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Mate selection in the threespine stickleback (Gasterosteus) Hay, Douglas Edward 1969

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M A T E S E L E C T I O N IN T H E T H R E E S P I N E STICKLEBACK  (Gasterosteus)  by  DOUGLAS EDWARD HAY B.Sc,  U n i v e r s i t y of B r i t i s h C o l u m b i a ,  A THESIS S U B M I T T E D  1966  IN P A R T I A L F U L F I L M E N T O F  THE REQUIREMENTS  FOR THEDEGREE OF  MASTER O F SCIENCE in the  Department of Zoology  W e a c c e p t t h i s t h e s i s a s c o n f o r m i n g to the required  standard  T H E UNIVERSITY  O F BRITISH  September,  1969  COLUMBIA  In  presenting  an  advanced  the 1  Library  further  for  degree shall  agree  scholarly  by  his  of  this  written  this  thesis  in p a r t i a l  fulfilment  at  University  of  the  make  tha  it  permission  purposes  may  representatives. thesis  for  for  It  financial  is  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, Canada  3>£>  by  the  understood  gain  Columbia  for  extensive  be g r a n t e d  shall  the  requirements  B r i t i s h Columbia,  available  permission.  Department  Date  freely  of  copying Head o f  that  not  reference  be  of  I agree and this  or  allowed  without  that  study. thesis  my D e p a r t m e n t  copying  for  or  publication my  ii  ABSTRACT  T h e threespine stickleback (Gasterosteus aculeatus L . ) is a highly v a r i e d a n d w i d e l y d i s t r i b u t e d s p e c i e s of s m a l l f i s h . t h e r e a r e two d i s t i n c t f o r m s .  T h r o u g h o u t m o s t of i t s r a n g e  O n e f o r m ( t r a c h u r u s ) i s a n a d r o m o u s a n d the  other f o r m (leiurus) is sedentary and l i v e s e n t i r e l y i n f r e s h ' w a t e r .  H a g e n (1967) c o n c l u d e d that t h e s e two f o r m s w e r e r e p r o d u c t i v e l y i s o l a t e d a n d that b o t h l e i u r u s a n d t r a c h u r u s s h o u l d b e c o n s i d e r e d a s  species.  H a g e n ' s c o n c l u s i o n w a s b a s e d o n d i f f e r e n c e s he f o u n d i n e c o l o g i c a l h a b i t a t s , breeding times,  a n d the a p p a r e n t a b s e n c e . o f i n t r o g r e s s i o n b e t w e e n , l e i u r u s  and t r a c h u r u s .  T h e p u r p o s e o f t h i s study w a s to d e t e r m i n e if e t h o l o g i c a l f a c t o r s o r mate  s e l e c t i o n c o n t r i b u t e to r e p r o d u c t i v e i s o l a t i o n .  Mate selection tests  w e r e c o n d u c t e d i n w h i c h (1) c o u r t i n g m a l e s w e r e s i m u l t a n e o u s l y e x p o s e d to receptive females  of b o t h t y p e s ,  a n d (2) r e c e p t i v e f e m a l e s  e x p o s e d to b o t h t y p e s of c o u r t i n g m a l e s .  were  simultaneously  T h e r e s u l t s of b o t h t h e s e t e s t s  c l e a r l y d e m o n s t r a t e that m a t i n g s b e t w e e n s i m i l a r p h e n o t y p e s  occur  s i g n i f i c a n t l y m o r e often t h a n m a t i n g s b e t w e e n d i s s i m i l a r p h e n o t y p e s .  A d d i t i o n a l e x p e r i m e n t s a t t e m p t to d o c u m e n t the s p e c i f i c b e h a v i o u r a l m e c h a n i s m s r e s p o n s i b l e for mate selectivity. females,  a n d f e m a l e s to m a l e s ,  f o u n d to o r i e n t , phenotype.  T h e o r i e n t a t i o n of m a l e s to  was o b s e r v e d and quantified.  o r d i r e c t m o s t of t h e i r c o u r t s h i p , to f e m a l e s  Males were of t h e i r o w n  F e m a l e s a l s o t e n d e d to o r i e n t to m a l e s of t h e i r own p h e n o t y p e .  C e r t a i n b e h a v i o u r a l patterns  of m a l e c o u r t s h i p w e r e q u a n t i f i e d a n d  c o m p a r e d between l e i u r u s and t r a c h u r u s . i n a n u m b e r of c o u r t s h i p a c t i v i t i e s :  Significant differences  w e r e found  leiurus m a l e s p e r f o r m significantly  z i g - z a g s p e r minute than t r a c h u r u s m a l e s , l e i u r u s m a l e s is u s u a l l y a z i g - z a g ' w h i l e  more  the f i r s t c o u r t s h i p r e s p o n s e of  the f i r s t r e s p o n s e of t r a c h u r u s  m a l e s is usually a bite.  N o n - r a n d o m mating between l e i u r u s and t r a c h u r u s m a y g r e a t l y to t h e i r r e p r o d u c t i v e i s o l a t i o n . be e x p l a i n e d by difference during courtship.  contribute  N o n - r a n d o m or s e l e c t i v e m a t i n g  i n b e h a v i o u r b e t w e e n the two f o r m s ,  may  particularly  iv  TABLE  O F CONTENTS Page  TITLE PAGE  1  ABSTRACT  ii  T A B L E O F CONTENTS  .'  iv  LIST O F FIGURES  v  LIST O F T A B L E S  v  LIST O F A P P E N D I C E S  i  i  i  i  i  x  I.  INTRODUCTION  1  II.  METHODS AND MATERIALS  4  1.  The Collecting A r e a s  4  2.  T h e T i m e s of C o l l e c t i o n s  4  3.  T h e M a i n t e n a n c e of L a b o r a t o r y F i s h  6  4.  The Experimental Tanks  6  EXPERIMENTS AND RESULTS  9  III.  1.  C h o i c e of m a l e s b y f e m a l e s  9  a)  Females  ii  b)  Males  H  c)  T h e c r i t e r i o n of c h o i c e  13  d)  T h e r e p e t i t i v e u s e of the s a m e f e m a l e s  14  e)  T h e testing p r o c e d u r e  15  f)  R e s u l t s of the f e m a l e p r e f e r e n c e t e s t s  17  i)  C o m p a r i s o n of i n d i v i d u a l s f e m a l e s of the s a m e phenotype  ii)  2.  17  T h e r e s u l t s of r e p e t i t i v e t e s t s  17  iii)  T h e u s e of d i f f e r e n t m a l e p a i r s  20  iv)  F e m a l e mate preference  22  Choice by males  23  a)  T h e e x p e r i m e n t a l design and testing p r o c e d u r e  23  b)  Results  3. F e m a l e O r i e n t a t i o n T e s t s  24 •  26  a)  E x p e r i m e n t a l design and testing p r o c e d u r e  26  b)  Results  28  4. M a l e O r i e n t a t i o n T e s t s  33  a)  E x p e r i m e n t a l design and testing p r o c e d u r e  33  b)  Results  3  5  Page 5. Q u a n t i t a t i v e C o m p a r i s o n s of C o u r t s h i p A c t i v i t i e s a) T h e o b s e r v a t i o n s b) T h e t y p e s of b e h a v i o u r e x a m i n e d i)  40 40 41  T h e z i g - z a g dance  41  Aggressive behaviour  41  iii)  Fanning during courtship  42  iv)  O t h e r b e h a v i o u r p a t t e r n s a s s o c i a t e d w i t h the n e s t . . .  43  T h e f i r s t r e s p o n s e of m a l e s  44  ii)  v) c)  T h e r a t i o n a l e of the s t a t i s t i c a l t e s t s  44  d)  Results  4  i)  T h e n u m b e r of z i g - z a g b o u t s p e r m i n u t e  48  T h e n u m b e r of z i g - z a g s p e r b o u t  48  iii)  T h e n u m b e r of z i g - z a g s p e r m i n u t e  48  iv)  T h e n u m b e r of b i t e s p e r m i n u t e  49  ii)  v) vi) vii) viii) ix)  T h e n u m b e r of s e c o n d s f a n n i n g p e r m i n u t e  51  T h e n u m b e r of f a n n i n g b o u t s p e r m i n u t e  51  T h e n u m b e r of g l u i n g m o t i o n s p e r m i n u t e  51  C r e e p i n g t h r o u g h the n e s t  51  T h e f i r s t r e s p o n s e of m a l e s  51  IV.  DISCUSSION  V.  CONCLUSIONS  5  APPENDIX  3  65  ACKNOWLEDGMENTS REFERENCES  6  67 '.  68 71  vi  LIST O F F I G U R E S FIGURE 1  Page T h e L i t t l e C a m p b e l l R i v e r s h o w i n g a r e a s of l e i u r u s a n d trachurus collections  5  B r e e d i n g s e a s o n s f o r the r a c e s of s t i c k l e b a c k i n the L i t t l e C a m p b e l l R i v e r - i n 1964  7  3  T h e d e s i g n a n d d i m e n s i o n s of the e x p e r i m e n t a l t a n k s  8  4  T h e i n t e r i o r d e s i g n of the e x p e r i m e n t a l t a n k s s h o w i n g n e s t i n g  2  t r a y s a n d p o s i t i o n s of g r a v e l 5  A r r a n g e m e n t of e x p e r i m e n t a l t a n k s f o r f e m a l e c h o i c e t e s t s . The  6  10  s h a d e d a r e a r e p r e s e n t s r e g i o n of t e r r i t o r i a l c o n f l i c t s  A r r a n g e m e n t of e x p e r i m e n t a l t a n k s f o r f e m a l e o r i e n t a t i o n tests showing m a l e and f e m a l e e n c l o s u r e a r e a s  7  16  R e s u l t s of f e m a l e o r i e n t a t i o n t e s t s .  29  T h e n u m b e r of o b s e r v a -  t i o n s m a d e w h i l e a l e i u r u s f e m a l e w a s o r i e n t e d to a l e i u r u s m a l e ( o r d i n a t e ) i s c o m p a r e d to the n u m b e r of o b s e r v a t i o n s m a d e w h i l e a t r a c h u r u s f e m a l e w a s o r i e n t e d to a t r a c h u r u s male (abscissa).  8  9  32  T h e e x p e r i m e n t a l d e s i g n f o r the m a l e o r i e n t a t i o n t e s t s . T h e f i r s t 15 m i n u t e o b s e r v a t i o n w a s c o n d u c t e d w h i l e the f e m a l e s w e r e i n the p o s i t i o n s s h o w n i n e i t h e r (a) o r (b). T h e s e c o n d o b s e r v a t i o n p e r i o d was c o n d u c t e d w h e n the f e m a l e s w e r e i n opposite positions  34  R e s u l t s of the m a l e o r i e n t a t i o n t e s t s . T h e n u m b e r of o b s e r v a tions m a d e while a m a l e was c o u r t i n g a l e i u r u s f e m a l e ( o r d i n a t e ) i s c o m p a r e d to the n u m b e r of o b s e r v a t i o n s m a d e while courting a t r a c h u r u s female (abscissa). Results which a r e e i t h e r a b o v e o r b e l o w the d o t t e d l i n e s s h o w s i g n i f i c a n t (p  10  T h e d o t t e d l i n e s r e p r e s e n t the 5% s i g n i f i -  cance levels determined by chi squares  (a)  .0 5) d e v i a t i o n f r o m r a n d o m n e s s  39  T h e n u m b e r of z i g - z a g b o u t s p e r m i n u t e i s c o n t r a s t e d a g a i n s t the n u m b e r of z i g - z a g s p e r b o u t f o r l e i u r u s m a l e s ,  (b)  T h e n u m b e r of z i g - z a g b o u t s p e r m i n u t e i s c o n t r a s t e d a g a i n s t the n u m b e r of z i g - z a g s p e r bout f o r t r a c h u r u s males  50  vii  FIGURE 11  Page C o n t r a s t of m e a n v a l u e s f o r v a r i o u s b e h a v i o u r a l  reactions  between l e i u r u s and t r a c h u r u s m a l e s with l e i u r u s and trachurus females  52  viii  LIST O F T A B L E S TABLE  Page  I  Results  of the m a t e s e l e c t i o n t e s t s w i t h l e i u r u s f e m a l e s  18  II  Results  of the m a t e s e l e c t i o n t e s t s w i t h t r a c h u r u s f e m a l e s  19  III  A c o m p a r i s o n of c o r r e c t a n d i n c o r r e c t c h o i c e s b e t w e e n successive trials  IV  21  A c o m p a r i s o n of c o r r e c t a n d i n c o r r e c t c h o i c e s b e t w e e n s e v e n d i f f e r e n t p a i r s of l e i u r u s a n d t r a c h u r u s m a l e s  21  V  Results  of p r e f e r e n c e t e s t s f o r l e i u r u s m a l e s  25  VI  Results  of p r e f e r e n c e t e s t s f o r t r a c h u r u s m a l e s  25  VII  VIII IX  C o n t i n g e n c y t a b l e of the m a l e p h e n o t y p e a n d the n u m b e r of t i m e s f e m a l e s of e a c h p h e n o t y p e w e r e c h o s e n  26  Results  30  of the f e m a l e  orientation tests  Positions and activities  of m a l e s d u r i n g o r i e n t a t i o n t e s t s  35  X  Results  of o r i e n t a t i o n t e s t s o n l e i u r u s m a l e s  37  XI  Results  of o r i e n t a t i o n t e s t s o n t r a c h u r u s m a l e s  38  XII  Results  of the c o m p a r i s o n of c o u r t s h i p b e h a v i o u r b e t w e e n  l e i u r u s and t r a c h u r u s m a l e s using l e i u r u s and t r a c h u r u s females  ^  ix APPENDIX Page I  T h e a v e r a g e n u m b e r of z i g - z a g b o u t s p e r m i n u t e  obtained  with l e i u r u s and t r a c h u r u s m a l e s using l e i u r u s and  II  III  IV  V  VI  trachurus females  71  T h e a v e r a g e n u m b e r of z i g - z a g s p e r bout o b t a i n e d w i t h l e i u r u s a n d t r a c h u r u s m a l e s u s i n g l e i u r u s and t r a c h u r u s f e m a l e s  72  T h e a v e r a g e n u m b e r of z i g - z a g s p e r m i n u t e o b t a i n e d w i t h l e i u r u s and t r a c h u r u s m a l e s using l e i u r u s and t r a c h u r u s females  73  T h e a v e r a g e n u m b e r of b i t e s p e r m i n u t e o b t a i n e d w i t h l e i u r u s and t r a c h u r u s m a l e s u s i n g l e i u r u s and t r a c h u r u s f e m a l e s  74  T h e a v e r a g e n u m b e r of s e c o n d f a n n i n g p e r m i n u t e o b t a i n e d with l e i u r u s and t r a c h u r u s m a l e s using l e i u r u s and t r a c h u r u s females ,  75  T h e a v e r a g e n u m b e r of f a n n i n g b o u t s p e r m i n u t e o b t a i n e d w i t h l e i u r u s and t r a c h u r u s m a l e s u s i n g l e i u r u s and t r a c h u r u s females  VII  T h e a v e r a g e n u m b e r of g l u i n g m o v e m e n t s p e r m i n u t e  76 obtained  with l e i u r u s and t r a c h u r u s m a l e s using l e i u r u s and t r a c h u r u s  VIII  IX  females  77  T h e i n c i d e n c e of " c r a w l i n g t h r o u g h " n e s t s d u r i n g c o u r t s h i p by l e i u r u s and t r a c h u r u s m a l e s using l e i u r u s and t r a c h u r u s females  78  T h e f i r s t c o u r t s h i p r e s p o n s e of l e i u r u s a n d t r a c h u r u s m a l e s using l e i u r u s and t r a c h u r u s f e m a l e s  78  I.  The  threespine  INTRODUCTION  stickleback (Gasterosteus  aculeatus L . ) is an abundant  a n d w i d e l y d i s t r i b u t e d s p e c i e s of s m a l l f i s h i n the m a r i n e a n d f r e s h w a t e r coastal areas  of the n o r t h e r n h e m i s p h e r e .  T h r o u g h o u t m o s t of i t s  two f o r m s o c c u r w h i c h a r e p r e s e n t l y r e c o g n i z e d a s s u b s p e c i e s . species (Gasterosteus (G. aculeatus The  aculeatus aculeatus)  microcephalus) is  total body size,  the s p i n e l e n g t h s ,  the f i n r a y n u m b e r s ,  w i t h the n o n - a n a d r o m o u s f o r m b e i n g s o m e w h a t  stenohaline  the g i l l r a k e r  and salinity (Heuts,  M u n z i n g (1963) a n d H a g e n (1967),  m a n y of the d i f f e r e n c e s b e t w e e n the two f o r m s a r e g e n e t i c a l l y  Ecologically,  tolerance  1947).  showed  R i v e r in B r i t i s h Columbia,  for  In a study of the L i t t l e C a m p b e l l  h e f o u n d that the a n a d r o m o u s s u b s p e c i e s n e s t s  i n a r e a s f a i r l y c l o s e to the m o u t h of the r i v e r a n d that t h e y p e n e t r a t e short distance upstream.  that  determined.  H a g e n (1967) f o u n d that the two s u b s p e c i e s b r e e d ,  the m o s t p a r t , i n quite d i f f e r e n t h a b i t a t s .  as:  a n d the v e r t e b r a l n u m b e r . 1967),  w o r k of L i n d s e y (1962),  water.  colour and  M o r p h o l o g i c a l l y they d i f f e r i n s u c h c h a r a c t e r s  P h y s i o l o g i c a l l y they differ i n fecundity (Hagen,  The  other  sedentary and l i v e s a l l its life i n f r e s h  the n u m b e r of b o n y s c a l e s o r s c u t e s o n the s i d e of the b o d y , number,  One sub-  i s a n a d r o m o u s w h i l e the  two s u b s p e c i e s d i f f e r f r o m e a c h o t h e r i n :  general physiognomy.  range  only a  The non-anadromous subspecies occupied virtually  a l l the r e m a i n i n g s u i t a b l e b r e e d i n g a r e a s , a r e a s o c c u p i e d b y the a n a d r o m o u s f i s h .  f r o m the h e a d w a t e r s  d o w n to the  2  D u r i n g the b r e e d i n g s e a s o n the r a n g e s of the two s u b s p e c i e s a n d a n u m b e r of m o r p h o l o g i c a l l y i n t e r m e d i a t e f i s h a r e p r o d u c e d . morphological intermediates,  or 'hybrids',  f a i r l y n a r r o w z o n e w i t h i n the r i v e r .  overlap These  a p p e a r to be r e s t r i c t e d to a  A l t h o u g h H a g e n c o u l d f i n d no  evidence  of h y b r i d i n v i a b i l i t y or i n f e r i o r i t y , he n e v e r t h e l e s s c o n c l u d e d t h a t h y b r i d i z a t i o n w a s not l e a d i n g to the m u t u a l i n t r o g r e s s i o n of the two p a r e n t a l p h e n o types.  H e n c e he c o n c l u d e d that the two s u b s p e c i e s w e r e ,  i n effect,  repro-  d u c t i v e l y i s o l a t e d f r o m one a n o t h e r a n d s h o u l d p r o b a b l y be r e g a r d e d as distinct  species.  This  study i s c o n c e r n e d w i t h the p o s s i b i l i t y that m a t e  selection,  r e s u l t i n g i n n o n - r a n d o m m a t i n g b e t w e e n the two f o r m s i n a r e a s of s y m p a t r y , i s one m e a n s  of r e d u c i n g the extent of h y b r i d i z a t i o n a n d thus c o n t r i b u t i n g to  reproductive isolation.  Also,  certain ethological differences  two f o r m s w e r e e x a m i n e d as p o s s i b l e  c a u s a l factors in mate  b e t w e e n the selection.  A d i f f i c u l t y w i t h r e s p e c t to the n o m e n c l a t u r e of the two f o r m s i s taxonomic  status.  their  I m p l i c i t i n a n y study of r e p r o d u c t i v e i s o l a t i o n i s that the  two g r o u p s of o r g a n i s m s c o n c e r n e d a r e s o m e t h i n g m o r e t h a n s u b s p e c i e s . A f t e r d o c u m e n t i n g s o m e of the i s o l a t i n g m e c h a n i s m s b e t w e e n the two f o r m s , H a g e n (1967) s u g g e s t e d that b o t h the s u b s p e c i e s be e l e v a t e d to s p e c i f i c  status.  O n the b a s i s of a p r e c e d e n t e s t a b l i s h e d i n the e a r l y t a x o n o m i c l i t e r a t u r e he a d v o c a t e d the n a m e of G a s t e r o s t e u s  l e i u r u s for G . aculeatus  (the s e d e n t a r y fish) a n d G a s t e r o s t e u s (the a n a d r o m o u s f i s h ) .  However,  microcephalus  t r a c h u r u s f o r CL a c u l e a t u s  aculeatus  M i l l e r a n d H u b b s (1969) d i s a g r e e w i t h b o t h  3  H a g e n ' s i n t e r p r e t a t i o n of r e p r o d u c t i v e i s o l a t i o n w i t h i n G a s t e r o s t e u s a n d h i s p r o p o s e d changes in n o m e n c l a t u r e .  T h e y s u g g e s t the r e t e n t i o n of the  b l i s h e d s p e c i f i c and s u b s p e c i f i c n a m e s . names leiurus and trachurus are used, (1966) e m p l o y s t h e m ,  esta-  F o r c o n v e n i e n c e i n t h i s study,  the  but i n the s a m e m a n n e r that P e n c z a k  a n d that i s "as t e m p o r a r y c o n v e n t i o n a l s y m b o l s ,  h a v i n g n o t h i n g to do w i t h z o o l o g i c a l n o m e n c l a t u r e . "  A f t e r a n e x t e n s i v e s t u d y of i s o l a t i n g m e c h a n i s m s b e t w e e n t h e  same  p o p u l a t i o n s of s t i c k l e b a c k s that t h i s s t u d y d e a l s w i t h , H a g e n (1967) c o n c l u d e d that e t h o l o g i c a l i s o l a t i o n w a s e s s e n t i a l l y n o n - e x i s t e n t . i n t e n d e d to take i s s u e w i t h H a g e n ' s c o n c l u s i o n s ,  I n i t i a l l y it w a s not  and some  preliminary  e x p e r i m e n t s w e r e s t a r t e d to t r y a n d e s t a b l i s h w h a t p a r t i c u l a r a s p e c t s of the e n v i r o n m e n t w e r e m o s t i m p o r t a n t f o r e c o l o g i c a l i s o l a t i o n or h a b i t a t  selection.  D u r i n g the c o u r s e of t h e s e e x p e r i m e n t s it w a s o b s e r v e d that t e r r i t o r i a l m a l e s t e n d e d to s e l e c t i v e l y  c o u r t females.of s i m i l a r phenotypes.  s o m e a s p e c t s of t h e i r c o u r t s h i p s s e e m e d to d i f f e r . observations,  Furthermore,  F r o m these and other  it a p p e a r e d that a r e - e x a m i n a t i o n of e t h o l o g i c a l i s o l a t i o n  b e t w e e n l e i u r u s a n d t r a c h u r u s m i g h t be p r o f i t a b l e .  F i v e d i f f e r e n t s e r i e s of e x p e r i m e n t s w e r e c o n d u c t e d i n t h i s s t u d y . f i r s t two e x p e r i m e n t s : f e m a l e s by m a l e s ,  (1) a c h o i c e of m a l e s b y f e m a l e s ,  The  a n d (2) a c h o i c e of  are c o n c e r n e d with demonstrating mate selection or a  d e p a r t u r e f r o m r a n d o m m a t i n g b y b o t h s e x e s of b o t h p h e n o t y p e s . remaining experiments: o r i e n t a t i o n to m a l e s ,  (3) m a l e o r i e n t a t i o n to f e m a l e s ,  (4)  The  female  a n d (5) e t h o l o g i c a l d i f f e r e n c e s b e t w e e n m a l e  phenotypes  during courtship, for  mate  The  a r e a t t e m p t s to e l u c i d a t e  s o m e of the f a c t o r s  selection.  general methodology  a n d a d i s c u s s i o n of c e r t a i n f a c t o r s u n i q u e to  e a c h e x p e r i m e n t a r e c o n s i d e r e d p r i o r to the p r e s e n t a t i o n of  II.  1.  responsible  results.  METHODS AND MATERIALS  The Collecting A r e a s  Figure  1 s h o w s the L i t t l e C a m p b e l l R i v e r a n d the a p p r o x i m a t e  occupied by leiurus,  t r a c h u r u s a n d the i n t e r m e d i a t e ,  or h y b r i d ,  a r r o w s r e f e r to the two l o c a t i o n s w h e r e m y c o l l e c t i o n s  forms.  were made:  w e r e c o l l e c t e d i n a n a r e a i m m e d i a t e l y a d j a c e n t to H a g e n ' s " h y b r i d l e i u r u s w e r e c o l l e c t e d i n a n a r e a a b o u t 10 k m u p s t r e a m . the t r a c h u r u s c o l l e c t i o n s , a n i m a l s w e r e not u s e d i n  B a s e d on H a g e n ' s  zone",  Occasionally,  the n u m b e r of l a t e r a l p l a t e s i s u s e d as  P l a t e c o u n t s of 3 to 7 a r e d i a g n o s t i c f o r l e i u r u s ,  2.  trachurus  in  experiments.  study,  for t r a c h u r u s ,  The  s o m e l e i u r u s and h y b r i d types o c c u r r e d , but such  b e s t s i n g l e c r i t e r i o n to d i s t i n g u i s h b e t w e e n l e i u r u s ,  diagnostic  areas  and i n t e r m e d i a t e  the  t r a c h u r u s and h y b r i d s .  c o u n t s of 30 o r m o r e  are  n u m b e r s a r e u n i q u e to h y b r i d s .  T i m e s of C o l l e c t i o n s  H a g e n i n d i c a t e s that t h e r e i s a t e m p o r a l d i f f e r e n c e between l e i u r u s and t r a c h u r u s .  in breeding  seasons  M o s t l e i u r u s b r e e d f r o m e a r l y M a r c h to the  e n d of M a y but a s m a l l p r o p o r t i o n of the p o p u l a t i o n c o n t i n u e s b r e e d i n g  into  5  FIGURE  1.  T h e L i t t l e C a m p b e l l R i v e r s h o w i n g a r e a s of l e i u r u s and t r a c h u r u s f r o m F i g . 1, H a g e n ,  collections 1967).  (adapted  6  July. (Fig.  T r a c h u r u s starts b r e e d i n g i n late M a y and continues until late A u g u s t  2). D u r i n g 1968 c o l l e c t i o n s w e r e m a d e i n M a y a n d J u n e so that s o m e i n d i v i -  d u a l s of b o t h l e i u r u s a n d t r a c h u r u s w e r e i n b r e e d i n g c o n d i t i o n w h e n c a p t u r e d . In 1969.  collections  were made p r i m a r i l y i n F e b r u a r y and e a r l y M a r c h .  The  e x p e r i m e n t a l a n i m a l s (both l e i u r u s a n d t r a c h u r u s ) w e r e a r t i f i c i a l l y b r o u g h t i n t o b r e e d i n g c o n d i t i o n i n the l a b o r a t o r y by m a n i p u l a t i n g l i g h t a n d t e m p e r a t u r e .  3.  M a i n t e n a n c e of L a b o r a t o r y  Fish  B o t h l e i u r u s and t r a c h u r u s w e r e p l a c e d i n l a b o r a t o r y conditions diately after capture. constantly aerated,  imme-  T h e f i s h w e r e p l a c e d i n 10 g a l l o n g l a s s a q u a r i a w i t h  dechlprinated water.  T h e photo p e r i o d w a s  (16 h o u r s of l i g h t a n d 8 h o u r s of d a r k n e s s ) . o  Water temperatures  16 h o u r s fluctuated  o  b e t w e e n 15 C (at night) to 20 C ( m i d - d a y ) .  F o l l o w i n g the m e a s u r e m e n t s  of  B e u k e m a (1966), the f i s h w e r e fed l i v e T u b i f e x w o r m s d a i l y i n q u a n t i t i e s r o u g h l y p r o p o r t i o n a l to 10 p e r c e n t of t h e i r b o d y 4.  weight.  The Experimental Tanks  E i g h t s p e c i a l l y d e s i g n e d and c o n s t r u c t e d tanks w e r e u s e d for a l l experiments.  E a c h tank w a s  c o n s t r u c t e d of h e a v y (7/8 inch) p l y w o o d a n d a  s i n g l e p i e c e of 1/4 i n c h p l a t e g l a s s . sions is  s h o w n i n F i g u r e 3.  g a l l o n s (142  liters).  A d i a g r a m of one tank w i t h the d i m e n -  T h e s e t a n k s h a d a c a p a c i t y of 30 I m p e r i a l  7  F I G U R E 2.  Breeding  s e a s o n s f o r the r a c e s of  sticklebacks  i n the L i t t l e C a m p b e l l R i v e r i n 1964 Hagen,  1967).  (from F i g .  13,  NUMBER OF FISH PER AVERMGE SEINE HAUL  \  FIGURE  3.  T h e d e s i g n a n d d i m e n s i o n s of the e x p e r i m e n t a l tank s.  9  The fiberglass  i n t e r i o r of e a c h tank w a s s e a l e d a n d c o a t e d w i t h a n o n - t o x i c r e s i n containing a q u a - g r e e n coloured pigment.  E a c h tank could  b e d i v i d e d into two s e p a r a t e a r e a s b y m e a n s of a p a r t i a l w o o d e n d i v i d e r and a d d i t i o n a l opaque o r t r a n s p a r e n t d i v i d e r s .  L i g h t was p r o v i d e d by a  single  " c o o l w h i t e " G e n e r a l E l e c t r i c f l u o r e s c e n t l a m p set to the s a m e p h o t o p e r i o d (16 h o u r s ) a s the h o l d i n g a q u a r i a .  Also,  the t e m p e r a t u r e f l u c t u a t i o n s  were  s i m i l a r to that of the h o l d i n g a q u a r i a .  F o r nesting purposes,  e a c h h a l f of the e x p e r i m e n t a l t a n k s w a s p r o v i d e d  w i t h a s m a l l " n e s t i n g t r a y " m a d e b y m o d i f y i n g an a l u m i n u m p i e p l a t e i n t o a semicircular container.  A n e s t i n g t r a y ( f i l l e d w i t h s a n d a n d mud) was p l a c e d  a g a i n s t the r e a r w a l l of e a c h h a l f of the tank so that t h e y w e r e a p p r o x i m a t e l y e q u i d i s t a n t f r o m the m i d d l e a n d the s i d e s .  T o discourage nest building in  o t h e r a r e a s g r a v e l w a s p l a c e d i n the c o r n e r s a n d a l o n g the s i d e s . s h o w s the p o s i t i o n s  of t h e n e s t i n g t r a y s a n d the g r a v e l .  Figure 4  Nesting material,  c o n s i s t i n g of a s s o r t e d a q u a t i c v e g e t a t i o n f r o m the L i t t l e C a m p b e l l R i v e r d i s t r i b u t e d u n i f o r m l y a l o n g the f l o o r s of the t a n k s .  III.  1.  A c h o i c e bf m a l e s by  These experiments  EXPERIMENTS AND RESULTS  females.  w e r e d e s i g n e d to d e t e r m i n e w h e t h e r l e i u r u s a n d  t r a c h u r u s f e m a l e s t e n d to c h o o s e m a t e s of t h e i r p h e n o t y p e s choice.  when given a  was  F I G U R E 4.  T h e i n t e r i o r d e s i g n of the e x p e r i m e n t a l t a n k s h o w i n g n e s t i n g t r a y s a n d p o s i t i o n s of g r a v e  LOOSE  TING TRAYS,  (FILLED WITH  GRAVEL NESTING MATERIAL (VARIOUS KINDS OF AQUATIC  REMOVABLE  PARTITION  (OPAQUE OR 'GLASS FRONT OF TANK  VEGETATION)  TRANSPARENT)  a)  Females. A t o t a l of 69 f e m a l e s  trachurus.  E a c h female,  were u s e d in these tests: b e f o r e the c h o i c e test,  32 l e i u r u s a n d 37  was p r e - t e s t e d with a  s o l i t a r y m a l e to e n s u r e h e r r e c e p t i v i t y to m a l e c o u r t s h i p .  If a f e m a l e  d i d l n o t r e s p o n d to m a l e c o u r t s h i p b y d i s p l a y i n g the c h a r a c t e r i s t i c "head-up" movements  and "following" b e h a v i o u r ( T i n b e r g e n ,  1951),  she  w a s not u s e d f o r the c h o i c e t e s t .  b)  Males.  A t o t a l of s e v e n d i f f e r e n t p a i r s of l e i u r u s a n d t r a c h u r u s m a l e s w e r e u s e d f o r the c h o i c e t e s t s .  Initially,  e a c h m e m b e r of a p a i r  p l a c e d o n s e p a r a t e s i d e s of the e x p e r i m e n t a l t a n k s , an opaque d i v i d e r .  the  A t this point v i g o r o u s fighting a l w a y s  a n d u s u a l l y a f t e r s e v e r a l m i n u t e s of c o n t i n u o u s c o m b a t one  male became aggressive  and separated by  After both m a l e s completed nest construction,  opaque d i v i d e r was r e m o v e d . occurred,  was  completely dominant.  T h e subordinate male halted a l l  a c t i o n s a n d s w a m s l o w l y n e a r the s u r f a c e .  Murkensturm  (1966) d e s c r i b e d t h i s p o s i t i o n a s c h a r a c t e r i s t i c of s u b o r d i n a t e  males.  T h e i n i t i a l m u t u a l a g g r e s s i v e n e s s of the m a l e s m a k e it d i f f i c u l t to e s t a b l i s h two c o e x i s t i n g m a l e s of d i f f e r e n t p h e n o t y p e s i n the tank.  same  T h e s e v e n m a l e p a i r s r e p r e s e n t l e s s t h a n o n e - h a l f of a l l the  p a i r s of m a l e s a t t e m p t e d .  E v e n a m o n g the f i n a l s e v e n p a i r s c o e x i s t e n c e  w a s not a l w a y s s t a b l e a n d d e t e r i o r a t e d w i t h t i m e .  O n l y two p a i r s w e r e  12  a b l e to e s t a b l i s h a n d m a i n t a i n s t a b l e t e r r i t o r i a l b o u n d a r i e s w h e n the partitions were removed, (established  territorial boundaries were  u s u a l l y at the m i d d l e o r c l o s e to the m i d d l e of the t a n k ) . i n a n u m b e r of w a y s , pairs.  B y intervening  c o e x i s t e n c e was e s t a b l i s h e d i n five other  I n t e r v e n t i o n i n c l u d e d a n u m b e r of f a c t o r s :  male  (1) c l i p p i n g the  s h a r p e d g e s off the p e l v i c s p i n e s of d o m i n a n t m a l e s ;  (2) s e p a r a t i n g  two  i n c o m p a t i b l e m a l e s w i t h t r a n s p a r e n t d i v i d e r s f o r s e v e r a l d a y s so that they c o u l d see e a c h o t h e r but c o u l d not fight; (3) i n t r o d u c i n g a n o t h e r m a l e to b o t h h a l v e s of the t a n k .  In the l a t t e r c a s e ,  new m a l e s  placed  i n a tank with a t e r r i t o r i a l m a l e i n v a r i a b l y a s s u m e d a subordinate p o s i t i o n and w e r e frequently attacked.  W h e n the p a r t i t i o n w a s the  removed  again,  a l l o w i n g p h y s i c a l contact between a l l four m a l e s ,  nest-owning  males  s p e n t m o s t of t h e i r t i m e c h a s i n g the s u b o r d i n a t e s a w a y f r o m t h e i r  immediate nest a r e a .  In t h i s way,  the t e r r i t o r i a l m a l e s .  A n y s u b o r d i n a t e m a l e s w e r e r e m o v e d p r i o r to  the f e m a l e  choice tests.  the c h o i c e t e s t s ,  fighting was g r e a t l y r e d u c e d between  B e f o r e two c o e x i s t i n g m a l e s w e r e u s e d i n  t h e y w e r e s e p a r a t e d b r i e f l y (with a n opaque d i v i d e r )  a n d e x a m i n e d for c o u r t s h i p b e h a v i o u r b y p r e s e n t i n g e a c h w i t h a g r a v i d female.  Their readiness  to m a t e i s e a s i l y d e t e r m i n e d b y the d i s p l a y of  s u c h c h a r a c t e r i s t i c b e h a v i o u r p a t t e r n s a s the " z i g - z a g c o u r t s h i p d a n c e " a n d " c r e e p i n g t h r o u g h " the n e s t ( V a n I e r s e l ,  1953).  13  c)  T h e C r i t e r i o n of C h o i c e  In the t e s t s c o n d u c t e d o n the f i r s t 12 l e i u r u s f e m a l e s a n d the 15 t r a c h u r u s f e m a l e s ,  a f e m a l e was designated as having made a choice  i f she f o l l o w e d a m a l e to h i s ne st.  Usually before a female enters a  n e s t the m a l e e x h i b i t s s o m e r a p i d f a n n i n g a n d p o i n t i n g m o v e m e n t s at the n e s t e n t r a n c e w h i l e the f e m a l e r e m a i n s d i r e c t l y b e h i n d h i m .  During  t h i s p o i n t i n g d i s p l a y the m a l e g r a d u a l l y r o l l s o v e r to h i s s i d e w h i l e the f e m a l e p l a c e s h e r s e l f u n d e r n e a t h the m a l e . p o i n t of the t e s t .  T h i s w a s t a k e n a s the end  A f e m a l e h a d to f o l l o w the m a l e to h i s n e s t a n d r e a c h  t h i s p o s i t i o n b e f o r e it w a s r e c o r d e d that a c h o i c e h a d b e e n m a d e .  From  m a n y o b s e r v a t i o n s of c o m p l e t e c o u r t s h i p s t h r o u g h o u t the e x p e r i m e n t s , i t w a s s e e n that o n c e a f e m a l e f o l l o w e d a m a l e to h i s n e s t she t i m e s f a i l e d to e n t e r the n e s t ,  some-  but i f she r e a c h e d the p o i n t w h e r e  she  w a s p o s i t i o n e d b e n e a t h the m a l e a s he w a s p o i n t i n g at the n e s t e n t r a n c e , t h e n f a i l u r e to e n t e r the n e s t w a s v e r y r a r e .  However,  a s the e n d - p o i n t u s e d a b o v e i s s o m e w h a t a r b i t r a r y ,  the t e s t s w i t h the r e s t of the f e m a l e s females) a nest.  in  (20 l e i u r u s a n d 22 t r a c h u r u s  a c h o i c e w a s r e c o r d e d o n l y w h e n the f e m a l e s a c t u a l l y e n t e r e d A f e m a l e w i l l not r e l e a s e h e r eggs u n l e s s the m a l e d e l i v e r s a  v e r y r a p i d s e r i e s of p o u n d i n g m o v e m e n t s w i t h h i s snout a g a i n s t the a b d o m e n of the f e m a l e . as "trembling".  T i n b e r g e n (19 51) r e f e r s to t h e s e  Therefore,  o n c e a f e m a l e e n t e r e d a nest,  movements the m a l e  was prevented f r o m contacting h e r .  T h e female was then r e m o v e d  f r o m the n e s t by g e n t l y g r a b b i n g h e r c a u d a l p e d u n c l e w i t h a p a i r of f o r c e p s a n d p u s h i n g h e r t h r o u g h the n e s t :  d)  T h e R e p e t i t i v e U s e of the S a m e F e m a l e s  P r e l i m i n a r y e x p e r i m e n t s i n d i c a t e d that a n i n d i v i d u a l f e m a l e w o u l d r e s p o n d at one t i m e to a l e i u r u s m a l e a n d at a n o t h e r t i m e to a trachurus male.  A f t e r a n u m b e r of t e s t s ,  however,  individual female!  s e e m e d to s h o w a b i a s t o w a r d s s e l e c t i n g m a l e s of t h e i r o w n p h e n o t y p e Therefore,  t h e s e t e s t s w e r e d e s i g n e d to q u a n t i f y d e v i a t i o n f r o m r a n d o  m a t i n g o n the p a r t of a s m a n y i n d i v i d u a l f e m a l e s a s  possible.  O n c e a f e m a l e was p l a c e d i n a tank with a l e i u r u s and t r a c h u r u s m a l e a n d h a d m a d e a c h o i c e b y one of the a b o v e c r i t e r i a , r e m o v e d arid p l a c e d i n a h o l d i n g t a n k .  she  was  T h e f e m a l e w a s p l a c e d i n the  h o l d i n g t a n k f o r at l e a s t 5 m i n u t e s ( u s u a l l y m u c h l o n g e r ) b e f o r e b e i n g tested again.  Generally, possible.  as m a n y t e s t s w e r e c o n d u c t e d w i t h a s i n g l e f e m a l e a;  S o m e t i m e s f e m a l e s w o u l d r e l e a s e t h e i r e g g s i n n e s t s inspite  of the a b o v e p r e c a u t i o n s .  Also,  with repetitive testing,  some  females  s e e m e d to l o s e v i g o r o r t a k e i n c r e a s i n g l y l o n g e r to r e s p o n d to m a l e courtship.  W h e n it a p p e a r e d that a f e m a l e b e c a m e v i s i b l y s l o w e r i n  her responses,  t h e n i n that p a r t i c u l a r t e s t the e v e n t s of s p a w n i n g a n d  15  f e r t i l i z a t i o n w e r e not p r e v e n t e d .  T h i s s e r v e d a s a n a d d i t i o n a l c h e c k to  e n s u r e that the c r i t e r i a u s e d to e s t a b l i s h c h o i c e a c t u a l l y , l e a d to f e r t i l i zation.  e)  The Testing Procedure  T h e f e m a l e s w e r e p l a c e d i n the m i d d l e of the t a n k a s s h o w n i n F i g u r e 5 so that t h e y w e r e a p p r o x i m a t e l y e q u i d i s t a n t f r o m b o t h m a l e nests.  In t h i s p o s i t i o n the f e m a l e s  w e r e i m m e d i a t e l y c o u r t e d by b o t h  males.  T h e p r o c e d u r e n e c e s s i t a t e d h a v i n g one o r m o r e r e c e p t i v e  females  of e a c h p h e n o t y p e .  A f t e r one f e m a l e w a s t e s t e d ,  r e m o v e d a n d p l a c e d i n all h o l d i n g tank. other phenotype) was tested,  she  T h e n the o t h e r f e m a l e  was (of'.'the  a n d u s u a l l y w i t h a n o t h e r p a i r of m a l e s .  If f e m a l e s w e r e p r e s e n t e d to the s a m e p a i r of m a l e s i n s u c c e s s i o n , t h e n a n i n t e r v a l of s e v e r a l m i n u t e s w a s a l l o w e d b e t w e e n t e s t s . a c l u t c h of e g g s w a s d e p o s i t e d i n a m a l e ' s n e s t ,  When  at l e a s t one h o u r w a s  a l l o w e d b e t w e e n the t i m e w h e n the eggs w e r e r e m o v e d a n d the n e x t t e s t was  started.  T h e s e t e s t s i n c l u d e two c o n t r o l m e a s u r e s  so that i f d e v i a t i o n s  f r o m r a n d o m c h o i c e e x i s t on the p a r t of e i t h e r f e m a l e p h e n o t y p e , p o s s i b l e to d i s t i n g u i s h b e t w e e n :  it i s  (1) d e v i a t i o n s d e r i v e d f r o m d i f f e r ence s  b e t w e e n m a l e s not n e c e s s a r i l y c o n c e r n e d with phenotype,  a n d (2)  d e v i a t i o n s d e r i v e d f r o m f e m a l e a t t r a c t i o n to the m a l e p h e n o t y p e .  O n e c o n t r o l i s the u s e of s e v e n d i f f e r e n t m a l e p a i r s so that i f  FIGURE  5.  A r r a n g e m e n t of e x p e r i m e n t a l t a n k s f o r f e m a l choice tests.  T h e shaded a r e a  r e g i o n of t e r r i t o r i a l  conflicts.  represents  17  d e v i a t i o n s f r o m r a n d o m n e s s a r e a c o n s e q u e n c e of p h e n o t y p e ,  t h e n the  r e s u l t s of the c h o i c e t e s t s s h o u l d b e h o m o g e n e o u s b e t w e e n m a l e p a i r s . T h e o t h e r c o n t r o l i n v o l v e s the a l t e r n a t e p r e s e n t a t i o n of b o t h f e m a l e p h e n o t y p e s to a s i n g l e p a i r of m a l e s w i t h i n a r e l a t i v e l y s h o r t t i m e period.  T h i s e n s u r e s that i f e i t h e r f e m a l e p h e n o t y p e g e n u i n e l y c h o o s e s  one m a l e p h e n o t y p e o v e r the o t h e r , t h e n s u c h a c h o i c e i s m a d e a g a i n s t the s a m e e n v i r o n m e n t a l b a c k g r o u n d to w h i c h the o t h e r f e m a l e w a s  sub-  jected.  f)  R e s u l t s of the F e m a l e P r e f e r e n c e T e s t s 1)  C o m p a r i s o n o f i n d i v i d u a l f e m a l e s of the s a m e p h e n o t y p e . T h e r e s u l t s of the p r e f e r e n c e t e s t s f o r l e i u r u s f e m a l e s a r e s h o w n  i n T a b l e I,  a n d f o r t r a c h u r u s f e m a l e s i n T a b l e II.  T h e r e s u l t s of  i n d i v i d u a l s w i t h i n e a c h t y p e a r e c o m p a r e d w i t h a c h i s q u a r e t e s t of homogeneity.  F o r e a c h female phenotype  the n u l l h y p o t h e s e s ,  that  there a r e no significant differences between i n d i v i d u a l s , a r e c o m p a r e d a g a i n s t the a l t e r n a t i v e h y p o t h e s e s that t h e r e a r e s i g n i f i c a n t d i f f e r e n c e s between individuals.  In b o t h c a s e s the n u l l h y p o t h e s e s c a n n o t b e  r e j e c t e d at the 5 p e r c e n t l e v e l o f s i g n i f i c a n c e (see T a b l e s I a n d II). It i s t h e r e f o r e c o n c l u d e d that the r e s u l t s f o r i n d i v i d u a l s w i t h i n e a c h phenotype a r e ii)  homogeneous,  T h e r e s u l t s of r e p e t i t i v e t e s t s . T h e r e s u l t s of s u c c e s s i v e t r i a l s a r e c o m p a r e d i n o r d e r to d e t e r -  mine whether female choice changed with repetitive testing.  The  18  TABLE  I.  R e s u l t s of the m a t e s e l e c t i o n t e s t s w i t h l e i u r u s  N u m b e r of  N u m b e r of t i m e s leiurus  female  cf c h o s e n  1  4  2  4  3 4  4 1  5  N u m b e r of t i m e s trachurus  cf c h o s e n  females.  Total number choice  tests  •2 1  6  0  4  2  4 1  5 3  6  2  1  3  7  3  1  4  8  2 6 6 7  1 1  3 7  3 5 3  9 12 6  0 3 1  5 4  1  5 1  9 10 11 12  3  5  13 14  5 1  15  4  16 17  4 1  0  18  3 0  3 3  6  2 2  0 1  2 3  22  1  0  1  23  2  24  0  0 1  2 1  25  0  1  1  26  0 ,  2  2  27  2  0  2  28  2  0  2  29 30 31  1  1  1 1  0  2 1  0  1  32  0  2  2  76  42  118  19 20 21  homogeneity  v.  2  = 39.609 (31. df)  (0.10 <p  < 0.2 5)  5  3  19  TABLE  II.  R e s u l t s of the m a t e s e l e c t i o n t e s t s w i t h t r a c h u r u s f e m a l e s .  N u m b e r of  N u m b e r of t i m e s  female  l e i u r u s o" c h o s e n  1  Total number choice  tests  2 4  5 1  6  5 11  2  3  0  1  1  2 1  3  5  7  8  8  1  3  4  9 10 11  5  2  7  4  4  8  1 1  1.4 15 16 17 18  1 1  2 3 2 2  3 4 3 3  3 3 0 1  3 1 5 3  19 20  1  0  6 4 5 4 1  0  2  2  21  2  1  3  22  1  3  4  23  0  1  1  24  5  11  25  6 1  1  26 27  0 1  2 3  2 2 4  28  2 4  4 2  6 6  3  i  o" c h o s e n  2 1  2  )  N u m b e r of t i m e s trachurus  4 5  6 7  12 13  29 30  4  1  1  2  31  2  1  3  32  0  2  33 34  0  2 6  1  6 1  35  2  0  2  36  0  2  2  37  0  1  1  57  93  homogeneity  x  2  = 2 0 . 8 4 9 (36 d f ) . (0J90  < p  < 0.95).  2  150  20  d a t a a r e s h o w n i n T a b l e III. females  T h e r e s u l t s of the f i r s t t e s t s w i t h a l l  ( w i t h i n e a c h phenotype) a r e c o m p a r e d w i t h the r e s u l t s of  the s e c o n d t r i a l ,  third trial,  etc.  T h e r e s u l t s f o r the s e v e n t h a n d  g r e a t e r t r i a l s a r e p o o l e d a s the s a m p l e s i z e s a r e s m a l l .  A homo-  geneity c h i s q u a r e i s c a l c u l a t e d for both f e m a l e p h e n o t y p e s .  The  n u l l h y p o t h e s e s that the r e s u l t s d i d not v a r y f r o m one t r i a l to the n e x t i s t e s t e d a g a i n s t the a l t e r n a t i v e h y p o t h e s e s that t h e r e a r e s i g n i f i c a n t d i f f e r e n c e s b e t w e e n the t r i a l s .  In b o t h c a s e s the n u l l h y p o -  t h e s e s c o u l d not be r e j e c t e d at the 5 p e r c e n t l e v e l of c o n f i d e n c e , a n d i t i s c o n c l u d e d that the r e s u l t s of s u c c e s s i v e  trials are homo-  g e n e o u s (see T a b l e III).  iii)  T h e u s e of D i f f e r e n t M a l e  Pairs  A s m o r e t h a n one p a i r of m a l e s w a s u s e d to t e s t f e m a l e p r e f e r e n c e , it i s v a l u a b l e to k n o w w h e t h e r the r e s u l t s a r e c o m p a r a b l e f r o m one p a i r of m a l e s to a n o t h e r .  Therefore,  a homogeneity chi square  v a l u e w a s c a l c u l a t e d on f e m a l e c h o i c e s b e t w e e n d i f f e r e n t m a l e p a i r s . T h e r a t i o s of " c o r r e c t " f e m a l e c h o i c e s ( l e i u r u s f e m a l e to l e i u r u s m a l e a n d t r a c h u r u s f e m a l e to t r a c h u r u s m a l e ) w e r e c o m p a r e d w i t h " i n c o r r e c t " f e m a l e c h o i c e s ( l e i u r u s f e m a l e to t r a c h u r u s m a l e a n d t r a c h u r u s f e m a l e to l e i u r u s m a l e ) b e t w e e n the s e v e n m a l e p a i r s . T h e r e s u l t s a r e shown in T a b l e I V .  T h e homogeneity chi square is  n o t r e j e c t e d at t h e 5 p e r c e n t l e v e l of s i g n i f i c a n c e a n d t h e r e f o r e  21  TABLE  III.  A c o m p a r i s o n of c o r r e c t a n d i n c o r r e c t c h o i c e s b e t w e e n successive trials. Leiurus  females  Trachurus  females  Correct  Incorrect  Trial No.  Correct  1 2 3 4 5 6 7 -  Incorrect  Totals  Totals  19  13  32  23  14  37  19  7  26  20  13  33  11  9 '  20  14  11  25  12*  7  7  14  14  5  19  8  3  11  8  4  12  4  2  6  6  3  9  8  1  9  8  7  5  118  93  57  150  76  42  homogeneity  homogeneity  X  X  2  = 6.152  (0.25  (6 df)  < p <  0.5)  2  = 2.2326 (6 df)  (0.75  < p  <0.90)  * T h e r e s u l t s f r o m the s e v e n t h a n d s u c c e s s i v e t e s t s a r e p o o l e d i n o r d e r to a v o i d i n f l a t e d x v a l u e s due to s m a l l s a m p l e s i z e . 2  T A B L E IV.  A c o m p a r i s o n of c o r r e c t a n d i n c o r r e c t c h o i c e s b e t w e e n s e v e n d i f f e r e n t p a i r s of l e i u r u s a n d t r a c h u r u s  Male Pair s  Incorrect  C o r r e c t choices by l e i u r u s and trachurus females  by leiurus  males.  choices and  trachurus females  Total  number  of c h o i c e s  1  69  33  102  2  32  20  52  3  12 10  9 5  21  4 5  6  6  12  6 7  28 12  19 7  47  169  99  268  homogeneity  x  2  = 2.50  (6 df)  (0.75  < p  15  19  <0.90)  22  d i f f e r e n c e s of f e m a l e c h o i c e f r o m one m a l e p a i r to a n o t h e r do not a p p e a r to v a r y b y m o r e t h a n c h a n c e .  iv)  F e m a l e Mate Preference  A s the r e s u l t s f o r b o t h l e i u r u s a n d t r a c h u r u s f e m a l e s a r e h o m o g e n e o u s w i t h r e s p e c t to i n d i v i d u a l d i f f e r e n c e s ,  successive  t r i a l s and  d i f f e r e n t m a l e p a i r s , the d a t a s h o w n i n T a b l e s I a n d II c a n be p o o l e d a n d a t e s t of s i g n i f i c a n c e c a n b e c a l c u l a t e d o n the t o t a l s . hypothesis,  that f e m a l e c h o i c e i s r a n d o m ,  The null  was tested s e p a r a t e l y for  b o t h p h e n o t y p e s a g a i n s t the a l t e r n a t i v e h y p o t h e s i s that f e m a l e s to s e l e c t m a l e s of t h e i r own p h e n o t y p e s .  tend  T h e chi square value for  l e i u r u s f e m a l e s i s 9.23 (ldf) a n d the v a l u e f o r t r a c h u r u s f e m a l e s 8.17  (ldf).  A c o r r e c t i o n for continuity was made i n both c a s e s .  is The  n u l l h y p o t h e s i s c a n b e r e j e c t e d i n b o t h c a s e s at the 0.5 p e r c e n t l e v e l of  significance.  T h e r e s u l t s w e r e a l s o t e s t e d a g a i n s t the s a m e h y p o t h e s e s  using  the n o n - p a r a m e t r i c o n e - t a i l e d W i l c o x e n m a t c h e d - p a i r s i g n e d - r a n k t e s t d e s c r i b e d i n S i e g e l (1956).  T h e p r o b a b i l i t y of the d e v i a t i o n s  f r o m r a n d o m n e s s o c c u r r i n g by chance a r e 0.0025 for l e i u r u s a n d 0.00 26 f o r t r a c h u r u s f e m a l e s .  females  The precise probability estimates  f r o m t h i s t e s t a r e d i r e c t l y c o m p a r a b l e to the p r o b a b i l i t i e s o b t a i n e d f r o m the  chi square tests,  random mating.  and both tests indicate d e p a r t u r e f r o m  23  2.  Choice by males.  T o d e t e r m i n e w h e t h e r m a l e s p r e f e r to m a t e w i t h f e m a l e s phenotype,  of e i t h e r  a s e r i e s of t e s t s w a s c o n d u c t e d i n w h i c h a s i n g l e m a l e  was  s i m u l t a n e o u s l y e x p o s e d to b o t h r e c e p t i v e l e i u r u s a n d t r a c h u r u s f e m a l e s .  a)  T h e e x p e r i m e n t a l d e s i g n and testing p r o c e d u r e .  A t o t a l of 8 l e i u r u s a n d 9 t r a c h u r u s m a l e s w e r e u s e d .  Each  male  had fully c o m p l e t e d nest c o n s t r u c t i o n and was i s o l a t e d f r o m other f i s h with an opaque d i v i d e r .  Two females,  a g r a v i d l e i u r u s and a g r a v i d t r a c h u r u s , were  i n the t a n k w i t h the m a l e .  placed  O n l y f e m a l e s that h a d p r e v i o u s l y r e s p o n d e d  to c o u r t s h i p b y a n o t h e r m a l e w e r e u s e d i n t h e s e t e s t s .  W h e n a p a i r of f e m a l e s  w a s p l a c e d i n a tank w i t h a m a l e ,  the p h e n o -  t y p e of the f e m a l e that w a s f i r s t l e d to the n e s t w a s r e c o r d e d . females  The  w e r e not a l l o w e d to m a t e w i t h the m a l e s a n d the c r i t e r i o n of  c h o i c e w a s the s a m e a s d e s c r i b e d e a r l i e r f o r the f e m a l e  preference  tests.  W h e n a test with a p a r t i c u l a r m a l e was completed, w e r e r e m o v e d a n d p l a c e d i n a h o l d i n g tank. the f e m a l e s phenotype) manner,  the two  A f t e r about five  females minutes  w e r e p l a c e d i n a t a n k w i t h a n o t h e r m a l e (of a d i f f e r e n t and h i s p a r t i c u l a r c h o i c e was r e c o r d e d .  the s a m e p a i r of f e m a l e s  conditions would p e r m i t .  However,  In a n i d e n t i c a l  was u s e d to t e s t a s m a n y m a l e s no m a l e w a s e x p o s e d to the  as  same  f e m a l e p a i r m o r e than once.  A t o t a l of 14 p a i r s of f e m a l e s w e r e u s e d  i n the te s t s .  b)  Results.  T h e r e s u l t s of the m a l e p r e f e r e n c e t e s t s a r e s h o w n i n T a b l e V f o r l e i u r u s m a l e s and i n T a b l e V I f o r t r a c h u r u s m a l e s .  T a b l e V i n d i c a t e s that l e i u r u s m a l e s . t e n d to c h o o s e l e i u r u s f e m a l e s m o r e often t h a n t r a c h u r u s f e m a l e s .  T h e homogeneity chi square is  i n s i g n i f i c a n t (9.2 w i t h 7 df) i n d i c a t i n g that the d e g r e e of p r e f e r e n c e  is  s i m i l a r between individual m a l e s .  Similarly,  t r a c h u r u s m a l e s t e n d e d to c h o o s e t r a c h u r u s f e m a l e s  m o r e than l e i u r u s f e m a l e s ; h o w e v e r ,  the c h i s q u a r e on the t o t a l s  o n l y s i g n i f i c a n t at the 10 p e r c e n t l e v e l .  A s with l e i u r u s males,  is  the  h o m o g e n e i t y c h i s q u a r e i s i n s i g n i f i c a n t (9.23 w i t h 7 df) i n d i c a t i n g that the r e s u l t s a r e s i m i l a r b e t w e e n i n d i v i d u a l m a l e s  B o t h m a l e p h e n o t y p e s s h o w a b i a s t o w a r d s s e l e c t i n g f e m a l e s of s i m i l a r phenotypes, either case.  b u t the d e g r e e of p r e f e r e n c e i s n o t s t r o n g i n  A m o r e s t r i n g e n t d e m o n s t r a t i o n of the d i f f e r e n c e s  between  m a l e p h e n o t y p e s w i t h r e s p e c t ; to f e m a l e p r e f e r e n c e i s p o s s i b l e b y g r o u p i n g the d a t a f r o m b o t h p h e n o t y p e s i n the f o r m of a c o n t i n g e n c y table.  (See T a b l e V I I ) .  25  TABLE  V.  R e s u l t s of p r e f e r e n c e t e s t s f o r l e i u r u s m a l e s .  of  tests  1  11  2  11  3 4  leiurus  10 7  5  10  6 7  3 1  8  N u m b e r of t i m e s  N u m b e r of t i m e s  Total number  Male No.  60  female  chosen  trachurus female  chosen  3  8 7  4  5 6  2 4  2  5 1  9 1  2  1  0  39  21  7 homogeneity x  =9.23(7df)  (0.10 < p < 0.25)  X  = 4.82 ( 1 df)  (0.0 1 < p < 0 .0 5)  on totals  T A B L E VI.  R e s u l t s of p r e f e r e n c e t e s t s f o r t r a c h u r u s  Total number  Male No.  of te sts  N u m b e r of t i m e s  N u m b e r of t i m e s "trachurus female  males.  chosen  leiurus female  1  12  7  5  2  10  7  3 4  8  6  3 2  5 11 4  2 5 3 1  6 1  3 1  0 0  35  21  5 6 7  2 3 1  8 9  56  3  1  homogeniety \  = 6.10 56 (8 df)  (0. 50 < p < 0 .75)  X  =3.02 ( l d f )  (0.0 5 < p < 0.10)  2  on totals  chosen  26  T A B L E VII.  C o n t i n g e n c y t a b l e of m a l e p h e n o t y p e a n d the n u m b e r of t i m e s f e m a l e s of e a c h p h e n o t y p e w e r e c h o s e n . trachurus  leiurus females leiurus  males  trachurus  males  X  '= 7.71 (1 df)  39  21  60  21  35  56  60  56  116  (0.00 5 < p  The null hypothesis,  Totals  female s  < 0.0 10)  C o r r e c t e d for continuity.  that l e i u r u s and t r a c h u r u s m a l e s d i d not d i f f e r  w i t h r e s p e c t to t h e i r c h o i c e of f e m a l e s ,  w a s t e s t e d a g a i n s t the a l t e r n a -  t i v e h y p o t h e s i s that m a l e s t e n d e d to c h o o s e f e m a l e s of t h e i r own p h e n o type.  B y g r o u p i n g the r e s u l t s f r o m b o t h p h e n o t y p e s ,  b e t w e e n the two b e c o m e m o r e a p p a r e n t .  the  differences  The null hypothesis is rejected  at the 1 p e r c e n t l e v e l of s i g n i f i c a n c e .  3.  F e m a l e Orientation Tests.  a)  E x p e r i m e n t a l design and testing p r o c e d u r e .  A n u m b e r of a t t e m p t s w e r e m a d e to m e a s u r e f e m a l e o r i e n t a t i o n to males.  Generally,  this is a difficult task in a l a b o r a t o r y situation  b e c a u s e two b r e e d i n g m a l e s w i t h n e s t s m u s t b e p r e s e n t i n the tank and, i d e a l l y ,  same  t h e r e s h o u l d be s o m e n o n - t e r r i t o r i a l a r e a i n w h i c h  a female might orient herself. d i f f i c u l t to d e t e r m i n e .  Also,  a c r i t e r i o n of o r i e n t a t i o n i s  T h e f e m a l e i s the p a s s i v e m e m b e r of the  c o u r t s h i p p a i r so that she g e n e r a l l y r e q u i r e s s o m e s t i m u l u s s u c h a s a c o u r t s h i p d a n c e to i n d i c a t e h e r r e c e p t i v e n e s s  to m a t e .  H a g e n (1967) t e s t e d f e m a l e p r e f e r e n c e b y a t y p e of f e m a l e tion experiment.  orienta-  H e c o n f i n e d a l e i u r u s m a l e to one s i d e of a t a n k a n d a  t r a c h u r u s m a l e to the o t h e r s i d e of the t a n k by m e a n s of t r a n s p a r e n t dividers.  A r e c e p t i v e f e m a l e w a s t h e n p l a c e d b e t w e e n the two t r a n s -  p a r e n t d i v i d e r s so that b o t h m a l e s  could c o u r t h e r . H a g e n r e c o r d e d the  p h e n o t y p e of the m a l e to w h i c h a p a r t i c u l a r f e m a l e f i r s t r e s p o n d e d w i t h a "head-up" motion. results.  I t r i e d the s a m e type of t e s t s a n d o b t a i n e d s i m i l a r  T h e f i r s t r e s p o n s e of a f e m a l e t e n d e d to be r a n d o m w i t h  r e s p e c t to the p h e n o t y p e of the m a l e .  However,  f e m a l e s would continue  to r e s p o n d to one o r b o t h m a l e s f o r a c o n s i d e r a b l e p e r i o d of t i m e . response,  b y m e a n s of the " h e a d - u p " m o t i o n ,  o c c u r r e d frequently.  Also,  The  w a s not c o n t i n u o u s b u t  i n a situation where a female was s i m u l -  t a n e o u s l y e x p o s e d to two m a l e s ,  \she f r e q u e n t l y m o v e d f r o m one s i d e  of the e n c l o s u r e ( w h e r e she r e s p o n d e d to one m a l e ) to the o t h e r ( w h e r e she r e s p o n d e d to the o t h e r m a l e ) .  side  T h e r e f o r e , the p r e s e n t t e s t s  w e r e d e s i g n e d to m e a s u r e w h e t h e r a f e m a l e  spent m o r e t i m e o r i e n t e d  t o w a r d a m a l e of h e r o w n p h e n o t y p e t h a n t o w a r d a m a l e of the o t h e r phenotype.  A s a c o n t r o l the t e s t s w e r e c o n d u c t e d u s i n g two r e c e p t i v e one of e a c h p h e n o t y p e ,  at the s a m e t i m e .  females,  If a n y b i a s of o r i e n t a t i o n  e x i s t e d w h i c h w a s not c o n n e c t e d w i t h the f e m a l e r e c o g n i t i o n of the m a l e  28  phenotype, manner.  t h e n : i t w o u l d p r e s u m a b l y a c t on b o t h f e m a l e s i n a s i m i l a r  O n l y two f e m a l e p o s i t i o n s w e r e r e c o r d e d :  (1) w h e t h e r a  f e m a l e w a s i n that s i d e of the e n c l o s u r e w h i c h w a s c l o s e s t to the leiurus male,  or (2) that s i d e w h i c h was c l o s e s t to the t r a c h u r u s m a l e .  T h e p o s i t i o n s w e r e r e c o r d e d e v e r y 5 s e c o n d s f o r a 15 m i n u t e p e r i o d to g i v e a t o t a l of 180 o b s e r v a t i o n s f o r e a c h f e m a l e . t a n k s i s p r e s e n t e d i n F i g u r e 6.  T h e d e s i g n of the  A t o t a l of t e n t e s t s w e r e c o n d u c t e d  u s i n g t e n d i f f e r e n t p a i r s of f e m a l e s .  b)  Results  T h e r e s u l t s a r e s h o w n i n T a b l e VIII.  F o r e a c h t e s t the t o t a l  n u m b e r of o b s e r v a t i o n s m a d e w h i l e a f e m a l e w a s i n the s i d e of the e n c l o s u r e c l o s e s t to the m a l e of h e r own p h e n o t y p e i s s h o w n u n d e r the column "Correct observations."  Similarly,  the n u m b e r of o b s e r v a t i o n s  m a d e w h i l e a f e m a l e w a s c l o s e s t to a m a l e of a d i f f e r e n t p h e n o t y p e i s s h o w n u n d e r the c o l u m n " I n c o r r e c t o b s e r v a t i o n s . "  A l s o included in  T a b l e VIII a r e the t o t a l c o m b i n e d " c o r r e c t " a n d " i n c o r r e c t o b s e r v a tions for both f e m a l e s .  F o r b o t h l e i u r u s a n d t r a c h u r u s f e m a l e s the n u m b e r of  correct  p o s i t i o n s w e r e c o m p a r e d to the n u m b e r of i n c o r r e c t p o s i t i o n s w i t h a o n e - t a i l e d W i l c o x e n m a t c h e d - p a i r s i g n e d - r a n k test (Siegel, null hypothesis,  1956).  The  that the n u m b e r of c o r r e c t p o s i t i o n s i s not s i g n i f i c a n t l y  d i f f e r e n t f r o m the n u m b e r of i n c o r r e c t p o s i t i o n s ,  was  tested  against  29  F I G U R E 6.  A r r a n g e m e n t of e x p e r i m e n t a l t a n k s f o r f e m a l e orientation tests showing m a l e and female enclosure areas.  LI  DIVIDER -a  TABLE  VIII.  Results  of the f e m a l e  Correct  Incorrect observations on l e i u r u s  ob s e r v a t i o n s Female Pair  on l e i u r u s females  1  109/180  -  orientation tests.  female s  Incorrect  Correct  Correct observations on t r a c h u r u s  Incorrect on t r a c h u r u s  on b o t h  on b o t h  female s  females  female s  females  observations  observations  ob s e r v a t i o n s  71/180  111/180  69/180  220/360  140/360  2  87  93  112  68  199  161  3  139  41  100  80  239  121  4  128  52  96  84  224  136  5  123  57  91  89  214  146  6  107  73  60  120  167  193  7  71  109  64  116  135  225  8  9  171  164  16  173  187  9  119  61  115  65  234  126  10  83  97  119  61  202  158  -  825/1800  975/1800  homogeneity  \  1032/ 1800  for leiurus females =  768/1800  287.07  2007/3600  1593/3600  (p < 0.00 5)  2 homogeneity  x  f o r t r a c h u r u s f e m a l e s = 178.0 1  (p < 0.005)  O n e - t a i l e d W i l c o x e n m a t c h e d - p a i r s i g n e d - r a n k t e s t s f o r (1) l e i u r u s f e m a l e s :  T = 17.5 (0.1 < p < 0.2)  (2) t r a c h u r u s f e m a l e s :  T = 16.0 (0.1  (3) b o t h f e m a l e s :  T = 60. 5 (0 .0 1 S p' < 0.0 5)  <p<0.2)  31  the a l t e r n a t i v e h y p o t h e s i s that the n u m b e r of c o r r e c t p o s i t i o n s  is  s i g n i f i c a n t l y g r e a t e r t h a n the n u m b e r of i n c o r r e c t p o s i t i o n s .  F o r both l e i u r u s and t r a c h u r u s f e m a l e s ,  the n u l l h y p o t h e s e s c a n n o t  b e r e j e c t e d at the 5 p e r c e n t l e v e l of s i g n i f i c a n c e .  However,  i f the  c o m b i n e d r e s u l t s a r e t e s t e d a g a i n s t the s a m e set of a l t e r n a t i v e s ,  then  the n u l l h y p o t h e s i s c a n be r e j e c t e d at the 5 p e r c e n t l e v e l of s i g n i f i c a n c e . It is c o n c l u d e d , t h e r e f o r e ,  that the t o t a l n u m b e r of c o r r e c t p o s i t i o n s  is  s i g n i f i c a n t l y g r e a t e r t h a n the t o t a l n u m b e r of i n c o r r e c t p o s i t i o n s .  T h e t e n d e n c y f o r f e m a l e s to s p e n d m o r e t i m e c l o s e s t to the of t h e i r own p h e n o t y p e c a n b e s e e n i n F i g u r e 7. F o r e a c h t e s t ,  males the  n u m b e r of c o r r e c t o b s e r v a t i o n s for l e i u r u s f e m a l e s i s c o m p a r e d to the n u m b e r of c o r r e c t o b s e r v a t i o n s f o r t r a c h u r u s f e m a l e s .  T h e dotted  l i n e s p a r a l l e l i n g the a b s c i s s a a n d the o r d i n a t e r e p r e s e n t the 5 p e r c e n t significant levels  for individual  results.  . Therefore,  the  w h i c h f a l l a b o v e a n d b e l o w the h o r i z o n t a l l i n e s r e p r e s e n t  results  significant  d e p a r t u r e s f r o m r a n d o m n e s s by l e i u r u s f e m a l e s and t h o s e w h i c h a r e e i t h e r to t h e l e f t o r the r i g h t of the v e r t i c a l l i n e s r e p r e s e n t  significant  d e p a r t u r e s f r o m r a n d o m n e s s for t r a c h u r u s f e m a l e s .  F r o m F i g u r e 7 it i s s e e n that s i x out' of t e n r e s u l t s f o r l e i u r u s females  show s i g n i f i c a n t o r i e n t a t i o n i n the c o r r e c t d i r e c t i o n , two out  of t e n a r e not s i g n i f i c a n t , . and two out of t e n a r e s i g n i f i c a n t i n the w r o n g direction.  Similarly,  five out of t e n r e s u l t s f o r t r a c h u r u s f e m a l e s  show  32  F I G U R E 7.  R e s u l t s of f e m a l e o r i e n t a t i o n t e s t s .  T h e n u m b e r of  observations made while a l e i u r u s female  was  o r i e n t e d to a l e i u r u s m a l e ( o r d i n a t e ) i s c o m p a r e d to the n u m b e r of o b s e r v a t i o n s m a d e w h i l e a t r a c h u r u s f e m a l e w a s o r i e n t e d to a t r a c h u r u s m a l e T h e d o t t e d l i n e s r e p r e s e n t the 5% determined by chi squares.  (abscissa).  significance levels  NUMBER OF OBSERVATIONS MADE WHILE LEIURUS FEMALl: WAS ORIENTED TO LEIURUS MALE  o -I  1  U  1  91 O  I  Q O  J  l_  J  1  1  L  CD O  8 _L_  5 o. e2.  s|  O  *o  °2  9. «a t a » a.  H  -» to  m to  3*° o _  33  s i g n i f i c a n t o r i e n t a t i o n i n the c o r r e c t d i r e c t i o n , significant,  4.  t h r e e out of t e n a r e not  a n d two out of t e n a r e s i g n i f i c a n t i n the w r o n g d i r e c t i o n .  Male Orientation Tests.  a) E x p e r i m e n t a l d e s i g n a n d t e s t i n g  procedure.  O n l y solitary m a l e s were used i n these tests. c o m p l e t e d the c o n s t r u c t i o n of h i s n e s t ,  After a male had  two c l e a r c y l i n d r i c a l g l a s s j a r s  (3.8 l i t r e c a p a c i t y ) w e r e p l a c e d i n the t a n k w i t h the m a l e .  Each  was  a p p r o x i m a t e l y e q u i d i s t a n t f r o m h i s n e s t ( F i g u r e 8).  A g r a v i d l e i u r u s f e m a l e w a s p l a c e d i n one j a r a n d a g r a v i d t r a c h u r u s f e m a l e i n the o t h e r .  T h e m a l e s a l w a y s b e g i n to c o u r t the f e m a l e s  a f t e r t h e y a r e p l a c e d i n the j a r s . females,  A f t e r the m a l e h a d c o u r t e d b o t h  o r v i s i t e d b o t h of the j a r s ,  was begun.  soon  a n o b s e r v a t i o n p e r i o d of 15 m i n u t e s  T h e p o s i t i o n a n d a c t i v i t y of the m a l e w a s r e c o r d e d e v e r y  t e n s e c o n d s to give a t o t a l of 90 o b s e r v a t i o n s .  Through preliminary  o b s e r v a t i o n i t w a s d e t e r m i n e d that the p o s i t i o n a n d a c t i v i t y of the d u r i n g t h e s e p e r i o d s c o u l d be r o u g h l y s e p a r a t e d into the  male  categories  shown i n T a b l e IX.  A f t e r a, 15 m i n u t e o b s e r v a t i o n p e r i o d w a s c o m p l e t e ,  the p o s i t i o n s  of  the l e i u r u s a n d t r a c h u r u s f e m a l e s w e r e r e v e r s e d as i s s h o w n i n F i g u r e 8.  F o l l o w i n g this,  a second  15 m i n u t e o b s e r v a t i o n p e r i o d w a s b e g u n .  T h e r e v e r s i n g of the p o s i t i o n s of the f e m a l e s s e r v e d as a c o n t r o l  34  F I G U R E 8.  T h e e x p e r i m e n t a l d e s i g n f o r the m a l e o r i e n t a t i o n tests.  T h e f i r s t 15 m i n u t e o b s e r v a t i o n w a s  con-  d u c t e d w h i l e the f e m a l e s w e r e i n the p o s i t i o n s i n e i t h e r (a) o r (b).  shown  T h e second observation p e r i o d  w a s c o n d u c t e d w h e n the f e m a l e s w e r e i n o p p o s i t e positions.  b) SECOND  POSITION OF  F E M A L E S  35  TABLE  IX.  P o s i t i o n s a n d a c t i v i t i e s of m a l e s d u r i n g o r i e n t a t i o n t e s t s . Position  Activity  Fanning,  Nest  p o k i n g at n e s t e n t r a n c e ,  crawling through nest L e f t s i d e of tank, o r i e n t e d to the f e m a l e ( w i t h i n s e v e r a l i n c h e s of the j a r )  A c t i v e l y courting female by z i g - z a g d a n c e , o r b y t h r u s t i n g a g a i n s t the s i d e of the j a r  R i g h t s i d e of tank, o r i e n t e d to f e m a l e ( w i t h i n s e v e r a l i n c h e s of the j a r )  As  L e f t s i d e of t a n k  S w i m m i n g o r m o t i o n l e s s b u t not  above  actively courting female R i g h t s i d e of t a n k  As  above  m e a s u r e a g a i n s t the p o s s i b i l i t y that a m a l e w o u l d c o u r t on one s i d e of the t a n k m o r e t h a n the o t h e r i r r e s p e c t i v e of ithe p h e n o t y p e s of the females.  In s o m e c a s e s t h e d i r e c t i o n of a m a l e ' s n e s t ( f r o m the  e n t r a n c e to the e x i s t ) was  s u c h t h a t a m a l e w a s v i s u a l l y e x p o s e d to one  s i d e of the t a n k m o r e t h a n the, o t h e r .  T h e r e f o r e , the r e s u l t s of the  two 15 m i n u t e o b s e r v a t i o n p e r i o d s w e r e p o o l e d to e l i m i n a t e a n y b i a s of this kind.  W h e n the r e s u l t s a r e p o o l e d ,  e a c h t e s t c o n s i s t e d of 180  i n d i v i d u a l o b s e r v a t i o n s m a d e at 10 s e c o n d i n t e r v a l s .  b)  Results  A t o t a l of 17 t e s t s w e r e c o n d u c t e d on 7 d i f f e r e n t l e i u r u s a n d 20 t e s t s w e r e c o n d u c t e d on 7 d i f f e r e n t t r a c h u r u s m a l e s .  males The  r e s u l t s a r e s h o w n i n T a b l e s X and X I .  F o r b o t h t a b l e s the n u m b e r s  l i s t e d u n d e r the c o l u m n s " l e i u r u s f e m a l e s " a n d " t r a c h u r u s f e m a l e s " r e p r e s e n t the n u m b e r of o b s e r v a t i o n s m a d e w h i l e a m a l e w a s c o u r t i n g that p a r t i c u l a r f e m a l e  phenotype.  A c h i s q u a r e t e s t of h o m o g e n e i t y w a s f i r s t c a l c u l a t e d on the f o r e a c h m a l e p h e n o t y p e (see T a b l e s X a n d X I ) .  results  In b o t h c a s e s i t w a s  h i g h l y s i g n i f i c a n t (p <.01) a n d t h e r e f o r e the r e s u l t s w i t h i n e a c h p h e n o t y p e a r e c o n c l u d e d to b e h e t e r o g e n e o u s . geneity,  A s a consequence  a n y s t a t i s t i c a l c o m p a r i s o n s on the t o t a l s i s s u b j e c t to q u e s t i o n .  However,  the r e s u l t s w i t h i n e a c h m a l e p h e n o t y p e c a n b e c o m p a r e d w i t h  a o n e - t a i l e d W i l c o x e n m a t c h e d - p a i r s s i g n e d - r a n k test. thesis,,  of h e t e r o -  The null hypo-  that t h e r e w a 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 the d i r e c t i o n s of m a l e  orientation,  w a s t e s t e d a g a i n s t the a l t e r n a t i v e h y p o t h e s i s t h a t m a l e s  o r i e n t e d s i g n i f i c a n t l y m o r e to f e m a l e s  of t h e i r own p h e n o t y p e s .  F o r b o t h l e i u r u s a n d t r a c h u r u s m a l e s the n u l l h y p o t h e s e s c a n be r e j e c t e d at the 0.5 p e r c e n t l e v e l of s i g n i f i c a n c e .  It i s t h e r e f o r e  c l u d e d that m a l e s o r i e n t s i g n i f i c a n t l y m o r e to f e m a l e s p h e n o t y p e t h a n to f e m a l e s  con-  of t h e i r own  of the o t h e r p h e n o t y p e .  T h e r e s u l t s of a l l the t e s t s c a n be s e e n i n Figure••.9.  T h e n u m b e r of  o b s e r v a t i o n s m a d e w h i l e a m a l e w a s o r i e n t e d to a l e i u r u s  female  ( o r d i n a t e ) i s c o m p a r e d to the n u m b e r m a d e w h i l e he w a s o r i e n t e d to a trachurus female.  T h e two d o t t e d l i n e s r e p r e s e n t the 5 p e r c e n t s i g n i f i -  T A B L E X . R e s u l t s of o r i e n t a t i o n t e s t s of l e i u r u s m a l e s .  Male  :  Test  N u m b e r of observations  N u m b e r of observations  made while courting leiurus  made while courting trachurus  female  female  1  (i)  58  13  2  (i)  46  14  (ii)  96  28  3  (i)  57  7  4  (i) (ii)  67  47  35  31  (iii)  41  41  (iv)  50  25  (v) (vi)  61 40  36 43  (i)  59  38  (ii) (iii)  91 93  39  (i)  27  (ii) (iii)  21  39 21  121  18  61  45  5  6  7  homogeneity One-tailed,  (i)  \  z  = 116.67 (16 df)  53  (p <0.001)  Wilcoxen matched-pair,  s i g n e d - r a n k test:  T  =  9  (p < 0 .  T A B L E X I . R e s u l t s of o r i e n t a t i o n t e s t s on t r a c h u r u s N u m b e r of  Male  Test  males. N u m b e r of  observations  ob s e r v a t i o n s  made  made  while  while  courting  courting  trachurus  leiurus  female  female 3  (i)  48  (ii) (iii) (iv)  33  14  75  13  61  6  2  (i)  73  65  •3  (i)  109  34  93  28  1  4 5  (i)  54  27  6  (i)  79  (ii) (iii) (iv)  99 47  54 31  50  37  (v) (vi)  48  7  homogeneity One-tailed,  52  (vii)  66 48  43 31 22  (viii)  94  34  (ix) (x)  49 67  42  (i) (iii)  69 83  30 28  y  2  = 142.69 (19 df)  53  (p < 0.001)  Wilcoxen matched-pair,  s i g n e d - r a n k test:  T = 15 (p < 0.005)  39  F I G U R E 9.  R e s u l t s of the m a l e o r i e n t a t i o n t e s t s .  T h e n u m b e r of  observations made while a male was courting a leiurus f e m a l e ( o r d i n a t e ) i s c o m p a r e d to the n u m b e r of observations made while courting a t r a c h u r u s female (abscissa).  R e s u l t s which a r e either above or below  the d o t t e d l i n e s s h o w s i g n i f i c a n t (p <. .05;.) d e v i a t i o n from randomness.  c a n c e l e v e l s b a s e d on a c h i s q u a r e ( c o r r e c t e d f o r c o n t i n u i t y ) w i t h one d e g r e e of f r e e d o m .  Therefore,  a l l of the r e s u l t s w h i c h a r e  above or below these lines r e p r e s e n t randomness.  significant departures  O f the 17 t e s t s c o n d u c t e d w i t h . l e i u r u s m a l e s ,  either from 10 s h o w  s i g n i f i c a n t o r i e n t a t i o n to l e i u r u s f e m a l e s a n d 7 a r e not s i g n i f i c a n t ; of the 20 t e s t s c o n d u c t e d w i t h t r a c h u r u s m a l e s ,  15 s h o w  o r i e n t a t i o n to t r a c h u r u s f e m a l e s a n d 5 a r e not  5.  significant  significant.  Q u a n t i t a t i v e C o m p a r i s o n s of C o u r t s h i p A c t i v i t i e s .  D u r i n g the p r e v i o u s t e s t s it w a s n o t i c e d that c e r t a i n c o u r t s h i p a p p e a r e d to d i f f e r b e t w e e n the two m a l e p h e n o t y p e s . p r e l i m i n a r y observations,  The  O n the b a s i s of s o m e  a fixed o b s e r v a t i o n a l routine was established  a n a t t e m p t to q u a n t i f y t h e s e  a)  activities  in  differences.  observations.  Individual l e i u r u s and t r a c h u r u s m a l e s were presented with g r a v i d f e m a l e s of b o t h p h e n o t y p e s .  F o l l o w i n g V a n I e r s e l (1953),  w e r e r e c o r d e d for 5 minute p e r i o d s .  A s i n the p r e v i o u s  a l l the m a l e s u s e d f o r t h e s e t e s t s w e r e p r e p a r e d to m a t e construction complete,  etc.)  observations experiments, (nest  a n d t h e i r n e s t s w e r e d e v o i d of e g g s .  The  f e m a l e s u s e d w e r e not p r e v i o u s l y t e s t e d for r e c e p t i v e n e s s but t h e y w e r e all conspicuously gravid.  F e m a l e s w e r e u s e d r e p e t i t i v e l y to e l i c i t  c o u r t s h i p b e h a v i o u r f r o m m o r e t h a n one m a l e but no p a r t i c u l a r m a l e female  c o m b i n a t i o n was u s e d m o r e t h a n o n c e .  A t o t a l of 11 l e i u r u s  a n d 11 t r a c h u r u s m a l e s w e r e u s e d a n d e a c h m a l e w a s e x p o s e d to b o t h female  phenotypes.  O b s e r v a t i o n s w e r e r e c o r d e d v o c a l l y w i t h a tape r e c o r d e r . tape r e c o r d i n g s w e r e p l a y e d back,  a stop w a t c h ' w a s u s e d to d e t e r m i n e  the d u r a t i o n of c e r t a i n b e h a v i o u r a l  b)  W h e n the  sequences.  T h e t y p e s of b e h a v i o u r e x a m i n e d .  i)  T h e z i g - z a g dance. T h e b e s t k n o w n f e a t u r e of the s t i c k l e b a c k c o u r t s h i p i s the  dance.  F o l l o w i n g the s t u d i e s of V a n l e r s e l (1953),  S e v e n s t e r - B o l (1963),  zig-zag  B o l (1961),  the t o t a l n u m b e r of z i g - z a g m o t i o n s d u r i n g a  5 minute p e r i o d was r e c o r d e d .  However,  there a r e c e r t a i n other  a s p e c t s of the z i g - z a g d a n c e w h i c h c a n b e m e a s u r e d .  Zig-zags  o c c u r i n "bouts" of a c t i v i t y so that a c o n t i n u o u s s e r i e s of  zig-zags  o c c u r i n t e r r u p t e d by other d i s t i n c t i v e b e h a v i o u r patterns such as " l e a d i n g to the n e s t " ( T i n b e r g e n , behaviour such as biting.  1951),  Therefore,  or p e r h a p s  aggressive  it i s a l s o p o s s i b l e to q u a n t i f y  the n u m b e r of z i g - z a g s i n a bout a n d the f r e q u e n c y of the b o u t s .  ii)  Aggressive behaviour.  D u r i n g c o u r t s h i p the m a l e often t e n d s to be s o m e w h a t  aggressive  t o w a r d s the f e m a l e .  Such aggressive behaviour is  manifested,  among other things,  by biting and fast sudden c h a r g i n g m o v e m e n t s  a g a i n s t the f e m a l e .  Biting is extremely v a r i e d and ranges  from  42 g e n t l e n i p s to v i g o r o u s g r i p p i n g a c t i o n s w h i c h r e s u l t i n s k i n w o u n d s o n the f e m a l e . specific areas,  Also,  b i t i n g often s e e m s to b e d i r e c t e d t o w a r d s  p a r t i c u l a r l y the h e a d a n d c a u d a l p e d u n c l e  A s t h i s t y p e of b e h a v i o u r o c c u r s v e r y r a p i d l y ,  it i s not a l w a y s  p o s s i b l e to d i s t i n g u i s h b e t w e e n b i t i n g a n d t h r u s t i n g However,  movements.  a s m o s t of the a g g r e s s i v e b e h a v i o u r i s b i t i n g ,  thrusting movements  regions.  both  a n d b i t i n g a r e c o m b i n e d u n d e r the c a t e g o r y of  " b i t i n g " a n d t h e n u m b e r of " b i t e s p e r m i n u t e " (both t h r u s t i n g a n d biting) was  iii)  calculated.  Fanning during courtship.  D u r i n g a c o u r t s h i p sequence,  b o t h t y p e s of m a l e s i n v a r i a b l y  s p e n d s o m e t i m e " f a n n i n g " at the e n t r a n c e s  of t h e i r n e s t s .  i s g e n e r a l l y c o n s i d e r e d to b e a b e h a v i o u r a l c h a r a c t e r i s t i c  Fanning associated  w i t h p a r e n t a l b e h a v i o u r a n d s e r v e s to a e r a t e the w a t e r s u r r o u n d i n g a c l u t c h of e g g s i n a n e s t ( V a n I e r s e l ,  1953).  It i s a v e r y d i s t i n c t i v e  b e h a v i o u r c h a r a c t e r i z e d b y the m a l e h o l d i n g a s t a t i o n a r y p o s i t i o n o v e r the n e s t w h i l e he p o i n t s d o w n w a r d t o w a r d s the e n t r a n c e a n d r a p i d l y beats with his p e c t o r a l fins.  A s w e l l as i t s f u n c t i o n a l i m p o r t a n c e d u r i n g the r e a r i n g of eggs, f a n n i n g m u s t h a v e a d a p t i v e v a l u e s d u r i n g o t h e r p h a s e s of s t i c k l e b a c k reproduction.  F o r example,  d u r i n g the c o n s t r u c t i o n of a n e s t  males  f r e q u e n t l y f a n at t h e i r p a r t i a l l y c o m p l e t e d s t r u c t u r e ,  especially  b e f o r e " g l u i n g " o r c e m e n t i n g the m a t e r i a l s t o g e t h e r .  Also,  during  43  courtship,  b o u t s of f a n n i n g o c c u r f r e q u e n t l y .  b a s i s of c o m p a r i s o n ,  Therefore,  fanning d u r i n g courtship'was  f o r the  c a l c u l a t e d in both  the n u m b e r of s e c o n d s of f a n n i n g p e r m i n u t e a n d the n u m b e r of fanning p e r i o d s or bouts per  iv)  minute.  O t h e r b e h a v i o u r p a t t e r n s a s s o c i a t e d w i t h the n e s t .  T w o other a c t i v i t i e s measured.  that o c c u r r e d d u r i n g c o u r t s h i p w e r e  T h e p r e v i o u s l y mentioned gluing motions a r e  generally  a s s o c i a t e d w i t h p r e - c o u r t s h i p r e p r o d u c t i v e b e h a v i o u r i n that the m a l e u s e s a k i d n e y s e c r e t i o n to c e m e n t f i b e r s t o g e t h e r d u r i n g n e s t construction.  However,  during courtship.  the s a m e ,  or a v e r y s i m i l a r activity,  occurs  ( T h i s a c t i v i t y m a y be " s i m i l a r " i n the s e n s e that  s p e r m m a y b e r e l e a s e d at t h i s t i m e a s w e l l as the k i d n e y s e c r e t i o n . )  T h e o t h e r a c t i v i t y o b s e r v e d a n d q u a n t i f i e d i s that of " c r e e p i n g t h r o u g h " the n e s t d u r i n g c o u r t s h i p . documented by V a n Iersel p h a s e of n e s t c o n s t r u c t i o n .  T h i s particular activity  is  ( 1 9 5 3 ) a s m a r k i n g the end of the b e h a v i o u r a l Also,  males must creep through their  n e s t s to f e r t i l i z e a r e c e n t l y d e p o s i t e d  c l u t c h of e g g s .  However,  the  i n s t a n c e s of c r e e p i n g t h r o u g h r e c o r d e d h e r e a r e d i s t i n c t f r o m the a b o v e i n that t h e y o c c u r r e d d u r i n g c o u r t s h i p , t i o n of the n e s t ,  w e l l a f t e r the  a n d b e f o r e the e n t r y of the f e m a l e  M a l e s which have successfully  construc-  into the n e s t .  f e r t i l i z e d a c l u t c h of e g g s s t i l l  through their nests during courtship with another female.  creep  Also,  44 c r e e p i n g t h r o u g h often o c c u r r e d d u r i n g the m a l e o r i e n t a t i o n t e s t s w h e r e the f e m a l e s w e r e c o n f i n e d to a j a r a n d c o u l d not p h y s i c a l l y c o n t a c t the m a l e .  Thus,  the c r e e p i n g t h r o u g h m o v e m e n t d u r i n g  c o u r t s h i p i s not n e c e s s a r i l y t i o n o r egg  v)  a s s o c i a t e d w i t h e i t h e r the n e s t  fertilization.  T h e f i r s t r e s p o n s e of  males.  D u r i n g p r e l i m i n a r y observation, of a m a l e ,  construc-  it was  s e e n that the f i r s t  when p r e s e n t e d w i t h a g r a v i d f e m a l e ,  dance or a biting attack.  Therefore,  response  was either a z i g - z a g  at the b e g i n n i n g of  every  o b s e r v a t i o n p e r i o d the f i r s t r e s p o n s e of a m a l e w a s r e c o r d e d  as  b e i n g e i t h e r a z i g - z a g d a n c e or a b i t e .  c)  T h e r a t i o n a l e of the s t a t i s t i c a l  tests.  A l t o g e t h e r n i n e d i f f e r e n t a s p e c t s of b e h a v i o u r d u r i n g c o u r t s h i p w e r e e x a m i n e d and a r e l i s t e d 1.  below.  N u m b e r of z i g - z a g b o u t s p e r  minute.  2. N u m b e r of z i g - z a g s p e r b o u t . 3.  N u m b e r of z i g - z a g s p e r m i n u t e .  4. N u m b e r of b i t e s . p e r 5.  minute.  N u m b e r of s e c o n d s f a n n i n g p e r  6. N u m b e r of f a n n i n g b o u t s p e r  minute.  minute.  7. N u m b e r of g l u i n g m o v e m e n t s p e r  minute.  8. N u m b e r of t i m e s m a l e s e x h i b i t e d " c r e e p i n g t h r o u g h " n e s t . 9.  F i r s t r e s p o n s e of  males.  A s e a c h t e s t r e p r e s e n t e d a d i f f e r e n t m a l e - f e m a l e c o m b i n a t i o n , the r e s u l t s f o r e a c h type of b e h a v i o u r w e r e c o m p a r e d i n the f o l l o w i n g manner.  T h e data c o n c e r n e d with l e i u r u s m a l e r e a c t i o n s with l e i u r u s  f e m a l e s a n d l e i u r u s m a l e r e a c t i o n s to t r a c h u r u s f e m a l e s w e r e combined separately.  Similarly,  each  t r a c h u r u s m a l e r e a c t i o n s w i t h the two  female phenotypes were combined separately.  Therefore,  four or five  different comparisons are possible: 1.  f o r l e i u r u s m a l e s the r e a c t i o n s to l e i u r u s a n d t r a c h u r u s f e m a l e s c a n be c o m p a r e d ;  2. f o r t r a c h u r u s m a l e s the r e a c t i o n s to l e i u r u s a n d t r a c h u r u s females 3.  c a n be c o m p a r e d ;  l e i u r u s m a l e r e a c t i o n s to l e i u r u s f e m a l e s  c a n be c o m p a r e d to  t r a c h u r u s m a l e r e a c t i o n s to l e i u r u s f e m a l e s ; 4.  l e i u r u s m a l e r e a c t i o n s to t r a c h u r u s f e m a l e s  c a n be c o m p a r e d to  t r a c h u r u s m a l e r e a c t i o n s to t r a c h u r u s f e m a l e s ; a n d , 5.  in some cases,  the l e i u r u s m a l e r e s p o n s e to b o t h f e m a l e p h e n o -  t y p e s c a n b e c o m p a r e d to t h e . t r a c h u r u s m a l e r e s p o n s e to b o t h female  phenotypes.  F o r the f i r s t s e v e n t y p e s of c o u r t s h i p b e h a v i o u r e x a m i n e d , h y p o t h e s i s of e q u a l i t y of v a r i a n c e s w a s f i r s t t e s t e d .  the  T h e null hypothesis,  that the v a r i a n c e s "are e q u a l , w a s t e s t e d a g a i n s t the a l t e r n a t i v e h y p o t h e s i s that the v a r i a n c e s a r e not e q u a l . rejected,  If the n u l l h y p o t h e s i s was not  t h e n the two s a m p l e m e a n s w e r e c o m p a r e d b y " S t u d e n t s t t e s t " 1  46  for u n p a i r e d o b s e r v a t i o n s and equal v a r i a n c e s .  However,  i f the n u l l  h y p o t h e s i s of e q u a l i t y of v a r i a n c e s w a s r e j e c t e d at the 5 p e r c e n t l e v e l of s i g n i f i c a n c e ,  t h e n a m o d i f i c a t i o n of the " S t u d e n t ' s t t e s t " w a s  used  w h i c h allows for both u n p a i r e d observations and unequal v a r i a n c e s . T h e p r o c e d u r e s f o r t e s t i n g the h y p o t h e s i s of e q u a l v a r i a n c e s a n d e q u a l m e a n s i s d e s c r i b e d by S t e e l e a n d T o r r i e  (I960).  T h e r e s u l t s o b t a i n e d f o r the b e h a v i o u r a l c a t e g o r i e s  of " c r e e p i n g  t h r o u g h " the n e s t a n d the " f i r s t r e s p o n s e " of m a l e s w e r e o b t a i n e d b y s c o r i n g the e v e n t s a s h a v i n g o c c u r r e d i n one of two p o s s i b l e w a y s . instance,  during a c o u r t s h i p sequence a m a l e was r e c o r d e d as  For  either  " c r e e p i n g t h r o u g h " h i s n e s t o r not " c r e e p i n g t h r o u g h " h i s n e s t .  (In  o n l y two o c c a s i o n s d i d a m a l e c r e e p t h o u g h h i s n e s t m o r e t h a n o n c e d u r i n g a single c o u r t s h i p sequence.)  Similarly,  for each o b s e r v a t i o n  p e r i o d t h e r e w a s o n l y one " f i r s t r e s p o n s e " b y m a l e s .  The results  were  tested by a chi square test for independent samples d e s c r i b e d i n S i e g e l (1956).  In a l l c o m p a r i s o n s the n u l l h y p o t h e s i s w a s that the  results were homogeneous,  both within and between phenotypes.  t h e s e t e s t s h a d o n l y one d e g r e e of f r e e d o m ,  As  a c o r r e c t i o n for continuity  was made i n a l l cases.  d)  Results.  T a b l e X I I s h o w s the p r o b a b i l i t y v a l u e s a s s o c i a t e d w i t h the c o m p a r i s o n s of m e a n s ,  a n d the c h i s q u a r e t e s t s of h o m o g e n e i t y ,  b e t w e e n the m a l e p h e n o t y p e s .  both within and  A p p e n d i x T a b l e s I to I X s h o w a l l the  R e s u l t s o f the c o m p a r i s o n s of c o u r t s h i p b e h a v i o u r between l e i u r u s a n d t r a c h u r u s m a l e s u s i n g U:lurus and t r a c h u r u s f e m a l e s . tt)  (ii)  (iii)  (iv)  '  1 Zig-sag  bo-.'»j p e r  i  minute l e i u r u s m a l e r e a c t i o n s to leiurus female a r e c o m pared to l e i u r u s m a l e r e a c t i o n s to t r a c h u r u s female.  trachurus male reactions lo l e i u r u s f e m a l e a r e c o m p a r e d to t r a c h u r u s m a l e r e a c t i o n s to trachurus female.  Zig-iags pc r bout  Zig-zags (ier minute  Bites per minute  (v)  (vi)  Seconds fanning per minute  Fanning bouts p e r minute  F = 1.890 (44, 29 df) *  F = 2.374 F = 3.420  t = 1.966  t'= 3.367 (28 df) **  t'= 3.450 (30 df) *  t' = 2.440 t' = 0.823  t' = 0.927  (30 df) *  ( 26 df)  F = 1.870  F = 1.000 (43, 29 df)  F = 5.190 43, 28 df) **  (71 df)  F = 1.040 (43, 28 df)  (43.  28 df)  31 df)  #  t = 0.373 (69 df)  f = 1.820 (27 df)  t = 0.314 (70 df)  (44, 31 df) **  t' = 2.780  (27  df)  F = 2.050 F = 4.560 (27,  43 df) *  (26 df)  (27, 43 df) *#  Secretions  per minute  X  t = 0.263 (63 df)  corrected for continuity  c o m p a r i s o n of m e a n s (i) to (vii)  X-  v a r i a n c e r a t i o teBt (i) to (vii)  c o m p a r i s o n of m e a n s (i) to (vii)  2  F = 2.306 F = 1.167 (29.  **  (26,  X  2  = 2.92 (1 df)  = 0-38 (1 df)  2  z  0.76 (1 df)  v a r i a n c e s (i) to (vii) r a t i o test  #  t' = 1.361 (28 df)  t'= 0.109 (28 df)  t = 0.223 (69 df)  corrected for continuity  corrected for continuity  F = 1.911 (44, 43 df)  F = 1.0 56 (43, 44 df)  X  x  t = 1.736  corrected for continuity  F = 1.040 (43, 44 df)  F = 4.330 (43, 42 df) **  F = 2.619 (44, 43 df)  F = 3.239 (44, 43 df) **  F = 1.810 (44, 43 df)  t = 3.47  f = 5.446 (41 df)  t' = 6.770 (42 df)  t' = 0.178 (42 df)  t' = 0.819 (42 df)  F = 3.888 (29, 28 df)  F = 1.104 (31, 29 df)  F = 2.133 (31, 28 df)  F = 2.670 F = 1.034  (85 df)  cor re cted for continuity  44 df)  **  l e i u r u s m a l e r e a c t i o n s to leiurus female a r e c o m p a r e d to t r a c h u r u s m a l e r e a c t i o n ? tc I c i u r u c female.  First rc aponse of m a l e  F = 1.714 X = 1-14 4 3 df) (1 df)  F = 2.370  44 df)  (ix) measurement  Crawl through nest  (22,  (44,  29 df)  (viii) Nominal  F = 1.106 (44. 29 df)  (44,  (vii)  *  *  f = 0.662 (42 df)  (85 df)  2  = 2-99 (1 df)  '~-  z  10.57  (1 df) cor re cted for continuity  v a r i a n c e r a t i o test (i) to (vii) c o m p a r i s o n of m e a n s (i) to (vii)  ** F = 1.370 X = 3.03 26 df) (1 df)  X  t = 0.974 (47 df)  corrected for • continuity  cor re cted for continuity  F = 1.011 (72, 70df)  F = ! . i 18 (65, 70 df)  X  t = 3.186  t = 1.350 (133 df)  corrected for continuity  i e i u r u s m a l e r e a c t i o n s to F = 1.100 trachurus female a r e c o m (28, 29 df) p a r e d to t r a c h u r u s r e a c t i o n s to t r a c h u r u s f e m a l e . t = 0.771 (55 df)  l e i u r u s m a l e r e a c t i o n s to ill females are compared to t r a c h u r u s m a l e r e a c t i o n s to a l l f e m a l e s [when v a l i d )  (27,  * f = 4.219 (27 df) **  t = 3.596 (58 df) **  t' - 0.530 (27 df)  29 df) #*  t' = 1.424 (26 df)  (27,  29 df)  t' = 0.330 (26 df)  (142 df) a*  2  (22,  2  = 2-59 (1 df)  2 x  .  2  = 9.06 (1 df)  = 21.05 (1 df)  corrected for continuity  ** * 3^- l e v e l o*' » i g i i I Z i C i « . c c  i > Level oi  significance  variance ratio test (i) to (vii)  c o m p a r i s o n of m e a n s (i) .to (vii)  v a r i a n c e r a t i o test (i) to (vii) c o m p a r i s o n of m e a n s (i) to (vii)  48 r e s u l t s f o r e a c h t y p e of b e h a v i o u r i)  examined.  T h e n u m b e r of z i g - z a g b o u t s p e r m i n u t e . N e i t h e r l e i u r u s nor t r a c h u r u s m a l e s show a significant  i n r e s p o n s e w i t h e i t h e r p h e n o t y p e of f e m a l e . types a r e c o m p a r e d with e a c h other,  difference  W h e n the m a l e  pheno-  l e i u r u s m a l e s do not d i f f e r  f r o m t r a c h u r u s m a l e s i n t h e i r r e s p o n s e s to t r a c h u r u s f e m a l e s , t h e y do d i f f e r  s i g n i f i c a n t l y i n t h e i r r e s p o n s e s to l e i u r u s  but  females.  T h e v a r i a n c e s a r e s i m i l a r i n a l l c a s e s so that it c a n be  concluded  that the m e a n r e s p o n s e of l e i u r u s m a l e s to b o t h f e m a l e  phenotypes  is  males.  ii)  significantly greater  (p  <.01)  t h a n that of t r a c h u r u s  T h e n u m b e r of z i g - z a g s p e r bout.  L e i u r u s m a l e s g i v e s i g n i f i c a n t l y m o r e (p <.01)  z i g - z a g s per bout  to l e i u r u s f e m a l e s t h a n t h e y do to t r a c h u r u s f e m a l e s ,  but the  of t r a c h u r u s m a l e s do not d i f f e r s i g n i f i c a n t l y b e t w e e n e i t h e r phenotype.  W h e n the m a l e s a r e c o m p a r e d to e a c h o t h e r ,  responses female  it i s  seen  that l e i u r u s m a l e s g i v e s i g n i f i c a n t l y m o r e z i g - z a g s p e r bout to b o t h t y p e s of f e m a l e s t h a n do t r a c h u r u s m a l e s (p <.01  iii)  T h e n u m b e r of z i g - z a g s p e r  in both cases).  minute.  T h i s p a r t i c u l a r a s s e s s m e n t i s s o m e w h a t a r t i f i c i a l i n that it i s the p r o d u c t of the f i r s t two m e a s u r e m e n t s during courtship behaviour, zig-zags minute  _  i.e.,  bouts  zig-zags  minute  bout  of the z i g - z a g  dance  49  However, as other studies have used the measurement of the number of zig-zags per minute, it i s also included here. The  results are  s i m i l a r to the zig-zags per bout measurement. L e i u r u s males give significantly m o r e (p < .01) zig-zags to l e i u r u s females than to t r a c h u r u s females, but t r a c h u r u s males do not differ in their responses to the female phenotypes. When compared to each other, l e i u r u s males give significantly more zig-zags to both female phenotypes than do t r a c h u r u s males (p < .0 1 i n both cases) . The relationship between differences i n phenotype and v a r i a t i o n of the zig-zag dance i s illustrated i n F i g u r e 10. H e r e the ordinate values represent the number of zig-zags per bout for each test and the a b s c i s s a values represent the number of bouts per minute. It can be seen that the o v e r a l l response of trachurus males i s cons i d e r a b l y lower than that of l e i u r u s males.  Further, t r a c h u r u s  males do not show any clear distinction between their reactions to the female phenotypes, whereas l e i u r u s males tend to display more zig-zags per bout and give m o r e bouts per minute to l e i u r u s females than to t r a c h u r u s females.  iv) The number of bites per minute. L e i u r u s and t r a c h u r u s males react s i m i l a r l y to both female phenotypes.  Both phenotypes of males give significantly more bites  to t r a c h u r u s females than to l e i u r u s females (p < .01, for t r a c h u r u s  FIGURE  10.  (a)  T h e n u m b e r of z i g - z a g b o u t s p e r m i n u t e c o n t r a s t e d a g a i n s t the n u m b e r of z i g - z a g p e r bout f o r l e i u r u s m a l e s ,  (b)  T h e n u m b e r of z i g - z a g b o u t s p e r m i n u t e c o n t r a s t e d a g a i n s t the n u m b e r of z i g - z a g p e r bout f o r t r a c h u r u s m a l e s .  12-  II-  TRACHURUS MALES  LEIURUS MALES  10-  ©  9-  o  ©  o O ©  o  O ©  6@©  ©  „  © © Ocjg) O©  CO  0 0  C O  a© 3-  ©  o  O  o© © o o ®@ o  0  o  o  © 0  u  % ©  <  90 <h  o  o© © o o ego  © ©  .  o  8  0  © 2 ©  o  3  0  4  5  6 7  NO. OF ZIG-ZAGS PER BOUT O male responses to leiurus females © male responses to trachurus females  1 10  o  0  l  11  12  NO. Cf ZIG-ZAGS PER BOUT  51  m a l e s a n d p < .0 5 f o r l e i u r u s m a l e s ) . c a n t d i f f e r e n c e b e t w e e n the m a l e s  However,  t h e r e i s no s i g n i f i -  either in their responses  to  leiurus females or trachurus females.  v),  vi),  vii)  T h e n u m b e r of s e c o n d s f a n n i n g p e r m i n u t e ,  the n u m b e r  of f a n n i n g b o u t s p e r m i n u t e a n d the n u m b e r of g l u i n g motions per minute.  W i t h r e s p e c t to t h e s e b e h a v i o u r a l c h a r a c t e r i s t i c s ,  neither leiurus  n o r t r a c h u r u s show a s i g n i f i c a n t d i f f e r e n c e i n r e s p o n s e to e i t h e r female phenotype.  Further,  t h e r e i s no s i g n i f i c a n t d i f f e r e n c e  males either in their responses  to l e i u r u s f e m a l e s  between  o r to t r a c h u r u s  females.  viii)  C r e e p i n g t h r o u g h the n e s t .  Again,  t h e r e i s n o s i g n i f i c a n t d i f f e r e n c e s i n the r e s p o n s e s  e i t h e r m a l e p h e n o t y p e to the f e m a l e p h e n o t y p e s , d i f f e r e n c e s b e t w e e n the m a l e  ix)  The first response  of  a n d t h e r e a r e no  phenotypes.  of m a l e s .  N e i t h e r l e i u r u s nor t r a c h u r u s m a l e s show significant i n t h e i r r e s p o n s e s b e t w e e n the f e m a l e p h e n o t y p e s .  differences  However,  leiurus  m a l e s z i g - z a g s i g n i f i c a n t l y m o r e than t r a c h u r u s m a l e s in t h e i r f i r s t responses cases).  to b o t h l e i u r u s and t r a c h u r u s f e m a l e s  Further,  the r e s p o n s e s  (p <.01  in both  t h e r e i s a s i g n i f i c a n t d i f f e r e n c e (p <.01)  between  of l e i u r u s m a l e s to b o t h f e m a l e p h e n o t y p e s a n d the  52  FIGURE  11.  C o n t r a s t of m e a n v a l u e s f o r v a r i o u s b e h a v i o u r a l r e a c t i o n s between l e i u r u s and t r a c h u r u s m a l e s with l e i u r u s and t r a c h u r u s f e m a l e s .  ZIG-ZAG BOUTS/MIN TcC-  f\r: . 7 A ^ C  /  Dm IT  \.<rZIG-ZAGS/MIN T  <r-  L<f-  BiTES/MIN J<f-  SECONDS FANNING/MIN To"-  FANNING BOUTS /MIN  TRACHURUS SS.  To*L o"-  GLUING ATTEMPTS /MIN To"-  1  20  responses  of t r a c h u r u s m a l e s to b o t h f e m a l e p h e n o t y p e s .  s h o w s that the r e s p o n s e s  This simply  are homogeneous within male phenotypes,  but heterogeneous between m a l e phenotypes. s e n t e d w i t h e i t h e r p h e n o t y p e of f e m a l e ,  Therefore,  when p r e -  l e i u r u s m a l e s t e n d to r e s p o n d  f i r s t w i t h a z i g - z a g w h i l e t r a c h u r u s m a l e s t e n d to r e s p o n d f i r s t w i t h a bite.  IV.  T h e f i r s t two e x p e r i m e n t s , f e m a l e s by m a l e s , random.  a c h o i c e of m a l e s b y f e m a l e s a n d a c h o i c e of  i n d i c a t e that m a t i n g b e t w e e n l e i u r u s a n d t r a c h u r u s i s not  Whether such n o n - r a n d o m mating o c c u r s in "natural" conditions is  o p e n to q u e s t i o n . qualification, nature.  DISCUSSION  Obviously,  one c a n n e v e r i n f e r ,  w i t h o u t at l e a s t  some  that p a r t i c u l a r r e s u l t s i n a l a b o r a t o r y r e p r e s e n t t r u e e v e n t s i n  M o r r i s (1958) p r e s e n t s a b r i e f but e x c e l l e n t r e v i e w of the v a l i d i t y of  l a b o r a t o r y r e s u l t s and a l s o s o m e w a y s i n w h i c h s u c h r e s u l t s s h o u l d be q u a l i fied.  A d i f f i c u l t y i n i n t e r p r e t i n g the r e s u l t s of the m a t e s e l e c t i o n t e s t s c o n -  d u c t e d i n the c o n t r o l l e d s i t u a t i o n of a l a b o r a t o r y i s that i n n a t u r e i t i s not k n o w n w h e t h e r the s i t u a t i o n a r i s e s i n w h i c h e i t h e r a m a l e o r a f e m a l e p r e s e n t e d w i t h a " c h o i c e " of m a t e s . d i f f i c u l t y w i t h the t e r m " c h o i c e . "  is  F o r one t h i n g , t h e r e i s s o m e c o n c e p t u a l  T h e distinction between "choice by m a l e s "  a n d " c h o i c e b y f e m a l e s " i s c o n v e n i e n t to d e s c r i b e l a b o r a t o r y e x p e r i m e n t s but in nature such a distinction is probably m e a n i n g l e s s .  T h e tendency for "like"  p h e n o t y p e s to m a t e m a y not b e a f u n c t i o n of a c h o i c e m a d e b y i n d i v i d u a l s of  54  e i t h e r sex,  so m u c h a s the r e s u l t of a n i n t e r a c t i o n b e t w e e n a m a l e a n d a  f e m a l e of the s a m e p h e n o t y p e .  S u c h a n i n t e r a c t i o n c o u l d w e l l be d i f f e r e n t  f r o m that p r o d u c e d b e t w e e n a m a l e a n d a f e m a l e of d i s s i m i l a r p h e n o t y p e s . Therefore,  a t e s t of a " c h o i c e b y f e m a l e s " a n d a t e s t of a " c h o i c e b y m a l e s "  m a y h a v e b e e n t e s t i n g the s a m e t h i n g :  a c o m p a r i s o n of i n t e r a c t i o n s p r o d u c e d  within phenotypes and those p r o d u c e d between  phenotypes.  F r o m g e n e r a l k n o w l e d g e about r e p r o d u c t i v e b e h a v i o u r i n G a s t e r o s t e u s , and f r o m field observations made during collecting trips,  certain sequential  a n d s p a t i a l a t t r i b u t e s of m a t i n g b e h a v i o u r c a n be d e d u c e d that a r e r e l e v a n t to non-random mating.  F o r example,  b e c a u s e of t h e i r t e r r i t o r i a l i t y ,  male  s t i c k l e b a c k s a r e not f r e e to r o a m at w i l l s c r u t i n i z i n g f e m a l e s a s p o t e n t i a l mates.  Instead,  the m a l e m u s t w a i t w i t h i n h i s t e r r i t o r y f o r a f e m a l e to  a r r i v e i n the v i c i n i t y .  C a t c h e s f r o m i n d i v i d u a l s e i n e h a u l s often y i e l d i n d i v i d u a l s e x c l u s i v e l y of the s a m e s e x . the r i v e r ,  In p a r t i c u l a r a r e a s ,  e s p e c i a l l y a l o n g the e d g e s o r b a n k s of  the n u m b e r s of m a l e s c a p t u r e d f a r e x c e e d the n u m b e r s of f e m a l e s .  In o t h e r a r e a s f e m a l e s  o u t n u m b e r the m a l e s .  T h i s observation agrees with  the l a b o r a t o r y o b s e r v a t i o n that t e r r i t o r i a l m a l e s w i l l not t o l e r a t e females males,  (unless receptive) within their r e a l m s . that i s s o m e t i m e s  even  T h e s p a t i a l d i s t r i b u t i o n of  d i s c e r n i b l e f r o m the edge of the r i v e r a n d w h i c h  c a n a l s o be d e t e r m i n e d f r o m seine haul catches, pacted i n some a r e a s and diffuse i n o t h e r s .  a p p e a r s , to b e t i g h t l y c o m -  V a n d e n A s s e m (1967) m a d e a  t h o r o u g h i n v e s t i g a t i o n of t e r r i t o r i a l i t y i n G a s t e r o s t e u s a n d c o n c l u d e d that  t e r r i t o r y s i z e i s often a c r i t i c a l f a c t o r i n c o u r t s h i p s u c c e s s . s e l e c t i o n t e s t s t e r r i t o r y s i z e w a s not v a r i e d .  However,  In m y  mate  what i s i m p o r t a n t  a b o u t the s p a t i a l d i s t r i b u t i o n of m a l e s i s that a f e m a l e ,  w h e n r e a d y to  w i l l u s u a l l y be e x p o s e d to a n u m b e r of p o t e n t i a l m a t e s .  Furthermore,  spawn,  collections  w i t h i n the h y b r i d z o n e (or the a r e a of s y m p a t r y of l e i u r u s a n d  trachurus)  often p r o d u c e b r e e d i n g m a l e s of b o t h p h e n o t y p e s f r o m the  locality.  Therefore,  the e x p e r i m e n t a l t e s t of the " f e m a l e  c h o i c e of  i s p r o b a b l y a r e a s o n a b l e a p p r o x i m a t i o n of a n a t u r a l s i t u a t i o n , the r e s u l t s  same  males"  even though  m a y be i n d i c a t i v e of a m o r e , c o m p l e x b e h a v i o u r a l i n t e r a c t i o n  i n s t e a d of a s i m p l e f e m a l e  However, male" tests.  "choice."  i t i s m o r e d i f f i c u l t to i n t e r p r e t the r e s u l t s of the " c h o i c e b y  Here,  a single male was  s i m u l t a n e o u s l y e x p o s e d to two  F o r t h i s to h a p p e n i n n a t u r e w o u l d r e q u i r e s c h o o l i n g , physiologically receptive females. aggregations  However,  Once in B o n s a l l Creek,  such  W h e t h e r o r not t h i s  on two s e p a r a t e  of g r a v i d f e m a l e s w e r e o b s e r v e d i n n a t u r e ,  Campbell River.  of  f o r m a t e s e l e c t i o n to o c c u r ,  m u s t c o n s i s t of f e m a l e s of b o t h p h e n o t y p e s .  o c c u r s i n n a t u r e i s not k n o w n . aggregations  Further,  or a g g r e g a t i o n s ,  females.  occasions, but not i n the L i t t l e  V a n c o u v e r Island,  s c h o o l of g r a v i d f e m a l e s w a s o b s e r v e d a n d l a t e r c a p t u r e d .  a tightly  swimming  The school con-  s i s t e d of b o t h l e i u r u s a n d h y b r i d f e m a l e s ( t r a c h u r u s w e r e not y e t i n s p a w n i n g condition).  O n another occasion,  d i s t i n c t s c h o o l s of g r a v i d f e m a l e s w e r e  v i e w e d i n a p o p u l a t i o n of s t i c k l e b a c k s that a p p e a r to b r e e d i n s a l t (or b r a c k i s h ) w a t e r s of F a l s e C r e e k ,  an i n d u s t r i a l h a r b o u r i n V a n c o u v e r .  However,  it is  56  n o t k n o w n at the p r e s e n t t i m e w h e t h e r o r the e x c e p t i o n i n G a s t e r o s t e u s Little Campbell River.  Also,  s c h o o l i n g b y g r a v i d f e m a l e s i s the r u l e  a n d p a r t i c u l a r l y i n the f e m a l e s w i t h i n the  even if schooling o c c u r s among g r a v i d females,  t h e r e i s no e v i d e n c e that i t c o n t i n u e s w h e n the f e m a l e s a r e p h y s i o l o g i c a l l y r e a d y to s p a w n . o p e n to q u e s t i o n .  Thus,  the i n t e r p r e t a t i o n of the " c h o i c e b y m a l e " t e s t s i s  T h e s i m u l t a n e o u s , e x p o s u r e of a s i n g l e m a l e to two  t i v e f e m a l e s of d i f f e r e n t p h e n o t y p e s i f so,  recep-  m a y be a r a r e o c c u r e n c e i n n a t u r e and,  c o u l d h a r d l y be e x p e c t e d to a c c o u n t f o r a n y s i g n i f i c a n t d e v i a t i o n f r o m  r a n d o m mating.  The results  of the m a t e c h o i c e e x p e r i m e n t s  b e t w e e n l e i u r u s and t r a c h u r u s a r e n o n - r a n d o m .  i n d i c a t e that  matings  What effect this n o n - r a n d o m  m a t i n g has i n p r e v e n t i n g h y b r i d i z a t i o n or gene flow between l e i u r u s and t r a c h u r u s i s not k n o w n .  H o p e f u l l y , t h i s study w i l l p r o v i d e a b a s i s f r o m w h i c h  f u t u r e e n q u i r i e s into the e f f e c t s of n o n - r a n d o m m a t i n g m a y p r o c e e d .  A n obvious,  but n e v e r t h e l e s s i m p o r t a n t ,  c o n s i d e r a t i o n of the  causal  f a c t o r s of m a t e s e l e c t i o n i s that two p o t e n t i a l m a t e s m u s t f i r s t m e e t e a c h other.  S o m e f a c t o r s a f f e c t i n g t h i s w e r e m e n t i o n e d p r e v i o u s l y ( i . e . the  d i s t r i b u t i o n of m a l e s a n d f e m a l e s p r i o r to m a t i n g ) .  However,  "meeting" in  s t i c k l e b a c k s i n v o l v e s m o r e t h a n a c h a n c e e n c o u n t e r b e t w e e n two and willing participants. Tinbergen,  1953,  spatial  receptive  Sticklebacks have evolved "signalling devices"  (see  1964) to p e r m i t a t e m p o r a r y r e l a x a t i o n of the t e r r i t o r i a l  p r o t e c t i o n by a m a l e .  Such signalling devices involve elaborate  courtship  d i s p l a y s b y the m a l e (the z i g - z a g dance) a n d a s u b m i s s i v e " h e a d - u p " p o s t u r e b y the f e m a l e .  Therefore,  if mate selection exists,  the q u e s t i o n a r i s e s a s to  w h e t h e r it i s a f u n c t i o n of q u a n t i t a t i v e a n d / o r q u a l i t a t i v e d i f f e r e n c e s i n c o u r t s h i p d i s p l a y s between l e i u r u s and t r a c h u r u s .  T o d e t e r m i n e whether quantitative differences in c o u r t s h i p exist between l e i u r u s and trachurus, t i m e that f e m a l e s  m e a s u r e m e n t s w e r e m a d e of the r e l a t i v e a m o u n t s of  s p e n t o r i e n t e d to e a c h of the two m a l e p h e n o t y p e s .  i n a d i f f e r e n t s e r i e s of t e s t s ,  t h e r e l a t i v e a m o u n t of t i m e that m a l e s  o r i e n t e d to e a c h of the two f e m a l e p h e n o t y p e s w a s m e a s u r e d .  Also, spent  T h e r e s u l t s of  b o t h the m a l e a n d f e m a l e o r i e n t a t i o n t e s t s i n d i c a t e that t h e r e i s a t e n d e n c y f o r b o t h m a l e s a n d f e m a l e s to s p e n d m o r e t i m e o r i e n t e d t o w a r d s t h e i r o w n p h e n o t y p e s t h a n t o w a r d s the o t h e r p h e n o t y p e .  T h e a m o u n t of t i m e that a m a l e  s p e n t o r i e n t e d to e a c h of the two f e m a l e s i s r e a l l y a n e s t i m a t e of the r e l a t i v e a m o u n t of c o u r t s h i p d i s p l a y e d to e a c h of the two f e m a l e p h e n o t y p e s .  This  o b v i o u s d u r i n g the t e s t s a s m o s t of the o r i e n t a t i o n b y a m a l e to a f e m a l e i n the f o r m o f the z i g - z a g d a n c e .  was was  F e m a l e o r i e n t a t i o n to m a l e s p r o b a b l y a l s o  r e f l e c t s d i f f e r e n t i a l c o u r t s h i p (or r e s p o n s e to m a l e c o u r t s h i p ) b y f e m a l e s . However,  unlike males,  the s i g n a l l i n g r e s p o n s e of f e m a l e s b y the " h e a d - u p "  m o t i o n i s often d i f f i c u l t to o b s e r v e .  Therefore,  it i s q u e s t i o n a b l e w h e t h e r  d i f f e r e n c e s i n the t i m e s of o r i e n t a t i o n b y f e m a l e s  precisely reflect  i n the r e l a t i v e a m o u n t s of f e m a l e c o u r t s h i p d i r e c t e d t o w a r d s m a l e s . sumably,  differences Pre-  any o r i e n t a t i o n b y f e m a l e s that i s not r e l a t e d to c o u r t s h i p , o r a  r e s p o n s e to m a l e c o u r t s h i p , i s r a n d o m b e t w e e n b o t h s i d e s of the e x p e r i m e n t a l  enclosure.  If t h e r e i s a r a n d o m c o m p o n e n t of f e m a l e o r i e n t a t i o n ,  a n o n - r a n d o m component concerned with courtship display, r e s u l t s t e n d to b e  a s w e l l as  t h e n the o v e r a l l  conservative.  Q u a l i t a t i v e d i f f e r e n c e s b e t w e e n the c o u r t s h i p s of l e i u r u s a n d t r a c h u r u s were also investigated.  However,  the d i s s e c t i o n of the e n t i r e ' c o u r t s h i p  b e h a v i o u r i n t o d i s c r e t e e n t i t i e s f o r c o m p a r i s o n , i n v o l v e s the q u a n t i f i c a t i o n of v a r i o u s d i s c r e t e b e h a v i o u r p a t t e r n s that c o m p r i s e c o u r t s h i p a c t i v i t y .  A great  d e a l of a t t e n t i o n h a s b e e n d e v o t e d to a n a l y z i n g the v a r i o u s c o m p o n e n t s of c o u r t s h i p i n m a l e s t i c k l e b a c k s (see V a n I e r s e l ,  1953; T i n b e r g e n ,  Sevenster,  1965).  1961; S e v e n s t e r - B o l ,  1962; S y m o n s ,  1951;  M a n y of the c h a r a c t e r -  i s t i c s e x a m i n e d h e r e have been s i m i l a r l y quantified i n p r e v i o u s studies. instance,  V a n I e r s e l f i r s t u s e d the n u m b e r of z i g - z a g s p e r u n i t t i m e as a n  e s t i m a t e of s e x d r i v e . ments used here;  studies (Symons,  Sevenster  (1962) a l s o u t i l i z e d a n u m b e r of m e a s u r e -  t h e n u m b e r of b i t e s p e r u n i t t i m e ,  fanning per unit time,  the n u m b e r of s e c o n d s  the n u m b e r of f a n n i n g b o u t s p e r u n i t t i m e ,  etc.  Some  1965) a n a l y z e i n d e t a i l c e r t a i n f a c t o r s not c o n s i d e r e d h e r e ,  s u c h as s p i n e - r a i s i n g ,  w h i c h m a y be i m p o r t a n t i n m a t e s e l e c t i v i t y .  d i f f e r e n c e i n m e t h o d o l o g y h e r e c o m p a r e d to o t h e r s t u d i e s , a n d m a l e s w e r e a l l o w e d to p h y s i c a l l y c o n t a c t e a c h o t h e r .  i s that  a r e a d v a n t a g e s a n d d i s a d v a n t a g e s to b o t h m e t h o d s . physiologically receptive females  i m m e d i a t e l y w i t h the c o n s u m m a t o r y a c t .  One females  In o t h e r s t u d i e s the  f e m a l e w a s a l w a y s c o n f i n e d to a "tube" o r s o m e s i m i l a r a p p a r a t u s .  permitted,  For  There  When p h y s i c a l contact is  often t e r m i n a t e the c o u r t s h i p  However,  tactile responses between  the m a l e a n d f e m a l e ceivably, female,  a r e e l i m i n a t e d b y e n c l o s i n g the f e m a l e i n a tube.  tactile responses,  as w e l l a s subtle o r i e n t a t i o n m o v e m e n t s b y the  m a y h a v e a n i m p o r t a n t c o n t r i b u t i o n to c o u r t s h i p b e h a v i o u r .  this difference  Con-  in methodology,  my r e s u l t s for such activities  Despite  a s the n u m b e r  of z i g - z a g s p e r m i n u t e and the n u m b e r of s e c o n d s f a n n i n g p e r m i n u t e , g e n e r a l l y c o m p a r a b l e to the r e s u l t s o b t a i n e d b y V a n I e r s e l ,  are  S e v e n s t e r and  Sevenster-Bol.  T h e c o m p a r a t i v e c o u r t s h i p t e s t s ( T a b l e XII) i n d i c a t e that s o m e a s p e c t s of b e h a v i o u r a p p e a r to be i d e n t i c a l b e t w e e n l e i u r u s a n d t r a c h u r u s w h i l e i n o t h e r r e s p e c t s the two a r e m a r k e d l y d i f f e r e n t .  F o r instance,  m e a n r e s p o n s e s between l e i u r u s and t r a c h u r u s were s i m i l a r for n u m b e r of b i t e s p e r m i n u t e ,  p e r m i n u t e and (5) the o c c u r r e n c e s  for  the  (1) the  (2) the n u m b e r of s e c o n d s f a n n i n g p e r  (3) the n u m b e r of f a n n i n g b o u t s p e r m i n u t e ,  hand,  males,  minute,  (4) the n u m b e r of g l u i n g a t t e m p t s  of c r a w l i n g t h r o u g h n e s t s .  O n the  other  the two m a l e p h e n o t y p e s d i f f e r e d s i g n i f i c a n t l y i n t h e i r m e a n r e s p o n s e s  (1) the n u m b e r of z i g - z a g s p e r bout,  (2) the n u m b e r of z i g - z a g b o u t s p e r  m i n u t e a n d (3) the n u m b e r of z i g - z a g s p e r m i n u t e .  They also differed  signifi-  c a n t l y i n t h e i r f i r s t r e s p o n s e s to f e m a l e s .  W h e n the r e a c t i o n s types are compared, z i g - z a g s p e r bout,  of l e i u r u s m a l e s to e a c h of the two f e m a l e  it i s  s e e n that l e i u r u s f e m a l e s r e c e i v e  pheno-  significantly  z i g - z a g s per m i n u t e and s i g n i f i c a n t l y fewer b i t e s per  minute than t r a c h u r u s f e m a l e s . s i m i l a r l y to b o t h f e m a l e  Trachurus  phenotypes except,  m a l e s a p p e a r to  react  like leiurus males,  they bite  more  60 t r a c h u r u s f e m a l e s s i g n i f i c a n t l y m o r e often t h a n l e i u r u s  Since leiurus males  z i g - z a g d i f f e r e n t i a l l y to the two f e m a l e  they m u s t m a k e s o m e v i s u a l (tactile, In c o n t r a s t ,  females.  phenotypes,  or c h e m i c a l ) d i s t i n c t i o n between t h e m .  t r a c h u r u s m a l e s do not s e e m to d i s t i n g u i s h b e t w e e n the  Curiously,  i n the n u m b e r of b i t e s p e r m i n u t e ,  both male  b i t e t r a c h u r u s f e m a l e s m o r e often t h a n l e i u r u s f e m a l e s .  females.  phenotypes  However,  the f u n c t i o n  of b i t i n g o r a g g r e s s i v e b e h a v i o u r d u r i n g c o u r t s h i p n e e d not n e c e s s a r i l y to r e p e l a f e m a l e . trachurus,  Sometimes  f e m a l e s of b o t h p h e n o t y p e s ,  appeared to r e a c t most positively (receptively)  but  serve  especially  to b i t i n g b y a m a l e .  S u c h f e m a l e s o f t e n r e s p o n d w i t h a " h e a d - u p " m o t i o n a n d f o l l o w the  male  d i r e c t l y to h i s n e s t w i t h o u t a n y i n t e r v e n i n g z i g - z a g d a n c e b y the m a l e .  Other  f e m a l e s f l e e o n the r e c e i p t of a b i t e f r o m a m a l e .  T h e f i r s t r e s p o n s e s of m a l e s to f e m a l e s i n d i c a t e that,  initially,  neither  l e i u r u s n o r t r a c h u r u s m a k e any d i s t i n c t i o n between f e m a l e phenotypes. ever,  the m a l e s d i f f e r s i g n i f i c a n t l y i n t h e i r f i r s t r e s p o n s e  z i g - z a g w h i l e t r a c h u r u s t e n d to b i t e o r t h r u s t ) .  (leiurus  How-  usually  T h i s difference in first  r e s p o n s e s b e t w e e n the m a l e s m a y be a v e r y s i g n i f i c a n t one r e l a t i v e to n o n random mating. and  T h e a n s w e r l i e s i n the f e m a l e r e a c t i o n to b i t i n g b y  p e r h a p s as w e l l ,  qualitative differences  males  i n the n a t u r e of b i t i n g ( w h e r e  the b i t e s a r e d i r e c t e d o n the f e m a l e a n d the f o r c e w i t h w h i c h t h e y a r e  delivered).  F r o m many observations  pheno-  types,  of c o u r t s h i p a c t i v i t i e s b e t w e e n the d i f f e r e n t  I h a v e the d i s t i n c t i m p r e s s i o n that the r e c e p t i v i t y of t r a c h u r u s  61  f e m a l e s i s not often d e t e r r e d b y b i t i n g b u t i s e v e n e n h a n c e d on  occasions.  In c o n t r a s t , . l e i u r u s f e m a l e s a p p e a r to b e m o r e s e n s i t i v e to b i t i n g a n d often flee.  T h e m e a n r e s p o n s e s of the o t h e r t y p e s of b e h a v i o u r e x a m i n e d b e t w e e n l e i u r u s a n d t r a c h u r u s a r e not s i g n i f i c a n t l y d i f f e r e n t .  Sevenster  (1962)  to s u c h b e h a v i o u r a s f a n n i n g a n d g l u i n g d u r i n g c o u r t s h i p a s " s e x u a l ment activities."  o r w h e t h e r i t h a s any f u n c t i o n at a l l i n a t t r a c t i n g  i s o p e n to q u e s t i o n .  to  females,  T i n b e r g e n (1965) p o i n t s out that the i d e a l i z e d c o u r t s h i p  sequence i n Gasterosteus  i s o f t e n the e x c e p t i o n a n d not the r u l e .  (1958) s a y s the s a m e t h i n g f o r P u n g i t i u s .  O n occasions  I saw  Morris  successful  s p a w n i n g s w h e r e the e n t i r e r i t u a l i z a t i o n of the c o u r t s h i p s e q u e n c e ,  apparent.  displace-  W h e t h e r o r not s u c h b e h a v i o u r c o u l d i n f l u e n c e a f e m a l e  mate with a male,  the z i g - z a g d a n c e ,  refers  "head-up" movement,  In a l l s u c h c a s e s the m a l e  including  a n d l e a d i n g to the n e s t w e r e not  seemed p r e o c c u p i e d with his nest and  the f e m a l e s o r i e n t e d d i r e c t l y to the n e s t a n d e n t e r e d as the m a l e w a s f a n n i n g . O n c e i n the n e s t ,  activities proceeded normally.  T o s u m m a r i z e the r e s u l t s  of the c o m p a r i s o n of c o u r t s h i p a c t i v i t i e s ,  a p p e a r s that the r e l a t i v e f r e q u e n c i e s associated  of s o m e b e h a v i o u r p a t t e r n s a r e  strongly  w i t h the p h e n o t y p e of the m a l e a n d the p h e n o t y p e of the f e m a l e  w h i c h the m a l e i s r e s p o n d i n g .  to  O t h e r t y p e s of b e h a v i o u r s e e m to be i n d e p e n -  d e n t of the p h e n o t y p e of the m a l e . m o s t in their z i g - z a g dance,  it  G e n e r a l l y , l e i u r u s and t r a c h u r u s differ  b o t h i n the n u m b e r of z i g - z a g s p e r m i n u t e a n d  i n the n u m b e r of b o u t s p e r m i n u t e .  62  The comments s o n s of m e a n s .  so f a r o n the c o m p a r i s o n of b e h a v i o u r d e a l w i t h c o m p a r i -  Hirsch  (1962) c a u t i o n s a g a i n s t p l a c i n g too m u c h e m p h a s i s u p o n  " a v e r a g e " r e s p o n s e s as they m a y r e p r e s e n t s t a t i s t i c a l a r t i f a c t s .  In t h i s  r e s p e c t the r e s u l t s of the V a r i a n c e R a t i o t e s t s ( T a b l e XII) i n d i c a t e that e v e n t h o u g h the m e a n s a r e s i m i l a r f o r c e r t a i n t e s t s b e t w e e n l e i u r u s a n d t r a c h u r u s males,  the v a r i a n c e s a r e s i g n i f i c a n t l y d i f f e r e n t .  variances are considered,  Thus,  when both means and  t h e two m a l e p h e n o t y p e s a p p e a r to d i f f e r  c a n t l y f r o m e a c h o t h e r i n a l m o s t a l l the b e h a v i o u r a l c h a r a c t e r i s t i c s  T h e o r i g i n of the d i f f e r e n c e s  explanations.  First,  However,  the d i f f e r e n c e  to l o c a l e n v i r o n m e n t a l c o n d i t i o n s .  examined.  in courtship behaviour between leiurus and  t r a c h u r u s can only be speculated upon. feasible  signifir  t h e r e s e e m to be two  m a y have evolved as  F o r instance,  adaptations  t r a c h u r u s (in the L i t t l e  C a m p b e l l R i v e r ) r e s i d e s i n a n a r e a w h e r e t h e r e a p p e a r s to b e m o r e p r e d a t o r s than i n t y p i c a l l e i u r u s habitats.  Thus,  potential  a g e n e r a l r e d u c t i o n of the  m o r e c o n s p i c u o u s a s p e c t s of c o u r t s h i p d i s p l a y m a y r e f l e c t a r e s p o n s e selection by predation. spine lengths, natively,  T h e g r e a t e r fecundity,  m a y a l l be r e s p o n s e s to t h i s  the b o n y a r m o u r , a n d the l o n g  same selective force.  Alter-  i t m a y be that l e i u r u s h a s r e s p o n d e d to s o m e s e l e c t i v e f o r c e to  e n h a n c e the r i t u a l i z a t i o n , courtship.  to  o r to g e n e r a l l y i n c r e a s e t h e z i g - z a g a c t i v i t y d u r i n g  T h i s m i g h t be e x p l a i n e d b y the c o m p l e t e l y f r e s h w a t e r  m e n t of l e i u r u s c o m p a r e d to t r a c h u r u s w h i c h , in areas under tidal influence.  environ-  f o r a g o o d p a r t of i t s r a n g e ,  In c o m p l e t e l y f r e s h ' w a t e r  is  s p e r m is viable for  a r e l a t i v e l y s h o r t e r p e r i o d of t i m e t h a n i n w a t e r s of h i g h e r s a l i n i t i e s ( H o a r ,  63  1957).  Thus,  the m o r e i n t e n s i v e c o u r t s h i p of l e i u r u s m a y s e r v e to p r e c i s e l y  s y n c h r o n i z e m a l e a n d f e m a l e r e a d i n e s s f o r the e o n s u m m a t o r y a c t .  T h e s e e x a m p l e s a r e g i v e n s i m p l y to i l l u s t r a t e h o w g e n e t i c , gical,  morpholo-  a n d b e h a v i o u r a l d i f f e r e n c e s m a y h a v e a r i s e n b e t w e e n the two p h e n o -  t y p e s ; s o l e l y a s the r e s u l t of s e l e c t i v e f o r c e s due to d i v e r g e n t e n v i r o n m e n t a l conditions.  T h e o t h e r e x p l a n a t i o n of the o r i g i n of e t h o l o g i c a l d i f f e r e n c e s  between  l e i u r u s a n d t r a c h u r u s n e c e s s i t a t e s that t h e y f u n c t i o n as i s o l a t i n g m e c h a n i s m s . T h i s e s s e n t i a l l y f o l l o w s the t h e o r y of D o b z h a n s k y (1951).  H e m a i n t a i n s that  isolating mechanisms (particularly pre-mating isolating mechanisms) f u l l y d e v e l o p e d b y r e i n f o r c e m e n t i n c o n d i t i o n s of s y m p a t r y .  are  F o r reinforce-  m e n t of e t h o l o g i c a l i s o l a t i n g m e c h a n i s m s to o c c u r , h y b r i d s b e t w e e n l e i u r u s a n d t r a c h u r u s m u s t be at a s e l e c t i v e d i s a d v a n t a g e c o m p a r e d to the p a r e n t a l types.  Also,  one m i g h t e x p e c t to f i n d that m a t e s e l e c t i o n i s m o r e h i g h l y  d e v e l o p e d i n a r e a s of s y m p a t r y t h a n i n a l l o p a t r i c a r e a s .  However,  Hagen  (1967) c o u l d f i n d no e v i d e n c e of h y b r i d i n f e r i o r i t y a l t h o u g h he h y p o t h e s i z e d that h y b r i d s w e r e s e l e c t e d a g a i n s t to e x p l a i n the d i s j u n c t d i s t r i b u t i o n s of l e i u r u s a n d t r a c h u r u s , a n d the a p p a r e n t a b s e n c e of i n t r o g r e s s i o n . the s t r o n g e s t  Perhaps  s u g g e s t i o n that e t h o l o g i c a l d i f f e r e n c e s m a y a r i s e o r b e  a m p l i f i e d t h r o u g h r e i n f o r c e m e n t i s H a g e n ' s o b s e r v a t i o n that "an i n c r e a s e i n m o r p h o l o g i c a l divergence between...." h y b r i d zone i s a p p r o a c h e d . " gical differences  occurs,  l e i u r u s a n d t r a c h u r u s o c c u r s "as the  T h i s s u g g e s t s that r e i n f o r c e m e n t of m o r p h o l o -  and hence  ethological differences  m a y a l s o be  64  s u b j e c t to r e i n f o r c e m e n t .  T h i s i s a l s o s u g g e s t e d b y the n a t u r e of the  b e h a v i o u r a l d i f f e r e n c e s b e t w e e n the two m a l e p h e n o t y p e s .  T h e phenotypes  d i f f e r m o s t i n t h o s e b e h a v i o u r p a t t e r n s that a r e p r o b a b l y m o s t i m p o r t a n t f o r courtship purposes.  Other behaviour,  d o e s not a p p e a r to b e v e r y d i f f e r e n t .  the " s e x u a l d i s p l a c e m e n t " b e h a v i o u r , T h i s s u g g e s t s that r e i n f o r c e m e n t  a c t e d on s p e c i f i c b e h a v i o u r p a t t e r n s i n c o u r t s h i p ,  specifically,  the  has  zig-zag  dance.  T h e speculations  on the o r i g i n a n d f u n c t i o n of e t h o l o g i c a l i s o l a t i n g  mechanisms in Gasterosteus  e m b o d y the b a s i c t e n e t s of the t h e o r e t i c a l c o n -  t r o v e r s y s u r r o u n d i n g the o r i g i n of a l l t y p e s of i s o l a t i n g Basically,  mechanisms.  the a r e a of d i s a g r e e m e n t c o n c e r n s the r e l a t i v e i m p o r t a n c e of  r e i n f o r c e m e n t a n d the r a w s o u r c e of v a r i a t i o n on w h i c h r e i n f o r c e m e n t c a n act.  I n s p i t e of m u c h c o n s i d e r a t i o n of t h i s s u b j e c t i n the l i t e r a t u r e ,  D o b z h a n s k y (1951) a n d M a y r Gasterosteus, maintenance,  (1963) a n d o t h e r s ,  by  the p r o b l e m r e m a i n s u n s o l v e d .  b y v i r t u e of i t s w i d e s p r e a d d i s t r i b u t i o n , e a s e of c a p t u r e a n d but m o s t i m p o r t a n t l y , i t s g e n e t i c v a r i a t i o n - - m o r p h o l o g i c a l  and e t h o l o g i c a l - - m a y ,  with future investigation,  some v e r y basic questions  provide some answers  concerning speciation and evolution.  to  65  V.  1.  CONCLUSIONS  In a l a b o r a t o r y s i t u a t i o n n o n - r a n d o m m a t i n g w a s f o u n d b e t w e e n l e i u r u s and t r a c h u r u s .  N o n - r a n d o m m a t i n g o c c u r r e d b o t h i n the  situations  w h e r e a f e m a l e was p r e s e n t e d w i t h two d i f f e r e n t m a l e p h e n o t y p e s a n d w h e r e a m a l e w a s p r e s e n t e d w i t h two d i f f e r e n t f e m a l e  2.  phenotypes.  A p o s s i b l e e x p l a n a t i o n of n o n - r a n d o m m a t i n g i s the o b s e r v e d d i f f e r e n c e s i n the d e g r e e that e a c h p h e n o t y p e c o u r t s the o t h e r . phenotypes,  given a choice,  T h e m a l e s of b o t h  c o u r t f e m a l e s of t h e i r o w n p h e n o t y p e s  s i g n i f i c a n t l y m o r e t h a n t h e y do f e m a l e s of the o t h e r p h e n o t y p e . Similarly,  f e m a l e s t e n d to o r i e n t (a f u n c t i o n of c o u r t s h i p ) to m a l e s of  t h e i r own p h e n o t y p e s ,  a l t h o u g h s e l e c t i v e n e s s o n the p a r t of the  females  i s not a s d i s t i n c t as that of the m a l e s .  3.  C e r t a i n a s p e c t s of the c o u r t s h i p r i t u a l i t s e l f d i f f e r b e t w e e n the two m a l e phenotypes.  L e i u r u s males give_significantly m o r e zig-zags per  bout and z i g - z a g bouts p e r m i n u t e than t r a c h u r u s m a l e s .  Also,  the  f i r s t r e s p o n s e s of l e i u r u s m a l e s i s s i g n i f i c a n t l y d i f f e r e n t f r o m t r a c h u r u s males. zag,  4.  L e i u r u s m a l e s t e n d to i n i t i a l l y r e s p o n d to a f e m a l e w i t h a z i g -  w h e r e a s t r a c h u r u s m a l e s t e n d to i n i t i a l l y b i t e  females.  L e i u r u s m a l e s differed i n c e r t a i n responses between l e i u r u s and trachurus females,  w h e r e a s t r a c h u r u s m a l e s s e l d o m showed any  d i f f e r e n c e i n t h e i r r e s p o n s e s to e i t h e r f e m a l e p h e n o t y p e .  C e r t a i n t y p e s of b e h a v i o u r d u r i n g c o u r t s h i p , r e f e r r e d to b y i n v e s t i g a t o r s as " s e x u a l d i s p l a c e m e n t a c t i v i t y " ,  some  d i d not a p p e a r to  d i f f e r a s m u c h between the m a l e phenotypes as d i d those b e h a v i o u r p a t t e r n s ( z i g - z a g d a n c e ) w h i c h a r e n o r m a l l y thought of a s f u n c t i o n i n g to a t t r a c t f e m a l e s .  67  ACKNOWLEDGMENTS  T h i s study r e c e i v e d f i n a n c i a l s u p p o r t f r o m the N a t i o n a l R e s e a r c h C o u n c i l a n d the I n s t i t u t e of F i s h e r i e s ,  U n i v e r s i t y of B r i t i s h C o l u m b i a .  I p a r t i c u l a r l y want to t h a n k m y s u p e r v i s o r , his guidance,  Drs.  Dr. J . D. McPhail,  e n t h u s i a s m a n d c r i t i c i s m s t h r o u g h o u t the  study.  D . H . C h i t t y a n d N . R . L i l e y r e a d the m a n u s c r i p t a n d  many useful suggestions.  M r . S. B o r d e n and D r . P . A . L a r k i n  h e l p f u l s u g g e s t i o n s f o r the s t a t i s t i c a l a n a l y s i s  offered  offered  of d a t a .  I a m g r a t e f u l to D r . D . H a g e n of the U n i v e r s i t y of W a s h i n g t o n , as other students and faculty m e m b e r s and  for  as  well  of t h i s U n i v e r s i t y f o r t h e i r d i s c u s s i o n s  criticisms.  M a n y p e o p l e i n the I n s t i t u t e of F i s h e r i e s a n d D e p a r t m e n t of Z o o l o g y a s s i s t e d in field collections  a n d I a m s i n c e r e l y g r a t e f u l to t h e m a l l ,  p a r t i c u l a r t h a n k s go to M r . L . L i c h t a n d M r . R . J o n e s .  Mrs.  J . L i c h t p r e p a r e d the  figures.  but  68 REFERENCES  Assem,  J . van den.  1967.  T e r r i t o r y i n the t h r e e - s p i n e d  Gasterosteus aculeatus L .  Beukema,  J. J.  1963.  Behaviour Suppl.,  stickleback  16: 1-164.  E x p e r i m e n t s of the e f f e c t s of the h u n g e r state a n d  of a l e a r n i n g p r o c e s s o n the r i s k of p r e y of the t h r e e - s p i n d e d s t i c k l e back (Gasterosteus  Bol,  A . C. A .  1959.  aculeatus L . ) . A r c h , neerl. Zool.,  A c o n s u m m a t o r y situation.  T h e e f f e c t of e g g s on the  s e x u a l b e h a v i o u r of the m a l e t h r e e - s p i n e d s t i c k l e b a c k aculeatus L . ) . Experimentia,  Dobzhansky,  T.  1951.  Hagen,  D. W.  1967.  Heuts,  M.  1947.  aculeatus L .  Hirsch,  J.  basis. Row,  Hoar,  W . S.  1962. In  3rd ed.  Columbia  New Y o r k .  Isolating m e c h a n i s m s in threespine  (Gasterosteus).  (Gasterosteus  15:115.  G e n e t i c s a n d the o r i g i n of s p e c i e s .  University Press,  15:358-361.  J . F i s h . R e s . B d . Canada,  sticklebacks  24:1637-1692.  E x p e r i m e n t a l studies on adaptive evolution in G a s t e r o s t e u s Evolution,  1:89-102.  I n d i v i d u a l d i f f e r e n c e s i n b e h a v i o u r and t h e i r genetic  E . L . Bliss.  R o o t s of B e h a v i o u r . P p . 3 - 2 3 .  H a r p e r and  New York.  1957.  T h e g o n a d s a n d r e p r o d u c t i o n . In  P h y s i o l o g y of F i s h e s .  V o l . 1:287-321.  M . E . Brown.  Academic Press,  The  New York.  Iersel,  J . J . van.  1953.  A n a n a l y s i s of p a r e n t a l b e h a v i o u r of the  threespined stickleback (Gasterosteus aculeatus L . ) .  male  Behaviour Suppl.,  3: 1 - 1 5 9 .  Lindsey,  C. C.  1962.  E x p e r i m e n t a l study of m e r i s t i c v a r i a t i o n i n a  p o p u l a t i o n of t h r e e s p i n e s t i c k l e b a c k s , Canadian J . Zool.,  Mayr,  E.  1963.  Harvard University Press,  Mass.  R. R. and C . L . Hubbs.  aculeatus,  1969.  Systematics  of  Gasterosteus  w i t h p a r t i c u l a r r e f e r e n c e to i n t e r g r a d a t i o n a n d i n t r o -  g r e s s i o n a l o n g the P a c i f i c C o a s t of N o r t h A m e r i c a : on a recent contribution.  Morris,  D.  1958.  B.  Copeia,  A commentary  1: 5 2 - 6 9 .  T h e r e p r o d u c t i v e b e h a v i o u r of the t e n - s p i n e d  (Pygosteus pungitius L . ) .  Muckensturm,  aculeatus.  40:271-312.  A n i m a l s p e c i e s and evolution.  Cambridge,  Miller,  Gasterosteus  1967.  Behaviour Suppl.,  stickleback  6:1-154.  N o t e p r e l i m i n a i r e s u r l a s i g n i f i c a t i o n de l a l i v r e e  n u p t i a l e de l ' E p i n o c h e m a l e .  C . R . A c a d . Sc. Paris,  t. 264, S e r i e D :  489-492.  Munzing,  J.  1963.  T h e e v o l u t i o n of v a r i a t i o n a n d d i s t r i b u t i o n a l p a t t e r n s i n  E u r o p e a n p o p u l a t i o n s of the t h r e e - s p i n e d s t i c k l e b a c k , aculeatus.  Penczak,  T.  back,  Evolution,  1966.  Gasterosteus  17:320-332.  C o m m e n t s on the t a x o n o m y of the t h r e e - s p i n e d  Gasterosteus aculeatus L i n n a e u s .  Ohio J . S c i . ,  66:81-87.  stickle-  Siegel,  S.  1956.  N o n p a r a m e t r i c s t a t i s t i c s f o r the b e h a v i o u r a l  McGraw-Hill,  Sevenster-Bol,  sciences.  New York.  A.C.A.  1962.  O n the c a u s a t i o n of d r i v e r e d u c t i o n a f t e r  c o n s u m m a t o r y a c t (in G a s t e r o s t e u s a c u l e a t u s ) .  Arch, neerl.  a  Zool.,  15:175-236.  Steel, . G . D . and J . H . T o r r i e .  I960.  statistics with special reference Hill,  Symons,  P r i n c i p l e s and p r o c e d u r e s to the b i o l o g i c a l s c i e n c e s .  of McGraw-  New York.  Ph. E . K.  Stickleback.  1965.  A n a l y s i s of s p i n e - r a i s i n g i n the m a l e  Behaviour,  Ten-spined  26:1-74.  Tinbergen,  N.  1951.  T h e study of i n s t i n c t .  Oxford,  Tinbergen,  N.  1965.  S o c i a l behaviour in a n i m a l s .  Clarendon Press.  Methuen,  London.  71 A P P E N D I X T A B L E I. T h e a v e r a g e n u m b e r of z i g - z a g . b o u t s p e r m i n u t e o b t a i n e d with l e i u r u s and t r a c h u r u s m a l e s u s i n g l e i u r u s and t r a c h u r u s f e m a l e s . leiurus males leiurus females 7.0  trachurus females  trachurus males leiurus females  trachurus females  4.8 5.3  0.5  10.2 6.6 4.2  3.2 2.7  6.4 3.7  5.2 3.4  2.6 7.2  3.0 1.2  6.6 5.1  5.6  8.0  4.6  7.6  . 3.8  4.0  0.8 0.4  8.0  5.6 1.2  0.6  1.6  3.4  2.4  4.8  4.6  1.3  1.3  6.8  7.0  2.8 2.0  3.4  6.4  3.2  0.8  6.0  3.6 4.4  3.2  0.4 3.0  5.2  3.5  2.6 2.2  10.2  7.6 3.0  4.0 0.9 4.0  4.4  5.2 0.8 5.4 3.4  3.8  7.0  4.6 7.0  7.4  5.2 5.0  3.0  6.0  2.0  1.6  6.0  7.4  6.4  0.8  5.0  6.6  5.0  0.6  5.0  2.8 3.7  7.1  3.8 4.4  8.0 1.3 5.0 6.6  5.6 5.4 5.0 4.0 4.0 6.0  2.6  2.6 5.3 3.0 9.8  4.6 4.0  5.2 6.0 7.0 9.2 6.8 3.8 1.0  2.4  8.0 3.8 5.2 2.6  7.4  11.8 8.0 3.0  6.8 4.8  6.2  4.6 0.5  0.4  0.4  7.6  0.8  6.3  2.8  4.0  1.0  5.8  3.4  4.8  1.6  7.2  0.8  4.8 means  5.5  4.1  3.7  3.8  72 A P P E N D I X T A B L E II.  T h e a v e r a g e n u m b e r of z i g - z a g s p e r bout o b t a i n e d w i t h  l e i u r u s and t r a c h u r u s m a l e s u s i n g l e i u r u s and t r a c h u r u s leiurus leiurus females  males  trachurus females  8.3  4.8  4.6 3.1  4.5 5.5  4.2 5.3  trachurus males leiurus females 2.0 2.3  trachurus females 4.0  2.3  2.9 2.6  5.9  4.2  2.0  5.3  5.3  2.6  4.5  3.0  3.7  1.0  5.8  3.9  3.2  2.8  4.7 3.1  2.9  2.2 1.3  3.8 4.3  females.  2.5  1.3 2.2  2.2  4.5  6.9  3.3  2.4 2.0  9.2  5.9  3.5  2.7  3.2  2.0  2.9  3.8  4.5  4.5  1.5  1.7  4.3  5.1  3.5  6.8  2.3  4.1  3.5 4.0  2.4  3.6 4.6 7.6 2.6  3.5 2.4  3.0  2.3  2.6 2.9  4.8 3.0 3.0 2.2  5.6  2.2  4.0 2.8 4.2  1.5 1.4  3.3 2.5 3.4  6.2 7.8  3.9 7.0 5.7 4.1  4.2  4.6  2.5 3.7  6.1  3.1  4.8  3.2  1.8  2.6  4.1 3.7  1-2 1.5 3.8  3.2  3.4  2.8  1.9  3.4  2.3  5.0  1.9  9.3 10.6  1.8 2.0  3.2  2.1  5.1 2.1  2.4  2.0  3.0  3.0  3.6  2.5 2.8  3.1  2.3  5.9  2.0  3.3  3.1  3.8  2.5 2.0  2.9  3.9 3.7 means  4.7  3.8  2.9  2.5  73 A P P E N D I X T A B L E III.  T h e a v e r a g e n u m b e r of z i g - z a g s p e r m i n u t e o b t a i n e d w i t h  l e i u r u s and t r a c h u r u s m a l e s using l e i u r u s and t r a c h u r u s leiurus males leiurus females  trachurus females  trachurus males leiurus  females  trachurus  58.0  23.0  1.0  8.8  46.8  24.0  10.0  20.2  20.6  17.8  14.6  19.6  17.8 27.4  15.6 13.8  9.0  4.8 15.4  15.4 32.2  21.4  5.2  1.6  31.0  14.6  1.8  21.6 30.4 17.0  17.8 16.6 3.0  11.8 0.8 7.7  0.8 13.0 10.4  2.0  33.0  15.0  16.4  37.0 22.6 15.2 15.4  16.6 4.0 3.6 16.4  4.6 9.4 0.6 10.4  10.3 19.8 4.4 18.2  30.0  12.2  14.5  3.0  24.1  27.2  13.2  13.8  26.4  14.0  11.0  3.3  19.8  11.4 17.0  34.0  13.8  12.4 7.0  8.0  14.6  41.2  23.2  11.2  1.0  43.4  24.0  25.4  19.4  22.2  14.3  0.6 2.0  34.8  19.6  30.0  31.8  6.2  24.0  15.4  21.4 22.0  23.0  6.4 20.0  22.6 25.0  21.6  24.5 19.1 30.0  20.3  23.0  6.0  9.4 31.2  7.4  42.6  14.6  37.4  14.0  40.8  11.2 13.0  25.6 11.6  1.5 1.2 2.2  1.2 27.4 19.4 23.4  6.4 2.0  19.0 18.4  10.8 4.0  28.6 17.8 2 5.6  2.8 2.0  1.8  42.2  6.2 12.0  means  females,  1.6.  17.5  10.9  10.3  female  74  A P P E N D I X T A B L E IV.  T h e a v e r a g e n u m b e r of b i t e s p e r m i n u t e o b t a i n e d w i t h  l e i u r u s a n d t r a c h u r u s m a l e s u s i n g l e i u r u s and t r a c h u r u s f e m a l e s . leiurus leiurus  females  males  trachurus females  trachurus males leiurus females  trachurus females  0.2  0.2  1.5  1.8  0.8  5.3  6.6  4.0  8.6  1.9 1.7  0.4  5.4  4.2  0.2 0.3  0.4  2.0  3.0 2.0  8.2  2.4  1.6  1.4  3.0  1.0  1.0  8.0  0.4  6.4  2.0  3.6  2.6  1.2  0.6  9.6 25.8  2.8  15.4  5.7  1.4  9.6  0.4 9.0  0.2 3.0  7.4 2.0 1.4  3.6  0.4 0.0  1.6 0.8  0.4 3.2  6.6 4.0  1.6 16.7 9.8 5.3  22.8  0.5  2.4  4.0 1.0  1.4 6.2  7.6 8.4  6.4  5.2  7.0  2.4  14.2  1.8  6.6 7.0  5.0 3.2  8.3 6.0  2.2  16.4  1.5 1.2 3.4  18.0  5.2  0.8  3.8  0.4 5.0 1.8 2.0  9.2 6.6  1.7  14.8 19.3  4.2  24.6 22.2  3.0  21.0  4.0  2.2  1.0  6.0  6.2  0.7  6.6 2.0  11.2  5.1  0.6  5.0  5.8  1.4  3.8  2.4  0.6 1.0  6.4  1.4  4.0  9.6  3.4 3.0  7.8  10.6 17.6 3.4  1.8  5.3 2.2  1.6 1.4  0.6  2.0  1.4 1.2  2.4  1.8  4.6  0.8 means  3.6  7.3  3.4  6.4  75 A P P E N D I X T A B L E V . T h e a v e r a g e n u m b e r of s e c o n d s f a n n i n g p e r m i n u t e obtained with l e i u r u s and t r a c h u r u s m a l e s u s i n g l e i u r u s and trachurus females. leiurus leiurus females 4.4  2.0 2.6 5.2  males  trachurus females  10.5 9.3 13.3  trachurus males leiurus  females  trachurus females  3.5  1.8  1.0 0.0  3.0 4.0  8.0  11.2  3.0  0.0  5.2  4.5  3.2  3.4  1.0  16.4  2.5  12.8 2.7  2.2  13.0  6.4  9.8  14.4  3.8  4.6  19.0  21.2  4.4  15.1  9.4  2.6  10.6 7.4  1.6 5.6 3.8 3.4 5.4  23.0 9.6  0.0  5.8  0.2  0.6  6.0 4.0  7.4  6.5  8.0 5.0  3.4  10.1  6.0  0.6  20.0  6.0 5.5  4.0 5.0  11.4 12.0  13.6  3.6  8.2  4.0  9.8  5.4  1.4  6.4  9.0 2.0  0.0  8.0  8.4  1.4  5.0 13.0  6.5 7.3  9.4  2.4  10.6  3.0  3.8  5.8  . 2.0  4.4  8.0  7.7  3.6  12.0  3.0  0.4 7.2  1.0 3.0  5.0  1.8  4.6  6.6  1.9  8.0 6.0  16.4  6.7 6.6  4.8  3.2  7.4  1.6  5.7 8.0  5.0 13.6  0.4  0.8 19.4  2.5  7.7  5.8  6.0 8.9  5.6  7.4  6.6 3.4  15.6  5.8  26.0 12.0 7.0  8.6  9.0 10.2  7.2 means  6.3  7.3  7.1  5.5  76 A P P E N D I X T A B L E V I . T h e a v e r a g e n u m b e r of f a n n i n g b o u t s p e r m i n u t e obtained with l e i u r u s and t r a c h u r u s m a l e s u s i n g l e i u r u s and trachurus females. leiurus males leiurus females  trachurus females  trachurus males leiurus females  trachurus females  0.50 0.20 0.00  0.20 0.60 0.20 0.00  1.00  0.64  0.40 0.52 1.04  2.70 0.67 0.80  0.60 0.97  0.60 0.20  1.75 1.50 1.40  0.80  0.60  1.20  0.67  1.00  1.20  0.25 0.20 0.60 0.60  1.20  3.00 1.00  1.20 0.57  0.60  0-.40 0.80  2.00  1.20  1.00  0.00  1.26 1.00  0.60  0.60  0.80  0.20  0.80  0.20  1.00  0.80  0.60  1.40  0.60  0.94  0.60  1.25 0.80  0.60  1.00  0.20  3.00  1.33  0.80  0.60  1.00  0.88  1.00  1.20  1.00  0.80  0.00  2.00  0.80  1.00  1.40  0.40  1.00  0.20  1.00  0.40  0.80  3.00  1.62  0.60  0.80  0.20  •1.60  1.00  0.60  0.60  1.00  1.33  0.60 2.00  0.60 0.40  0.20  0.50  0.40  0.20 1.00 1.00 0.80  2.80  0.47 '  1.67  0.40  0.80 0.40  0.40 1.40  0.40 1.40  1.14 1.20  0.40 0.27 1.20  0.20 0.25 0.40  0.40  0.40  1.10  0.60  0.40  1.60  0.60 0.60  1.40  1.00  1.00  1.40  0.20  0.80 0.60 2.57  1.40  1.40 means  0.81  0.96  0.87  0.89  77 A P P E N D I X T A B L E V I I . T h e a v e r a g e n u m b e r of g l u i n g m o v e m e n t s p e r m i n u t e obtained with l e i u r u s and t r a c h u r u s m a l e s using l e i u r u s and trachurus females. leiurus leiurus  females  0.6 0.4 0.2 0.4 0.2  0.6 0.4 0.7 0.4 0.9 . 0.2  males  trachurus females  trachurus males leiurus  females  trachurus females  0.3 0.2 0.2 0.2 0.0 0.4 2.0 0.4 0.0 0.4  0.0 0.0 0.0 0.8 0.5 0.0 0.4 0.4 0.0  0.6  0.2 0.0 0.0 0.0 0.0 0.2 0.2 0.0 0.4 0.8 0.0 0.8 0.2  0.6  0.6  0.0  0.4  0.6  0.4 0.0 0.4  0.6  0.4  0.6  0.6  0.4  0.6  0.6  0.0 1.0 0.2  0.5 0.4 0.0 0.2 0.0 0.8 0.5 1.4 0.8 0.8 0.2 0.8  1.2 0.4 1.3 o;o 0.0 0.0 0.2 0.0 0.2 0.2 0.4  0.6  0.3  0.2 0.0 0.5 0.2 0.4 0.2  0.6 0.4 0.2 0.4  0.6 0.6 0.8 2.0 1.0 0.2 0.3  0.6  0.4 0.0 0.4  0.4 0.4  0.6 0.6  0.6  0.3 0.0 0.4 0.2 0.2  0.2 0.0 0.0 0.0 0.0 0.0 0.2 0.2 0.0 0.0  0.6  .0.0  0.4 0.3 0.0  0.6  0.6  1.0 means  0.45  0.42  0.33  0.30  APPENDIX TABLE  VIII.  T h e i n c i d e n c e of ' ' c r a w l i n g t h r o u g h ' n e s t s d u r i n g c o u r t s h i p b y l e i u r u s a n d 1  t r a c h u r u s m a l e s using l e i u r u s and t r a c h u r u s f e m a l e s . l e i u r u s m a l es  Totals  "trachurus males  trachurus  trachurus  leiurus  trachurus  leiurus  females  females  females  female s  male's  C r a w l through  11  12  19  19  23  38  No c r a w l t h r o u g h  34  17  24  9  51  33  leiurus  A P P E N D I X T A B L E IX.  male s  '  T h e f i r s t c o u r t s h i p r e s p o n s e of l e i u r u s a n d t r a c h u r u s m a l e s u s i n g l e i u r u s a n d t r a c h u r u s females". leiurus males trachurus  leiurus  trachurus  females  female s  females  females  Zig-zag  27  17  11  Bites  11  11  • 25  leiurus  Totals  t r a c h u r u s male's  '  trachurus  leiurus males  5  44  23  22  male s :  16 48  

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