green' wood t o a n a e r o b i c  conditions,  of the wood.  wood m a t e r i a l used f o r t h i s  of slabs of Douglas-fir  Btudy of a t t r a c t a n t f o r m a t i o n  consisted  (Pseudotsuga m e n z i e s i i M i r b . F r a n c o ) sapwood taken  16  from f r e s h l y - f e l l e d t r e e s .  The  bark was  removed t o reduce p o t e n t i a l  c o n t a m i n a t i o n by micro-organisms from the bark s u r f a c e . a t -18°C  The  s l a b s were s t o r e d  u n t i l r e q u i r e d f o r experiments.  A c h o i c e had  t o be made as t o the f u r t h e r p r e p a r a t i o n  o f the wood.  Preliminary  s t u d i e s by Graham (1962) showed t h a t  be m o d i f i e d  i n r e s p e c t t o a t t r a c t a n c y by withdrawing the a i r under vacuum,  solid  or by d i s p l a c i n g t h e a i r w i t h l i q u i d under vacuum. t h e r e a f t e r under a n a e r o b i c c o n d i t i o n s .  I t was  s e c t i o n s o f wood c o u l d  Attractancy  a l s o found t h a t  developed solid  were u n s u i t a b l e f o r t h e study o f b i o l o g i c a l l y a c t i v e c h e m i c a l s on  blocks  processes  i n the wood because the d i s s o l v e d c h e m i c a l s d i d not n e c e s s a r i l y move i n w i t h the aqueous phase.  The  r e s p o n s e s ( F r a n c i a , 1965)  development o f b i o a s s a y  techniques using o r i e n t a t i o n  i n s t e a d o f b o r i n g - i n a c t i v i t y , has  made i t p o s s i b l e  t o use wood i n a more f i n e l y d i v i d e d s t a t e such as  sawdust o r shavings i n  which p e r f u s i o n w i t h s o l u t i o n s p r e s e n t s  obstacle.  no  serious  Three a l t e r n a t i v e s p r e s e n t e d themselves f o r the d i v i s i o n o f wood substance i n t o a d i m e n s i o n a l l y a n o t h e r o f c h i p p i n g and  reduced s t a t e .  the t h i r d o f s h a v i n g .  One  consisted of g r i n d i n g ,  Chipping  was  because o f the n o n - u n i f o r m i t y o f s i z e o f the r e s u l t a n t wood.  eliminated Shaving  was  chosen over g r i n d i n g beoause i t appeared t o o f f e r t h e d e s i r e d degree o f u n i f o r m i t y o f d i v i s i o n w i t h a minimum o f damage t o the r a y c e l l s i n which it  i s presumed t h e a t t r a c t a n t forming p r o c e s s e s r e s i d e .  along 3.5  r a d i a l faces with a carpenters'  centimeters  0.5  i n w i d t h and  planer  i n t o a s e r i e s o f 250  wood was  millimeters i n thickness.  Immediately a f t e r  s e c t i o n s which were t h e n  m i l l i l i t e r Erlenmeyer f l a s k s f o r treatment.  c h i p s t o r e a c h t h e neck o f each f l a s k were used i n each i n s t a n c e . a l s o taken t o a v o i d  planed  t o produce s h a v i n g s a p p r o x i m a t e l y  p l a n i n g , the shavings were cut i n t o s m a l l r e c t a n g u l a r placed  The  excessive  Care  Enough was  d r y i n g o f the c h i p s as t h i s c o u l d r e n d e r them  u n s u i t a b l e f o r the  experiments a t hand.  A l t h o u g h s e v e r a l d i f f e r e n t t r e a t m e n t s were a p p l i e d t o the 'green  1  wood c h i p s , the m a j o r i t y  o f samples were s u b j e c t e d  under oxygen d e f i c i e n t c o n d i t i o n s f o r v a r y i n g 2 t o 47  hours.  These u n t r e a t e d  t h e chamber was  26-28 i n c h e s  wood c h i p s were p l a c e d  T h i s c o n d i t i o n was n i t r o g e n gas  was  not  The a d d i t i o n o f the n i t r o g e n was any  way,  but  o f the wood c h i p s and  o f mercury.  In a l l  ( g e n e r a l l y between  s i n c e mixed w i t h  o f about o n e - h a l f  gas.  the  o f one  per  cent.  not d e s i g n e d t o modify the changes i n wood i n  merely t o e q u a l i z e t h e p r e s s u r e  s u r r o u n d i n g medium.  inches  slowly r e f i l l e d with nitrogen  however s t r i c t l y anaerobicj,  oxygen a t a c o n c e n t r a t i o n  from  i n t o a vacuum  pumped f r e e o f a i r t o near c a p a c i t y  o f mercury) f o r 20 minutes and  t o placement  p e r i o d s o f time r a n g i n g  chamber ( F i g . 5) c a p a b l e o f c r e a t i n g a vacuum t o 30 cases,  unattractive  An unequal p r e s s u r e  between wood c h i p s and  the  between the i n t e r n a l environment  the s u r r o u n d i n g vacuum would tend t o draw out  any  a t t r a c t a n t formed i n the wood from the l a t t e r , thus r e s u l t i n g i n a much reduced e s t i m a t e o f t h e a c t u a l degree o f a t t r a c t i v e n e s s o f t h e t r e a t e d wood. Preliminary  experiments w i t h o u t n i t r o g e n y i e l d e d wood which l o s t i t s  a t t r a c t i v e properties very q u i c k l y .  A l s o t o i n c r e a s e the p o s s i b l e q u a n t i t y  a t t r a c t a n t formed, t h e r e b y i n c r e a s i n g t h e time a v a i l a b l e f o r b i o a s s a y m a t e r i a l , two  b o t t l e s o f each treatment were t e s t e d s i m u l t a n e o u s l y  interconnecting  them by a l e n g t h o f rubber  'anaerobic'  series.  This s e r i e s , designated  the  i n v o l v e d the p l a c i n g o f b o t t l e s c o n t a i n i n g u n t r e a t e d a l a r g e s e a l e d p l a s t i c bag r e q u i r e d p e r i o d o f time. at  the  ( F i g . 6) and  by  designed to  'aerobic'  and  parallel  control  'green' wood c h i p s  l e f t under t h i s c o n d i t i o n f o r  Both 'anaerobic'  the  tubing.  A comparable c o n t r o l s e r i e s o f doubled b o t t l e s was the  of  of  'aerobic'  into  the  s e r i e s were removed  same time from t h e i r r e s p e c t i v e environments when t e s t i n g w i t h b e e t l e s  F i g . 5.  Double samples o f wood c h i p s i n 250 ml Erlenmeyer f l a s k s p l a c e d i n t h e ' a n a e r o b i c ' chamber. A l l gases were pumped out f o r 20 minutes and n i t r o g e n gas was then r e f i l l e d i n t o t h e chamber. Samples remained i n t h e chamber f o r p e r i o d s r a n g i n g from 2 t o 4-6.5 h o u r s .  19  Fig. 6.  'Aerobic' control series of wood chips in 250 ml Erlenmeyer flasks and placed into a large plastic bag and sealed. These controls were designed to parallel the treated 'anaerobic' samples.  20 demanded them. was  expected from the  untreated one  In c o n t r a s t t o the  wood was  'anaerobic'  'aerobic' c o n t r o l s .  series, l i t t l e  An a d d i t i o n a l c o n t r o l o f  a l s o p l a c e d i n t o a f r e e z e r and  hour b e f o r e a b i o a s s a y  was  or no  t o be conducted.  was  change 'green'  removed a p p r o x i m a t e l y  T h i s c o n t r o l was  not always  used i n every p e r i o d o f t e s t i n g but r e g u l a r p e r i o d i c examination o f t h i s 'green' wood was unattractive. fir  undertaken t o r e - e s t a b l i s h t h a t t h i s o r i g i n a l wood was  A l s o as an a d d i t i o n a l c o n t r o l , a s e r i e s o f a t t r a c t i v e Douglas-  sapwood samples was  used; t h i s t o ensure t h a t t e s t , specimens were r e a c t i n g  s a t i s f a c t o r i l y to s u i t a b l e host m a t e r i a l . two  o l d , but  May  o f 1961  was  s i m i l a r to t h a t f o l l o w e d  still and  T h i s D o u g l a s - f i r was  stored i n a freeze*. f o r the  P r e p a r a t i o n o f t h i s wood f o r t e s t i n g 'green' wood c o n t r o l .  a l s o made to f u r t h e r modify the  by the a d d i t i o n o f d i s t i l l e d water t o the samples. by t h e f a c t t h a t i f c h e m i c a l  t o examine t h e e f f e c t s o f water a l o n e the t r a n s i t i o n o f wood from conducted on v a r i o u s  'green' t o  T h i s endeavour i s prompted  I t i s t h e r e f o r e necessary  i n a l t e r i n g the p r o c e s s e s 'ripe'.  involved i n  P r e l i m i n a r y s t u d i e s were  s i z e s o f D o u g l a s - f i r sapwood b l o c k s t o o b t a i n a  T h i s gave a q u a n t i t a t i v e e s t i m a t e  d i s t i l l e d water to the ,test chips? was  'green' wood, t h i s time  m o d i f i e r s a r e i n f u t u r e t o be added t o the wood  t h e s e a r e t o be added i n l i q u i d form.  saturation level.  taken from  h i g h l y a t t r a c t i v e samples g a t h e r e d a t Cowichan Lake i n  An attempt was  shavings,  f o r which t o  solutes. given  Extreme c a r e was  a l s o taken t o a v o i d any  Samples were a g a i n d i v i d e d i n t o 'anaerobic'  s i m i l a r treatments as o u t l i n e d f o r the  (b)  Bioassay  100$  add  however i n most cases somewhat more water  r e q u i r e d t o s a t u r a t e them s i n c e much water c o l l e c t e d on the  containers.  indeed  sides of  l e a c h i n g o f the and  the  chemical  ' a e r o b i c ' groups  and  'unwetted' s e r i e s .  techniques.  F o r the b i o a s s a y  o f wood samples, two  a l t e r n a t i v e s presented  themselves,  21  b o t h proposed by F r a n c i a  (1965).  One depended upon t h e c e n t r i p e t a l  response  o f b e e t l e s i n a f i e l d o f odour, w h i l e t h e o t h e r depended upon t h e a n e m o - o l f a c t o r y o r i e n t a t i o n and l o c o m o t i o n o f b e e t l e s i n an odour-laden a i r s t r e a m . F o r t h e c e n t r i p e t a l r e s p o n s e , t h e l e n g t h o f a meandering path o r t h e d u r a t i o n o f c o n t a c t w i t h t h e odour f i e l d a r i s i n g  from below t h e substratum, would  p r o v i d e a measure o f a t t r a c t i v e n e s s o f any wood sample.  The a n e m o - o l f a c t o r y  r e s p o n s e on t h e o t h e r hand, would depend upon d i r e c t i n g an odour-laden a i r s t r e a m towards f l i g h t - i n e x p e r i e n c e d b e e t l e s In darkness o r towards flight=.experienced b e e t l e s i n t h e presence o f an opposing l i g h t  source.  In  t h i s t e s t , t h e s t r e n g t h o f o l f a c t o r y a t t r a c t i o n would be measured i n terms o f the strength o f l i g h t necessary t o i n h i b i t  the o l f a c t o r y  influence.  P r e l i m i n a r y s t u d i e s w i t h wood samples o f v a r y i n g degrees o f a t t r a c t i v e n e s s y i e l d e d r e s u l t s f a v o u r i n g t h e a n e m o - o l f a c t o r y t e s t over t h e c e n t r i p e t a l The main r e a s o n was t h a t i t appeared  t o be more s e n s i t i v e than t h e o t h e r i n  d i s t i n g u i s h i n g d i f f e r e n c e s i n a t t r a c t i v e n e s s o f wood. insect displays a traversal, f i r s t  test.  towards,  The f a c t t h a t an  then f i n a l l y r e a c h e s t h e source o f  olfactory influence yields a clearly indisputable result of attractive p r o p e r t i e s i n the source.  I t would a l s o tend t o be l e s s time-consuming  use t h e a n e m o - o l f a c t o r y t e c h n i q u e a l t h o u g h r e p l i c a t i n g o f t e s t s would this  to reduce  advantage. To produce t h i s odour-stream,  a i r was d i r e c t e d through t h e double  series  o f b o t t l e s , t h e s u p p l y o f a i r a r i s i n g from a s t a n d a r d l a b o r a t o r y o u t l e t .  The  a i r s t r e a m was p r e s e n t e d t o t h e t e s t arena by a s h o r t l e n g t h o f rubber t u b i n g w i t h a f i n e g l a s s n o z z l e a t t h e end.  V e l o c i t y o f f l o w was measured w i t h a  'Wallac-Thermex' thermo-anemometer and s e t a t 0.5 meters per second,  this  b e i n g r e g u l a t e d w i t h a s m a l l a d j u s t a b l e clamp p l a c e d a c r o s s t h e a i r s u p p l y hose.  22 The t e s t arena c o n s i s t e d e s s e n t i a l l y o f a p i e c e o f cardboard w i t h 8^" s h e e t s o f w h i t e w r i t i n g paper mounted on t o p . . T h i s white w r i t i n g  x 11"  paper  s e r v e d as a medium on which t o mark t h e r e s u l t s , t h e s e b e i n g i n t h e form of l i n e t r a c i n g s o f t h e paths taken by b e e t l e s i n r e s p o n s e t o the v a r i o u s t e s t factors. l i n e was  From t h e c e n t r a l s t a r t i n g p o i n t on t h e t e s t  surface, a thin  pencil  used t o f o l l o w t h e path o f a b e e t l e t o one of t h e edges o f the t e s t  arena. The b i o a s s a y as such was  performed  using three different  lighting  s i t u a t i o n s , each d e s i g n e d t o a c t i n o p p o s i t i o n t o t h e source of odour. first  was  a s e r i e s whereby l i g h t was  produced by t h e monochromator,  p r e v i o u s l y c a l i b r a t e d and t e s t e d t o produce wavelength 735 mu (Fig. 7).  a source of red l i g h t  of the  at such an i n t e n s i t y as t o s i m u l a t e darkness t o T.  T h i s however l e f t t h e t e s t  t h a t t h e experimenter  could s t i l l  The  arena s u f f i c i e n t l y i l l u m i n a t e d  c l e a r l y view t h e r e s p o n s e s of the  lineatum such insects.  However i n t h i s c a s e , s i n c e no p h o t i c s t i m u l i were sensed by t h e b e e t l e s , a t t r a c t i v e wood samples s h o u l d a t t r a c t t h e i n s e c t s , b o t h non-flown  any  and f l o w n .  B e e t l e s when a t t r a c t e d d i s p l a y e d an anemotactic b e h a v i o u r , w a l k i n g a g a i n s t t h e g r a d i e n t o f odour t o r e a c h t h e s o u r c e . a i m l e s s l y about t h e t e s t  arena.  I f not a t t r a c t e d , they wandered  For the present i n v e s t i g a t i o n s a l l b e e t l e s  t e s t e d were f l i g h t - e x p e r i e n c e d , t h e p e r i o d o f f l i g h t - e x e r c i s e r a n g i n g from a p p r o x i m a t e l y 10 t o 35 minutes.  T h i s was  accomplished  by mounting b e e t l e s  w i t h 'Permount' g l u e by t h e pronotum on s t a n d a r d e n t o m o l o g i c a l cardboard p o i n t s mounted on p i n s and p l a c i n g t h e s e over a d i s h of water ( F i g s . 8a & b ) . T h i s l a t t e r p r e c a u t i o n was experimental i n s e c t s .  taken t o minimize any water l o s s by t h e  B e e t l e s i n t h i s mounted p o s i t i o n expanded and beat  t h e i r wings i n an attempt  to f l y .  Most c o n t i n u e d t h i s f l i g h t - e x e r c i s e f o r  t h e whole p e r i o d o f time a l l o t e d but some however d i s p l a y e d a f l i g h t  behaviour  23  Fig. 7.  Apparatus used for the bioassay of wood using monochromatic light (735 mu), this simulating darkness to T. lineatum. Wood factors were presented in double series via a fine glass nozzle located at the right of the test arena. A controlled velocity of a i r from a standard laboratory outlet was used to produce the odour-laden airstream.  2A  Fig.  8b.  Female T. l i n e a t u m specimen mounted f o r c a p t i v e f l i g h t exercise. Specimen i s seen r e t r a c t i n g i t s wings a f t e r flight.  25 w i t h many i n t e r m i t t e n t s t o p s .  Whenever b e e t l e s were r e q u i r e d f o r t e s t i n g ,  t h e y were c a r e f u l l y removed from t h e p o i n t s and s t o r e d i n covered c o n t a i n i n g moistened f i l t e r The  t h e 'green' wood and  attractive  'anaerobic' samples, then  conducted  a i r a l o n e as a c o n t r o l .  each b e e t l e was  The number of t r i a l s  s o u r c e was  s i t u a t i o n except  w h i t e l i g h t was  factor.  procedure  t h a t t h i s time an opposing w h i t e l i g h t  l i g h t s remained e l i m i n a t e d .  The  ( F i g . 9),  source o f t h i s  from t h e R e i c h e r t m i c r o s c o p e i l l u m i n a t o r p r e v i o u s l y d e s c r i b e d .  T h i s lamp, s e t at 3.0 light  cases  a limiting  s u b s t i t u t e d i n p l a c e of the r e d monochromatic l i g h t  w h i l e a l l other extraneous  being  given  a l s o q u i t e v a r i a b l e because i n most  second s t a g e of b i o a s s a y i n v o l v e d e s s e n t i a l l y the same  as i n t h e 'dark'  of  the  o n l y from time t o t i m e j t h e s e  t h e time r e q u i r e d t o t e s t the many samples and b e e t l e s was The  the  Depending on i t s n e c e s s i t y however, a r e - b i o a s s a y of  t h e v a r i o u s other samples was  each sample and  q u i t e uniform d u r i n g  each s e r i e s commencing w i t h an  D o u g l a s - f i r c o n t r o l , f o l l o w e d by the ' a e r o b i c ' samples.  dishes  paper.  order of p r e s e n t a t i o n of wood samples was  course of t h e experiments,  Petri  a c r o s s one  measuring t h e output  amperes was  end  a d j u s t e d t o produce a broad  of t h e t e s t  arena.  The  Photovolt  diffuse  photometer  of t h i s lamp showed i t t o be a p p r o x i m a t e l y  c a n d l e s at t h e c e n t r e of t h e t e s t f i e l d .  14 f o o t -  To e l i m i n a t e t h e e f f e c t s o f heat  e m i t t e d from t h i s t u n g s t e n lampy a Bausch and Lomb heat f i l t e r was t h e path o f t h e beam o f l i g h t .  field  Beetles tested p r e v i o u s l y i n the  placed i n 'dark'  s i t u a t i o n o f t h e b i o a s s a y were again t e s t e d w i t h t h e wood samples, but i n t h o s e cases where a c o n s i d e r a b l e d u r a t i o n o f time had r e - f l o w n t o ensure t h a t t h e y were t h o r o u g h l y Whenever a t t r a c t i v e wood was  presented  e l a p s e d , b e e t l e s were  flight-exercised. t o a b e e t l e , i t was  t h a t t h e l a t t e r would walk a g a i n s t the o d o u r - b e a r i n g  expected  airstream t o reach  the  26 source.  Samples t h a t were h i g h l y a t t r a c t i v e should a t t r a c t  an i n s e c t most o f  t h e , t i m e , w h i l e t h o s e samples not as a t t r a c t i v e should not a t t r a c t an i n s e c t at a l l ,  i n t h i s case as w i t h weakly a t t r a c t i v e samples, b e e t l e s were  t o e i t h e r be a t t r a c t e d t o t h e opposing l i g h t  expected  or d i s p l a y an i n d i f f e r e n t  b e h a v i o u r , t h a t i s not b e i n g a t t r a c t e d t o e i t h e r a l t e r n a t i v e . b i o a s s a y s i t u a t i o n , h a v i n g t h e s t a n d a r d source o f opposing  In t h i s  illumination, i t  would t h e r e f o r e be p o s s i b l e t o t e s t t h e s t r e n g t h s o f a t t r a c t i v e n e s s o f any number o f samples r a n g i n g from h i g h l y a t t r a c t i v e t o u n a t t r a c t i v e . I n t h e t h i r d s t a g e o f t h e b i o a s s a y , t h e l i g h t i n g was again m o d i f i e d ( F i g . 1 0 ) . T h i s time l i g h t  o r i g i n a t e d from t h e overhead  ceiling  lamps,  c o n s i s t i n g o f f o u r C o o l - r a y f l o u r e s c e n t lamps l o c a t e d about 2 meters above the t e s t  stage.  Measurements w i t h t h e P h o t o v o l t photometer i n d i c a t e d an  output r a t i n g from t h e s e f l o u r e s c e n t lamps o f a p p r o x i m a t e l y at t h e s o u r c e and a p p r o x i m a t e l y U s i n g t h e same procedure  40 f o o t - c a n d l e s  10-12 f o o t - c a n d l e s at t h e t e s t  arena.  f o r t h e p r e s e n t a t i o n o f wood odour and p r e p a r a t i o n  o f b e e t l e s as d e s c r i b e d f o r t h e other two l i g h t i n g s i t u a t i o n s , i t was again p o s s i b l e t o t e s t t h e degree o f a t t r a c t i v e n e s s o f t h e samples.  Those  a t t r a c t i v e should a g a i n a t t r a c t t h e e x p e r i m e n t a l specimens w h i l e u n a t t r a c t i v e again should not do s o .  those  In t h i s case, b e e t l e o r i e n t a t i o n would  a g a i n be expected t o be random. The r e s u l t s o f t h e wood m o d i f i c a t i o n study a r e based series of t r i a l s  and u t i l i z i n g  on 50 i n d i v i d u a l  a t o t a l o f 90 Trypodendron a d u l t s .  be mentioned here t h a t not a l l o f t h e t h r e e b i o a s s a y l i g h t i n g d e s c r i b e d e a r l i e r were used i n t h e s e 50 s e r i e s o f t r i a l s ,  I t should  situations  i n most cases  this  v a r i a t i o n was again due t o t h e l a c k o f time r e q u i r e d f o r t h e immediate t e s t i n g of the treated m a t e r i a l . A l s o t h e r e s u l t s from t h i s wood study, o r i g i n a l l y i n t h e form o f b e e t l e  Fig. 9.  Apparatus used to test wood in the 'opposing' light situation. The Reichert illuminator with a Bausch and Lomb heat f i l t e r was used to produce a broad diffuse beam of light. The same apparatus as described for the 'dark' situation was used to present the wood factors.  Fig. 10. Apparatus used to test wood with the overhead ceiling lights produced by four flourescent lamps located about 2 meters above the test stage. The apparatus for the presentation of wood factors was the same as that described for the 'dark' and 'opposing' light situations.  28  t r a c i n g s , were computed and summarized i n t a b l e form. were examined between t r e a t e d  and u n t r e a t e d  b o t h a t t r a c t i v e and u n a t t r a c t i v e controls„ analyzing  t h e e f f e c t s of varying  periods  Relative  samples, t h e l a t t e r  differences Including  Much emphasis was p l a c e d on  o f a n a e r o b i c treatment on t h e  a t t r a c t i v e n e s s o f wood c h i p s as i n d i c a t e d by t h e b e e t l e  responses.  Experiments i n t h e present study were conducted from October, 1965 t o July,  1966.  29  EXPERIMENTAL RESULTS 1.  Study of responses to monochromatic light. (a) . Varying wavelengths at a constant intensity. An analysis of the data for the 29 specimens and 2,577 individual t r i a l s  yielded several interesting and highly significant results.  Of the 9  wavelengths tested from 348 mu to 735 mu at an equal intensity, the greatest positive attraction to light occurred with the wavelength 543 mu i n the electromagnetic spectrum.  Positive responses decreased gradually on either  side of this peak, but somewhat more rapidly towards the longer wavelengths (Fig. 11 and Table l ) .  Of a l l the 29 male and female specimens tested at  this most stimulating wavelength, the mean positive response was 82.4 cent of individuals tested, and ranging from 77.8 confidence level.  to 87.0  per  per cent at the 0.05  In the longer wavelengths, 686 mu had the lowest  •stimulative efficiency' recorded, while in the shorter wavelengths a similar result occurred at 397  mu.  At the extreme limit of testing with one constant intensity of light an unexpected phenomenon was recorded in the shorter or ultraviolet wavelength of 348 mu.  Responses of beetles were recorded as approximately 40.3  per cent,  which was about a two-fold increase over the low adjacent wavelength of 397 (18.6  per cent)(Table l ) .  mu  Further examination Into the ultraviolet wavelengths  below 348 mu with this method of equal intensities was not possible with the limited emissive capacity of the monochromator. Variance analyses on the responses of the 29 beetles tested showed conclusively that the 'stimulative efficiency' of a given wavelength was similar between individuals (Table 2).  Males and females appeared to respond  equally well to any given wavelength (Fig. 11),  although the variability for  T a b l e 1.  Summarized r e s u l t s of b e e t l e responses t o v a r i o u s o f monochromatic l i g h t at an e q u a l i n t e n s i t y .  Wavelength  (nap.)  Total females +  Per cent positive (females)  Total males +  Per cent positive (males)  wavelengths  T o t a l females & males +  Grand total  Per cent p o s i t i v e ( f e m a l e s & males)  348 mu ultraviolet  83  117  41.5$  34  56  37.8$  117  173  290  40.3$  397 mu ultraviolet  34  166  17.0%  20  70  22.2$  54  236  290  18.6$  446 mu violet  56  144  28.0$  24  66  26.7$  80  2l0  290  27.6$  495 mu green  88  112  44.0$  36  54  40.0$  124  166  290  42.6$  28  86.0$  67  23  74.0$  239  51  290  82.4$  543 mu yellow-green  172  590 mji yellow  132  68  66.0$  51  39  56.7$  183  107  290  63.1$  65  131  33.2$  32  58  35.6$  97  189  286  33.9$  686 mu red  20  170  10.5$  19  71  21.1$  39  241  280  13.9$  735 mu red  1  179  0.6$  3  3.3$  4  266  270  1.5$  642 mu red  87  F i g u r e 11.  Graphs of t o t a l l e d percentage p o s i t i v e and near p o s i t i v e (?+) r e s p o n s e s o f Trypodendron t o v a r i o u s wavelengths o f monochromatic l i g h t at an e q u a l i n t e n s i t y .  32 T a b l e 2.  Wavelength  Summarized s t a t i s t i c s o f p o s i t i v e p h o t i c r e s p o n s e s o f Trypodendron a d u l t s t o v a r i o u s wavelengths o f monochromatic l i g h t at an e q u a l intensity, a b b r e v i a t i o n s ! S^ - v a r i a n c e , S - s t a n d a r d d e v i a t i o n , S j - s t a n d a r d e r r o r o f t h e mean  Beetles  S2  %  S  %  %  Mean  %  Upper limit (.05)  Lower limit (,05)  41.5 37.8 40.3  45.3 44.4 43.4  37.7 31.2 37.2  21.3 32.2 22.6  12.7 12.2 14.6  348 mu  females males summed  66.05 74.45 67.74  8.13 8.63 8.23  1.82 2.88 1.53  397 mu  females males summed  85.26 169.45 112.32  9.23 13.02 10.60  4.34 1.97  17.0 22.2 18.6  446 mu  females males summed  101.05 100.00 97.54  10.05 10.00 9.88  2.25 3.33 1.84  28'. 0 26.7 27.6  32.7 34.4 31.4  23.3 19.0 23.8  495 ngi  females males summed  141.05 125.00 134.98  11.88 11.18 11.62  2.66 3.73 2.16  44.0 40.0 42.8  49.6 48.6 47.2  38.4 31.4 38.4  543 mn  females males summed  120.00 127.78 147.54  10.95 11.30 12.15  2.45 3.76 2.26  86.0 74.0 82.0  91.4 82.7 87.0  80.6 65.3 77.8  590 mu  females males summed  172.63 100.00 165.03  13.14 10.00 12.85  2.94 3.33 2.39  66.0 56.7 63.1  72.2 64.4 68.0  59.8 49.0 58.2  642 mu  females males summed  103.10 127.79 113.00  10.15 11.30 10.63  2.27 3.76 1.97  33.2 35.6 33.9  37.9 44.3 37.9  28.5 . 26.9 29.9  686 mu  females males summed  60.82 161.11 113.63  7.80 12.69 10.66  1.79 4.23 2.02  10.5 21.1 13.9  14.3 30.8 18.0  11.4 9.8  735 mu  females males summed  approx. 0 n  -  -  -  -  2.06  ,  6.7  -  33 males a l o n e was  g r e a t e r than t h a t f o r f e m a l e s .  between t h e sexes however may examined.  T h i s apparent d i f f e r e n c e  have been due t o t h e l i m i t e d number of males  A l s o i n t h e m a j o r i t y o f b e e t l e s t e s t e d , specimens appeared t o  respond somewhat more q u i c k l y t o t h e more s t i m u l a t i n g as opposed t o t h e l e s s e r T a b l e 3 summarizes  s t i m u l a t i n g wavelengths.  between t h e v a r i o u s wavelengths  (b)  the resultant variance analyses  tested.  V a r y i n g b o t h wavelength and  intensity.  P h o t i c r e s p o n s e s o f b e e t l e s t e s t e d u s i n g t h i s method are based on 7 females and 3 males, w i t h a t o t a l o f 1,843  individual beetle t r i a l s .  Responses,  a l t h o u g h much more v a r i a b l e than t h o s e d e s c r i b e d e a r l i e r i n t h e method employing a c o n s t a n t i n t e n s i t y , were i n most cases q u i t e s i m i l a r f o r t h e range o f wavelengths from 348 mu t o 735 mu.  Several t r i a l s with  Trypodendron i h t h e more extreme u l t r a v i o l e t range a g a i n s u b s t a n t i a t e d t h e f i n d i n g d e r i v e d by t h e f i r s t methodj t h a t i s , t h e wavelengths 348 mu, and 299 mu  are i n f a c t q u i t e s t i m u l a t i n g t o T. l i n e a t u m .  o c c u r r e d i n r e s p o n s e s t o 348 mu  as e a r l i e r  described.  extremely s t i m u l a t i n g t o Trypodendron, b e i n g  perhaps 3 t o 4 t i m e s g r e a t e r than any o t h e r wavelength t e s t e d , 543 mu  difference  and 319 mu r e s p e c t i v e l y , but a h i g h l y  s i g n i f i c a n t d i f f e r e n c e e x i s t e d between t h e s e and 397 mu A wavelength o f 299 mu was  Little  319 mu  i n t h e v i s i b l e range ( T a b l e  including  4).  I n e s t a b l i s h i n g t h e extreme l i m i t  of s t i m u l a t i o n t o Trypodendron i n t h e  l o n g e r wavelengths o f t h e e l e c t r o m a g n e t i c spectrum, a r e g i o n i n t h e r e d p o r t i o n o f t h e spectrum was reached whereby t h e author was w i t h o u t much d i f f i c u l t y , r e d monochromatic (735 mu),  light.  able to perceive  a l l a c t i o n s taken by T. l i n e a t u m i n response t o t h e B e e t l e s however d i d not respond t o t h i s r e d l i g h t  t h i s i n d i c a t i n g a t o t a l i n s e n s i t i v i t y t o t h i s wavelength a t t h e  T a b l e 3.  V a r i a n c e a n a l y s i s r e s u l t s t e s t e d a t t h e 5% l e v e l o f s i g n i f i c a n c e showing t h e d i f f e r e n c e s i h Trypodendron p o s i t i v e p h o t i c responses between wavelengths t e s t e d at an e q u a l i n t e n s i t y . V a l u e s g r e a t e r than 8.6 a r e s i g n i f i c a n t ( * ) .  1.5 (735 mu)  1.5 (735 mu)  -  13.9 (686 mu)  33.9 (642 mu)  63.1 (590 mu)  82.6 (543 mu)  42.6 (495 mn)  40.3 (348 mn)  32.4 *  61.6*  81.1*  41.1*  26.1*  17.1*  38.8*  -  20.0 *  49.2*  68.7 *  28.7 *  13.7*  4.7'  26.4*  29.2  48.7  8.7*  6.3  12.4 *  33.9 (642 mu)  32.4  63.1 (590 mu)  61.6 *  49.2 *  29.2 *  82.6 (543 mu)  81.1*  68.7*  48.7 *  19.5*  42.6 (495 mu)  41.1 *  28.7 *  8.7"  20.5*  40.0*  27 ;6 (446 mu)  26.1  13.7 *  6.3  35.5*  55.0 *  15.0 *  18.6  18.6 (397 mu]  12.4*  13.9 (686 mu)  *  27.6 (446 mu)  20.0 *  -  -  K  19.5 *  -  20.5  *  40.0  6.2  15.3  35.5 *  44.5*  22.8*  55.5*  62.0*  42.3 *  *  15.0  -  (397 mu)  17.1*  4.7  15.3*  44.5*  62.0*  24.0*  9.0*  40.3 (348 mu)  38.8 *  26.4*  6.2  22.8*  42.3*  2.3  12.7 *  * 24.0 9.0*  21.7*  2.3 12.7* 21.7*  -  35  T a b l e A,  T a b l e o f v a l u e s from t h e monochromator c a l i b r a t i o n graphs (appendix 2) showing the percentage o f p o s i t i v e r e s p o n s e s f o r 10 per cent i n t e r v a l s r a n g i n g from 0 t o 60 per c e n t (appendix l ) and t h e c o r r e s p o n d i n g r e q u i r e d energy output o f monochromatic l i g h t f o r the wavelengths t e s t e d . a b b r e v i a t i o n s : M.S.= monochromator s l i t w i d t h t r a n s . = energy output o f any g i v e n wavelength  Posit..ve response 1evels 20$ 30$ 4 0 $ M.S. trans. M.S. trans. M.S. trans.  Wavelengths  0$ 10$ M.S. trans. M.S. trans.  299 mu ultraviolet  1.70  319 mu ultraviolet  1.00 32.0$  1.23 48.0$  1.45  65.0$  1.70  88.0$  348 mu ultraviolet  0.32 25.0$  0.41 43.0$  0.49  60.0$  0.62  397 mu ultraviolet  0.14  0.26  83.0$  3.0$  23.0$  1.92  3.9$  -  50$ M.S. trans.  6 0 $  M.S. trans.  -  -  1.95 117.0$  -  -  95.0$  0.73 135.0$  0.85  0.38 175.0$  0.53 295.0$  0.70 505.0$  0.88 765.0$  1.09 1065.0$  -  -.  180.0$  0.99  243.0$  446 mu violet  0.10 35.0$  0.18 110.0$  0.28 260.0$  0.40 440.0$  0.53 645.0$  0.66  840.0$  0.84 1140.0$  495 mu green  0.08 42.0$  0.09 50.0$  0.10  65.0$  0.12  90.0$  0.15 145.0$  0.18  210.0$  0.24  543 mu yellow-green  0.04 10.0$  0.05 17.0$  0.06  25.0$  0.07  37.0$  0.09  65.0$  0.10  82.0$  0.13 140.0$  590 rap. yellow  0.07  23.0$  0.075 27.0$  0.08  32.0$  0.09  43.0$  0.11  62.0$  0.13  88.0$  0.17  642 mu red  0.16  22.0$  0.19 35.0$  0.25  60.0$  0.32  93.0$  0.40 145.0$  0.49 210.0$  0.62 325.0$  686 mu red  0.40  50.0$  0.47 65.0$  0.57  95.0$  0.68 135.0$  0.82 185.0$  0.95  1.15  735 mu red  1.55 175.0$ 1.60 188.0$  1.68 210.0$  1.80 240.0$ 1.98 300.0$  240.0$  -  340.0$  160.0$  335.0$  i n t e n s i t y employed. i n t e n s i t i e s of l i g h t  F u r t h e r t e s t s w i t h t h e method u s i n g  several  showed q u i t e c l e a r l y t h a t f o r most o f t h e wavelengths  t e s t e d i n t h e s h o r t e r wavelengths o f t h e r e d r e g i o n of t h e spectrum, t h e i n a b i l i t y o f Trypodendron t o respond t o v a r i o u s wavelengths i s a f u n c t i o n not o n l y o f t h e wavelength i t s e l f , but a l s o t h e i n t e n s i t y i s t r u e f o r t h e whole range o f wavelengths examined. s t i m u l a t i o n was  reached at about 780 mu  No f u r t h e r t e s t i n g was energy output was  and beyond  attempted beyond 880 mu  (Table 4 ) .  A r e g i o n of no  i n t o t h e l o n g e r wavelengths.  s i n c e t h e monochromator  d e c r e a s i n g q u i t e r a p i d l y beyond t h i s  point.  As f o r t h e e f f e c t i v e n e s s o f t h e opposing r e - a l i g n m e n t l i g h t , a t t r a c t i o n f o r Trypodendron was  observed.  2.  no  The p r e s e n c e o f t h i s s o u r c e o f  w h i t e i l l u m i n a t i o n t h e r e f o r e d i d not appear t o a f f e c t r e s p o n s e s t o monochromatic  This  i n any way t h e b e e t l e  light.  Study o f t h e e f f e c t o f water l o s s on p h o t i c r e s p o n s e . Of t h e 14 b e e t l e s exposed t o t h i s treatment, none l i v e d l o n g e r than  hours.  Pronounced d i f f e r e n c e s i n l o n g e v i t y o c c u r r e d between t h e two  93  groups  t e s t e d j t h o s e i n t h e humid environment l i v i n g a p p r o x i m a t e l y t w i c e as l o n g as t h o s e i n t h e d r y environment  (Table 5 ) .  E s s e n t i a l l y no d i f f e r e n c e i n t h e  s u r v i v a l t i m e s e x i s t e d between males and females i n t h e d r y environment. However a d i f f e r e n c e appeared i n some but not a l l o f t h e i n d i v i d u a l s i n t h e m o i s t environment group, t h e f e m a l e s s u r v i v i n g somewhat l o n g e r than t h e males. As f o r t h e weight l o s s o f t h e b e e t l e s , t h e d a t a suggest t h a t t h e r e i s e s s e n t i a l l y no p r o p o r t i o n a t e d i f f e r e n c e i n weight l o s s e s between males, and f e m a l e s i n t h e i r r e s p e c t i v e environments.  However t h e r e was a s i g n i f i c a n t  d i f f e r e n c e between t h e b e e t l e s i n t h e two groups, t h e m o i s t environment group l o s i n g between o n e - s i x t h t o o n e - h a l f o f t h a t l o s t by b e e t l e s i n t h e d r y  37  Table 5.  Comparison o f t h e s u r v i v a l t i m e s o f t h e two groups o f b e e t l e s , one i n t h e ' h u m i d ' environment and t h e other i n t h e ' d r y ' environment as measured at t h e e a r l i e s t time a f t e r d e a t h . The t i m e i n t e r v a l s i n which b e e t l e s died are shown.  Dry environment (time i n hours)  Humid environment (time i n hours)  (females)  (females)  (males)  29.0  - 44.5  27.5 - 31.5  1.0 -  29.0  - 44.5  22.5 - 27.5  7.5  - 18.5  52.5 - 6 8 . 5  29.0  - 44.5  7.5  - 18.5  79.0  29.0  - 44.5  7.5  - 18.5  Table 6 .  - 93.0  5.5  '  (males)  7.5 - 1 8 . 5 7.5  - 18.5  Comparison o f weight l o s s e s b y Trypodendron i n t h e ' d r y ' and ' h u m i d ' e n v i r o n m e n t s , t h e f i n a l f i g u r e was r e c o r d e d at t h e e a r l i e s t p o s s i b l e measurement a f t e r d e a t h .  Dry environment (% of o r i g i n a l weight)  Humid environment {%  of o r i g i n a l weight)  (females)  (males)  8.53  7.56  18.37  18.19  15.43  \5.69  17.05  4.53  (females)  +  +  "^tested at d i f f e r e n t  (males)  40.22  31.08  41.30  48.93  34.98 32.92 time  38  Figure 12.  Graphs of the cumulative percentage weight losses of individual Trypodendron adults with increased exposure time i n the two environments. a. Desiccated group (dry environment) b. Non-desiccated group (humid environment)  Time (hours)  T a b l e 7.  Summarized" i n d i v i d u a l comparisons o f d i f f e r e n c e s i n p h o t i c r e s p o n s e s w i t h water l o s s f o r t h e ' r e f r a c t o r y ' and ' r e a c t i o n ' times as d i s p l a y e d by a d u l t Trypodendron t o w h i t e l i g h t at t h e 1% l e v e l o f s i g n i f i c a n c e . abbreviations:  Beetle No.  N.S. - n o n - s i g n i f i c a n t comparisons S. - s i g n i f i c a n t comparisons  Refractory Period  Reaction Time  1 N.S.  2  -  1 N.S.  3  1 N.S.  1 N.S.  4  2 N.S. 1 S.  2 N.S.. 1 S.  5  1 N.S.  1 N.S.  6  1..N.S.  1 N.S.  7  3 S.  3 N.S.  8  10 N.S.  10 N.S.  9  3 N.S.  1 N.S. 2 S.  10  21 N.S.  21 N.S.  11  -  -  1  -  -  12 13  3 N.S.  2 N.S. 1 s.  14  3 N.S.  3 N.S.  Totals  46 N.S. 4 S.  46 N.S. 4 S.  50  50  40  Table 8.  Tabulated results of the various photic responses of adult Trypodendron to white light with increasing water loss. abbreviations:  m = male f = female  Responses  6.0 h r s .  1 (f)  7  1  8  0  2 (f)  7  1  3 (f)  8  0  8  0  4 (f)  8  0  o  5 (m)  8  0  to  o  6  8  0  to  o  Desic cated gr oup  0 hours  to  B e e t l e No. & Sex  (m)  0 hours  ated gro  ft  o o  •H C CQ D T3  18.0 h r s .  Responses •  t  Responses •  Responses +  Responses  f  25.0 h r s .  -  7  1  29.0 h r s . 47.0 h r s .  8  0  8  0  8  0  8 (f)  8  0  8  0  8  0  9 (f)  8  0  8  0  6  2  10 ( f )  8  0  8  0  8  0  11 (m)  8  0  12 (m)  2  6  53.0 h r s .  67.0 h r s .  77.0 h r s .  8  0  7  1  0  8  0  -  8  8  0  6  2  -  0 hours  7.0 h r s .  22.0 h r s .  13 (m) *  7  1  7  1  7  1  14 (m)f  8  0  8  0  8  0  1  Responses  18.0 h r s .  7 (f)  1  a o a•  Responses +  t e s t e d at d i f f e r e n t t i m e  27.0 h r s . —  -  a  F i g u r e 13.  l i n e tracings of paths taken by two flight-inexperienced female Trypodendron adults to white light while being subjected to v a r y i n g periods of desiccation. a. Responses of a beetle from the desiccated group 1 4:15 p.m. May 2 i i 9:45 p.m. May 2 i i i 9:40 a.m. May 3  b.  Responses of a beetle from the non-desiccated group. i 5:10 p.m. May 2 i i 11:00 a.m. May 3 i i i 9:40 p.m. May 3  abbreviations:  RP = refractory period RT = reaction time (measured in one-hundredth of a minute intervals)  Fig. 1 3 a i . Desiccated group Beetle No. 4 (female) Time: 4:15 p.m. May 2 T r i a l RP RT Response 1 2 3 4 5 6 7 8  49 52 44 40 36 72 40 30  44 73 109 48 62 54 47 55  + + + + +  t  + +  Fig. 13aii.  D e s i c c a t e d group  B e e t l e No. T i m e : 9:45 T r i a l HP 1 144 2 60 52 3 112 4 48 5 16 6 30 7 8 35  4 (female) p.m . May 2 RT Response 38 55 + 105 + 58 + 48 + 32 + 42 35  Fig. 13aiii.  Desiccated group  B e e t l e No. T i m e : 9:40 T r i a l RP 2 1 7 2 17 3 14 4 18 5 12 6 17 7 8 8  4 (female) a.m. May 3 RT Response • 109 + 150 • 90 + 116 + 72 + 55 188 + 62  -  13bi.  Non-desiccated group  Beetle No. Time: 5:10 T r i a l RP 1 31 2 22 3 39 4 32 5 24 6 37 7 18 8 12  9 (female) p.m. May 2 RT Response 12 + 28 + 18 + 30 + 18 • 21 + 22 + 15 •  Fig. 13bii.  Non-desiccated group  Beetle No. 9 (female) Time: 11:00 ajm. May 3 T r i a l RP RT Response 1 3 17 + 2 4 14 + 3 7 15 + 4 14 19 + 5 16 24 + 6 5 18 + 7 31 21 + 8 38 22 +  f  Fig. 13biil.  Non-desiccated  B e e t l e No. T i m e : 9:40 Trial RP 1 125 2 19 3 27 4 32 5 18 6 21  CD O  F-i  O CO  •a  group  9 (female) p.m. May 3 RT Response 122 • 54 + 276 269 + 84 + 27 -  7  45  114  •  8  40  90  +  environment group' (Table 6 ) .  Cumulative weight l o s s d a t a (Appendix 3) were  plotted against titae for males and females i n both e x p e r i m e n t a l groups (Figs. 12a and b). Variance analyses f o r t h e ' r e f r a c t o r y ' and ' r e a c t i o n ' times y i e l d e d  a total of 50 individual comparisons at t h e 1% l e v e l o f s i g n i f i c a n c e ( T a b l e 7 ) . As summarized in T a b l e 8 and i l l u s t r a t e d i n F i g u r e s 13a and b f o r d e s i c c a t e d and non-desiccated g r o u p s , no s i g n i f i c a n t d i f f e r e n c e i n p h o t i c responses t o  white light appeared i n t h e s e f l i g h t - i n e x p e r i e n c e d b e e t l e s .  A comparison  between the number of d i r e c t v e r s u s i n d i r e c t p o s i t i v e r e s p o n s e s o f Trypodendron between t h e groups o f t r i a l s was not a t t e m p t e d , as t h e d i s t a n c e  covered by a beetle i s i m p l i c i t i n t h e ' r e a c t i o n ' times a l r e a d y a n a l y z e d . I n a few i s o l a t e d i n c i d e n t s b e e t l e responses d i d not f o l l o w a consistent pattern.  T h i s t y p e o f behaviour accounted f o r t h e s i g n i f i c a n t  d i f f e r e n c e s found i n T a b l e 7 .  3. The effect o f s u b j e c t i n g ' g r e e n ' wood t o a n a e r o b i c c o n d i t i o n s . Modified 'green' wood p r e s e n t e d t o Trypodendron a d u l t s prompted varying degrees o f r e s p o n s e .  These r e s p o n s e s , r e c o r d e d as b e e t l e  path  tracings (Figs. 14 and 15) were summarized and c l a s s i f i e d under t h e following t h r e e h e a d i n g s . (1) (2) (3)  p o s i t i v e a t t r a c t i o n t o wood samples (+)  n e g a t i v e a t t r a c t i o n t o wood samples (-) a t t r a c t i o n t o wood samples t h a t appeared t o be p o s i t i v e but were in most cases i n c o m p l e t e (?+)  The degree o f a t t r a c t i v e n e s s  o f a n a e r o b i c a l l y t r e a t e d wood i n i t s  normally moist s t a t e was r e l a t e d t o t h e d u r a t i o n o f s u b j e c t i o n t o oxygen deficient c o n d i t i o n s .  F o r t h e f i r s t 4 hours o f a n a e r o b i o s i s , no t r a n s i t i o n  t The f i n a l weight was e s t a b l i s h e d at t h e time o f t h e e a r l i e s t weighing a f t e r death.  A3  Figure 14.  Line tracings of the paths taken by .two flight-experienced female Trypodendron adults in the three different lighting situations and tested to the various types of wood. a. attractive Douglas-fir b. 'anaerobic sample ( 2 3 . 5 c. 'aerobic' control ( 2 3 . 5 d. a i r only e. 'green' control f. attractive Douglas-fir 1  abbreviations: I II 1 2 3 a b c  = = = = = = =  sapwood control hours) hours) control again  beetle no. I beetle no. II tested In 'dark' tested in 'opposing' light situation tested in 'overhead' light situation first trial second t r i a l third t r i a l  I2i  135  L3a I2h>odour  jpposing and red l i g h t  II2b Ilia F i g . 14b. Ila t lib Ilia + Illb + I2a -  12b +  - 'anaerobic'  sample (23.5  hours lib  II2a +  112b * I3a  13b  -  -  II3a • II3b +  I3b  44  Figure 15.  Line tracings of the paths taken by two male and one female flight-experienced Trypodendron adults tested in the 'dark' and 'opposing' light situations. Wood factors include: a. attractive Douglas-fir sapwood control b. 'anaerobic* sample (21 hours) c. 'aerobic' control (21 hours) abbreviations:  I II III 1 2 a b  beetle no. I (female) beetle no. II (male) beetle ho. I l l (male) tested in 'dark' tested i n 'opposing' light situation first trial second t r i a l  V Illb  _oposing and r e d l i g h t  Fig.  15a. - a t t r a c t i v e D o u g l a s - f i r  B e e t l e No. I - flown 20 min. B e e t l e No. I I - flown 20 min. B e e t l e No. I l l - flown 20 min. Ila lib Ilia Illb Illla Illlb  + + + + +  I2a I2b II2a II2b III2a III2b  + + ?+ +  (intermittent)  I2b  Fig.  15b. Ila lib Ilia Illb Illla Illlb  - 'anaerobic' sample (21 hours) + + + + +  I2a I2b II2a II2b III2a III2b  + ?+ + +  4-5 from the o r i g i n a l 'green' s t a t e was exemplified  noted.  by b e e t l e responses g r a d u a l l y  a p p r o x i m a t e l y 4 to between 20 to anaerobiosis  20 hours, and  26 h o u r s .  increased  attractiveness,  i n the  Subjection  of the wood t o l o n g e r  treatment r e n d e r e d the wood u n a t t r a c t i v e  and  ( F i g . 16).  Both males and  and  Trypodendron b e e t l e s  sapwood as a c o n t r o l a l s o  ( F i g s . 14a,  f j 15a).  to t h i s c o n t r o l i n a l l of t h e t h r e e  judged by t h e Douglas-fir  per  Also  control.  b,  o).  attracted  i n a l l three  10).  s i t u a t i o n s , the l a t t e r  the  as  never as a t t r a c t i v e as  the  A s i m i l a r r e s u l t occurred  be  lighted situations  w i t h the a t t r a c t i v e D o u g l a s - f i r  With 'anaerobic' wood i n a l l time i n t e r v a l s a s l i g h t l y h i g h e r i n d i c a t e d when t h e  c e i l i n g l i g h t s were used,  as compared w i t h t h e t e s t i n which an opposing l i g h t was ( F i g s . 17b  and  15b).  ' a n a e r o b i c ' wood t e s t e d i n darkness appeared t o  p o s i t i v e o l f a c t o r y response wgs  The  and  responded extremely w e l l  more a t t r a c t i v e t h a n t h a t t e s t e d i n e i t h e r of the two ( F i g s . 17a,  peak  t o t h i s c o n t r o l when compared w i t h  cent of p o s i t i v e r e s p o n s e s was  control.  Some  s e p a r a t e t e s t s i t u a t i o n s (Table  Of p a r t i c u l a r s i g n i f i c a n c e w i t h r e g a r d a n a e r o b i c a l l y t r e a t e d wood i s t h a t  Beetles  hour  females  appeared t o respond e q u g l l y w e l l t o t h i s t r e a t e d wood ( F i g s . 14b Attractive Douglas-fir  of  A 30  Table 9).  i n t h e time i n t e r v a l t o produce i n i t i a l  a t t r a c t i v e n e s s as w e l l as f a l l - o f f  attractiveness  periods  in attractiveness. ( F i g . 16  as  i n t e r v a l from  appeared t o r e a c h i t s peak of  resulted in a rapid f a l l - o f f  v a r i a b i l i t y occurred  However the  and  reference  c).  'green' sap-jood c o n t r o l s showed no  Table 10).  used as a  S i m i l a r l y the  attractive properties  control series l e f t  i n normal  c o n d i t i o n s d i d not d i s p l a y any  a t t r a c t i v e properties  T a b l e 10)  lineatum.  when p r e s e n t e d t o T.  i n t e r v a l s t e s t e d r a n g i n g from 2 t o 46.5  hours.  14e  aerobic  ( F i g s . 14c,  T h i s r e s u l t was  (Fig.  15c  and  common t o a l l time  L e a v i n g wood under  46  Figure 16. P o i n t graph o f t o t a l l e d percentage p o s i t i v e and near positive'"(?*•) r e s p o n s e s t o wood shavings p l a c e d under a n a e r o b i c c o n d i t i o n s f o r v a r y i n g p e r i o d s o f time (2 t o 4-6.5 h o u r s ) . Three s e t s o f p o i n t s have been i n c l u d e d f o r the t h r e e d i f f e r e n t l i g h t i n g s i t u a t i o n s ( d a r k , o p p o s i n g and o v e r h e a d ) .  100 90 -  • Beetles tested in 'dark'  80 •  0  5* 70  O Beetles tested in 'overhead' light situation  a 13  a CQ  <r>  *  to  60 50  aO  CO H  1  £>  tn O CD  s  Beetles tested in 'opposing' light situation  o  40  ••  30  o  OA Oboo  o  20 10 -  o  o o • •o  o » o  00  cP  10  —r 15  1  ^> - q -  —r 20  O  •O  • • o*o  r~  1  25  30  o  o o» o»  O  i 35  40  Duration of exposure to anaerobic treatment (hours)  45  50  47  Table 9.  Summarized data of Trypodendron responses from bioassay tests of wood samples subjected to varying times under anaerobic conditions. Responses are computed as percentages i n 4 hour intervals for the three different lighting situations. abbreviations:  dk = tested in 'dark' ov - tested in 'overhead' light situation op = tested in 'opposing' light situation Tot. = Total  i  Time interval  Tot.  Tot. ?+  Tot.  op.  0 0 0  0 0 0  10 10 14  10 10 14  4.5-8  dk. ov. op.  0 0 0  0 1 1  11 10 14  11 11 15  8.5-12  dk. ov. op.  2 7 0  5 0 0  11 15 20  12.5-16  dk. ov. op.  8 4 0  0 3 1  16.5-20  dk. ov. op.  5 5 1  20.5-24  dk. ov. op.  t  -  Grand total  %  %  ?+  +  -  + & ?+  0 0 0  0 0 0  100.0 100.0 100.0  0 0 0  0 0 0  0 9.1 6.7  100.0 90.9 93.3  0 9.1 6.7  18 22 20  11.1 31.8 0  27.8 0 0  61.1 68.2 100.0  38.9 31.8 0  7 16 18  15 23 19  53.3 17.4 0  0 13.0 5.3  46.7 69.6 94.7  53.3 30.4 5.3  3 2 3  12 13 16  20 20 20  25.0 25.0 5.0  15.0 10.0 15.0  60.0 65.0 80.0  40.0 35.0 20.0  33 14 21  5 1 6  22 16 20  60 31 47  55.0 45.2 44.7  8.3 3.2 12.8  36.7 51.6 42.5  63.3 48.4 57.5  24.5-28  dk.. ov. op.  6 5 1  7 7 3  29 35 28  42 47 32  14.3 10.6 3.1  16.7 14.9 9.4  69.0 74.5 87.5  31.0 25.5 12.5  28.5-32  dk. ov. op.  0 0 0  0 1 0  10 9 10  10 10 10  0 0 0  0 10.0 0  100.0 90.0 100.0  32.5-36  dk. ov. op.  0 0 0  1 0 0  4 5 10  5 5 10  0 , 0 0  20.0t 0 0  80.0 100.0 100.0  20.0 0 0  36.5-40  dk. ov. op.  0 1 0  1 0 0  12 s-3  12  13 4 12  0 25.5 0  7.7 0' 0  92.3 75.0 100.0  7.7 25.0+ 0  40.5-44  dk. ov. op.  0 0 0  0 0 0  4 4 4  4 4 4  0 0 0  0 0 0  100.0 100.0 100.0  0 0 0  44.5-48  dk. ov. op.  0 0 0  0 0 0  7 0 0  7  0  0  100.0  0  1-4  dk. OV.  +  i n s u f f i c i e n t data  —  -  +  -  -  —  0 10.0 0 f  -  48  F i g u r e 17.  Frequency h i s t o g r a m s o f t o t a l l e d percentage p o s i t i v e and near p o s i t i v e responses o f Trypodendron t o ' a n a e r o b i c ' samples d i v i d e d i n t o 4 hour treatment c l a s s e s and t e s t e d under t h e t h r e e l i g h t i n g s i t u a t i o n s : a. b. c.  b e e t l e s t e s t e d i n 'dark' b e e t l e s t e s t e d i n 'overhead' l i g h t s i t u a t i o n b e e t l e s t e s t e d i n 'opposing' l i g h t s i t u a t i o n  a.  Beetles  t e s t e d i n 'dark'  60 mber of beetles respondi  w c  &  50 40 , • 30 " 20 " 10 •  0  4  8  12  16  20  24  28  32  D u r a t i o n o f exposure t o a n a e r o b i c treatment  36 (hours)  40  44  70 -  b.  Beetles tested i n 'overhead'  light  situation  28  32  60 •50  40 30 20 10  0  4  8  12  16  20  24  D u r a t i o n o f exposure t o a n a e r o b i c treatment  c.  Beetles tested in  'opposing'  light  36  4  8  12  16  20  24  28  32  D u r a t i o n of exposure t o a n a e r o b i c treatment  44  (hours)  situation  T——i 0  40  36 (hours)  r 40  44  laboratory conditions for these periods of time therefore has no noticeable effects on 'green' wood, so long as a satisfactory moisture level was retained as i t was with chips kept in plastic bags.  Anaerobically treated  wood i n the vacuum chamber also appeared to be at normal moisture levels after treatment, and no condensation was seen on the wall surfaces of the chamber. Air alone as a control also did not induce any responses by T. lineatum (Fig.  14d and Table 10).  An interesting difference between the 'anaerobic' and 'aerobic' groups was immediately noticed on opening either the vacuum chamber or the plastic bag.  A rather sweet and highly fragrant woody odour was released from the  'anaerobic' chamber, this probably associated with the attractiveness of wood. This fragrance was similar to the human sense as was the odour from Douglas-fir sapwood which had become attractive under f i e l d conditions. No similar detectable fragrance was noticed from the 'aerobic' controls, these possessing only the odour of fresh wood as found in 'green' wood. Results of the few tests involving the addition of water to 'green' wood are inconclusive at the present time. Wood that was moistened and then placed under 'anaerobic' conditions for 20-24 hours did not become as attractive as wood not moistened and otherwise treated similarly. However, wetted wood placed only in 'aerobic' conditions also became somewhat attractive to Trypodendron  (Table 10).  As for the behaviour of the beetles themselves, a definite positive attraction to the attractive samples and controls was observed.  In these  instances, both male and female Trypodendron walked either directly or, more often indirectly towards the source of odour.  Direct responses were those in  which beetles followed along the gradient of odour, seldom deviating from odour-stream (Figs. 14a, b, f j 15a, b). Indirect responses in most cases  T a b l e 10.  Summarized d a t a and response percentages o f Trypodendron t o v a r i o u s wood samples and c o n t r o l s . abbreviations:  dk. - t e s t e d i n 'dark' s i t u a t i o n ov. - t e s t e d i n 'overhead' l i g h t s i t u a t i o n op. - t e s t e d i n 'opposing' l i g h t s i t u a t i o n  Wood sample or c o n t r o l  'aerobic' controls ( a l l time i n t e r v a l s )  adults  Total + dk. ov. op.  0 0^ o  Total  Total  Grand total  %  %  ?+  -  3 0 ,1  80 51 53  83 51 54  0 0 0  ii?  +  ?+  3.6 0  — 96.4 100.0 98.1  %  + & ?+ 3.6 0 1.9  dk. ov. op.  82 66 70  22 9 20  28 42 49  132 117 139  62.1 56.4 50.3  16.7 7.7 14.4  21.2 35.9 35.3  64.1 64,7  dk. ov. op.  2 7 0  2 0  13  1  10 18  17 17 19  11.8 41.2 0  11.8 0 5.3  76.4 58.8 94.7  23.6 41.2 5.3  dk. ov. op.  0 5 1  5 0 1  8 15 10  13 20 12  0 25.0 8.3  38.5 0 8.3  61.5 75.0 83.3  38.5 25.0 16.6  'green' c o n t r o l  dk. 6v. op.  0 1 0  1 2 0  33 20 26  34 23 26  0 4.3 o  2.9 8.7 0  97.1 87.0 100.0  2.9 13.0 0  a i r alone  dk. 6v. op.  0 0 0  1 0 0  19 16 31  20 16 31  0 . 0 0  5.0 0 0  95.0 100.0 100.0  5.0 0 0  .  .  ..  attractive Douglas-fir  ' a n a e r o b i c ' wetted samples  ' a e r o b i c ' wetted control  78.8  51 were t h o s e i n which b e e t l e s e i t h e r walked paths t o r e a c h t h e source or walked at  an a n g l e t o i t ( F i g . 14a).  odour-stream,  i n somewhat c i r c u l a r meandering  away, then towards t h e s o u r c e , g e n e r a l l y  Whenever a b e e t l e c r o s s e d t h e path o f t h e  i t s head would a l i g n d i r e c t l y towards t h e s o u r c e as though t h e  i n s e c t was r e - e s t a b l i s h i n g i t s b e a r i n g s r e l a t i v e t o t h e s o u r c e .  I n t h e odour-  stream i t s e l f , a s t r o n g i n v e s t i g a t i v e behaviour was d i s p l a y e d as a conspicuous sideward movement o f t h e b e e t l e s ' head and f r a n t i c a l l y v i b r a t i n g antennae. On r e a c h i n g t h e s o u r c e however, t h e b e e t l e s i n most cases touched t h e i r heads t o t h e g l a s s n o z z l e , c i r c l e d a few t i m e s , but e v e n t u a l l y walked approach t h e s o u r c e o f 'opposing' l i g h t a r e n a , depending  or s t r i c t l y meandering about t h e t e s t  on t h e s i t u a t i o n .  When p o s i t i v e responses were incomplete m e r e l y responded  away, e i t h e r t o  ( r e c o r d e d as ?+), a b e e t l e  t o t h e h o s t wood by w a l k i n g a g a i n s t t h e g r a d i e n t o f odour but  never a c t u a l l y r e a c h i n g t h e s o u r c e ( F i g . 1 4 a ) . s l i g h t l y c r e a t e d no apparent  R e d u c t i o n o f t h e a i r speed  change o f r e s p o n s e .  When u n a t t r a c t i v e samples were p r e s e n t e d , i n t h e m a j o r i t y o f cases t h e a t t r a c t i o n by t h e b e e t l e s t o t h e 'opposing' s o u r c e o f i l l u m i n a t i o n was q u i t e direct  ( F i g s . 14c, d, e| 15o), w h i l e f o r t h e 'overhead'  t h e responses appeared  and 'dark'  situations,  as meandering paths or s t r a i g h t paths towards t h e  edges o f t h e t e s t arena ( F i g s . 14c, d , e j 1 5 c ) .  52  DISCUSSION I  The effects of various physical factors on the responses of Trypodendron lineatum  1.  (Olivier).  Monochromatic light, a.  General considerations. The data from this phase of the study show that the criterion for  relative strength of response to the photic stimulus was the percentage of individuals responding in a test population, the stronger the stimulative effect, the greater the number of individuals responding.  Post-diapause,  flight-inexperienced adult Trypodendron. both male and female were most strongly attracted to yellow-green monochromatic light at the wavelength of 54-3 millimicrons.  This region of peak response resembles that recorded by  other investigators for certain other insects.  It should be noted here that  this wavelength was one of the points chosen for experimental convenience, thereby not truly demonstrating precisely that 543 mu i s the most stimulating wavelength in the visible spectrum to Trypodendron. Wigglesworth (1965) has described for the honeybee Apis mellifera Linn., the most efficient part of the visible spectrum in attracting the bee i s the yellow-green at about 543 mu or 530 mu.  Also the larvae of the mealworm Tenebrio have been found to be  readily aroused by the light of 535 mu (Bertholf, 1 9 3 1 ) .  This peak of  greatest stimulation also varies greatly between insects however, for in the visible spectrum the cockroach Periplaneta has a peak response at 500 mu (green)(Walther, 1 9 5 8 ) ; and for the ground beetle Carabus, 430 (Hasselmann, 1962).  mu  Other insects have two peaks of stimulation, such as the  blowfly Calllphora at 507 mu (green) and 630 mji (red)(Walther and Dodt, 1 9 5 7 ) . Burkhardt (1962) describes only one peak in the visible spectrum at 490 mu for Calllphora.  The single peak of stimulation in the visible spectrum however  53 appears t o be most common i n i n s e c t s  (Wigglesworth,  The g r a d u a l d e c r e a s e i n ' s t i m u l a t i v e violet  1965).  efficiency'  on t h e one hand and t h e r e d wavelengths  from t h e peak t o  on t h e other i n d i c a t e  the  clearly  t h a t Trypodendron e x h i b i t s s t r o n g p o s i t i v e r e s p o n s e s o n l y t o t h e one r e g i o n i n the v i s i b l e  spectrum.  T h i s d e c r e a s e i s more g r a d u a l toward t h e  than t h e l o n g e r w a v e l e n g t h s . t h a t d i s c o v e r e d by Jahn (1946) peak s e n s i t i v i t y  shorter  T h i s form of l u m i n o s i t y curve i s s i m i l a r  to  f o r t h e grasshopper M e l a n o p l u s , which has a  i n t h e b l u e - g r e e n at about 500 mu.  The l e a s t  stimulating  wavelength o f 397 mu c l o s e l y approximates t h a t d e s c r i b e d by Burkhardt  (1962)  f o r t h e b l o w f l y C a l l l p h o r a (400 mu). For the longer wavelengths,  not o n l y d i d t h e ' s t i m u l a t i v e  efficiency'  f a l l more a b r u p t l y from t h e peak, but a l s o i n t h i s range of t h e spectrum t h e r o l e of t h e i n t e n s i t y has been found t o be a primary v a r i a b l e effectiveness  of t h e w a v e l e n g t h .  i n l i m i t i n g the  In t h e r e d range p a r t i c u l a r l y ,  the  i s not t h e o n l y determinant o f b e e t l e r e s p o n s i v e n e s s , but a l s o t h e from t h e e m i t t i n g s o u r c e .  Wavelengths  which i n i t i a l l y  l i m i t i n g t o T . l i n e a t u m c o u l d i n d u c e a response i f to a s a t i s f a c t o r y l e v e l .  Mazokhin-Porshnyakov  phenomenon t o e x i s t f o r other i n s e c t s .  intensity  appeared t o be  t h e i n t e n s i t y was  (1964)  However,  wavelength  raised  describes a similar  eventually  a point  (780 mu)  i s reached whereby t h e r e i s no f u r t h e r r e s p o n s e i n t h e r e d p o r t i o n of electromagnetic spectrum. t o assume t h a t t h e l i m i t  With t h e s e l o n g e r wavelengths  it  is  i n d i c a t e d f o r wavelength s e n s i t i v i t y  f u n c t i o n o f wavelength r a t h e r t h a n i n t e n s i t y ,  the  reasonable is truly  s i n c e an i n c r e a s e of  a  intensity  d i d not provoke a r e s p o n s e . Wigglesworth  (1965)  t h e deeper shades of r e d . wavelengths  s t a t e s t h a t most i n s e c t s seem t o be i n s e n s i t i v e The honeybee f o r i n s t a n c e , does not respond t o  beyond 650 mu (von F r i s c h , 1914J Kuhn, 1 9 2 7 ) .  Wasps (Vespa)  to  54 a f t e r being t r a i n e d to v i s i t or r e d  (Schremmer, 1 9 4 1 ) .  a b l a c k s u r f a c e can be d i v i d e d e q u a l l y by  S i m i l a r l y i n t h e b l o w f l y C a l l i p h o r a , the  spectrum extends as f a r as 730 mu hand other  (Autrum and Stumpf, 1 9 5 3 ) .  i n s e c t s such as t h e b u t t e r f l i e s P i e r i s b r a s s i c a e  Vanessa u r t i c a e L i n n , have an undoubted p e r c e p t i o n f o r r e d when presented  w i t h r e d paper models or f l o w e r s ,  On  visible  the  (Linn.) (Use,  black  other and  1928),  even show a p r e f e r e n c e  and for  these objects. At the other  end  of t h e e l e c t r o m a g n e t i c  responses appeared t o i n c r e a s e a f t e r r e a c h i n g i n c r e a s e was abruptly.  examined o n l y up t o 299 mu,  spectrum towards the a low  ultraviolet,  r e s p o n s e at 397 mu.  This  but f o r t h i s s h o r t i n t e r v a l i t r o s e  Although the e v i d e n c e t o d a t e i s s t i l l l i m i t e d , immediate  i n d i c a t i o n s are t h a t Trypodendron responds e x c e p t i o n a l l y w e l l i n t h e u l t r a v i o l e t wavelengths, p o s s i b l y much more so than t o the  extremely  s t i m u l a t i n g wavelengths of the o r d i n a r y d i s p e r s i o n spectrum. has been put f o r t h by s e v e r a l other Bertholf  (1931) and  Lutz  A p i s m e l l i f e r a L i n n , and efficiency  1  (1924).  authors f o r other  The  the f r u i t f l y  t h e peak at about 340  t o 350 mu  l a t t e r have found t h a t i n t h e honeybee Drosophila,  a second peak of  Walther and  f o r P e r i p l a n e t a and  Dodt  'stimulative the  (1957) have d e s c r i b e d  for Calliphora.  i n the v i s i b l e range of t h e spectrum but  h i g h peak at about 365 mu  and  insects including  Cameron  found a l s o t h a t i n the h o u s e f l y Musea no peak of s t i m u l a t i o n  c o u l d be d e t e c t e d  302 mu.  conclusion  f o u r or f i v e times as h i g h as t h e peak i n the v i s i b l e p a r t of  spectrum has been observed at 365 mu.  (1938) has  This  and  another e v e n . f u r t h e r  No t r a c e o f t h e maximum at 365 mu  Wigglesworth (1965).  recorded  a very  i n t o the u l t r a v i o l e t  has been d e s c r i b e d by Sander  at (1933)  The weak e m i s s i v i t y of the monochromator f o r t h e  s h o r t e r wavelengths p r o h i b i t e d t h e e s t a b l i s h m e n t l i m i t f o r t h e s e n s i t i v i t y of Trypodendron t o  of t h e u l t i m a t e wavelength,  ultraviolet.  Whether or not t h e r e i s any v a r i a b i l i t y i n s e n s i t i v i t y i n e i t h e r of two  p a r t s ^ of t h e Trypodendron eye has y e t t o be a s c e r t a i n e d .  the high s e n s i t i v i t y to u l t r a v i o l e t  Hertz  In P e r i p l a n e t a  i s l i m i t e d t o the d o r s a l h a l f of the  w h i l e t h e g r e e n , s e n s i t i v e r e c e p t o r s a r e found i n a l l p a r t s  as a t r u e c o l o u r t o i n s e c t s , even though i t i s i n v i s i b l e t o man.  t h a n 300 mu  out  Mazokhin-Porshnyakov  (1964) concludes  1961).  (1958) u s i n g t r a p s i n v o l v i n g u l t r a v i o l e t l i g h t  probably  because of low  a t t r a c t T. l i n e a t u m  of these  shorter  Because of t h i s  T e s t s by Chapman and  although  attractive  Kinghorn  to  Kinghorn, 1 9 5 5 ) , f a i l e d t o c a t c h l a r g e numbers,  evening  temperatures which were not s u f f i c i e n t  s t i m u l a t e Trypodendron t o f l y . A l s o t h e use not  Ozone i n  that i n nature u l t r a v i o l e t r a d i a t i o n  p l a y s a minor r o l e i n t h e r e a c t i o n s of i n s e c t s .  Trypodendron (Chapman and  perceived  a l l t h e f a r u l t r a v i o l e t , and l i t t l e  reaches t h e e a r t h (Goldsmith,  of c o l o u r e d  cardboard  I t i s probable  numbers  t h a t other  s t i m u l a t i n g f a c t o r s such as a t t r a c t i v e host odour were at t h i s time  external determining  b e e t l e responses s i n c e b e e t l e s were i n t h e i r normal p o s t - h i b e r n a t i n g  factor  In t h i s l a b o r a t o r y however, monochromatic l i g h t was  attack only  presented.  Three types  of r e c e p t o r  f o r the b l o w f l y C a l l i p h o r a . f o r almost 75 per and  the  to  traps did  even d u r i n g d a y l i g h t hours when s i g n i f i c a n t  i n s e c t s were observed i n f l i g h t .  condition.  eye  1958).  (Walther,  (1938) suggested t h a t t h e u l t r a v i o l e t r e g i o n i s p r o b a b l y  t h e upper atmosphere f i l t e r s  the  yellow-green  c e l l s have been d e s c r i b e d by Burkhardt The  (1962)  green s e n s i t i v e r e c e p t o r s however account  cent of t h e t o t a l complement, w h i l e b l u e s e n s i t i v e (470 (520  mp)  c e l l s comprise t h e remainder.  t h e g r e a t e s t s t i m u l a t i n g wavelength (490  mu)  predominance of t h e green type r e c e p t o r c e l l .  Trypodendron has d i v i d e d eyes.  mp.)  I t i s suggested t h a t  i s a direct result  of  the  In Trypodendron, i t i s  56 p o s s i b l e t h a t t h e m a j o r i t y of c e l l s are of t h e y e l l o w - g r e e n account f o r t h e peak of s t i m u l a t i o n at 543 Burkhardt  i n the u l t r a v i o l e t .  i n t h e case of T. l i n e a t u m . types  i n the v i s i b l e  (1962) d e s c r i b e d a l s o t h a t a l l 3 r e c e p t o r types  s t i m u l a t i o n at 350 mu  two  mu  while the other  i s s p e c i a l i z e d t o the v i s i b l e  only  wavelengths  spectrum. s u b j e c t e d t o white l i g h t apparent changes i n response  t h r o u g h b e e t l e s becoming dark adapted were n o t e d .  D o l l e y (1929) has  found t h a t  f o r one hour i n c r e a s e d t h e s e n s i t i v i t y of t h e eye of t h e h o v e r f l y  E r 1 s t a l l s tenax ( L i n n . ) by 21  New  show a peak of  s p e c i a l i z e d t o the u l t r a v i o l e t  d u r i n g t h e r e - a l i g n i n g p e r i o d s o f t h i s study, no  b.  spectrum.  (1959) however d e s c r i b e d  A l t h o u g h t h e b e e t l e s were c o n t i n u a l l y b e i n g  dark adaption  could  T h i s phenomenon i s a l s o p o s s i b l e  Walther and Dodt  o f r e c e p t o r systems, one  type: t h i s  times.  information f o r the bioassay  Future bioassay e s s e n t i a l standards  of e x p e r i m e n t a l  technique.  wood samples w i l l depend on c e r t a i n  as w e l l as r e f i n e d t e c h n i q u e s .  study of t h e a c t i o n of monochromatic l i g h t  The  r e s u l t s of t h e  on t h e p h o t i c responses of  Trypodendron make p o s s i b l e t h e d e f i n i t i o n of p h o t i c standards f o r t h e b i o a s s a y of o l f a c t o r y s t i m u l i .  The  present  of  reference  f i n d i n g s demonstrate t h e  o f wavelength as f a c t o r s i n a t t r a c t i o n of b e e t l e s t o l i g h t .  The  importance  relative  • s t i m u l a t i v e e f f i c i e n c y ' of an odour can t h e r e f o r e be a s c e r t a i n e d o n l y i f i t i s t e s t e d a g a i n s t a l i g h t which i s s t a n d a r d i z e d Previous standard  s t u d i e s by F r a n c i a  of white l i g h t  (1965)  as a p h o t i c r e f e r e n c e f o r p h o t i c r e s p o n s e s . has  s a t i s f a c t o r i l y considered  light  and  parameters.  depended on an a r b i t r a r i l y chosen  i n v e s t i g a t i o n on monochromatic l i g h t  t o t e s t host m a t e r i a l s .  i n respect to these  a constant  e s t a b l i s h e d what would  be  source t o be p l a c e d i n o p p o s i t i o n  S i n c e t h e wavelength 543  found t o be e x t r e m e l y e f f i c i e n t  The  mu  has  been t h o r o u g h l y  i n a t t r a c t i n g T. l i n e a t u m  even at  low  tested  i n t e n s i t y l e v e l s , i t appears t o be an i d e a l s o u r c e o f standard l i g h t .  Being  i n t h e v i s i b l e range o f t h e spectrum a l s o adds t o t h e advantages f o r t h e investigator. Two measures o f host a t t r a c t i v e n e s s  can be a t t a i n e d u s i n g  a standard  s o u r c e o f l i g h t , one i n v o l v i n g a constant i n t e n s i t y w h i l e t h e other uses varying  intensities.  With c o n s t a n t i n t e n s i t y t h e response o f b e e t l e s  would  depend on t h e a t t r a c t i v e n e s s of d i f f e r e n t wood samples, t h e more a t t r a c t i v e the  sample, t h e g r e a t e r  t h e number o f p o s i t i v e responses t o i t . T h i s method  would g i v e a s o l i d measure o f a t t r a c t i v e n e s s o f any number o f wood samples o f v a r y i n g degrees o f a t t r a c t i v e n e s s .  T h i s has i n f a c t been t h e method o f  b i o a s s a y adopted i n t h e present i n v e s t i g a t i o n on t h e m o d i f i c a t i o n wood a l t h o u g h t h r e e  o f 'green'  d i f f e r e n t c o n s t a n t i l l u m i n a t i o n sources were used.  When i n t e n s i t y o f t h e s t a n d a r d l i g h t  i s v a r i e d however, l i g h t i n t e n s i t y  becomes an i n d i r e c t but p o s s i b l y more p r e c i s e measure o f host wood  attractiveness.  The  and wood  quantity  of l i g h t r e q u i r e d  t o e q u a l i z e responses between l i g h t  c o u l d be used f o r Trypodendron; t h e r e f o r e w i t h a c o n s t a n t wavelength o f l i g h t , a sample which i s e x t r e m e l y a t t r a c t i v e would r e q u i r e more energy t o e q u a l i z e t h e responses o f t h e i n s e c t s t o an approximate one-to-one r a t i o than a weakly u n a t t r a c t i v e sample.  Any combination o f r a t i o s between l i g h t  c o u l d be used, i n c l u d i n g t h e minimum q u a n t i t y the  i n s e c t s away from t h e wood s o u r c e .  considerable  o f energy r e q u i r e d  and wood  to attract a l l  I t must be expected however, t h a t  v a r i a t i o n i n responses o f d i f f e r e n t i n d i v i d u a l s w i l l  appear.  V a r i a t i o n w i l l be t h e r e s u l t o f i n t r i n s i c d i f f e r e n c e s i n t h e r e a c t i v i t y o f different  i n d i v i d u a l s , as w e l l as o f d i f f e r e n t i a l s u s c e p t i b i l i t y t o  modification The  by f l i g h t  experience.  s t u d y has a l s o e s t a b l i s h e d  the wavelength o f 7 3 5 mu t o s i m u l a t e  a s t a n d a r d o f r e d monochromatic l i g h t a t darkness t o t h e b e e t l e s , w h i l e l e a v i n g  58  the test arena sufficiently visible to the investigator.  Previous studies of  Francia (1965) and Wright (1966) used red cellophane over a source of light to reduce the photic stimulus. Since red monochromatic light of specific wavelengths and intensities has been found to be non-stimulating to Trypodendron, this affords an opportunity to study the effects of olfactory stimuli alone in determining beetle responses. 2.  Water loss versus photic responses and i t s implications to the bioassay technique. The study on the effects of water loss on the photic responses of  Trypodendron to white light showed conclusively that l i t t l e or no change occurred in flight-inexperienced individuals.  Although this phase of the  study was a purely a r t i f i c a l situation as such, a number of important implications can be derived from i t for the bioassay technique. Assuming that the principle of water loss applies to attraction to the odour factors as well, i t i s possible that for the bioassay i t s e l f , flight-inexperienced or unflown T. lineatum adults may therefore be tested in darkness or under dark red illumination without any apparent side-effects arising from this water loss.  Although this study did not cover a comparable situation for  flight-exercised or flown beetles, indications from the bioassay of the present investigation are that no observable changes had occurred. Specimens in the bioassay however were kept in moistened containers to minimize any possible loss, but in most cases they were tested for extensive periods of time under laboratory conditions.  In these instances, a beetle was  continually being tested and retested for periods of up to six hours without any apparent modifications in the orientation to either light or host material. This result was most easily observed in situations where attractive Douglas-fir controls were offered to Trypodendron at the commencement and then at the  59 conclusion of a s e r i e s of t e s t s .  It  is s t i l l  p o s s i b l e however t h a t  other  u n d e t e c t e d changes i n b e e t l e r e s p o n s e s may have r e s u l t e d , e s p e c i a l l y flight-experience i t s e l f  i s a g r e a t m o d i f i e r of p h o t i c o r i e n t a t i o n  since (Francia,  1965). The f a c t t h a t Trypodendron l o s t water c o n t i n u o u s l y under  laboratory  temperatures and h u m i d i t i e s s i g n i f i e s t h e importance of m a i n t a i n i n g moisture l e v e l s .  adequate  The maximum water l o s s o f 25 per cent b e f o r e d e a t h r e s u l t s ,  as d e s c r i b e d by N i j o l t  and Chapman  (1964) approximates q u i t e c l o s e l y t h e  v a l u e s o b t a i n e d from t h i s i n v e s t i g a t i o n .  An i n t e r e s t i n g o b s e r v a t i o n r e g a r d i n g  t h e s u r v i v a l t i m e s and water l o s s e s i n t h e two b e e t l e groups was noted where t h o s e i n t h e humid environment s u r v i v e d l o n g e r but l o s t much l e s s water than t h o s e i n t h e d r y environment, as measured a f t e r  death.  This possibly  signifies  t h a t water i s not t h e o n l y f a c t o r which determines t h e s u r v i v a l o f t h e Food has been d i s c o u n t e d by Chapman (1955a).  Temperature however i s  another important f a c t o r a f f e c t i n g t h e s u r v i v a l o f t h e i n s e c t s .  insects.  probably  Direct  c o n t a c t w i t h c o n t r o l l e d q u a n t i t i e s o f water are a l s o p r e r e q u i s i t e s t o  their  s u r v i v a l (Chapman, 1955a). The few minor d i f f e r e n c e s i n some of t h e r e s u l t s f o r t h e and ' r e a c t i o n ' the i n s e c t 8 trials,  'refractory'  times can most r e a d i l y be e x p l a i n e d as a random b e h a v i o u r  in question.  of  S i n c e each group at any p e r i o d of t e s t i n g had o n l y  even one extremely p r o l o n g e d r e s p o n s e by a b e e t l e c o u l d e a s i l y  u p s e t t h e o v e r a l l group r e s p o n s e .  These extreme r e s p o n s e s were i n many cases  so g r e a t t h a t t h e y g e n e r a l l y exceeded t h e combined t o t a l f o r t h e remainder of the t r i a l s  i n a group, e i t h e r f o r the  'refractory'  (Appendix 4 - b e e t l e Ho. 9 and N o . 1 0 ) . d i d not respond i n t h e  'refractory'  or ' r e a c t i o n '  times  In t h e s e i n s t a n c e s any given  period t e s t s | i t  movement f o r a p r o l o n g e d p e r i o d of time as i f  beetle  e x h i b i t e d l i t t l e or no  not r e s p o n d i n g t o any  external  60 stimuli. stops  In the 'reaction' t e s t s , beetles  e x h i b i t e d e i t h e r frequent  prolonged  or g e n e r a l l y l o n g meandering paths o f r e s p o n s e , t h u s , e x t e n d i n g g r e a t l y  the r e c o r d e d  time o f r e s p o n s e .  The m a j o r i t y  o f groups o f 8 t r i a l s however  were f a i r l y c o n s i s t e n t f o r each b e e t l e under c o n s i d e r a t i o n . e i t h e r s h o r t or l o n g  ' r e f r a c t o r y ' or ' r e a c t i o n ' t i m e s tended t o reproduce  t h i s t y p e o f b e h a v i o u r as many times as each was t e s t e d . analyses  Beetle exhibiting  In t h i s way  o f d a t a y i e l d e d r e s u l t s t h a t were n o t s i g n i f i c a n t l y d i f f e r e n t f o r  each o f t h e times a b e e t l e was t e s t e d .  II  The m o d i f i c a t i o n and b i o a s s a y  o f 'green' wood u s i n g t h e newly-proposed  technique of a n a l y s i s .  1.  The wood f a c t o r s . T h i s s t u d y shows c o n c l u s i v e l y t h a t t h e s u b j e c t i o n  Douglas-fir  sapwood t o oxygen d e f i c i e n t c o n d i t i o n s  the ambrosia b e e t l e Trypodendron l i n e a t u m  o f 'green' u n a t t r a c t i v e  induced a t t r a c t i v e n e s s f o r  (Olivier).  I t was a l s o shown t h a t  the degree o f a t t r a c t i v e n e s s o f t h i s wood depended l a r g e l y on t h e d u r a t i o n of subjection t o anaerobic c o n d i t i o n s . f o r s i m i l a r periods Originally  Wood not p l a c e d under t h e s e  o f time d i d not become a t t r a c t i v e .  'green', a sample o f host m a t e r i a l became s l i g h t l y a t t r a c t i v e  a f t e r L hours under 'anaerobic' with f u r t h e r periods  conditions  of anaerobiosis.  and g r a d u a l l y r o s e i n a t t r a c t i v e n e s s  F o r t h e s e experiments, t h e t r a n s i t i o n  from t h e 'green' u n a t t r a c t i v e t o t h e ' r i p e  1  a t t r a c t i v e c o n d i t i o n reached i t s  optimum between t h e time i n t e r v a l from 20 t o 26 h o u r s . a t t r a c t i v e n e s s t h e wood l o s t deficient given  conditions  conditions.  s i m i l a r periods  A f t e r t h i s peak o f  i t s a t t r a c t i v e n e s s a f t e r about 30 hours o f oxygen  Some v a r i a b i l i t y d i d occur however between wood samples of treatment.  T h i s c o u l d p o s s i b l y have been a r e s u l t  o f t h e t e s t b e e t l e s themselves i n a d d i t i o n t o t h e wood.  In the f i e l d ,  61  Chapman of  (1962) and Dyer and Chapman  (1965) have r e c o r d e d a c o n s i d e r a b l e degree  v a r i a b i l i t y between l o g s o f s i m i l a r f e l l i n g d a t e s .  apparent  d i s p a r i t y remains unknown a t t h e present t i m e .  a n a e r o b i c c o n d i t i o n s f o r p e r i o d s r a n g i n g from  The reason f o r t h i s Wood p l a c e d under  30 t o 4 6 . 5 hours a l s o y i e l d e d  r e s u l t s i n d i c a t i n g t h a t l i t t l e i f any a t t r a c t i v e p r o p e r t i e s remained. significant anaerobic  A  change i n 'green' wood can t h e r e f o r e be a t t r i b u t e d t o t h e  treatment.  Wood i n t h e o r i g i n a l 'green' u n a t t r a c t i v e s t a t e had a s l i g h t l y pungent fragrance while that i n the a t t r a c t i v e 'ripe' f r u i t y fragrance.  c o n d i t i o n possessed  U n a t t r a c t i v e wood i n t h e 'spent'  a sweet  c o n d i t i o n had a r a t h e r f l a t  woody odour, d i s t i n c t l y s e p a r a b l e from t h e o t h e r two c o n d i t i o n s .  In some i n -  s t a n c e s , a s l i g h t l y sour odour c o u l d be d e t e c t e d i n t h o s e samples l e f t f o r t h e longer periods of time.  Because o f i t s h i g h l y t r a n s i e n t n a t u r e , t h e s e odours  were found t o d i s s i p a t e q u i c k l y d u r i n g or a f t e r l a b o r a t o r y t e s t i n g . e x p e r i m e n t a l treatment  appears  The  t o have induced i n 20 h o u r s , odour changes which  i n t h e f i e l d r e q u i r e s e v e r a l weeks o r months (Dyer and Chapman, 1965}  Gaumann,  1930} Hadorn, 1933} Mathers, 1935} P r e b b l e and Graham, 1 9 5 7 ) . The  f o r e g o i n g f i n d i n g s which s t r o n g l y i n d i c a t e t h e involvement  p r o c e s s e s , p r o v i d e a p o s s i b l e e x p l a n a t i o n f o r some o f t h e f i e l d r e p o r t e d by v a r i o u s a u t h o r s . b i l i t y with moisture content.  S e v e r a l authors attempted Kinghorn  i n d i c a t o r o f a t t a c k d e n s i t y but merely  of anaerobic  observations  to correlate  suscepti-  (1956) used m o i s t u r e content as an found t h a t t h e apparent  l a c k o f moisture  may have l i m i t e d t h e d e n s i t y o f a t t a c k s , but an excess o f m o i s t u r e d i d not i n any way i n c r e a s e l o g a t t r a c t i v e n e s s . shown t h a t s e c t i o n s o f l o g s o f western  Johnson (1961) i n western  Washington has  hemlock w i t h branches remaining were  not a t t a c k e d w h i l e t h e r e m a i n i n g p o r t i o n s o f t h e b o l e s u f f e r e d c o n s i d e r a b l e attacks.  I n comparison,  a d j a c e n t t o p s w i t h branches removed s u s t a i n e d  fairly  62 heavy a t t a c k s .  A l s o t h e p o r t i o n of t h e b o l e w i t h t o p s i n t a c t were found t o  have a s i g n i f i c a n t l y lower m o i s t u r e c o n t e n t . t r e e s w i t h crowns i n t a c t  Later  s t u d i e s a l s o showed t h a t  s u s t a i n e d no Trypodendron a t t a c k s w h i l e t r e e s  branches s u s t a i n e d heavy a t t a c k s .  without  M o i s t u r e samples of t h e t r e e s showed t h e  l e v e l to have dropped t o a p p r o x i m a t e l y AO per cent from w e l l over 100 per  cent  i n t h o s e t r e e s w i t h tops i n t a c t  of  Kinghorn (1957)  and Dyer  (Johnson,  (1963),  it  1964).  has been suggested t h a t the r a t e of d r y i n g  has i n h i b i t e d t h e f o r m a t i o n of a t t r a c t a n t  substances.  C h r i s t i a n (1932)  and F i s h e r and Thompson (1952)  essential factor  affecting beetle  We  Contrary to the r e s u l t s  Bletchly  (1961)j  a l s o b e l i e v e m o i s t u r e t o be an  attack.  are now c o n f r o n t e d w i t h t h e q u e s t i o n as t o why m o i s t u r e content c o u l d  be i m p o r t a n t , and whether  it  i s important per se or merely an i n c i d e n t a l  c o r r e l a t e which accompanies t h e t r u e i n f l u e n c e .  When t h e a n a e r o b i c  experiments  were u n d e r t a k e n , t h e y were based on the h y p o t h e s i s of Graham (1962) t h a t  one of  the accompaniments t o s t r e s s or d e a t h i n a t r e e i s t h e r e d u c t i o n or c e s s a t i o n , of sap movement. s o i l moisture.  T h i s i n t u r n would a r r e s t t h e i n t a k e of d i s s o l v e d oxygen w i t h It i s assumed t h a t t h e l i v i n g c e l l s of t h e sapwood, namely the  wood cambium and t h e r a y c e l l s  (MacDougal et a l , 1 9 2 9 ) , n o r m a l l y depend on  d i s s o l v e d oxygen i n t h e s a p , o r f r e e oxygen i n t h e i n t r a - and spaces f o r normal m e t a b o l i s m .  G e n e r a l knowledge o f i n t e r m e d i a r y metabolism  would i n d i c a t e t h a t d e p r i v a t i o n o f oxygen would r e s u l t f e r m e n t a t i v e metabolism which y i e l d s f e r m e n t a t i v e 1960).  intercellular  in glycolytic  of*  end p r o d u c t s (Meyer et  T h i s may e x p l a i n t h e n a t u r e o f o r i g i n of a t t r a c t a n t s  al,  i n wood i f  oxygen  really  p l a y s a s i g n i f i c a n t r o l e i n normal metabolism o f c a m b i a l and ray  cells,  and i f  oxygen does f a l l below a c r i t i c a l  tree.  At p r e s e n t , d i r e c t d a t a are l a c k i n g on changes i n t h e gas c o m p o s i t i o n  within a tree.  c o n c e n t r a t i o n i n a f e l l e d or d y i n g  The r e p o r t s on m o i s t u r e changes i n l o g s may however  have  63 significance.  When moisture i s lost from a tree, a i r must replace i t , thereby-  providing a substitute form of aeration which would delay the onset of fermentative metabolism and thus prevent attractants from forming. The work of several authors on autoclaving and starch content also offer possible bases for theories on the processes occurring in felled trees or logs. Kinghorn and Chapman (1957) have studied the effects of autoclaving and aging in Douglas-fir blocks.  Sections were obtained from freshly felled trees,  treated, then stored until flight and attack by T. lineatum.  It was found that  autoclaving and aging together rendered them unsusceptible to attack.  This  result could have arisen through either the prevention or the depletion of any attractant substances, the effect was in most likelihood due to the heat treatment rather than the aging.  This could possibly indicate that an enzymic  process may be involved in the attractant formation process.  Busgen (1929)  contends that the starch level i s a good indicator of changes in the physiology of living trees.  Chapman et a l (1963) studied the effects of starch content  as a determinant of log attractiveness. They concluded however that a high starch content was correlated with a low density of attacks but also that a. low starch content did not induce attack.  High starch contents are prevalent  in standing trees and freshly cut timber, these have been shown to be unattractive to Trypodendron (Chapman, L959, 1961; Dyer, 1964} 1965? Francia, 1965}  Dyer and Chapman,  Hadorn, 1933; Kinghorn and Chapman, 1957}  Prebble and Graham, 1957).  Novak, I960}  Jones (i960) in West Africa however studied various  aspects of ambrosia beetle biology and found no correlation to exist between the degree of susceptibility to either starch or moisture content. Meyer et a l (I960) described the possible outcome in higher plants, normally aerobic which have been exposed for varying periods of time to anaerqbic environments. At least two possible injurious effects have been  described as resulting from this process.  One i s that i n metabolically active  tissues especially, the curtailed rate of energy release i s probably inadequate for the normal maintenance of c e l l processes and deleterious effects are soon engendered within the cells.  Another possible result of fermentation i s the  accumulation of substances which exert toxic effects on the protoplasm.  Ethyl  alcohol and other more or less toxic compounds are known to be accumulated i n the c e l l s .  The presence of volatile substances f a l l s closely i n line with the  pattern of events found i n susceptible host wood. Browne (1952) has reported that the injection of alcohol into trees causes attraction of some ambrosia beetles, even after wood has become unattractive through seasoning. The process of metabolic fermentation has also been postulated by other investigators studying host selection including Baker (1956), Champlain and Kirk (1926), Chapman (1956), Ohnesorge (1953) and Person (1931).  Binion (1962) reported  attraction by T. lineatum to fermenting mixtures in beer dregs. MacDougal et a l (1929) and Boberg and Juhlin-Dannfelt (1926, 1928) investigated the changes i n cut logs and found conclusively that fermentative and other changes occur i n the living cells of sapwood leading to changes i n the composition of gas.  Carbon dioxide i s always present i n amounts much  greater than in the atmosphere (sometimes 60 times as great) while the amount of oxygen i s much less, and the sum of oxygen and carbon dioxide i s less than in a i r .  Scarth (1930) and Scarth and Gibbs (1930) testing wood from floated  logs found very high concentrations of carbon dioxide. Fermentation inside floated logs of balsam and spruce has been described by Scarth and Jahn (1930). Attacks by Trypodendron have been studied in floated water-soaked logs by Dyer and Chapman (1962). The results obtained from the phase of the study with the addition of water to the wood shavings need further clarification.  A possible explanation  as to why both 'anaerobic' and 'aerobic' samples became attractive to Trypodendron may be that water may somehow be blocking the normal function of gas exchange associated with the woody tissues, thus again providing another a r t i f i c i a l anaerobic situation. Dyer and Chapman (1962) concluded that water i s not a deterrent to the formation of attractant substances. Essentially a l l authors today studying the mechanism of origin of host attractant suggest that the phenomenon i s purely metabolic in nature rather than the result of extraneous biological factors such as micro-organisms. It is not impossible however that the production of attractants is under some influence of bacteria, yeasts or even fungi.  There is no doubt that micro-  organisms are present on Douglas-fir sapwood and are probably functioning at or near the sites of cellular activity (Bier, 1966).  Their effect on the  production of attractants however remains an open question. (1962)  Yite and Gara  have ruled out the role of yeasts and other micro-organisms as a  possible source of attractants but this applies only to those associated directly with the insect.  Person (1931) provides three possible alternatives  regarding the nature of this attractant formation.  The f i r s t that he suggests  is that of micro-organisms solelyj the second i s the cellular activity of wood alone, and the third i s a combination of both micro-organisms and wood factors. It i s noteworthy that of a l l the various treatments tested, none produced the level of attractiveness of naturally 'ripened' wood in logs.  This phenome-  non may signify that much of the attractant substance produced anaerobically from 'green' wood could have dissipated from the shavings before they were tested.  The use of interconnected double series of bottles however appeared  to minimize this effect. The fact that T. lineatum when attracted to the source are not retained  at this site has been described earlier by Francia (1965).  A considerable  degree of variability in the period of retention was observed between beetles. It i s most probable that other stimuli must be involved in retaining the insects at the source.  Rudinsky (1966) has postulated a visual cue to be necessary  for the Douglas-fir beetle Dendroctonus psQudotsugae Hopkins once this insect has entered the perimeter of attraction.  Tactile stimuli must also become a  part of the host selection requirements once the beetles have reached the source of attraction (Rudinsky and Daterman, 1964). In any event, the importance of the 'anaerobic' hypothesis must be recognized such that i t can now play a significant role in the formulation of a working hypothesis to further investigate the manner in which wood becomes susceptible to beetle attack.  Perhaps the next line of pursuit would be to  test for oxygen levels in both trees and logs (Graham, 1 9 6 6 ) . 2.  The bioaseay^technique. As for the bioassay technique used in the present investigation, several  important comments should be made in reference to i t s effectiveness.  It has  become apparent that the anemo-olfactory technique offers a satisfactory degree of sensitivity when distinguishing host factors of various degrees of attractiveness.  Pencil tracings have been found to be appropriate for recording  responses, mainly because they are permanent records of the exact paths taken by a beetle.  However when this type of record is not required, i t is possible  to record only the mere presence or absence of a traversal by a beetle (Wood and Bushing, 1 9 6 3 ) .  In future studies, traversal times would prove useful i f  c r i t i c a l measurements of differences are required (Anderson and Fisher, I960; Pertunnen, 1957).  It is the aim of any investigator to accomplish as much as possible with a limited supply of experimental equipment in the shortest possible time.  It  67 would therefore seem more logical to use more experimental beetles, a l l tested at the same time to give a sample population response to one specific host treatment.  This contrasts with the present undertaking in which individual  beetles were used.  Wellington et a l (1954) have briefly mentioned this very  subject and have stated i t to be for one, dependent on i t s convenience to the observer. With Trypodendron. at least for the present time, i t i s easier to handle individual specimens.  Results are eventually discussed i n terms of  groups irrespective of the method of study.  Although the study of wood  susceptibility i s related to the whole beetle population, i t i s also important to study the variations i n individual behaviour.  This has been repeatedly  demonstrated i n the experiments where much variability was encountered with this Trypodendron population. It was found that certain beetles consistently gave poor responses while others gave highly favourable responses.  Unless  individual beetles could be identified within a group, this particular behavioural pattern would probably go undetected. Even with the three lighting situations of this study, i t became clearly established that the intensity of the opposing light can be used in future studies as a measure of attractiveness.  The data obtained on wood attraction  when overhead light was used did not differ as much from that with the opposing light, but i t was strikingly different when the dark red light situation was compared to the other two situations.  This reflects clearly the role of light  in attracting insects away from any source of olfactory stimulation.  A  slightly higher positive response to wood however appeared lti the 'overhead' light situation, the latter having an approximate light intensity of 10 to 12 foot-candles at the arena test f i e l d .  The 'opposing' light was approximately  14 foot-candles on the test field,, this higher intensity would therefore draw more beetles away from the host wood source.  The implications for future  68 bioassay studies of this finding have been discussed earlier in this text with reference to the use of monochromatic light as a possible source of standard opposing illumination.  69  CONCLUSIONS  •  1.  Of t h e wavelengths o f monochromatic l i g h t t e s t e d u s i n g t h e two methods o f a n a l y s i s , a peak o f ' s t i m u l a t i v e e f f i c i e n c y ' o c c u r r e d a t 54-3 mu. On e i t h e r s i d e o f t h i s maximum, t h e ' s t i m u l a t i v e e f f i c i e n c y ' d e c r e a s e d , t h i s d e c r e a s e was more g r a d u a l towards t h e l o n g e r wavelengths o f t h e ultraviolet.  2.  A t h r e s h o l d o f s t i m u l a t i o n was reached i n t h e l o n g e r wavelengths o f t h e r e d p o r t i o n o f t h e spectrum a t which time and beyond which T. l i n e a t u m was not c a p a b l e o f d e t e c t i n g any s o u r c e o f t h i s i l l u m i n a t i o n , w h i l e t h e a u t h o r was s t i l l c a p a b l e o f o b s e r v i n g t h e b e e t l e s ' r e s p o n s e s .  3.  Towards t h e u l t r a v i o l e t range o f t h e spectrum, i n d i c a t i o n s from the r e s u l t s u s i n g t h e two methods o f t e s t i n g a r e t h a t an i n c r e a s e i n ' s t i m u l a t i v e e f f i c i e n c y ' appears from a p p r o x i m a t e l y 4-00 mu and c o n t i n u e s i n t o t h e u l t r a v i o l e t wavelengths. U s i n g t h e method o f v a r y i n g i n t e n s i t i e s , r e s u l t s suggest t h a t t h e ' s t i m u l a t i v e e f f i c i e n c y ' i s h i g h e s t i n t h i s r e g i o n , perhaps 3 t o 4 times g r e a t e r t h a n t h e v i s i b l e wavelength 543 mu.  4.  From t h e study o f monochromatic l i g h t , i t was shown t h a t t h e wavelength i s not t h e o n l y f a c t o r d e t e r m i n i n g t h e p h o t i c o r i e n t a t i o n o f T. l i n e a t u m , but a l s o t h e i n t e n s i t y o f any g i v e n wavelength.  5.  Male and female T. l i n e a t u m appear matic i l l u m i n a t i o n .  6.  t o respond  e q u a l l y w e l l t o monochro-  The use o f monochromatic l i g h t i n t h e b i o a s s a y t e c h n i q u e can now justified. to simulate lengths are implication  Not o n l y darkness proposed has been  be  has a t h r e s h o l d o f response been found a t 735 mu t o T. l i n e a t u m , but a l s o h i g h l y s t i m u l a t i n g waveas p o s s i b l e s t a n d a r d sources o f i l l u m i n a t i o n . This discussed i n the t e x t .  7.  The use o f t h e a n e m o - o l f a c t o r y b e h a v i o u r o f T. l i n e a t u m can a l s o now be j u s t i f i e d as a method o f b i o a s s a y . As p e d e s t r i a n s , t h i s i n s e c t i s q u i t e amenable t o use as a t e s t instrument f o r d e t e r m i n i n g t h e a t t r a c t i v e n e s s o f any number o f wood samples, p r o v i d e d proper e n v i r o n m e n t a l c o n d i t i o n s a r e m a i n t a i n e d and b e e t l e s a r e i n t h e i r proper p h y s i o l o g i c a l s t a g e .  8.  'Green' u n a t t r a c t i v e D o u g l a s - f i r sapwood can be made t o undergo a c h e m i c a l t r a n s i t i o n t o an a t t r a c t i v e ' r i p e ' s t a t e and a f u r t h e r 'spent' u n a t t r a c t i v e s t a t e as i n d i c a t e d by Trypodendron r e s p o n s e s , by placement o f such wood under oxygen d e f i c i e n t c o n d i t i o n s f o r v a r y i n g p e r i o d s o f time.  9.  F o r wood shavings o f D o u g l a s - f i r sapwood, an optimum o f a t t r a c t i v e n e s s developed f o r p e r i o d s o f 20 t o 26 hours o f a n a e r o b i c treatment; t h i s a t t r a c t i v e n e s s b e g i n n i n g a t a p p r o x i m a t e l y 4 hours and r e a c h i n g an u n a t t r a c t i v e o r 'spent' s t a t e a t a p p r o x i m a t e l y 30 hours. However, some v a r i a b i l i t y d i d r e s u l t between samples o f s i m i l a r treatment t i m e s .  10.  No change o c c u r r e d i n t h e ' a e r o b i c ' c o n t r o l wood shavings l e f t under l a b o r a t o r y c o n d i t i o n s . A s i g n i f i c a n t change t o wood can t h e r e f o r e be a t t r i b u t e d t o the anaerobic treatment.  70 11.  'Green' wood was also unattractive to T. lineatum. this result agreeing with the findings of other i n v e s t i g a t o r s . .  12.  No significant difference was found to occur in the photic responses of T. lineatum to white light as a result of increasing water loss. This not only applied to the ratio of positive to negative responses, but also to the reactivity of both males and females.  13.  Trypodendron males and females did not appear to be able to withstand water loss while being subjected to laboratory conditions (44-4-6 per cent R.H., 23-26 degrees Centigrade). Extreme care in storage and handling must be taken to prolong the survival time of these insects.  71  LITERATURE CITED  A n d e r s o n , J . "Mr and K . C F i s h e r , I960. The response o f the w h i t e p i n e w e e v i l t o n a t u r a l l y o c c u r r i n g r e p e l l e n t s . -Can. J . Zoology 54-7-564. Autrum, H. and H. Stumpf. 1953. E l e k t r o p h y s i o l o g i s c h e Untersuchungen uber das Farbensehen von C a l l i p h o r a . Z. v e r g l . P h y s i o l . j_5: 71-104-. B a k e r , J\  M. 1956.  Investigations on" the oak p i n h o l e b o r e r ,  cyllndrus Fab.  A p r o g r e s s r e p o r t . B.  Platypus  W. P. A . A n n u a l C o n v e n t i o n , 1956.  B e r t h o l f , L.M. 1931. The d i s t r i b u t i o n o f s t i m u l a t i v e e f f i c i e n c y i n the u l t r a v i o l e t spectrum f o r the honeybee. J . A g r . Research __2* 379-4-19. Bier, J .  E,  1966.  P e r s o n a l communication.  B i n i o n , W. 1962. A t t r a c t i o n o f t h e ambrosia b e e t l e Trypodendron by beer d r e g s . P r o c . E n t . S o c . B. C. __h 53. B l e t c h l y , J . D, 1961. A review o f f a c t o r s a f f e c t i n g ambrosia b e e t l e a t t a c k i n t r e e s and f e l l e d l o g s . The Empire F o r e s t r y Review LO ( l ) ( 1 0 3 ) : 13-18. Boberg, S. and M. J u h l i n - D a n n f e l t . 1926._ V i k t s u n d e r s u k n i n g a r a f l o t t g o d s (weight o f d r i v e n l o g s ) . S k o g s v a r d s f o r . T i d s k r . 2 _ : 262-282. (See a l s o B i o l . A b s t r . 1: 7400, 1 9 2 7 . ) ,  1928,  On f l y t b a r h e t e n hos f u r u f l o t t o g d d s  (the buoyancy o f p i n e l o g s ) . S k o g s v a r d s f o r . T i d s k r . 26: 1-38. a l s o B i o l . A b s t r . 2: 15148, 1929.) Browne,  (See  F. G. 1952. S u g g e s t i o n s f o r f u t u r e r e s e a r c h i n the c o n t r o l o f ambrosia beetles. Malayan F o r e s t e r 1_»: 197-206.  B u r k h a r d t , D. 1962. S p e c t r a l s e n s i t i v i t y and other response c h a r a c t e r i s t i c s o f s i n g l e v i s u a l c e l l s i n the a r t h r o p o d e y e . S o c . E x p . B i o l . Symp. 16: 86-109. Busgen, M, 1929. The s t r u c t u r e and l i f e o f f o r e s t t r e e s . (3rd e d . , r e v . Munch, t r a n s . T . Thompson), Chapman and H a l l , London.  E.  Cameron, J . W."M. 1938. "The l i g h t r e a c t i o n s o f the h o u s e f l y Musca domestica L i n n , t o l i g h t of d i f f e r e n t wavelengths. Can. J . R e s e a r c h , D, 1 6 : 307-342. C h a m p l a i n , B.C. 291.  and H. B.  K i r k . 1926.  B a i t pan i n s e c t s .  Chapman, J . A . 1955a. S u r v i v a l o f T r y p o d e n d r o n . Canada, D e p t . o f F o r e s t r y 11 ( 2 ) : 3=4.  Ent.  News J 2  Bi-monthly Progress  :  2  8  8  =  Report,  1955b. P h y s i o l o g i c a l and b i o l o g i c a l s t u d i e s on the ambrosia b e e t l e Trypodendron l i n e a t u m ( O l i v . ) and the D o u g l a s - f i r b e e t l e Dendroctonus pseudotsugae Hopk. I n t e r i m R e p o r t , Canada, D e p t . o f A g r i c u l t u r e , Forest Biology Laboratory, V i c t o r i a , B.C.  72  Chapman, J. A. 1956. Physiological and biological studies on the ambrosia beetle Trypodendron lineatum (Oliv.). Interim Report 1955-2, Canada, Dept. of Agriculture, Forest Biology Division, Victoria, B.C. 1959. Forced attacks by the ambrosia beetle Trypodendron. Bi-monthly Progress Report, Canada, Dept. of Agriculture, Forest Biology Division 15. ( 5 ) : 3. 1961. A note on felling date i n relation to log attack by the ambrosia beetle Trypodendron. Bi-monthly Progress Report, Canada, Dept. of Forestry 17 (5)s 3-4. 1962. Field studies on attack flight and log selection by the ambrosia beetle Trypodendron lineatum (Oliv.)(Coleopteras Scolytidae) The Can. Ent. 2 4 ( 1 ) : 74-92.  1966. The effect of attack by the ambrosia beetle Trypodendron lineatum (Olivier) on log attractiveness. The Can. Ent. 9JS ( l ) : 50-59.  and J. M. Kinghorn. 1955. Flight trap studies of forest coleoptera and other insects with special reference to Trypodendron lineatum (Oliv.). Interim Report 1954-4, Forest Biology Laboratory, Canada, Dept. of Agriculture, Victoria, B.C. ; 1958. Studies of flight and attack activity of the ambrosia beetle Trypodendron lineatum (Oliv.) and other scolytids. The Can. Ent. 9J) (6)s 362-372. Chapman, J.A., S. H„ Farris and J. M. Kinghorn. 1963. Douglas-fir"sapwood starch i n relation to log attack by the ambrosia beetle Trypodendron. Forest Science 9_ ( 4 ) : 430-439. Christian, M. B. 1939. Experiments on the prevention of ambrosia beetle damage in hardwoods. Southern Lumberman 159 (2009)s 110-112. Dolley, W. L. 1929. Dark adaptation i n the eye of E r l s t a l i s tenax. Zool. 2s 483-489.  Physiol.  Dyer, E. D. A. 1963. Attack and brood production of ambrosia beetles i n logging debris. The Can. Ent. 9J> ( 6 ) : 624-631. 1964. Studies of ambrosia beetles in relation to felling date of"trees. Annual Report, Canada, Dept. of Forestry, Forest Entomology and Pathology Branch, March, p. 130. and J. A. Chapman. 1962. Brood productivity of ambrosia beetles in water-soaked logs. Bi-monthly Progress Report, Canada, Dept. of  Forestry 18 ( 5 ) s 3 .  1965. Flight and attack of the ambrosia beetle Trypodendron lineatum (Oliv.) i n relation to f e l l i n g date of logs. The Can. Ent. 9J7 (1): 42=57.  73  Dyer, E. D„ A. and J. M. Klnghorn. 1961. Factors influencing the distribution of overwintering ambrosia beetles, Trypodendron lineatum (Oliv.). The  Can.  Ent. 9J. ( 9 ) :  74-6-759.  Fisher, R. 0. and G. H. Thompson. 1952. Recent developments in the prevention of attack by ambrosia (pinhole bprer) beetles in standing trees and logs.' Sixth British Commonwealth Forestry Conference, Canada, August, 16 pp. Francia, F. C. 1965. Studies of some aspects of behaviour in the ambrosia beetle Trypodendron lineatum (Olivier). Doctor of Philosophy Thesis, University of British Columbia. Frisch, K. von.  1914. Der Farbensinn und Formansinn der Biene.  Physiol. 25_: 1-188.  Zool. Jahrb.,  Gara, R. I. 1963. Studies on the flight behaviour of Tps confusus (Lec.) (Coleoptera: Scolytidae) in response to attractive material. Contr. Boyce Thompson Inst. 22s 51-66. Gaumann, E. 1930. Untersuchungen uber den Einfluss der Fallungszeit auf die Eigenschaften des Fichten-und Tannenholzes. II. T e i l . Einfluss der Fallungszeit auf die'Dauerhaftigkeit des Flchten-und Tannenholzes. Beihefte zu den Zeitschriften des Schweiz. Forstvereins 6s 26-32. Buchler and Co., Bern. Goldsmith, T. H. 1961, The color vision of insects. In Light and Life. (V. D. McElroy and B. Glass, edd.) John Hopkins Prates, pp. 771-794-. Graham, K. 1959. Release by flight <exercise"of a chemotroplc response from photopositive domination in a scolytid beetle. Nature 184-s 283-284-. 1961. Air-swallowing: a mechanism of photic reversal of the beetle Trypodendron. Nature 19_i (4-787) s 519-520. 1962.  Unpublished data.  1966.  Personal communication.  and A. E." Werner. 1956. Chemical aspects:"of log selection by ambrosia"beetles. Unpublished Interim Report, Canada, Dept. of Agriculture, Forest Biology Division, March, 25 pp. Hadorn, C. 1933. Recherches sur l a morphologie, les stades evolutifs et l'hivernage du bostryche lisere (Xyloterus lineatus Oliv.). Supplement aux organes de l a Societe forestiere suisse. No. 1 1 . Hasselmann, E. M. 1962, Uberdie relative spektrale Empfindlichkeit von Kafer-und Schmetterlingsaugen bei verschiedenen Helligkeiten. Zool. Jahrb., Physiol. 69s 537-576. Hertz, M. 1938. New experiments on colour vision i n bees. 16:  1-8.  J . Exp. Biol.  Use, D. 1928.  Farbensinn der Tagfalter. ,Z. vergl. Physiol. 8s 658-692.  Jahn, T. L. 1946. The electroretinogram as a measure of wavelength sensitivity to light. J. N.Y. Ent. Soc. 54? 1-8. Johnson, N. E. 1961. Ambrosia"beetle attacks i n young-growth western hemlock. Bi-monthly Progress Report, Canada, Dept. of Forestry 17 (5)s 3. '  1964. Effects of different drying rates and two insecticides on beetle attacks in felled Douglas-fir and western hemlock. Weyerhauser Company Research Note No. 58 s, 16 pp.  Jones, T. I960. Ambrosia beetle research in West Africa. wealth Ent. Conference Report, pp. 88-97.  Seventh Common-  Kinghorn, J. M. 1956. Sapwood moisture in relation to Trypodendron attacks. Bi-monthly Progress Report, Canada, Dept. of Agriculture, Forest Biology Division 12 (5)s 3-4. •"' 1957. An induced differential bark-beetle attack. Bi-monthly Progress Report, Canada, Dept. of Agriculture, Forest Biology Division  _3  (2)s  3-4.  and J . A. Chapman. 1957. The effect of Douglas-fir log age oh attack by the ambrosia beetle Trypodendron lineatum (Oliv.). Ent. Soc. of B.C. Proc. __: 46-49. Kuhn, A. 1927.  Farbensinn der Bienen.  Z. vergl. Physiol. 5s 762-800.  Lutz, F . T E . I924. Apparent non-selective characters and combinations of characters" The colors of flowers and the vision of insects, with special reference to ultraviolet. Ann. N.Y. Acad. Sci. 29s 233-283. MacDougal, D. T., J. B. Overton and G. M. Smith". 1929. The hydrostatic-' pneumatic system of certain trees? Movement of liquids and gases. Carnegie Institution of Washington, Washington. Mathers, W. G. 1935. Time df felling In relation to Injury from ambrosia beetles or pinworms. B.C. Lumberman 12 (8)s 14. Mazokhin-Porshnyakov, G. A. 1964. Color vision in insects - study methods and the present state of our knowledge. Ent. Rev. 42 (3)s 257-266. Meyer, B. S., D. B. Anderson and R. L. Bohning. I 9 6 0 . Introduction to plant physiology. D. van Nostrand Company, Inc. Toronto. Nijolt, W. W. and J . A. Chapman. 1964. Uptake of water by the beetle Trypodendron following desiccation. Bi-monthly Progress Report, Canada, Dept. of Forestry 20 (6)s 3-4. Novak, V. I960. The striped wood-boring^beetle (ambrosia beetle) and the fight against i t . Statnf Zemelelske Nakladatelstvf, Prague.  75 Ohnesorge," B. 1953. Der Einfluss von Geruchs; und Geschmackstoffen auf die Wahl der Frasspflanzen biem grossen braunen Riisselkafer Hylobius abietis L. Bietrage zur Entomologie 3_s 437-468. Person, H. L . 1931. Theory in explanation of the selection of certain trees by the western pine beetle. J. Forestry 29696-699. Pertunnen, V. 1957. Reactions of two bark beetle species Hylurgops palliatus Gyll". and Hylastes ater Payk. (Coleopteras Scolytidae) to the terpene oC -pinene. Ann. Ent. Fenn. 23s 101-110. Prebble, M. L. and K. Graham! 1957. Studies of attack by ambrosia beetles"in softwood logs on Vancouver Island, British Columbia. Forest Science . 2: 90-112. Rudinsky, J7 A. 1966." Host selection and invasion by the Douglas-fir beetle Dendroctonus pseudotsugae Hopkins in coastal Douglas-fir forests. The Can. Ent. |8 (1); 98-111. ' and G. E, Daterman, 1964. Field studies on flight patterns and olfactory responses of ambrosia beetles in Douglas-fir forests of Western Oregon. The Can. Ent. 26 (10)s 1339-1352. Sander, W. 1933. Phototaktische Reaktionen der Bienen auf Llchter verscheidener Wellenlange. Z. vergl. Physiol. 20s 267-286. Scarth, G. W. 1930. Sinkage studies. IV. Themechanism of absorption of water by wood blocks. Can. J. Research 3_t 107-114. and E. C. Jahn. 1930. Sinkage studies. I. The mode of penetration of water i n logs: preliminary f i e l d experiments. Can. J. Research 2: 409-424. and R. D„ Bibbs. 1930. Sinkage studies. III. Changes in the water-gas system in 16gs during seasoning and flotation. Can J. Research 3_: 80-93. Schremmer, F. 1941. Zum Nachweis der Rot-blindheit von Vespa. Physiol. 28: 457-466.  Z. vergl.  Vite, J. P. and R. I. Gara. 1962. Volatile attractants from ponderosa pine by bark beetles (Coleopteras Scolytidae). Confer. Boyce Thompson Inst. 21 (5): 251-274. Walther, J. B. 1958. Changes induced in spectral sensitivity and form of retinal action potentials of the cockroach eye by selective adaptation.  J. Insect Physiol. 2: 142-151.  •  and E. Dodt. 1957. Elektrophysiologische Untersuchungen liber die Ultraviolettempfindlichkeit von Insektenaugen. Experientia J3 s 333-334.  76  Walther, J. B. and E. Dodt. 1959. "Die Spektralsehsitivitat von Ihsektenkomplexaugen im Ultraviolett bis 290 mu. Elektrophysiologische Untersuchungen an Calllphora und Periplaneta. Z. Naturf. 1J^> 273-278. Wellington, W. G., C. R. Sullivan and W. R. Hensen. 1954. Tne light reactions of larvae of the spotless Fall webworm"Hyphantria textor Harr. (Lepidiptera: Arctiidae). The Can. Ent. 86; 529-542. Wigglesworth, V. B. 1965. The Principles of Insect Physiology. 4th ed. Methuen and Co.Limited., 741 PP. Wood, D. L. and R. W. Bushing."1963. The olfactory response of Ips confusus (Leconte) (Col.; Scolytidae) to the secondary attractant in the laboratory. The Can. Ent. 25 (10): 1066-1077. Wright, R. H. 1966.  An insect olfactometer.  The Can. Ent. 22  (3):  282-285.  77  APPENDICES Appendix No. 1.  Page Graphs of responses of T. lineatum to varying wavelengths and intensities of monochromatic light. From these graphs, figures were derived at 10 per cent intervals for the range from 0 to 60 per cent positive response; these to be then correlated to an energy output of the monochromator Example graphs includes i 319 mu i i 348 mu i i i 543 mu  78  2.  Graphs derived by extrapolation of calibrations for the monochromator yielding relative energy output ratios by the tungsten filament for various wavelengths ............ 79 Example graphs includes i 319 mu i i 348 mji i i i 543 mu  3.  Cumulative weight loss data of Trypodendron adults with time and expressed as a percentage of the original weight .... SO Abbreviations: dry wt. = oven dry weight  4.  Summarized data of responses of two flight-inexperienced Trypodendron adults (No. 9 & 10) to the humid environment and tested for 'refractory' and 'reaction' times. Positive and negative responses have been included Abbreviations: RP = refractory period RT = reaction time (measured i n one-hundredth of a minute intervals)  %l  78  Appendix 1 i .  319 mu  0.9  I 0  . — — i  10  20  • —r— 30  40  1  50  1  60  —T-  70  1  80  Number o f b e e t l e s r e s p o n d i n g (%)  1  r  90  100  0  10  20  30  40  50  60-  70-  80  Number of beetles responding- (%)  90  100  Appendix 1 i i i .  543  Number of beetles responding {%)  79  Appendix 2 i . 319 mu  Monochromator.energy transmission values (%)  Appendix 2 i i . 348 mu 1.00  0.90  0.80  0.70 CQ  Xi  •p —I •rl  -p 0.60  0.32 - 25.0$  ca  0.41 - 43.0$  u  o  •s s  5 0.50 o o c o s  0.40  0.30  0.20  50  100  150  200  Monochromator energy transmission values ($)  250  543 mu  Monochromator energy t r a n s m i s s i o n v a l u e s  (%)  Per cent beetle,weight change from original weight with cumulative time (hours) Beetle No, P. o CD O O •H  in  CD Q  0  o tto  u  "8 o o  5.5  7.5  18.5  25.5  30.0  46.5  54.5  70.5  1 (if)  -9.48  -11.75  -40.22t  -62.83  -67.82  -69.01  -69.36  -69.98  2 (f)  -41.30+  -50.20  -65.57  -66.06  -65.81  ^65.46  -65.92  -66.34  3 (f)  -9.14  -12.20:  -34-98+  -58.62  -65.26  -66.46  -67.18  -67.38  4 (f)  -11.15  -13.85  -32.92 "  -47.26  -55.05  -70.35  -70.98  -71.35  5 (m)  -7.93  -11.17  -31.08*  -46.66  -54.72  -66.17  -66.46  -67.12  6 (m)  -20.50  -24.24  -48.93  -60.10  -66.10  -68.80  -68.46  -69.04  7 (f)  -0.19  +3.73  -1.79  -3.30  -7.53  -8.53*  -9.52  -13.55  -17.08  8 (f)  -0.63  +1.65  -2.66  -2.78  -3.76  -7.21  -12.34  -18.37*  -19.24  9 (f)  -4.20  -3.81  -6.70  -7.66  -13.84  -15.43  -19.56  -22.80  -22.80  10 .(f)  -1.27  -1.55  -3.68  -5.89  -8.19  -8.38  -9.02  -14.70  -15.50  11 (m)  -0.00  -0.73  -2.47  -5.52  -6.56  -7.56  f  -7.56  -9.17  -9.44  12 (m)  -3.73  -4.69  -8.60  -14.31  -15.94  -18.19  +  -18.31  -22.27  -24.37  1  +  1  •H  01  CD 13 I  n  78.5  7.5  22.5  27.5  31.5 -5.69'  (m)*  -2.51  •3.05  -4.48  14 (m)*  -0.38  -2.54  -4153  13  1  tweight established at f i r s t weighing after death of beetle 'N'data for two male beetles tested at a different time  92.0  -17.05  dry wt.  Appendix L, Beetle No* 9 Trial 1 2 3 4  5 6  Non-desiccated group (humid environment) 5:10 p.m. May 2 RP RT Response 31 12 22 28 39 18 t n 18  32 37  36  7  16  21 22 15  Total  213  164  6  Beetle No. 10 Trial 1 2 3 4 5  6  7 8  Total Beetle No. 10 Trial 1 2 3 4 5 6  7 8 Total Beetle No. 10 Trial 1  12  133  77  69  634  RP  4 7 9 2 1 2 1 1  + + + +  -  17 14 15 19 24 18 21 22  + + t +  +  a.m .May 3 RT Response 12 f 19 24 14 24 33 25 28  4 3 2 2 2  $ 1 8  +  •f + + +  179  p.,m. May 4 RT Response  + 36 + 69 30 23 + 23 20 • 4 118 + 31 350  9:40  RP  125 19 27 32 18 21 45 40 327  150  10:00  RP  25  9:30 p.m. May 5 RP RT Response  a.m..May 3 RT Response  11:10  27  199  Total  3 4 7 14 16 5 31 38  118  3:35 p.m. May 4 RT Response RP 1 22 11 15 2 28 + 11 18 + 8 29 + 26 16 + 20 24 + 8 37  7 8  6  +  274  47 119 154 154 110 34 76 71  3 4 5  t  5:15 p.m. May 2 RP RT Response f 100 12 + 5 12 3 17 5 16 A 28 8 18 i • 26 4 4 145  3 4 10 7 24 10 3 8  2  +  11:00  RP  p.m. May 3 RT Response 122 54 276 269 84 27 114 90  +  1036  p.m /May ; RT Response  10:00  RP  30 5 5 1 1 1 3 1  47  15 20 28 95 12  + + +  31 35  + +  23  +  259  a.m. May : RT Response  12:00  RP  1 2 2 7 2 7 7 3  31  50 27 26 35 36 30 32 29  265  + + + + +  •f  

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