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An external and cranial mophometric study of altitudinal variation in Microtus arvalis in Switzerland Prescott-Allen, Christine 1981

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AN EXTERNAL AND CRANIAL MORPHOMETRIC STUDY OF ALTITUDINAL VARIATION IN MICROTUS ARVALIS IN SWITZERLAND BY CHRISTINE/ PRESCOTT-ALLEN B.A. MCGILL UNIVERSITY, 1971 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN THE FACULTY OF GRADUATE STUDIES ZOOLOGY DEPARTMENT WE ACCEPT THIS THESIS AS CONFORMING TO THE REQUIRED STANDARD THE UNIVERSITY OF BRITISH COLUMBIA APRIL, 1981 Q CHRISTINE PRESCOTT-ALLEN, 1981 I n p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f t h e r e q u i r e m e n t s f o r an advanced degree a t t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a , I a g r e e t h a t t h e L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and s t u d y . I f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may be g r a n t e d by t h e head o f my department o r by h i s o r h e r r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l n o t be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . Department o f The U n i v e r s i t y o f B r i t i s h C o l u m b i a 2075 Wesbrook P l a c e V ancouver, Canada V6T lW5v ABSTRACT i i C r a n i a l and e x t e r n a l measurements i n 422 museum spec imens o f the common v o l e , M i c r o t u s a r v a l i s , from S w i t z e r l a n d were e x -amined to d e t e r m i n e whether they v a r i e d w i t h a l t i t u d e i n a c -co rdance w i t h e i t h e r (1) Bergmann ' s R u l e , o r (2) s u b s p e c i a t i o n . C o r r e l a t i o n c o e f f i c i e n t s between a l t i t u d e and s i z e were c a l c u l a t e d on 32 d i m e n s i o n s , each o f wh ich had been d i v i d e d i n -to sex s e g r e g a t e d age g roups . In not one o f the 108 t e s t s was c o r r e l a t i o n s i g n i f i c a n t . The l a c k o f adherence t o Bergmann ' s Ru le was i n v e s t i g a t e d by (1) r e v i e w i n g the b a s i c c o n c e p t s o f the R u l e , as a p p l i e d to homeotherms; (2) i d e n t i f y i n g the major a b i o t i c and b i o t i c s e -l e c t i o n p r e s s u r e s t h a t might a f f e c t growth i n M i c r o t u s a r v a l i s , i n c l u d i n g c l i m a t e and c o m p e t i t i o n w i t h s y m p a t r i c c o n g e n e r i c s ; and (3) i n d i c a t i n g d e f i c i e n c i e s i n da ta d e r i v e d from museum spec imens wh ich might have i n f l u e n c e d the c o m p u t a t i o n s . There were s e v e r a l r e f e r e n c e s i n the l i t e r a t u r e to the o c c u r r e n c e o f two s u b s p e c i e s o f M i c r o t u s a r v a l i s i n S w i t z e r l a n d - the nominate s u b s p e c i e s M. a . a r v a l i s ( P a l l a s , 1779) and a montane s u b s p e c i e s c a l l e d e i t h e r M. a. i n c e r t u s ( S e l y s -Longchamps, 1841) o r M. a . r u f e s c e n t e f u s c u s ( S c h i n z , 1845) . The l a c k o f e v i d e n c e i n t h i s s tudy f o r the e x i s t e n c e o f two p h e n o t y p i c a l l y and d i s t r i b u t i o n a l l y d i s t i n c t s u b s p e c i e s was c o n s i d e r e d by (1) examin ing the g e n e r a l a p p r o p r i a t e n e s s o f d i s -c u s s i n g v a r i a t i o n i n M i c r o t u s a r v a l i s i n terms o f s u b s p e c i a -t i o n ; and (2) r e v i e w i n g the l i t e r a t u r e on the d i a g n o s t i c i i i c h a r a c t e r s and d i s t r i b u t i o n a t t r i b u t e d to the montane morph. Two major c o n c l u s i o n s were drawn. The f i r s t was t h a t Bergmann ' s Ru le s hou ld not be c o n s i d e r e d a " r u l e " u n t i l f i r m d e f i n i t i o n s a re e s t a b l i s h e d on a t l e a s t two o f i t s f o u n d i n g p r e c e p t s - the groups o f a n i m a l s t o which i t a p p l i e s and the taxonomic l e v e l at wh ich i t a p p l i e s - and u n t i l i t i s found to app l y t o a m a j o r i t y o f the ca se s f o r which i t i s i n t e n d e d . The second c o n c l u s i o n was t h a t f o r s p e c i e s l i k e M i c r o t u s a r v a l i s , i n wh ich growth i s h i g h l y v a r i a b l e and d i s t r i b u t i o n i s by and l a r g e c o n t i n u o u s , the u s e f u l n e s s of f o r m a l r e c o g n i t i o n o f i n -f r a s p e c i f i c p o p u l a t i o n s i s q u e s t i o n a b l e u n t i l an o v e r v i e w o f the geog r aph i c v a r i a b i l i t y o f the s p e c i e s as a whole i s w e l l documented. i v TABLE OF CONTENTS TI T L E PAGE i ABSTRACT i i TABLE OF CONTENTS i v LI S T OF TABLES IN TEXT v i LIST OF TABLES IN APPENDIX v i i L I S T OF FIGURES IN TEXT x ACKNOWLEDGEMENTS x i INTRODUCTION 1 MATERIALS AND METHODS 2 1. S k u l l D i m e n s i o n s 2 1.1. C r a n i a l m e a surements 2 1.2. M a n d i b u l a r m e a s u r e m e n t s 10 2. E x t e r n a l D i m e n s i o n s 10 2.1. M e a s u r i n g t e c h n i q u e s i n t h e l i t e r a t u r e 10 2.2. T e c h n i c i a n s - i n v o l v e d 12 3. S e x u a l D i f f e r e n c e s 12 4. A g i n g t h e S p e c i m e n s . . , 12 4.1. A g i n g t e c h n i q u e s i n t h e l i t e r a t u r e 12 5. A l t i t u d e and S i z e 14 5.1. Home r a n g e 15 5.2. M i g r a t i o n 15 RESULTS 18 1. S k u l l D i m e n s i o n s 18 1.1. P a i r e d s t r u c t u r e s 18 1.2. M e a s u r i n g c o n s i s t e n c y 18 1.3. B r a c h y o s t i s m 21 2. S e x u a l D i f f e r e n c e s 21 2.1. S e x u a l d i m o r p h i s m 21 2.2. Sex r a t i o 23 3. A g i n g t h e S p e c i m e n s 26 3.1. A g i n g t e c h n i q u e s a p p l i e d . . . ...26 3.2. Changes i n i n d i v i d u a l d i m e n s i o n s 33 3.3. Changes i n p r o p o r t i o n a l r e l a t i o n s h i p s ..34 4. A l t i t u d e and S i z e C o r r e l a t i o n 34 V D I S C U S S I O N . . . : ^ I . : . : : . . . : . . . . . : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 7 1. Bergmann ' s Ru le AO 111. G e n e r a l r e v i ew o f Bergmann ' s r u l e AO 1.2. Bergmann ' s r u l e and M i e r o t u s a r v a l i s AA 2. S u b s p e c i a t i o n 5A 2 . 1 . M o r p h o l o g i c a l v a r i a t i o n 73 2 .2 . Geog raph i c range 76 2 .3 . Nomenc la tu re 77 CONCLUSIONS 80 APPENDIX 81 LITERATURE CITED 125 v i h1ST - OF•TABLES - IN-TEXT Tab le I: L i t e r a t u r e S y n o p s i s o f Home Range S i z e i n M i c r o t u s a r v a l i s 16 Table I I : L e f t - R i g h t S k u l l D i f f e r e n c e s i n M i c r o t u s a r v a l i s . . . . 19 Tab le I I I : C o n s i s t e n c y o f Mea su r i n g Technique 20 Tab le IV: L i t e r a t u r e S y n o p s i s o f S e xua l D imorphism i n M i c r o t u s a r v a l i s 22 Tab le V: L i t e r a t u r e S y n o p s i s o f S e a s o n a l Sex R a t i o i n M i c r o t u s a r v a l i s 24 Tab le V I : Age and Sex A n a l y s i s i n M i c r o t u s a r v a l i s by Month o f Captu re 25 Tab le V I I : L i t e r a t u r e S y n o p s i s o f Body Length i n L a b o r a t o r y M i c r o t u s a r v a l i s 27 Tab le V I I I : L i t e r a t u r e S y n o p s i s o f Body Length i n W i l d M i -c r o t u s a r v a l i s 28 Tab le IX: Body Lengths from Tab l e s V I I and V I I I o f J u v e n i l e M i c r o t u s a r v a l i s 29 Tab le X: L i t e r a t u r e S y n o p s i s o f Date o f B i r t h and Growth Rate o f M i c r o t u s a r v a l i s 31 Tab le X I : Age and Sex A n a l y s i s o f M i c r o t u s a r v a l i s S pec imen s . . 3 3 Tab le X I I : Compar i son o f C r a n i a l Measurements i n M i c r o t u s a r v a l i s Age C l a s s e s 35 Tab le X I I I : P r o p o r t i o n a l R e l a t i o n s h i p s i n S k u l l D imens ions i n Two S p e c i e s o f M i c r o t u s 36 Tab le X IV: Trends i n Body Length w i t h A l t i t u d e i n M i c r o t u s a r v a l i s ( D o t t r e n s , 1962; Jone s , 1970; Th i s T h e s i s ) 37 Tab le XV: Some Methods o f T h e r m o r e g u l a t i o n 42 Tab le XV I : L i f e H i s t o r i e s o f Three S p e c i e s o f M i c r o t u s 55 Tab le X V I I : Compar i son o f Body Lengths w i t h A l t i t u d e i n M i c r o -tu s a r v a l i s ( D o t t r e n s , 1962; Jones , 1970; Th i s T h e s i s ) . . 7 4 Tab le X V I I I : B r i e f N o m e n c l a t u r a l H i s t o r y o f M i c r o t u s a r v a l i s r u f e s c e n t e f u s c u s 7 8 Tab le X IX : B r i e f N o m e n c l a t u r a l H i s t o r y o f M i c r o t u s a r v a l i s i n c e r t u s 79 L I S T • O F - T A B L E S - I N APPENDIX A p p e n d i x T a b l e l a : M e a s u r i n g A c c u r a c y : T o t a l L e n g t h o f S k u l l . 82 A p p e n d i x T a b l e l b : M e a s u r i n g A c c u r a c y : N a s a l W i d t h 83 A p p e n d i x T a b l e l c : M e a s u r i n g A c c u r a c y : R o s t r u m W i d t h 84 A p p e n d i x T a b l e I d : M e a s u r i n g A c c u r a c y : Z y g o m a t i c W i d t h 85 A p p e n d i x T a b l e l e : M e a s u r i n g A c c u r a c y : L e a s t I n t e r o r b i t a l W i d t h 86 A p p e n d i x T a b l e I f : M e a s u r i n g A c c u r a c y : B r a i n c a s e W i d t h 87 A p p e n d i x T a b l e l g : M e a s u r i n g A c c u r a c y : P o s t Zygoma W i d t h 88 A p p e n d i x T a b l e l h : M e a s u r i n g A c c u r a c y : M a s t o i d W i d t h 89 A p p e n d i x T a b l e l i : M e a s u r i n g A c c u r a c y : F o r a m e n Magnum H e i g h t 90 A p p e n d i x T a b l e l j : M e a s u r i n g A c c u r a c y : F o r a m e n Magnum W i d t h 91 A p p e n d i x T a b l e l k : M e a s u r i n g A c c u r a c y : S k u l l H e i g h t 92 A p p e n d i x T a b l e 1 1 : M e a s u r i n g A c c u r a c y : C o n d y l o b a s a l L e n g t h . . . 9 3 A p p e n d i x T a b l e l m : M e a s u r i n g A c c u r a c y : B a s a l L e n g t h 94 A p p e n d i x T a b l e I n : M e a s u r i n g A c c u r a c y : B a s i l a r L e n g t h 95 A p p e n d i x T a b l e l o : M e a s u r i n g A c c u r a c y : P a l a t a l L e n g t h 96 A p p e n d i x T a b l e l p : M e a s u r i n g A c c u r a c y : P a l a t a l B r i d g e L e n g t h 97 A p p e n d i x T a b l e l q ; M e a s u r i n g A c c u r a c y : P a l a t a l F o r a m e n L e n g t h 98 A p p e n d i x T a b l e l r : M e a s u r i n g A c c u r a c y : P a l a t a l F o r a m e n W i d t h 99 A p p e n d i x T a b l e I s : M e a s u r i n g A c c u r a c y : M a x i l l a r y D i a s t e m a L e n g t h 100 A p p e n d i x T a b l e I t : M e a s u r i n g A c c u r a c y : M a x i l l a r y T o o t h Row L e n g t h 101 v i i i Appendix Tab le l u : Mea su r i ng A c c u r a c y : M a x i l l a r y Outer Mo-l a r w i d t h . . . . . . 102 Appendix Tab le l v : Mea su r i ng A c c u r a c y : M a x i l l a r y Inner Mo-l a r W idth 103 Appendix Tab le l w : Measu r i ng A c c u r a c y : Mand ib l e Length 104 Append ix Tab l e l x : Mea su r i n g A c c u r a c y : Jaw Length 105 Appendix Tab le l y : Mea su r i ng A c c u r a c y : M a n d i b u l a r Tooth Row Length 106 Appendix Tab le 2a : S e x u a l D imorphism and . C o r r e l a t i o n C o e f -f i c i e n t f o r A l t i t u d e and T o t a l Length o f S k u l l , N a s a l W i d t h , Rostrum Width 107 Appendix Tab le 2b: S e x u a l D imorphism and C o r r e l a t i o n C o e f -f i c e n t f o r A l t i t u d e and Zygomat ic W i d t h , Lea s t I n t e r o r b i t a l W i d t h , B r a i n c a s e Width 108 Appendix Tab le 2 c : S e x u a l D imorphi sm and C o r r e l a t i o n C o e f -f i c i e n t f o r A l t i t u d e and Pos t Zygoma W i d t h , Mas-t o i d W i d t h , Foramen Magnum He ight 109 Appendix Tab le 2d: S e x u a l D imorphism and C o r r e l a t i o n C o e f -f i c i e n t f o r A l t i t u d e and Foramen Magnum W i d t h , S k u l l H e i g h t , C o n d y l o b a s a l Length . . . 110 Appendix Tab le 2e: S e x u a l D imorphism and C o r r e l a t i o n C o e f -f i c i e n t f o r A l t i t u d e and B a s a l L eng th , B a s i l a r L e n g t h , P a l a t a l Leng th I l l Appendix Tab le 2 f : S e x u a l D imorphism and C o r r e l a t i o n C o e f -f i c i e n t f o r A l t i t u d e and P a l a t a l B r i d g e Leng t h , P a l a t a l Foramen Leng th , P a l a t a l Foramen Width 112 Appendix Tab le 2g: S e x u a l D imorphism and C o r r e l a t i o n C o e f -f i c i e n t f o r A l t i t u d e and M a x i l l a r y D ias tema Leng th , M a x i l l a r y Tooth Row Leng th , M a x i l l a r y Outer Mo l a r Width 113 Appendix Tab le 2h: S e x u a l D imorphism and C o r r e l a t i o n C o e f -f i c i e n t f o r A l t i t u d e and M a x i l l a r y Inner Mo l a r W i d t h , M o l a r W i d t h , M a n d i b l e Length 114 Appendix Tab le 2 i : S e x u a l D imorphism and C o r r e l a t i o n C o e f -f i c i e n t f o r A l t i t u d e and Jaw Leng th , M a n d i b u l a r D ia s tema Leng th , M a n d i b u l a r Tooth Row Length 115 Appendix Tab le 2 j : S e x u a l D imorphism and C o r r e l a t i o n C o e f -f i c i e n t f o r A l t i t u d e and Body ( P l u s Head) Leng th , T a i l L eng t h , Hind Foot Length 116 A p p e n d i x T a b l e 2k: S e x u a l D i m o r p h i s m and C o r r e l a t i o n C o e f -f i c i e n t f o r A l t i t u d e and E a r L e n g t h , W e i g h t 117 A p p e n d i x T a b l e 3 a : Age D i f f e r e n c e s i n T o t a l L e n g t h o f S k u l l , N a s a l W i d t h , R o s t r u m W i d t h , Z y g o m a t i c W i d t h , L e a s t I n t e r o r b i t a l W i d t h , B r a i n c a s e W i d t h . . . 1 1 8 A p p e n d i x T a b l e 3b: Age D i f f e r e n c e s i n P o s t Zygoma W i d t h , M a s t o i d W i d t h , Foramen Magnum H e i g h t , Foramen Magnum W i d t h , S k u l l H e i g h t , C o n d y l o b a s a l L e n g t h . . . . 119 A p p e n d i x T a b l e 3 c : Age D i f f e r e n c e s i n B a s a l L e n g t h , B a s -i l a r L e n g t h , P a l a t a l L e n g t h , P a l a t a l B r i d g e L e n g t h , P a l a t a l Foramen L e n g t h , P a l a t a l Foramen W i d t h 120 A p p e n d i x T a b l e 3d: Age D i f f e r e n c e s i n M a x i l l a r y D i a s t e m a L e n g t h , M a x i l l a r y T o o t h Row L e n g t h , M a x i l l a r y O u t e r M o l a r W i d t h , M a x i l l a r y I n n e r M o l a r W i d t h , M a x i l l a r y M o l a r W i d t h , M a n d i b l e L e n g t h 121 A p p e n d i x T a b l e 3e: Age D i f f e r e n c e s i n Jaw L e n g t h , M a n d i -b u l a r D i a s t e m a L e n g t h , M a n d i b u l a r T o o t h Row L e n g t h , Body L e n g t h , T a i l L e n g t h , H i n d F o o t L e n g t h A p p e n d i x T a b l e 3 f : Age D i f f e r e n c e s i n E a r L e n g t h , W e i g h t . 122 123 A p p e n d i x T a b l e 4: P r o p o r t i o n a l R e l a t i o n s h i p s w i t h Age i n C r a n i a l M e a s u r e m e n t s o f M i c r o t u s a r v a l i s 124 LIST-OF-FIGURES- IN-TEXT x F i g u r e 1; S i t e o f Captu re and Number of Specimens by Canton i n S w i t z e r l a n d 3 F i g u r e 2: L a t e r a l C r a n i a l Measurements . . . . A F i g u r e 3: Foramen Magnum Measurements A F i g u r e A; M a n d i b u l a r Measurements A F i g u r e 5: D o r s a l C r a n i a l Measurements 6 F i g u r e 6; V e n t r a l C r a n i a l Measurements 8 F i g u r e 7: N o n - j u v e n i l e Body Lengths i n M i c r o t u s a r v a l i s ( D o t t r e n s , 1962; Jone s , 1970; Th i s T h e s i s ) 38 F i g u r e 8: A l t i t u d e Ranges o f Three S p e c i e s o f M i c r o t u s 51 ACKNOWLEDGEMENTS x i I t h a n k t h e f o l l o w i n g p e r s o n s i n t h e s i x i n s t i t u t i o n s w h i c h l e n t t h e M i c r o t u s m a t e r i a l : Dr. F. Baud (Musee d ' H i s t o i r e N a t u r e l l e ) , Dr. C. C l a u d e ( Z o o l o g i s c h e s Museum d e r U n i v e r s i t a t Z u r i c h ) , Dr. R. H u t t e r e r ( Z o o l o g i s c h e s F o r s c h u n g s i n s t i t u t und Museum A l e x a n d e r K o e n i g ) , Dr. P. Lups ( N a t u r h i s t o r i s c h e s Museum B e r n ) , Dr. A. M e y l a n ( S t a t i o n F e d e r a l e de R e c h e r c h e s A g r o n o m i q u e s ) and Dr. J . M u l l e r ( B u n d n e r N a t u r h i s t o r i s c h e s und N a t i o n a l p a r k m u s e u m ) . I a l s o t h a n k M a r g u e r i t e J u r g e n s e n f o r h e r t r a n s l a t i o n s o f German a r t i c l e s , P a t r i c k V i r o l l e f o r h i s map and s k u l l d r a w-i n g s , V e r e n a W i e s t n e r f o r h e r t y p i n g , Dr. H. Dean F i s h e r and Dr. H a r o l d N o r d a n f o r t h e i r comments on t h e f i r s t d r a f t . I want t o e x p r e s s a v e r y s p e c i a l t h a n k you t o Dr. H i l a r y S e a l , my s t a t i s t i c a l m e n t o r , who so g e n e r o u s l y - and w i t h c h a r a c t e r i s t i c humour and s u r p r i s i n g t o l e r a n c e - gave h i s t i m e and a d v i c e i n g u i d i n g me t h r o u g h t h e c o m p u t e r a n a l y s i s ; and t o Dr. J . Mary T a y l o r , my s u p e r v i s o r , who so c o n s i s t e n t l y s u p p o r t -ed my l o n g d i s t a n c e work w i t h c h e e r f u l e n c o u r a g e m e n t and v a l u -a b l e d i r e c t i o n . INTRODUCTION 1 In S w i t z e r l a n d , the common v o l e , M i c r o t u s a r v a l i s , i s found a t a l t i t u d e s r a n g i n g from a p p r o x i m a t e l y 300 meters t o 2600 m e t e r s . Th i s 2000+ meter a l t i t u d i n a l range i n a r e l a t i v e -l y s m a l l c o u n t r y makes the v o l e a pr ime c a n d i d a t e f o r s t u d i e s i n g e o g r a p h i c v a r i a t i o n . To da te two major r e p o r t s ( D o t t r e n s , 1962; Jone s , 1970) and an a r t i c l e (Lehmann, 1967) have appeared on t h i s s u b j e c t . A l s o , r e f e r e n c e s t o v a r i a t i o n i n the common v o l e i n the A l p s have been made i n at l e a s t two books ( G d l d i , 1914; A l l e e and S chm id t , 1962 ) . However the da ta p r e s e n t e d and the s t a t e m e n t s made about g e o g r a p h i c v a r i a t i o n i n Mj_ a r v a l i s c o n f l i c t . On the one hand t h e r e a re t ho se who contend t h a t v a r i a t i o n i n M. a r v a l i s e x e m p l i f i e s Bergmann ' s Ru le by showing a c l i n e i n which s i z e i n c r e a s e s w i t h a l t i t u d e ( G o l d i , 1912; A l l e e and Schm id t , 1962) . On the o t h e r hand t h e r e a re tho se who r e p o r t t h a t a l t i t u d i n a l v a r i a t i o n i n M. a r v a l i s e i t h e r does not f o l l o w Bergmann ' s Ru le a t a l l ( D o t t r e n s , 1962) o r o n l y f o l l o w s i t i n p a r t o f i t s range ( J o n e s , 1970 ) . T h i s group ( i n c l u d i n g L e h -mann, 1967) , e x p l a i n s the v a r i a t i o n t r e n d s i n terms of s ub spe -c i a t i o n . Th i s s tudy a n a l y s e s c r a n i a l and e x t e r n a l d imens i on s i n Sw i s s spec imens o f M i c r o t u s a r v a l i s i n an a t tempt t o e s t a b l i s h whether t h e r e i s m o r p h o l o g i c a l v a r i a t i o n w i t h a l t i t u d e ; i f s o , to de te rm ine whether such v a r i a t i o n conforms t o Bergmann ' s Ru le o r , a l t e r n a t i v e l y , s ugges t s s u b s p e c i a t i o n ; i f n o t , to e x p l o r e the rea son s why n o t . 2 MATERIALS-AND•METHODS Four hundred and twen ty - two spec imens o f M i c r o t u s a r v a l i s were examined. A l l the a n i m a l s were t r a p p e d i n S w i t z e r l a n d ( F i g u r e 1) between 1930 and 1978. They r e p r e s e n t the common v o l e c o l l e c t i o n s o f f o u r Sw i s s museums, a Swi s s f e d e r a l a g r i -c u l t u r a l s t a t i o n and one German museum (Append ix 1; page 8 1 ) . Two s e t s o f measurements were s t u d i e d ; e x t e r n a l measurements t a ken by the c o l l e c t o r s and s k u l l measurements t aken by t h i s a u t h o r . A l l computer a n a l y s e s were pe r fo rmed on a CDC 6500 computer a t the E c o l e Po l y t !echn ique F e d e r a l e de Lausanne. 1. S k u l l - D i m e n s i o n s A t o t a l o f 27 s k u l l d imen s i on s - 23 c r a n i a l and f o u r man-d i b u l a r - was r e c o r d e d f o r each spec imen to the n e a r e s t .05 m i l l i m e t e r by means o f d i a l c a l i p e r s . These measurements a re i l l u s t r a t e d i n F i g u r e s 2-6 and a re d e s c r i b e d as f o l l o w s : 1.1. Cran_ia_l Mea;surement_ s_ 1 . 1 .1 . Greates^_ leng_th p_f_sku_l l ; maximum d i s t a n c e from the most p o s t e r i o r p r o j e c t i o n o f the o c c i p i t a l c o n d y l e s to the most a n t e r i o r p a r t o f the cu r ve o f the i n c i s o r s ( Snyder , 1954; Rose -v e a r , 1969 ) . F i g u r e 2 D i s t a n c e AB Page 4 1 .1.2. Condy_lobasal_ leng_th: d i s t a n c e from the a n t e r i o r edge o f the median i n c i s i v e a l v e o l i t o the p o s t e r i o r p r o j e c t i o n o f the o c c i p i t a l c o n d y l e s . F i g u r e 2 D i s t a n c e AC Page 4 FigureV.Site of capture and number of specimens by canton in Switzerland ^ FIGURE 2: LATERAL CRANIAL MEASUREMENTS A A FIGURE 3: FORAMEN MAGNUM MEASUREMENTS FIGURE -4: MANDIBULAR MEASUREMENTS B C D 5 1.1.3. Nasal^ w i d t h : maximum d i s t a n c e a c r o s s the n a s a l bones (DeBlase and M a r t i n , 1974). F i g u r e 5 L i n e A Page 6 1.1.4. Rostrum w i d t h : d i s t a n c e a c r o s s the rostrum taken by b a c k i n g each arm of the c a l i p e r s a g a i n s t the r e s p e c t i v e a n t e r -i o r edge of the m a x i l l a r y p r o c e s s e s of the zygoma, and p l a c i n g the n e e d l e p o i n t of each arm on the m a x i l l a below the r e s p e c t i v e i n f r a o r b i t a l foramen. F i g u r e 5 L i n e B Page 6 1.1.5. .__e.__sJ_ i.nt_e£0£b_ital_w_id_th: minimum d i s t a n c e between the o r b i t s t a k e n d o r s a l l y a c r o s s the f r o n t a l bones (Rosevear, 1969; G l a s s , 1974; DeBlase and M a r t i n 1974). F i g u r e 5 L i n e C Page 6 1.1.-6. Z_yg_oma_ti£ width_: d i s t a n c e between the o u t e r edges of the zygomatic a r c h e s a t the w i d e s t p o i n t s (Rosevear, 1969; G l a s s , 1974; DeBlase and M a r t i n , 1974). F i g u r e 5 L i n e D Page 6 1.1.7. B r a i n c a s e w i d t h : maximum d i s t a n c e a c r o s s the b r a i n c a s e taken j u s t above the r o o t s of the squamosal p r o c e s s e s o f the zygoma (Rosevear, 1969; DeBlase and M a r t i n , 1974). F i g u r e 5 L i n e E Page 6 1.1.8. Post_z^goma w i d t h : minimum w i d t h o f the cranium imme-d i a t e l y p o s t e r i o r t o the squamosal p r o c e s s e s of the zygoma. F i g u r e 5 L i n e F Page 6 1.1.9. Maj;toid_ w i d t h : maximum wi d t h a c r o s s the mastoid p r o -c e s s e s ( G l a s s , 1974). F i g u r e 5 L i n e G Page 6 FIGURE 5: DORSAL CRANIAL MEASUREMENTS 1.1.10. Fojramerj m a £ n u m _ h e i £ h _ t : maximum h e i g h t o f t h e f o r a m e n magnum. F i g u r e 3 L i n e A Page 4 1.1.11. Foramen^ ma£num_w_id_thj_ maximum w i d t h o f t h e f o r a m e n magnum. 1.1.12. S k u l _ l he _ig h t : d i s t a n c e f r o m t h e d o r s a l m i d l i n e o f t h e f r o n t a l b o n e s t o t h e v e n t r a l m i d l i n e o f t h e p a l a t i n e b o n e s d i -r e c t l y a n t e r i o r t o t h e m e s o p t e r y g o i d f o s s a ( R o s e v e a r , 1 9 6 9 ) . 1.1.13. Ba_sa_l . l e n g t h y d i s t a n c e f r o m t h e a n t e r i o r e d g e o f t h e m e d i a n i n c i s i v e a l v e o l i t o t h e a n t e r i o r m i d - p o i n t on t h e l o w e r e d g e o f t h e f o r a m e n magnum ( G l a s s , 1974; D e B l a s e a n d M a r t i n , 1 9 7 4 ) . 1.1.14. B a ^ i _ l a r j ^ e n g ^ h ^ d i s t a n c e f r o m t h e p o s t e r i o r e d g e o f t h e m e d i a n i n c i s i v e a l v e o l i t o t h e a n t e r i o r m i d - p o i n t on t h e l o w e r e d g e o f t h e f o r a m e n magnum ( G l a s s , 1 9 7 4; D e B l a s e and Mar-t i n , 1 9 7 4 ) . F i g u r e 6 D i s t a n c e AK Page 8 1'.-. 1.15. Pal.at_a_l . l e n g t h y d i s t a n c e f r o m t h e a n t e r i o r e d g e o f t h e m e d i a n i n c i s i v e a l v e o l i t o t h e a n t e r i o r e d g e o f t h e m e s o p t e r y -g o i d f o s s a . 1.1.16. Pa.la.ta_l jar_idjgie_le_n£t_h: d i s t a n c e f r o m t h e p o s t e r i o r e d g e o f t h e r i g h t p a l a t a l f o r a m e n t o t h e a n t e r i o r e d g e o f t h e m e s o p t e r y g o i d f o s s a ( C h i c a g o N a t u r a l H i s t o r y Museum, 1 9 6 2 ) . F i g u r e 6 D i s t a n c e E I Page 8 1.1.17. Pa_la_ta_l .foramen l e n g t _ h j _ d i s t a n c e f r o m t h e a n t e r i o r e d g e t o t h e p o s t e r i o r e d g e o f t h e r i g h t p a l a t a l f o r a m e n . F i g u r e 6 D i s t a n c e CE Page 8 F i g u r e 3 L i n e B Page 4 FIGURE 6: VENTRAL CRANIAL MEASUREMENTS 9 1.1.18. P a l a t a l _foramen w i d t h : d i s t a n c e f r o m t h e l a b i a l edge o f t h e r i g h t p a l a t a l f o r a m e n t o t h e l a b i a l edge o f t h e l e f t p a l a t a l f o r a m e n a t t h e w i d e s t p o i n t . F i g u r e 6 L i n e D Page 8 1.1.19. Ma2<i.lla_ry_ d _ i a s t e m a _ l e n c ) t h : d i s t a n c e f r o m t h e p o s t e r i o r edge o f t h e a l v e o l u s o f t h e r i g h t I"*" t o t h e a n t e r i o r edge o f t h e a l e v o l u s o f t h e o f t h e r i g h t m o l a r row ( D e B l a s e and M a r t i n , 1 9 7 4 ) . F i g u r e 6 D i s t a n c e BF Page 8 1.1.20. M a x i j ^ l a r ^ t_ooth _row jLengt_hj_ d i s t a n c e f r o m t h e a n t e r i o r edge o f t h e a l v e o l u s o f t h e M"*" t o t h e p o s t e r i o r edge o f t h e a l v e o l u s o f t h e l a s t c h e e k t o o t h i n t h e r i g h t m o l a r row ( D e B l a s e and M a r t i n , 1 9 7 4 ) . F i g u r e 6 D i s t a n c e F J Page 8 1.1.21. Maxi_lla_ry_ o u t e r ; mo_lar w i d t h : d i s t a n c e f r o m t h e l a b i a l edge o f t h e a l v e o l u s o f t h e M"*- o f t h e r i g h t m o l a r row t o t h e l a b i a l edge o f t h e a l e v o l u s o f t h e M"*" o f t h e l e f t m o l a r row. F i g u r e 6 L i n e G Page 8 1.1.22. Ma>^i_llary_ i^nnei; molar; w i d t j n : d i s t a n c e f r o m t h e l i n g u a l edge o f t h e a l v e o l u s o f t h e M 1 o f t h e r i g h t m o l a r row t o t h e l i n g u a l edge o f t h e a l v e o l u s o f t h e M 1 o f t h e l e f t m o l a r row. F i g u r e 6 L i n e H Page 8 1.1.23. Mo_la£ width_: r e m a i n d e r when t h e m a x i l l a r y i n n e r m o l a r w i d t h i s s u b t r a c t e d f r o m t h e m a x i l l a r y o u t e r m o l a r w i d t h . 1.2. Mand^bular_Measur_ement£ 1.2.1. Mand^b_le_leng_th: d i s t a n c e from the p o s t e r i o r edge of the r i g h t c o n d y l o i d process to the a n t e r i o r edge of the a l v e o -l u s o f the r i g h t i n c i s o r . F i g u r e 4 D i s t a n c e AE Page 4 1.2.2. £ a w . l.e2.gth2_ d i s t a n c e from the p o s t e r i o r edge of the a l v e o l u s o f the r i g h t 1^ to the p o s t e r i o r edge of the a l v e o -l u s of the l a s t cheektooth of the r i g h t molar row. Fig u r e 4 D i s t a n c e BD Page 4 1.2.3. Mand^bular_tooth_row_leng_th: d i s t a n c e from the a n t e r -i o r edge of the a l v e o l u s of the to the p o s t e r i o r edge of the a l v e o l u s o f the l a s t cheektooth of the r i g h t molar row. F i g u r e 4 D i s t a n c e CD Page 4 1.2.4. Mandibu 1 ar_di_as_tema _lengt_hj_ remainder when the mandib-u l a r t o o t h row l e n g t h i s s u b t r a c t e d from the jaw l e n g t h . 2. E x t e r n a l Dimensions F i v e e x t e r n a l body dimensions were analys e d : weight; body ( i n c l u d i n g head) l e n g t h ; t a i l l e n g t h ; h i n d f o o t l e n g t h ; and ear l e n g t h . The e x t e r n a l dimensions were p r o v i d e d by numerous, mostly u n i d e n t i f i e d c o l l e c t o r s u s i n g u n s p e c i f i e d techniques. Because measurements can vary depending both on the measuring technique adopted and on the person performing the technique, t h i s set of e x t e r n a l measurements may be u n r e l i a b l e . 2.1. Measuring_ Te c h n i q u e s _ i n the Lit_erat_ure J e w e l l and F u l l a g a r (1966) l i s t e d f i v e methods of measur-ing the body and t a i l l e n g t h : B r i t i s h Museum Old; Hanging; 11 M o r r i s o n - S c o t t P i n s ; B r i t i s h Museum New; and M o r r i s o n - S c o t t D i -v i d e r s . They a l s o noted t h a t the head and body measurement i s most v u l n e r a b l e to e r r o r because the s p i n a l column t a k e s a s i n u o u s form and when handled can be s t r e t c h e d out t o a v a r i -a b l e degree. A n s e l l (1965) l i s t e d t h r e e methods of measuring the t a i l a l o n e - from i t s j u n c t i o n w i t h the body or w i t h the p e l v i s or w i t h the anus. A l s o the t a i l l e n g t h may vary c o n s i d e r a b l y , up to f i v e p e r c e n t i n M i c r o t u s c a l i f o r n i e u s s a n c t i d i e g i ( H o w e l l , 1924), depending on the i n t e r v a l between death and measurement ( D a l e , 1940). Even the h i n d f o o t can be measured i n two ways - from the h e e l to the end o f the l o n g e s t d i g i t , e i t h e r i n c l u d i n g the n a i l or w i t h o u t i t . C o n v e n t i o n a l l y Americans measure cum ungue; o t h e r s s i n e ungue ( A n s e l l , 1965). Weight might appear to be a most s t r a i g h t f o r w a r d measure-ment, but even i t has p o t e n t i a l h a z a r d s . C a n t u e l (1940) ad-v i s e d t h a t i t was b e t t e r to weigh an a n i m a l w h i l e i t was a l i v e o r i m m e d i a t e l y a f t e r i t s death as weight drops q u i c k l y once d e c o m p o s i t i o n b e g i n s . He argued, however, t h a t measurements of weight are r e l a t i v e l y p r e c i s e , g i v e n t h a t a kilogramme can be weighed w i t h an e r r o r f a c t o r of o n l y one m i l l i g r a m m e but to o b t a i n the same a p p r o x i m a t i o n i n l i n e a r measurement, a k i l o -meter measurement must be a c c u r a t e t o a m i l l i m e t e r . 2.2. J e c h n i c i a n s I_nvo.lved E v e n i f a l l t h e c o l l e c t o r s o f t h e s p e c i m e n s a n a l y s e d had u s e d t h e same t e c h n i q u e s , t h e number o f i n d i v i d u a l s i n v o l v e d c o u l d s t i l l be a s o u r c e o f v a r i a t i o n . J e w e l l and F u l l a g a r ( 1 9 6 6 : page 5 0 ? ) c o n c l u d e d t h a t "two w o r k e r s , e v e n t h o u g h t h e y b e l i e v e t h e y a r e u s i n g t h e same t e c h n i q u e s , may d e v e l o p i d i o -s y n c r a c i e s o f p r o c e d u r e t h a t r e n d e r t h e i r m e a s u r e m e n t s u n -s u i t a b l e f o r c o m p a r i s o n " . 3. S e x u a l D i f f e r e n c e s Of t h e 422 s p e c i m e n s , 367 had been s e x e d by t h e c o l l e c -t o r s . A p a r t f r o m t h e 55 s p e c i m e n s o f unknown s e x , t h e r e were 230 f e m a l e s and 137 m a l e s . 4. A g i n g - t h e - S p e c i m e n s 4.1. Ag_in£ J _ e c h n i q u e s _ i n t_he L i t e r a t u r e A g i n g M i c r o t u s a r v a l i s s p e c i m e n s p o s e s f o r m i d a b l e p r o b -l e m s , y e t an age a n a l y s i s , no m a t t e r how r o u g h and i m p e r f e c t , i s n e c e s s a r y f o r any s t u d y o f v a r i a t i o n as t h e g r e a t e s t s i n g l e c a u s e o f v a r i a t i o n w i t h i n a s p e c i e s c a n p r o b a b l y be a s c r i b e d t o age ( D o u t t , 1 9 5 5 ) . 4.1.1. S ku 11 c ha rac_t e r i s t _ i c_s The t h r e e m a j o r a p p r o a c h e s t o a g i n g m i c r o t i n e s t h r o u g h s k u l l c h a r a c t e r i s t i c s i n c l u d e a n a l y s i n g s u t u r e l i n e s , c r e s t d e -v e l o p m e n t and t o o t h wear. A g i n g by s u t u r e l i n e s c a n n o t be a p p l i e d t o M i c r o t u s a r v a l i s . I n t h i s i t r e s e m b l e s M i c r o t u s  p e n n s y 1 v a n i c u s i n w h i c h S n y d e r ( 1 9 5 4 ) f o u n d s u t u r e l i n e s o f no a i d b e c a u s e some d i s a p p e a r q u i t e e a r l y w h i l e o t h e r s r e m a i n 13 a p p a r e n t e v e n i n t h e o l d e s t i n d i v i d u a l s . U n f o r t u n a t e l y , u n l i k e M. p e n n s y 1 v a n i c u s , t h e common v o l e does n o t a p p e a r t o m a n i f e s t v i s i b l e c h a n g e s i n l a m b d o i d a l o r m a s t o i d - e x o c c i p i t a l c r e s t s w i t h a g e . S p i t z ( 1 9 7 4 ) s t a t e d t h a t a g i n g M. a r v a l i s by t o o t h wear i s o u t o f t h e q u e s t i o n as t h e r e i s no v a r i a t i o n w i t h t i m e . 4.1.2. Eye l.ens_ I n 1959 L o r d d e s c r i b e d a p r o c e s s o f a g i n g r a b b i t s by de-t e r m i n i n g t h e d r y w e i g h t o f t h e eye l e n s . M a r t i n e t ( 1 9 6 6 ) , Le L o u a r n ( 1 9 7 1 ) and M e u n i e r and S o l a r i ( 1 9 7 2 ) a p p l i e d t h e same t e c h n i q u e t o s p e c i m e n s o f M. a r v a l i s . I t has been c a l l e d by S p i t z ( 1 9 7 4 ) t h e o n l y p r e c i s e method o f age d e t e r m i n a t i o n i n t h e common v o l e . However, i t i s n o t p o s s i b l e t o age museum s p e c i m e n s by t h i s t e c h n i q u e . 4.1.3. Bod y_we i g_h_t W e i g h t i s t h e i n d e x most o f t e n u s e d t o age l i v i n g s m a l l mammals, e s p e c i a l l y r o d e n t s (D. C h i t t y , 1952; K r e b s and M y e r s , 1 9 7 4 ) . However, i t was d e c i d e d n o t t o age t h e museum s p e c i -mens i n t h i s s t u d y by w e i g h t c l a s s due t o comments i n t h e l i t e r a t u r e on t h e d r a w b a c k s o f t h i s a p p r o a c h . W i t h i n any g i v e n age c o h o r t i n M i c r o t u s a r v a l i s body w e i g h t s may d i f f e r s i g n i f i c a n t l y ( M e u n i e r and S o l a r i , 1 9 7 2 ) . A 40 day o l d m a l e , f o r e x a m p l e , may be as heavy as v e r y o l d a n i m a l s ( F r a n k , 1 9 5 7 ) . A l s o w e i g h t v a r i e s i n b o t h s e x e s , w i t h d i e t a n d , i n f e m a l e s , w i t h p r e g n a n c y . I n c a p t i v e common v o l e s , w e i g h t d i m i n i s h e d when f o o d was u n f a v o u r a b l e ( M e u n i e r and S o l -a r i , 1972) and i n p r e g n a n t f e m a l e s l i t t e r w e i g h t was f o u n d t o amount t o 53.2% o f the m o t h e r ' s we ight ( F r ank , 1957 ) . Frank (1957) c o n c l u d e d t h e r e f o r e t h a t every a n a l y s i s o f v o l e p o p u l a -t i o n s f o r age c l a s s i f i c a t i o n based on we ight must l e a d t o s e r i -ous e r r o r s , and c o n c l u s i o n s based on them would be s u b j e c t t o q u e s t i o n . A. 1.4. Body_lenc_th Body l e n g t h a l s o has been used as a method o f a g i ng M i c r o -t u s a r v a l i s and i t was the benchmark by wh ich the spec imens i n t h i s s tudy were aged s i n c e ag ing e r r o r s due to pregnancy c o u l d be a v o i d e d and s i n c e more o f the spec imens had da t a on body l e n g t h than we i gh t (281 ve r s u s 2A5) . However, l i k e w e i g h t , body l e n g t h i n the common v o l e i s s u b j e c t t o i n d i v i d u a l v a r i a -t i o n ( F rank and Zimmermann, 1957b) . A l s o Meun ie r and S o l a r i (1972) h y p o t h e s i z e d t h a t body l e n g t h i n M. a r v a l i s was s t r o n g l y l i n k e d w i t h we i gh t wh ich made i t s u s c e p t i b l e t o f l u c t u a t i o n s w i t h d i e t . A d d i t i o n a l f a c t o r s a re the season o f b i r t h and pop -u l a t i o n c y c l i n g . These a re d i s c u s s e d on pages 30 and A5 t o A6 r e s p e c t i v e l y . 5. A l t i t u d e - and S i z e The f i n a l a r e a o f q u a n t i t a t i v e a n a l y s i s i n v o l v e d the r e l a -t i o n s h i p between spec imen s i z e and a l t i t u d e . Wh i l e i n f o r m a t i o n was p r o v i d e d on the a l t i t u d e s at wh ich a l l A22 spec imens had been t r a p p e d , two major p o i n t s had to be c o n s i d e r e d i n d e c i d i n g what r e p r e s e n t e d t he r e a l a l t i t u d e a t wh ich each a n i m a l l i v e d . These were home range and m i g r a t i o n . Home range i s " t h a t a rea t r a v e r s e d by the i n d i v i d u a l i n i t s normal a c t i v i t i e s o f food g a t h e r i n g , mat ing and c a r i n g f o r young" ( B u r t , 1943; page 351 ) . S p i t z (1970a) found t h a t the home ranges ( "domaine v i t a l " ) o f M. a r v a l i s i n d i v i d u a l s were u s u a l l y s t a b l e t h r oughou t t h e i r l i v e s , e x c e p t i n t he ca se o f a major event such as a f l o o d . E l t o n (1965) c i t e d work by Fenyuk and S h e i k i n a (1938) i n wh ich common v o l e s were marked and r e l e a s e d . When they were r e -l e a s e d i n o l d s t r aw s t a c k s they showed very l i t t l e i n c l i n a t i o n to wander f a r ; i n f a c t 126 out of 131 were s u b s e q u e n t l y r e t a k e n i n the same s t a c k s . When, however, they were r e l e a s e d on open p a s t u r e , they wandered f a r , sometimes as much as 2 1/2 k i l o m e t e r s , and they showed a r emarkab l e c a p a c i t y f o r f i n d i n g the s t a c k s i n wh i ch they had l i v e d b e f o r e . E l t o n (1965) a l s o c i t e d M. a r v a l i s r e s e a r c h conduc ted by V a r s h a v s k i i (1937) i n wh ich 51% o f the v o l e s marked and r e c a p t u r e d had moved a d i s -t ance between 0 and 100 meter s o n l y . Tab le I summarizes the home range d a t a on M i c r o t u s a r v a l i s from Tab le XVId (page 5 8 ) . 5.2. Mi£ra_ti_0£i Many a l p i n e mammals make r e g u l a r s e a s o n a l m i g r a t i o n s u p -ward and downward to a v o i d food s c a r c i t y and s eve re weather ( A l l e e and S c h m i d t , 1962 ) . M ight then a M. a r v a l i s spec imen t r apped a t 1000 meter s i n Oc tobe r be, i n f a c t , an a n i m a l wh ich has m i g r a t e d t o t h i s l owe r a l t i t u d e f o r the w i n t e r from i t s h i g h e r summer a l t i t u d e o f 2500 meter s ? I t i s p o s s i b l e , but TABLE I: LITERATURE SYNOPSIS OF HOME RANGE SIZE IN MICROTUS ARVALIS LENGTH (METERS) SEX Females 6.5 m i n July (Dub, 1971a) 5.8 m i n October (Dub, 1971a) DIAMETER (METERS) 10 to 20 m i n breeding season (Frank, 1957) AREA (SQUARE METERS) 1/4 of 146 t o 600 sq m ( N i k i t i n a , K a r u l i n and Zen'kovich, 1972) 300 to 500 sq m i n planta-t i o n ( R e i c h s t e i n , 1960b) Both Smaller than 10 m ( S p i t z , 1963b) 7.5 to 9 m ( S p i t z et a l , 1974) Each family occupies only a few square meters (Bernard, 1959) A few square meters a-round the burrow ( S a i n t Girons, 1973) Males 12.9 m i n July (Dub, 1971a) 6.8 m i n October (Dub, 1971a) 40 to 100 m i n winter (Frank, 1957) 1/4 of 828 to 1008 sq m ( N i k i t i n a , K a r u l i n and Zen'kovich, 1972) 1200 t o 1500 sq m i n p l a n -t a t i o n ( R e i c h s t e i n , 1960b) t—• 17 u n l i k e l y . R e s e a r c h i n d i c a t e s t h a t w h i l e t h e common v o l e i s p h y s i c a l l y c a p a b l e o f c o v e r i n g r e l a t i v e l y g r e a t d i s t a n c e s ( 1 % o f V a r s h a v s k i i ' s ( 1 9 3 7 ) marked s p e c i m e n s t r a v e l l e d 2000 m e t e r s t o 5000 m e t e r s ) , i t does n o t a p p e a r t o make t h i s a h a b i t . R a t h e r i t r e s t r i c t s i t s m i g r a t i o n s t o v e r y l o c a l movements ( R e g n i e r and P u s s a r d , 1926; B r i n k , 1 9 6 7 ) . These t e n d t o be s e a s o n a l i n n a t u r e due e i t h e r t o s h i f t s o u t o f t h e c u l t i v a t e d a r e a s a t p l o u g h i n g and h a r v e s t i n g t i m e ( C e c h o w i c z and P u c e k , 1 9 6 1 ; Dub, 1971b) o r t o c h a n g e s i n f o o d a v a i l a b i l i t y ( D e l o s t , 1 9 5 5 b ) . A l s o two h a b i t s o f M i c r o t u s a r v a l i s - b u r r o w i n g and s t o r i n g f o o d u n d e r g r o u n d - may m i t i g a t e t h e p r o b l e m s o f w i n t e r f a c e d by o t h e r a l p i n e mammals t o s u c h an e x t e n t t h a t t h e r e i s no need f o r m i g r a t i o n . I n c o n c l u s i o n , t h e home r a n g e s o f M i c r o t u s a r v a l i s a p p e a r t o be r e s t r i c t e d and m i g r a t i o n s l o c a l . The a l t i t u d e a t w h i c h e a c h s p e c i m e n was t r a p p e d , t h e r e f o r e , was c o n s i d e r e d t o r e p r e -s e n t i t s " t r u e " a l t i t u d e . RESULTS 18 1. S k u l l D i m e n s i o n s 1.1. E a i r£d_S;t ruc_turejs P a i r e d s t r u c t u r e s - t h e p a l a t a l f o r a m i n a , t h e d i a s t e m a s , t h e t o o t h r o w s , t h e m a n d i b l e s and t h e j a w s - were a l w a y s meas-u r e d on t h e r i g h t s i d e . To d e t e r m i n e w h e t h e r t h e r e was any r i g h t - l e f t d i f f e r e n c e , 25 s k u l l s were m e a s u r e d on b o t h s i d e s and a S t u d e n t ' s t - t e s t was r u n on t h e d i f f e r e n c e b e t w e e n t h e means f o r e a c h s e t o f p a i r e d s t r u c t u r e s . T h e r e was no d i f f e r -e n c e a t .001 l e v e l o f s i g n i f i c a n c e ( T a b l e I I ) . 1.2. M e a s u r i n c j Consi_s;tencj£ The a u t h o r ' s m e a s u r i n g t e c h n i q u e was t e s t e d f o r . i t s c o n -s i s t e n c y . T w e n t y - f i v e i n t a c t s k u l l s were e a c h m e a s u r e d t h r e e t i m e s f o r 25 o f t h e 2/ d i m e n s i o n s . ( A s m a x i l l a r y m o l a r w i d t h and m a n d i b u l a r d i a s t e m a l e n g t h were b a s e d e n t i r e l y on t h e r e l a -t i o n s h i p o f o t h e r s p e c i f i e d d i m e n s i o n s , t h e s e two were n o t i n -c l u d e d ) . The f i r s t r o u n d o f m e a s u r i n g t o o k p l a c e i n June 1 9 7 8 ; t h e s e c o n d i n mid O c t o b e r 1978; t h e t h i r d a t s t h e b e g i n n i n g o f No-vember 1978. The a v e r a g e o f t h e t h r e e m e a s u r e m e n t s f o r e a c h d i m e n s i o n p l u s o r m i n u s t h e s t a n d a r d e r r o r was c a l c u l a t e d and t h e c o e f f i c i e n t o f v a r i a t i o n c omputed ( A p p e n d i x T a b l e s l a t o l y : p a g e s 82 t o 1 0 6 ) . The l a t t e r c o m p u t a t i o n e n a b l e d c o m p a r i -son o f v a r i a b i l i t y among measurements w i t h w i d e l y d i f f e r i n g mean l e v e l s ( D a v i e s and G o l d s m i t h , 1 9 7 2 ) . T a b l e I I I , b a s e d on t h e m e d i a n c o e f f i c i e n t o f v a r i a t i o n f o r e a c h o f t h e 25 s k u l l TABLE I I : LEFT-RIGHT SKULL DIFFERENCES IN MICROTUS ARVALIS NAME OF 7 MEASUREMENTS MEAN (MM) OF MEASUREMENTS T-VALUE FOR DIFFERENCE (LEFT VS. RIGHT) (N=25) * STANDARD ERROR BETWEEN THE MEANS P a l a t a l foramen (L) 4.025 * .064 P a l a t a l foramen (R) 4.034 * .066 -.094 M a x i l l a r y diastema (L) 6.909 * .098 M a x i l l a r y diastema (R) 6.898 * .097 .076 M a x i l l a r y tooth row (L) 5.402 * .066 M a x i l l a r y tooth row (R) 5.417 i .066 155 Mandible length (L) 13.728 ± .154 Mandible length (R) 13.703 i .155 ,110 Jaw length (L) 8.922 * .093 Jaw length (R) 8.904 t .091 .133 Mandibular diastema (L) 3.528 4 .049 Mandibular diastema (R) 3.479 ± .050 .670 Mandibular tooth row (L) Mandibular tooth row (R) 5.394 ± .071 5.425 ± .072 -.003 20 TABLE I I I : CONSISTENCY OF MEASURING TECHNIQUE NAME OF MEASUREMENT RANGE OF MEDIANS RANGE OF MEDIANS (MEANS IN MM) (CVS IN %) Condylobasal l e n g t h T o t a l l e n g t h o f s k u l l 13.217 0.0 ^ x ^ < cv < Basa l l e n g t h P a l a t a l l e n g t h B a s i l a r l e n g t h 23.617 0.5 Zygomatic width Mandible l e n g t h B r a i n c a s e width Mandibular t o o t h row l e n g t h 5.400 0.5 Mastoid width Post zygoma width ^= x dzz. < ^ c v M a x i l l a r y diastema l e n g t h S k u l l h e i g h t 10.167 1.0 Jaw l e n g t h M a x i l l a r y t o o t h row le n g t h P a l a t a l foramen l e n g t h M a x i l l a r y outer molar width 0.833 1.0 Least i n t e r o r b i t a l width P a l a t a l b r i d g e l e n g t h Rostrum width Foramen magnum h e i g h t Nasal width M a x i l l a r y inner molar width 5.467 11.0 Foramen magnum width P a l a t a l foramen width ^ — x ^— ^ cv / 21 d i m e n s i o n s , s u m m a r i z e s t h e r e s u l t s f r o m A p p e n d i x T a b l e s l a t o l y ( p a g e s 82 t o 1 0 6 ) . I t i n d i c a t e s t h a t , i n g e n e r a l , t h e l a r g -e r t h e d i m e n s i o n m e a s u r e d , t h e more c o n s i s t e n t t h e m e a s u r i n g t e c h n i q u e . 1.3. Br achy os_ti_sm F r a n k ( 1 9 6 7 ) has d e s c r i b e d a homozygous r e c e s s i v e muta-t i o n , c a l l e d b r a c h y o s t i s m , w h i c h c a u s e s c o n s i d e r a b l e p r o p o r -t i o n a l v a r i a t i o n s i n a l l p a r t s o f t h e s k e l e t o n o f M i c r o t u s a r -v a l i s . The a n i m a l s a f f e c t e d had, among o t h e r f e a t u r e s , a mark-e d l y s h o r t e n e d and b r o a d e n e d s k u l l i n w h i c h t h e z y g o m a t i c w i d t h was 68% t o 7 3 % o f t h e c o n d y l o b a s a l l e n g t h . ( I n n o r m a l a n i m a l s i t i s 58% t o 62%.) The s p e c i m e n s u s e d i n t h i s s t u d y were t h e r e f o r e t e s t e d f o r b r a c h y o s t i s m . Of t h e 4 2 2 , 318 were m e a s u r a b l e f o r b o t h zygoma-t i c w i d t h and c o n d y l o b a s a l l e n g t h . In none o f t h e s e d i d t h e p r o p o r t i o n a l r e l a t i o n s h i p f a l l w i t h i n t h e m u t a t i o n r a n g e . As t h r e e q u a r t e r s o f t h e t o t a l had been t e s t e d and none had shown b r a c h y o s t i s m , i t was assumed t h a t t h e r e m a i n i n g u n t e s t e d s p e c i -mens were a l s o n o r m a l . 2. S e x u a l D i f f e r e n c e s 2.1. Se><ual_DiLm£r£hiLsm A s y n o p s i s o f t h e l i t e r a t u r e on s e x u a l d i m o r p h i s m i n M i -c r o t u s a r v a l i s i s p r e s e n t e d i n T a b l e IV. A s l i g h t d i m o r p h i s m i n e x t e r n a l body m e a s u r e m e n t s i s i n d i c a t e d , w i t h a d u l t f e m a l e s b e i n g s m a l l e r t h a n a d u l t m a l e s . T h e r e i s l e s s a g r e e m e n t on d i -morphism i n s k u l l d i m e n s i o n s . To q u a n t i f y p o s s i b l e d i m o r p h i s m TABLE IV: LITERATURE SYNOPSIS OF SEXUAL DIMORPHI! AGE GROUP 8-30 days More than 28 days "Adult v o l e s " 0-15 days More than 15 days "Younger v o l e s " 45 days 60 days "Adult v o l e s " DIMENSION Weight Weight Weight Body length Body length Body length Body length Body length Body length "Younger v o l e s " T a i l length "Younger v o l e s " Condylobasal length "Adult v o l e s " S k u l l dimensions iM IN MICROTUS ARVALIS SEXUAL DIMORPHISM No s i g n i f i c a n t d i f f e r e n c e (Delost, 1952) Female smaller ( R e i c h s t e i n , 1964) Female smaller (Frank and Zimmermann, 1957b) No s i g n i f i c a n t d i f f e r e n c e (Delost, 1952) Female smaller ( D e l o s t , 1952; S p i t z , 1963a) Female smaller (Cechowicz and Pucek, 1961) Female smaller ( S p i t z , 1963a) Female smaller ( D e l o s t , 1955b) Female smaller (Frank and Zimmermann, 1957b; S a i n t Girons, 1973) Female smaller (Cechowicz and Pucek, 1961) Female smaller (Cechowicz and Pucek, 1961) No s i g n i f i c a n t d i f f e r e n c e (Cechowicz and Pucek, 1961) 23 among t h e a n i m a l s i n t h i s s t u d y , t h e 55 u n s e x e d s p e c i m e n s were t e m p o r a r i l y s e t a s i d e and t h e r e m a i n i n g 367 a n i m a l s were d i -v i d e d i n t o t h r e e s e x s e g r e g a t e d age g r o u p s f o r e a c h o f t h e 32 d i m e n s i o n s . (The method o f a g i n g . t h e s p e c i m e n s i s d i s c u s s e d on p a g e s 26 t o 32.) A S t u d e n t ' s t - t e s t was r u n on t h e d i f f e r e n c e b etween t h e means. I n n o t one o f t h e 96 t e s t s was t h e r e a d i f f e r e n c e a t .001 l e v e l o f s i g n i f i c a n c e ( A p p e n d i x T a b l e s 2a t o 2k: p a g e s 107 t o 1 1 7 ) . 2.2. Sex R a t i o R e s e a r c h e r s d i f f e r on t h e s e x r a t i o i n M i c r o t u s a r v a l i s , and t h e r e a s o n s f o r i t . On t h e one hand D e l o s t ( 1 9 5 5 c ) f o u n d t h a t a g r e a t e r number o f e m b r y o s , f e t u s e s and newborns were male (61 v e r s u s 43) and f e l t t h i s a c c o u n t e d f o r t h e p r e d o m i -nance o f m a l e s he c a u g h t i n t h e w i l d (461 v e r s u s 2 8 0 ) . On t h e o t h e r hand S t e i n ( 1 9 5 7 ) r e p o r t e d a g r e a t e r number o f f e m a l e em-b r y o s ( 5 6 0 v e r s u s 488) and c o n c l u d e d t h a t t h i s f a c t o r c o u p l e d w i t h c o m p e t i t i o n among m a l e s r e s u l t e d i n an e x c e s s o f f e m a l e s . S i m i l a r l y t h e d a t a i n t h e l i t e r a t u r e on s e a s o n a l s h i f t s i n t h e sex r a t i o c o n f l i c t ( T a b l e V ) . The s p e c i m e n s i n t h i s s t u d y show a s i g n i f i c a n t s e x r a t i o d i f f e r e n c e - 230 f e m a l e s v e r s u s 137 m a l e s . I n T a b l e VI t h e s e x e s a r e s u b d i v i d e d i n t o age g r o u p s and month o f c a p t u r e . T h e r e a p p e a r s t o be a summer p r e d o m i n a n c e o f s u b a d u l t and a d u l t f e m a l e s and a f a l l i n c r e a s e i n t h e number o f s u b a d u l t m a l e s . TABLE V: LITERATURE SYNOPSIS OF SEASONAL SEX RATIO IN MICROTUS ARVALIS SEASON SEX RATIO NUMBERS Equal numbers ( R e i c h s t e i n , 1956) More females ( S t e i n , 1953) 333 vs. 221 More females (Adamczewska-Andrzejewska and Nabaglo, SPRING/ 1977) START More adult females than 35 vs. 21 SUMMER adul t males (Lapshov, Lorber and Polegaev, 197A) More males (Dub, 1971b) 53 vs. 20 More males (Grunwald, 1975) EXPLANATION BY AUTHOR(S) Rapid recruitment of females coupled with slower ra t e of disappearance of females B e t t e r s u r v i v a l a b i l i t y Onset of reproduction and increased sexual a c t i v i t y of males E a r l i e r achievement of sexual maturity of males SUMMER More females ( S t e i n , 1953) 6A8 vs. A39 END SUMMER More females ( S t e i n , 1953) More females ( R e i c h s t e i n , 1956) Equal numbers or s l i g h t l y more males (Adamczewska-Andrzejewska and Nabaglo, 1977) 201 vs. 129 F i g h t i n g among males during breeding season S i m i l a r recruitment o f females coupled with greater disappearance of females AUTUMN/ More females (Lapshov, Lorber 135 vs. 100 B e t t e r s u r v i v a l a b i l i t y START and Polegaev, 197A) WINTER More males (Dub, 1971b) 158 vs. 82 Mi g r a t i n g component of p o p u l a t i o n TABLE VI: AGE AND SEX ANALYSIS IN MICROTUS ARVALIS BY MONTH OF CAPTURE AGE AND SEX JUVENILES SUBADULTS ADULTS MONTH GROUP OF CAPTURE FEMALES MALES FEMALES MALES FEMALES MALE January - 1 1 - -February - 1 - - -March - 5 4 - -A p r i l - 6 2 - -May - 2 1 2 2 June 1 5 - 8 2 July 4 1 25 13 24 17 August 1 9 28 8 13 6 September 6 4 13 13 11 1 October 4 4 32 30 10 1 November 1 7 3 2 2 December _ 3 6 2 _ FEMALES MALES 1 1 12 3 26 3. A g i n g t h e S p e c i m e n s 3.1. i_9in£ J.ec_hrii_qu_es_A£p_li ed 3.1.1. S p e c i m e n s wi_th_body_ _leng_th_mea_sur_ement_s T a b l e s V I I and V I I I p r e s e n t a summary o f t h e l i t e r a t u r e a-v a i l a b l e on mean body l e n g t h s i n l a b o r a t o r y and w i l d s p e c i m e n s o f M i c r o t u s a r v a l i s . They a r e s e g r e g a t e d b e c a u s e o f M i c r o t u s  a g r e s t i s work i n w h i c h t h e v o l e s i n t h e l a b o r a t o r y a t t a i n e d l a r g e r s i z e s and l i v e d l o n g e r t h a n u n d e r f i e l d c o n d i t i o n s . G e b c z y n s k a (1964) a t t r i b u t e d t h e g r e a t e r s i z e and l o n g e v i t y o f l a b o r a t o r y a n i m a l s t o a d v a n t a g e o u s f o o d c o n d i t i o n s and f r e e d o m f r o m p r e d a t o r s , n o t i n g t h a t i n t h e l a b o r a t o r y a n i m a l s do n o t grow i n t h e same manner as i n t h e f i e l d . T h e r e f o r e , t h e c o r r e s p o n d i n g age g r o u p s f r o m t h e s e two d i f f e r e n t e n v i r o n m e n t s p r a c t i c a l l y c a n n o t be c o m p a r e d i n t h e d i r e c t manner. 3.1.1.1. Juven_i_les T h i s c a t e g o r y i s r e s t r i c t e d t o s e x u a l l y i m m a t u r e i n d i v i d u -a l s - t h o s e w h i c h had n o t y e t r e a c h e d t h e age o f f i r s t b r e e d -i n g . M. a r v a l i s f e m a l e s a r e a b l e t o r e p r o d u c e f r o m a b o u t t h r e e weeks o l d and m a l e s f r o m a b o u t f i v e weeks ( T a b l e XVIm; page 67). T a b l e I X l i s t s l a b o r a t o r y mean body l e n g t h s f r o m T a b l e V I I o f 21 day o l d f e m a l e s and 35 day o l d m a l e s and w i l d mean body l e n g t h s o f a n i m a l s c l a s s e d i n t h e y o u n g e s t g r o u p i n g s i n T a b l e V I I I . The a v e r a g e body l e n g t h f r o m t h e s e means was 80.71 mm (79.9 mm was s u b s t i t u t e d f o r D o t t r e n s s m a l l e r t h a n 80 mm g r o u p i n g ) . B a s e d on t h i s , any s p e c i m e n w i t h a body l e n g t h TABLE V I I : LITERATURE SYNOPSIS OF BODY LENGTHS IN LABORATORY MICROTUS ARVALIS AGE (DAYS) FEMALE MEAN LENGTHS (MM) MALE MEAN LENGTHS (MM) 0-1 26-28 (Delost, 1952) 28-30 (Delost, 1952) 0-2 23-30 (Delost, 1955a) 26-29 (Delost, 1955a) 14 59.0 ( S p i t z , 1963a) 61.4 ( S p i t z , 1963a) 15 67.1 (M a r t i n e t , 1966) 21 73.6 ( S p i t z , 1963a) 75.2 ( S p i t z , 1963a) 28 81.7 ( S p i t z , 1963a) 84.6 ( S p i t z , 1963a) 30 90.1 (Ma r t i n e t , 1966) 35 82.8 (Martinet, 1966) 36 84.1 (Ma r t i n e t , 1966) 42 87.6 ( S p i t z , 1963a) 94.0 ( S p i t z , 1963a) 44 94.0 (Ma r t i n e t , 1966) 51 86.9 (Mar t i n e t , 1966) 56 90.4 ( S p i t z , 1963a) 97.3 ( S p i t z , 1963a) 60 86 (Delost, 1952) 96 (Delost, 1952)' 85.8 (Martinet, 1966) 100.2 (Ma r t i n e t , 1966) 70 95.1 (M a r t i n e t , 1966) 84 92.7 ( S p i t z , 1963a) 101.8 ( S p i t z , 1963a) 90 102.4 (Martinet, 1966) 102.5 (Ma r t i n e t , 1966) 120 97.9 (Martinet, 1966) 106.9 (Ma r t i n e t , 1966) 126 98.3 ( S p i t z , 1963a) 106.6 ( S p i t z , 1963a) 150 100.3 (Ma r t i n e t , 1966) 114.5 (Ma r t i n e t , 1966) 180 102.5 ( S p i t z , 1963a) 111.1 ( S p i t z , 1963a) 110.4 (M a r t i n e t , 1966) 210 110.0 (Mar t i n e t , 1966) 112.0 (M a r t i n e t , 1966) 240 116.6 (M a r t i n e t , 1966) 270 105.2 (Mar t i n e t , 1966) 300 110.4 (Ma r t i n e t , 1966) 114.2 (Ma r t i n e t , 1966) 360 107.3 (Mar t i n e t , 1966) 390 119.8 (Ma r t i n e t , 1966) TABLE V I I I : LITERATURE SYNOPSIS OF BODY LENGTHS IN WILD MICROTUS ARVALIS AGE GROUP Young(May) Young(November). J u v e n i l e J u v e n i l e FEMALE MEAN LENGTHS (MM) 85.8 (Lapshov, Lorber and Polegaev, 1974) 78.2 (Lapshov, Lorber and Polegaev, 1974) MALE MEAN LENGTHS (MM) 87.2 (Lapshov, Lorber and Polegaev, 1974) 79.3 (Lapshov, Lorber and Polegaev, 1974) Semiadult(May) 94.1 (Lapshov, Lorber 91.4 (Lapshov, Lorber and Polegaev, 1974) and Polegaev, 1974) Semiadult(November) 95.1 (Lapshov, Lorber 93.9 (Lapshov, Lorber and Polegaev, 1974) and Polegaev, 1974) Immature(750m) Immature(1360m) Immature(1940m) Subadult Adult(May) Adult(November) Adult Adult Mature(750m) Mature(1360m) Mature(1940m) 107.4 (Lapshov, Lorber and Polegaev, 1974) 104.5 (Lapshov, Lorber and Polegaev, 1974) 109.9 (Lapshov, Lorber and Polegaev, 1974) 107.0 (Lapshov, Lorber and Polegaev, 1974) ? MEAN LENGTHS (MM) 78.0 (Cechowicz and Pucek. 1961) Smaller than 80 (Dottrens, 1962) 81.9 (Jones, 1970) 80.4 (Jones, 1970) 81.4 (Jones, 1970) 80-99.9 (Dottrens, 1962) 105.1 (Cechowicz and Pucek, 1961) 100+ (Dottrens, 1962) 94.4 (Jones. 1970) 92.7 (Jones, 1970) 101.1 (Jones, 1970) CO TABLE IX: BODY LENGTHS FROM TABLES VII AND V I I I OF JUVENILE MICROTUS ARVALIS SEX AND AGE GROUP LABORATORY OR WILD SPECIMENS MEAN BODY LENGTHS (MM) Females (21 days old) Laboratory specimens 73.6 ( S p i t z , 1963a) Females (young) Wild specimens 78.2 to 85.8 (Lapshov, Lorber and Polegaev, 1974) Both sexes ( j u v e n i l e ) Wild specimens 78.0 (Cechowicz and Pucek, 1961) Both sexes ( j u v e n i l e ) Wild specimens Smaller than 80.0 Dottrens, 1962) Both sexes (immature) Wild specimens 80.4 to 81.9 (Jones, 1970) Males (35 days o l d ) Laboratory specimens 82.8 (M a r t i n e t , 1966) Males (young) Wild specimens 79.3 to 87.2 (Lapshov, Lorber and Polegaev, 1974) 30 s m a l l e r t h a n 80 mm was c o n s i d e r e d a j u v e n i l e . F o r t h e 33 s p e c i -mens w i t h body l e n g t h m e a s u r e m e n t s w h i c h were c l a s s i f i e d as j u v e n i l e s , body l e n g t h a v e r a g e d 73.242 mm p l u s o r m i n u s a s t a n -d a r d e r r o r o f 1.277 mm ( A p p e n d i x T a b l e 3e: page 1 2 2 ) . 3.1.1.2. A d u l t s _ T h i s c a t e g o r y c o m p r i s e s t h o s e a n i m a l s whose g r o w t h r a t e by t h e t i m e o f c a p t u r e had l e v e l l e d t o s u c h an e x t e n t t h a t i n e f -f e c t t h e y had r e a c h e d t h e i r f u l l a d u l t s i z e . R e s e a r c h e r s a r e n o t i n a g r e e m e n t as t o when t h i s o c c u r s i n M i c r o t u s a r v a l i s . The e s t i m a t e s r a n g e f r o m t h e age o f 1 1/2 months ( M e u n i e r and S o l a r i , 1972) t o 2 months ( D e l o s t , 1952 and 1955b) t o 2 1/2 months ( R e g n i e r and P u s s a r d , 1926) t o 1 y e a r ( F r a n k and Zimmer-mann, 1 9 5 7 b ) . T h i s i s c o m p l i c a t e d f u r t h e r by t h e s e a s o n i n w h i c h e a c h a n i m a l i s b o r n . Growth r a t e s o f s p r i n g b o r n common v o l e s d i f f e r f r o m t h o s e o f autumn b o r n i n d i v i d u a l s ( T a b l e X ) . The a v e r a g e body l e n g t h f o r w i l d M. a r v a l i s s p e c i m e n s c l a s s e d as m a t u r e o r a d u l t ( T a b l e V I I I ) was 102.46 mm. In l a b -o r a t o r y s p e c i m e n s ( T a b l e V I I ) t h i s 100+ mm l e n g t h was r e a c h e d a t a b o u t t h r e e months i n m a l e s and t h r e e t o f i v e months i n f e -m a l e s . I n t h i s s t u d y , t h e r e f o r e , a s p e c i m e n was c o n s i d e r e d an a d u l t i f i t were 100 mm o r more i n l e n g t h . By u s i n g t h i s a p -p r o a c h , t h e s e a s o n o f b i r t h o f t h e a d u l t s d i d n o t m a t t e r . A s p r i n g b o r n a n i m a l m i g h t have r e a c h e d t h e 100 mm mark i n o n l y t h r e e m o n t h s , w h e r e a s an autumn b o r n a n i m a l m i g h t have t a k e n s i x months t o a c h i e v e t h e same s i z e , b u t i n t h e a g i n g s y s t e m a d o p t e d , b o t h w o u l d be c l a s s i f i e d , c o r r e c t l y , as a d u l t s . F o r TABLE X: LITERATURE SYNOPSIS OF DATE OF BIRTH AND GROWTH RATE OF MICROTUS ARVALIS DATE OF BIRTH J a n u a r y - A p r i l February-June March-May March-June March-June Summer June-August June-October July-August July-October Autumn Autumn A f t e r second h a l f of August September-October GROWTH RATE Rapid growth rat e Very quick growth Fast growth rat e u n t i l 3 to A months o f age Quick growth rate Rapid increase i n weight up to 47 gr Slower growth rate Intermediate growth rate Increase i n weight up to 15 to 22 gr ; remain u n t i l January/February at these low rate s Slow growth rat e Slow growth rate Slower growth rate Growth stopped during winter at 18 to 20 g r ; i n s p r i n g reach ad u l t weight Cease growth, reaching stage of subadult Low plateau when 1 to 2 months o l d ; grow again i n January REFERENCE Martinet (1967) Saint Girons (1973) Martinet and S p i t z (1971) S p i t z (1967) R e i c h s t e i n (1964) S a i n t Girons (1973) Martinet and S p i t z (1971) R e i c h s t e i n (1964) Mart i n e t (1967) S p i t z (1967) S a i n t Girons (1973) Wijngaarden (1960) Straka and Gerasimov (1971) Martinet and S p i t z (1971) 32 t h e 69 s p e c i m e n s w i t h body l e n g t h m e a surements w h i c h were c l a s -s i f i e d as a d u l t s , body l e n g t h a v e r a g e d 105.464 mm p l u s o r m i n u s a s t a n d a r d e r r o r o f 1.202 mm ( A p p e n d i x T a b l e 3e: page 1 2 2 ) . 3.1.1.3. Subadu_lt_s T h i s i n t e r m e d i a t e c a t e g o r y i n c l u d e s s p e c i m e n s l a r g e r t h a n j u v e n i l e s ( 8 0 mm o r more) and s m a l l e r t h a n a d u l t s ( s m a l l e r t h a n 100 mm). These a n i m a l s w o u l d be c a p a b l e o f b r e e d i n g b u t t h e y w o u l d s t i l l be i n a p e r i o d o f r e l a t i v e l y s i g n i f i c a n t g r o w t h . The a v e r a g e body l e n g t h f o r w i l d M. a r v a l i s c l a s s e d as s u b a d u l t o r s e m i a d u l t ( T a b l e V I I I ) was 92.89 mm ( 8 9 . 9 mm was s u b s t i t u t e d f o r D o t t r e n s ' 80 mm t o 99.9 mm g r o u p i n g ) . F o r t h e 179 s p e c i m e n s w i t h body l e n g t h m e a surements w h i c h were c l a s s i f i e d as s u b a d u l t s , body l e n g t h a v e r a g e d 89.453 mm p l u s o r m inus a s t a n d a r d e r r o r o f 3.925 mm ( A p p e n d i x T a b l e 3e; page 1 2 2 ) . 3.1.2. Spec_ime_n_s wi_thout. bod_y_le_ng_th mejaS_Jrem_en_ts Of t h e 422 s p e c i m e n s , 281 had body l e n g t h m e a s u r e m e n t s -33 j u v e n i l e s , 179 s u b a d u l t s and 69 a d u l t s . F o r t h e r e m a i n i n g 141 s p e c i m e n s w i t h no body l e n g t h d a t a , a t l e a s t one o f f i v e c r a n i a l m e a s u r e m e n t s was t a k e n - c o n d y l o b a s a l l e n g t h a n d / o r t o -t a l l e n g t h o f s k u l l a n d / o r b a s a l l e n g t h a n d / o r b a s i l a r l e n g t h a n d / o r z y g o m a t i c w i d t h . The r e s u l t o b t a i n e d was c ompared a-g a i n s t t h e r a n g e o f measurement f o r t h e same d i m e n s i o n i n t h e 281 s p e c i m e n s w h i c h had b een aged a c c o r d i n g t o body l e n g t h and b e l o n g e d t o an a l t i t u d e g r o u p w h i c h a p p r o x i m a t e d most c l o s e l y 33 t h e one from w h i c h t h e a n i m a l w i t h o u t body l e n g t h m e a s u r e m e n t s came. T a b l e XI l i s t s t h e c o m p l e t e s e x and age a n a l y s i s o f t h e 422 s p e c i m e n s . I t i n c l u d e s 33 a n i m a l s t h a t c o u l d n o t be aged b e c a u s e e x t e r n a l m e a s urements had n o t been p r o v i d e d f o r them and none o f t h e f i v e c r a n i a l m e a s u r e m e n t s c o u l d be p e r f o r m e d on them. TABLE XI : AGE AND SEX ANALYSIS OF MICROTUS ARVALIS SPECIMENS SEX (AND NUMBER) JUVENILES SUBADULTS ADULTS ? F e m a l e s ( 2 3 0 ) 17 128 72 13 M a l e s ( 1 3 7 ) 18 81 31 7 (55) 14 17 11 13 T o t a l ( 4 2 2 ) 49 226 114 33 3.2. Chancjes i n I n d i v i d u a l D i m e n s i o n s Of t h e 32 d i m e n s i o n s , 21 showed a s i g n i f i c a n t c h a n g e ( a t .001 l e v e l ) i n mean s i z e w i t h age between b o t h t h e j u v e n i l e and s u b a d u l t c l a s s e s and t h e s u b a d u l t and a d u l t c l a s s e s . The e l e v -en d i m e n s i o n s w h i c h e i t h e r showed a s i g n i f i c a n t c hange b e t w e e n o n l y two age c l a s s e s o r no s i g n i f i c a n t c hange among a l l t h r e e age c l a s s e s were m a x i l l a r y o u t e r m o l a r w i d t h , m a n d i b u l a r d i a -s tema l e n g t h , p o s t zygoma w i d t h , m a x i l l a r y i n n e r m o l a r w i d t h , e a r l e n g t h , m a x i l l a r y r n o l a r w i d t h , f o r a m e n magnum h e i g h t , f o r a -men magnum w i d t h , p a l a t a l f o r a m e n w i d t h , l e a s t i n t e r o r b i t a l w i d t h and h i n d f o o t l e n g t h . ( A p p e n d i x T a b l e s 3a t o 3 f : pages 118 t o 1 2 3 ) . A c o m p a r i s o n b e t w e e n a v e r a g e m e a s u r e m e n t s r e c o r d -ed i n t h i s s t u d y f o r some o f t h e c r a n i a l d i m e n s i o n s and d a t a 34 f r o m t h e l i t e r a t u r e on e q u i v a l e n t d i m e n s i o n s a p p e a r s i n T a b l e X I I . I t shows how v a r i a o l e s i n g l e c r a n i a l d i m e n s i o n s c a n be and how l i t t l e a c c o r d t h e r e i s . 3.3. Chan£es_ in_Pro£or_tion_a_i R e l a t i o n s h i p s D o t t r e n s ( 1 9 6 2) n o t e d i n M i c r o t u s n i v a l i s s e v e r a l t r e n d s w i t h age i n t h e p r o p o r t i o n a l r e l a t i o n s h i p b etween c e r t a i n s k u l l d i m e n s i o n s . F i v e s e t s o f t h e s e were e x a m i n e d i n t h e M i c r o t u s  a r v a l i s s p e c i m e n s u s e d i n t h i s s t u d y - t h e f o u r s e t s t h a t D o t -t r e n s r e p o r t e d had shown t h e most s i g n i f i c a n t c h a n g e s and one s e t he f o u n d t h a t had shown no s i g n i f i c a n t change ( A p p e n d i x Ta-b l e 4: page 1 2 4 ) . The t r e n d s i n p r o p o r t i o n a l r e l a t i o n s h i p w i t h age i n M. a r v a l i s matched t h o s e o f M. n i v a l i s i n t h r e e o f t h e f i v e s e t s . I n t h e r e m a i n i n g two s e t s , t h e p r o p o r t i o n a l t r e n d s i n M. a r v a l i s i n c r e a s e d w i t h age ( i n one s e t s i g n i f i c a n t l y ) w h e r e a s t h e y d e c r e a s e d i n M. n i v a l i s ( T a b l e X I I I ) . 4• A l t i t u d e and S i z e C o r r e l a t i o n The c o r r e l a t i o n c o e f f i c i e n t b e t ween s i z e o f s p e c i m e n and a l t i t u d e a t c a p t u r e was c a l c u l a t e d f o r t h e t h r e e s e x s e g r e g a t e d age g r o u p s f o r e a c h o f t h e 32 d i m e n s i o n s . In no c a s e was t h e r e c o r r e l a t i o n e ven t o t h e t h i r d d e c i m a l p l a c e ( A p p e n d i x T a b l e s 2a t o 2k: p a g es 107 t o 1 1 7 ) . TABLE XII: COMPARISON OF CRANIAL MEASUREMENTS IN MICROTUS ARVALIS AGE CLASSES REFERENCE Cechowicz and Pucek (1961) Dottrens (1962) This t h e s i s Dottrens (1962) This t h e s i s Cechowicz and Pucek (1961) Dottrens (1962) This t h e s i s NAME OF CRANIAL MEASUREMENT Condylobasal length M a x i l l a r y diastema length zygomatic width AGE GROUPS MEAN (MM) i STANDARD ERROR (WHEN GIVEN) SUBADULTS JUVENILES 22.25 20.5 * .13* 23.2 4 .10 ADULTS 24.24 25.1 * .16 20.346 4 .165 22.189 ± .718 23.939 * .084 6.1 4 .07 7 ; i * .04 7.7 4 .07 5.904 4 .062 6.587 i .274 7.285 ± .425 12.54 13.69 11.9 ± .09 13.6 4 .04 14.6 4 .09 11.570 4 .097 12.694 4 .496 13.845 * .599 Dottrens (1962) This t h e s i s S k u l l height 6.9 * .07 7.3 ± .05 7.6 * .08 6.214 * .057 6.634 4 .260 7.028 4 .387 M a x i l l a r y tooth row length Dottrens (1962) This t h e s i s ^-Presumably a l l Dottrens' a d d i t i o n s are standard e r r o r s 5.5 4 .05 5.9 4 .03 6.2 4 .04 5.081 * .042 5.396 4 .191 5.640 i .267 TABLE X I I I : PROPORTIONAL RELATIONSHIPS IN SKULL DIMENSIONS IN TWO SPECIES OF MICROTUS MICROTUS NIVALIS MICROTUS ARVALIS MEAN (IN MM) ± JUVENILES (NUMBER) STANDARD ERROR (IN %) T-VALUE TRENDS SETS OF TRENDS ADULTS DIFFERENCE WITH CRANIAL WITH (NUMBER) (AND DF) AGE DIMENSIONS AGE MEAN (IN MM) i JUVENILES (NUMBER) STANDARD ERROR (IN %) T-VALUE ADULTS DIFFERENCE (NUMBER) (AND DF) 110.7 ± 1.2 122.0 4 1.0 9.19* M a x i l l a r y 116.8 i 1.1 128.2 i 14.8 6.48* (15) (57) (70) A diastema A (48) (112) (158) ( M a x i l l a r y T tooth row I 68.6 i 0.6 63.1 i 0.5 -6.32* I n t e r o r b i t a l , 61.9 * 1.5 55.6 * 6.6 -5.12* (15) (57) (70) width (48) (112) (158) 1 X1 I L O I U J - U J . u u ± I width M a x i l l a r y 1 I I tooth row 29.6 * 0.3 25.6 4 0.2 -6.90* I I n t e r o r b i t a l | 37.2 * 0.9 33.7 * 3.9 -3.54* (15) (57) (70) | width I (44) . (110) (152) Jaw length » 59.4 4 1.0 54.5 4- 0.4 -5.33* I S k u l l height 42.2 ± 3.5 47.5 4 12.8 2.82 (15) (57) (70) j Zygomatic ~~ (42) (105) (145) width 58.9 4 0.5 57.0 * 0.4 -2.47 Zygomatic A 52.7 4-2.4 55.1 4 1.3 4.07* (15) (57) (70) ^ width T (40) (100) (138) Condylobasal length * S i g n i f i c a n t at .001 l e v e l DISCUSSION 37 T h i s s e c t i o n i s d i v i d e d i n t o two p a r t s - t h e f i r s t on t h e " e c o g e o g r a p h i c a l r u l e " ( M a y r , 1956:page 105) o f Bergmann, t h e s e c o n d on t h e i n f r a s p e c i f i c t a x o n o f s u b s p e c i e s . T h i s a p p r o a c h was p r o m p t e d by t h e q u e s t i o n a b l e c o n c l u s i o n s drawn i n t h e two m a j o r p a p e r s on a l t i t u d i n a l v a r i a t i o n i n M i c r o t u s  a r v a l i s i n S w i t z e r l a n d ( D o t t r e n s , 1962; J o n e s , 1 9 7 0 ) . The t r e n d s i n body s i z e w i t h a l t i t u d e d e s c r i b e d i n e a c h p a p e r and f o u n d i n t h i s t h e s i s a r e s u m m a r i z e d i n T a b l e XIV and F i g u r e 7. TABLE X I V : TRENDS IN BODY LENGTH WITH ALTITUDE IN MICROTUS ARVALIS (DOTTRENS, 1962; JONES, 1970; THIS THESIS) REFERENCE D o t t r e n s ( 1 9 6 2 ) J o n e s ( 1 970) T h i s t h e s i s BODY LENGTH TRENDS WITH ALTITUDE Lowest A l t i t u d e Group Lowes t A l t i t u d e Group Lowest A l t i t u d e = Group M i d A l t i t u d e Group Mid A l t i t u d e Group > < M i d A l t i t u d e =; Group H i g h e s t A l t i t u d e Group H i g h e s t A l t i t u d e Group H i g h e s t A l t i t u d e Group D o t t r e n s c o n c l u d e d f r o m h i s r e s u l t s t h a t t h e l o w e s t a l t i -t u d e g r o u p b e l o n g e d t o t h e n o m i n a t e s u b s p e c i e s M. a r v a l i s a r -v a l i s ( P a l l a s , 1779) whereas t h e mid and h i g h e s t a l t i t u d e g r o u p s b e l o n g e d t o a s u b s p e c i e s c a l l e d M. a r v a l i s r u f e s c e n t e -f u s c u s ( S c h i n z , . 1 8 4 5 ) . He s t a t e d t h a t i f t h e v a r i a t i o n had f o l l o w e d an a l t i t u d i n a l c l i n e (Bergmann's R u l e ) , t h e s p e c i m e n s 38 FIGURE 7: NON-JUVENILE BODY LENGTHS IN MICROTUS  ARVALIS (DOTTRENS, 1962; JONES, 1970; THIS THESIS) MM 108 106 90 L M H ALTITUDE GROUPS (LOW, MEDIUM, HIGH) — = DOTTRENS ( 1 9 6 2 ) = JONES ( 1 9 7 0 ) — = THIS THESIS 39 i n h i s 1200 m t o 1500 m g r o u p w o u l d have been b i g g e r t h a n h i s 405 m s p e c i m e n s and s m a l l e r t h a n h i s 2000+ m s p e c i m e n s . I f , h owever, t h e mid and h i g h e s t a l t i t u d e g r o u p s b e l o n g e d t o a d i f -f e r e n t s u b s p e c i e s t h e i r m e a s u r e m e n t s w o u l d have t o be a n a l y s e d s e p a r a t e l y f r o m t h o s e o f t h e n o m i n a t e s u b s p e c i e s . He h y p o t h e -s i z e d t h a t t h e c o n t i n u e d a b s e n c e o f v a r i a t i o n a c c o r d i n g t o Bergmann's R u l e w i t h i n t h e montane s u b s p e c i e s was due t o t h e f a c t t h a t t h e p o p u l a t i o n s l i v i n g a t t h e 1200 m t o 1500 m a l t i -t u d e were e x p o s e d t o a more m o d e r a t e c l i m a t e t h a n t h o s e a t 2000+ m, and t h e r e f o r e were l a r g e r . The t r e n d s r e c o r d e d by J o n e s i n 1970 were a t v a r i a n c e w i t h , and h i s mean body l e n g t h s d i f f e r e d s i g n i f i c a n t l y f r o m , t h o s e i n t h e c o r r e s p o n d i n g a l t i t u d e g r o u p s d e s c r i b e d by D o t t r e n s ( T a b l e X I V ; page 37 and T a b l e X V I I : page 7 4 ) . Y e t J o n e s n e v e r a d d r e s s e d t h e s e d i s p a r i t i e s . On t h e c o n t r a r y , he c l a i m e d h i s body l e n g t h m e asurements and D o t t r e n s ' were c o m p a t i b l e and t h a t h i s t r e n d s u p p o r t e d t h e h y p o t h e s i s o f a montane s u b s p e c i e s M. a___ r u f e s c e n t e f u s c u s "whose g r e a t s i z e i s a n e c e s s i t y t o meet t h e demands o f t h e m o u n t a i n e n v i r o n -m e n t . . . t h e l a r g e r head p l u s body s i z e a t t h e h i g h e r e l e v a t i o n s may p o i n t t o an a p p l i c a t i o n o f Bergmann's R u l e " ( J o n e s , 1970:page 6 2 ) . S i n c e D o t t r e n s and J o n e s b o t h r e s o r t e d t o Bergmann's R u l e and t o s u b s p e c i a t i o n t o j u s t i f y i d e n t i c a l c o n c l u s i o n s f r o m c o n -f l i c t i n g d a t a , t h e two c o n c e p t s a r e e x a m i n e d h e r e . 40 1. Be r g m a n n ' s • R u l e 1.1. G e n e r a l . Re _view_o£ Ber_gmannj_s_Rule_ Bergmann's R u l e i s one o f t h e " r u l e s " i n b i o l o g y w h i c h d e -s c r i b e p a r a l l e l i s m s b e t w e e n m o r p h o l o g i c a l v a r i a t i o n and p h y s i -o g e o g r a p h i c f e a t u r e s ( M a y r , 1 9 5 6 ) . I t s t a t e s t h a t t h e r e i s a l a t i t u d i n a l i n c r e a s e i n a v e r a g e body s i z e w i t h i n c r e a s i n g c o l d ( K e e t o n , 1967) and a c o r r e s p o n d i n g i n c r e a s e w i t h a l t i t u d e ( M a y r , 1 9 6 3 ) . 1.1.1. T h e r e . i s _ n o ag_reeme_nt_ on_whejthe_r_Be_rg_mann'_s Ru_le_i_s r e _ s t r i x t _ e d t_o_homeot_he r m s _ o r incj_ude_s p_o_iki_ loth_erms_. Some r e s e a r c h e r s ( D a l e , 1940; Mayr, 1956 and 1 9 6 3 ; A l l e e and S c h m i d t , 1 9 6 2 ; K e e t o n , 1967; A l l e e , P a r k , Emerson, P a r k and S c h m i d t , 1967; Brown and L e e , 1969) r e s t r i c t Bergmann's R u l e t o homeotherms. O t h e r s ( R u i b a l , 1 957; Ray, 1960; C a s e , 1976) c o n -t e n d i t has a p p l i c a t i o n f o r p o i k i l o t h e r m s as w e l l . As M i c r o t u s  a r v a l i s i s a homeotherm, o n l y t h e h o m e o t h e r m i c a p p l i c a t i o n o f t h e R u l e i s c o n s i d e r e d i n t h i s d i s c u s s i o n . 1.1.2. T_h£re_ i.s_no_ a_gj;ee_me_n t. on_the_ta_x£n£mi_c_leve_l_a;t wh_ich_ Ber_gmarin_|_s_Rule_ appli.e_s. Bergmann ( 1 8 4 7 ) and o t h e r e a r l y a u t h o r s a p p l i e d t h e R u l e e q u a l l y t o s p e c i e s and r a c e s , b u t most o f t h e i r s p e c i e s a r e c o n s i d e r e d r a c e s by modern a u t h o r s ( M a y r , 1956) - r a c e s b e i n g d e f i n e d as " p o p u l a t i o n s o r a g g r e g a t e s o f p o p u l a t i o n s w i t h i n f o r m a l l y r e c o g n i z e d s u b s p e c i e s " ( M a y r , 1963;page 3 5 0 ) . H i s t o r -i c a l l y , r a c e was p r o b a b l y synonymous w i t h s u b s p e c i e s ( M a y r , 1 9 6 3 ) . The v a l i d i t y o f Bergmann's R u l e i n homeotherms c o n t i n u e s t o be d i s c u s s e d a t v a r i o u s t a x o n o m i c l e v e l s by 41 modern day b i o l o g i s t s : among c l o s e l y r e l a t e d s p e c i e s ( D a l e , 1940; C o w l e s , 1 9 4 5 ) ; w i t h i n s p e c i e s ( t h a t i s , among s u b s p e c i e s o r among r a c e s o r demes) ( P a r k , 1949; Mayr, 1 9 5 6 ) ; o r b o t h ( A l l e e and S c h m i d t , 1962; Brown and L e e , 1 9 6 9 ) . ( D e f i n i t i o n s o f s p e c i e s and s u b s p e c i e s a p p e a r i n t h e d i s c u s s i o n on s u b s p e c i a -t i o n . ) 1.1.3. T h e r e i s _ n o a g r e e m e n t o n _ t h _ e _ v a l i d i t y _ o f _ t h e _ m a j o r physi£l£gical_inter p r e t a t i o n o.f_Ber£mann ' s^  R u ^ e^ As most h o m e o t h e r m i c a n i m a l s r e q u i r e m a i n t e n a n c e o f a c o n -s t a n t i n t e r n a l body t e m p e r a t u r e ( S c h o l a n d e r , 1 9 5 5 ) , t h e u s u a l p h y s i o l o g i c a l e x p l a n a t i o n o f Bergmann's R u l e i n homeotherms i s t h a t l a r g e a n i m a l s expend l e s s e n e r g y f o r t h e r m o r e g u l a t i o n be-c a u s e o f t h e i r s m a l l s u r f a c e - t o - v o l u m e r a t i o (McNab, 1 9 7 1 ) . The h e a t p r o d u c i n g volume i n c r e a s e s as t h e cube o f l i n e a r d i -m e n s i o n w h e r e a s t h e h e a t - r a d i a t i n g s u r f a c e i n c r e a s e s as t h e s q u a r e o f l i n e a r d i m e n s i o n ( C o w l e s , 1945; P a r k , 1949; A l l e e and S c h m i d t , 1962; Mayr, 1 9 6 3 ) . P r o p o n e n t s o f t h i s p h y s i o l o g i c a l i n t e r p r e t a t i o n add t h a t t h e r e i s a f u r t h e r s e l e c t i v e a d v a n t a g e i n a r e l a t i v e r e d u c t i o n o f t h e s u r f a c e s i n c e t h e m e t a b o l i c r a t e i s more n e a r l y p r o p o r t i o n a l t o body s u r f a c e t h a n t o body w e i g h t ( A l l e e and S c h m i d t , 1962; Mayr, 1 9 6 3 ) . Some r e s e a r c h e r s , h o w e v e r , a r e n o t c o n v i n c e d by t h i s a r g u -ment. McNab (1971) s t a t e d t h a t l a r g e i n d i v i d u a l s o f a s p e c i e s l o s e more h e a t v i a t h e i r s u r f a c e t h a n s m a l l i n d i v i d u a l s ( a l l o t h e r f a c t o r s b e i n g e q u a l ) s i m p l y b e c a u s e t h e y have l a r g e r s u r -f a c e a r e a s t h a n s m a l l i n d i v i d u a l s . S c h o l a n d e r ( 1 9 5 5 : p a g e 22) a l l u d e d t o t h e " h o p e l e s s i n a d e q u a c y " o f t h e s u r f a c e - t o - v o l u m e r a t i o r e d u c t i o n h y p o t h e s i s , d e c l a r i n g t h a t i n c o n s e r v i n g h e a t " t h e s i z e o f t h e s u r f a c e a r e a o f t h e a n i m a l i s o f m i n o r i m p o r t a n c e a t b e s t . . . n o t a n g i b l e e v i d e n c e t h a t t h e s i z e o f t h e s u r f a c e a r e a , a b s o l u t e o r r e l a t i v e , i s i n any way a c r i t i c a l f a c t o r i n a r c t i c o r n o r t h e r n p h y l o g e n e t i c a d a p t a t i o n " . W h i l e Z e u t h e n ( 1 9 4 7 ) a g r e e d t h a t t h e m e t a b o l i c r a t e d e c r e a s e d w i t h i n c r e a s i n g s i z e o f a n i m a l s , he s u g g e s t e d t h a t t h e d e c r e a s e had n o t h i n g t o do w i t h h e a t r e g u l a t i o n . 1.1.4. _There a r e s e v e r a _ l met_hods o f - t h e r m o r e g u l a t i o n - o t h e r -t h a r i £U£f£C£-£0_3_v£lume_ ra_ti£ _red_u£t_ion j_n_h_ig_h _la_titu_de_o_r £ l -t_i_tud_e_h£m£o_the rms. T a b l e XV l i s t s some o f t h e ways i n w h i c h a l p i n e and a r c t i c homeotherms r e g u l a t e body h e a t p r o d u c t i o n and h e a t l o s s ( H o f f -mann, 1974) TABLE XV; SOME METHODS OF THERMOREGULATION A. CONTROL OF HEAT LOSS (INSULATION) 1. F u r o r f e a t h e r t h i c k n e s s 2. C o n t r o l o f p e r i p h e r a l c i r c u l a t i o n 3. E v a p o r a t i v e c o o l i n g B. CONTROL OF HEAT PRODUCTION 1. Heat f r o m i n c r e a s e d m e t a b o l i c r a t e 2. Heat f r o m b a s a l m e t a b o l i c r a t e C. POSTURE AND BEHAVIOUR 1.1.5. J_here a r e d_iet_a£d_C£m£e_ti_to_r _1 inked_a_rgum£n_ts_t_ha_t may_ £X£l_airi £e_rtai£ c a s e s £f_B£r£mann '_s RujLe. McNab ( 1 9 7 1 ) s p e c u l a t e d t h a t a c o r r e l a t i o n o f body s i z e w i t h l a t i t u d e i n c a r n i v o r o u s mammals may r e f l e c t t h e s i z e o f t h e a v a i l a b l e p r e y , w h i c h i n t u r n i s i n f l u e n c e d by t h e d i s t r i -b u t i o n o f t h e p r e y and t h e d i s t r i b u t i o n o f o t h e r p r e d a t o r s w i t h w h i c h t h e y must s h a r e t h e p r e y and t h a t s i m i l a r p a t t e r n s be-tween body l e n g t h and l a t i t u d e i n g r a n i v o r o u s h e r b i v o r e s may r e f l e c t d i f f e r e n t i a l s e e d s e l e c t i o n and o c c a s i o n a l f o o d s c a r c i t y . T h r e e r e g i o n s -" h i g h l a t i t u d e s , i s l a n d s , and moun-t a i n s - a r e marked by a low d i v e r s i t y o f s p e c i e s , w h i c h s u g -g e s t s t h a t e a c h o f t h e s e t r e n d s r e f l e c t s an i n c r e a s e d s i z e o f a v a i l a b l e f o o d p a r t i c l e s due m a i n l y t o t h e r e d u c e d n e c e s s i t y o f s h a r i n g a l i m i t e d f o o d r e s o u r c e . Bergmann's R u l e u s u a l l y i s a s p e c i a l c a s e o f t h i s g e n e r a l phenomenon" (McNab, 1 9 7 1 : page 8 5 2 ) . 1.1.6. J_here i_s_n£t_S£f_fic_ie_n_t e v_ide_nce_t£ wa_rran_t t_he c o n -t i n u e d ap£licat_ion £f_th_e_te_rm __^r_ul_e"_t_o _the _ s i _ z e _ t r e n d d e -OCjrijDed^ b_y_Ber£ma_nn. A c c o r d i n g t o Mayr ( 1 9 5 6 : p a g e 105) t h e v a l i d i t y o f B e r g -mann's R u l e "does n o t depend on t h e v a l i d i t y o f t h e p h y s i o -l o g i c a l i n t e r p r e t a t i o n , b u t m e r e l y on t h e r e l i a b i l i t y ( o r r e g u l a r i t y ) o f t h e e m p i r i c a l f i n d i n g . " Bergmann's R u l e " i s v a l i d o n l y i f i t i s r e a l l y t r u e t h a t i n more t h a n 50 p e r c e n t o f s p e c i e s o f w a r m b l o o d e d v e r t e b r a t e s t h e r e i s an a v e r a g e i n c r e a s e o f s i z e i n t h e c o o l e r p o r t i o n s o f t h e r a n g e o f t h e s p e c i e s " ( M a y r , 1963;page 3 1 9 ) . By M a y r ' s s t a n d a r d s , t h e v a l i d i t y o f Bergmann's R u l e c o l l a p s e s . V a r i a t i o n has n o t been s t u d i e d i n enough s p e c i e s o f homeotherms n o r has i t been f o u n d i n enough c a s e s o f t h o s e s p e c i e s s t u d i e d , t o q u a l i f y B e r g -mann's R u l e as a r u l e . 44 1.2. Ber_gmannJ_s_Rule and M i c r o t u s _ a _ r v a l j L s A c c o r d i n g t o A l l e e and S c h m i d t ( 1 9 6 2 : p a g e 603) t h e " i n c r e a s e o f s i z e i n t h e c o l d e r z o n e s , i n a c c o r d a n c e w i t h t h e Bergmann R u l e , i s a f a m i l i a r phenomenon i n t h e a l p i n e z o n e . Thus i n t h e A l p s . . . t h e meadow m i c e ( E v o t o m y s g l a r e o l u s n a g e r i  a n a M i c r o t u s a r v a l i s ) a r e l a r g e r i n t h e a l p i n e zone t h a n i n t h e v a l l e y s " . Y e t t h e 422 s p e c i m e n s o f M i c r o t u s a r v a l i s e x a m i n e d i n t h i s s t u d y showed no v a r i a t i o n w i t h a l t i t u d e i n any o f 32 e x t e r n a l and s k u l l d i m e n s i o n s . T h e r e may oe s e v e r a l r e a s o n s f o r t h i s l a c k o f a l t i t u d i n a l v a r i a t i o n - f r o m d e f i c i e n c i e s i n d a t a t o a b i o t i c and b i o t i c s e -l e c t i o n p r e s s u r e s , w h i c h i n t h e n o r m a l c o u r s e o f e v e n t s so a f f e c t t h e g r o w t h o f M^ a r v a l i s t h a t any t h o r o u g h s t u d y i n S w i t z e r l a n d w o u l d p r o d u c e r e s u l t s s i m i l a r t o t h o s e o f t h i s t h e s i s and t h u s u n d e r m i n e t h e a s s e r t i o n t h a t a l t i t u d i n a l v a r i a t i o n i n t h e common v o l e i n t h e A l p s i s a f a m i l i a r phenomenon. 1.2.1. 2 e£iciencies_in d a t a _ 1.2.1.1. I n a c cu r_a_t e _ a . l t i. t u de l o c a l i t i es__ As n o t e d i n t h e m e t h o d o l o g y s e c t i o n , t h e a l t i t u d e r e c o r d e d by t h e c o l l e c t o r a t t h e s i t e o f c a p t u r e was t a k e n t o r e p r e s e n t t h e a l t i t u d e a t w h i c h t h e s p e c i m e n o f M. a r v a 1 i s l i v e d . No a d -j u s t m e n t was made f o r home r a n g e o r m i g r a t i o n . S l o p e , h o w e v e r , i s a l s o an i m p o r t a n t s o u r c e o f i n a c c u r a c y . On an a v e r a g e moun-t a i n i n t h e S w i s s A l p s , t h e v e g e t a t i o n l i m i t s on n o r t h and s o u t h a s p e c t s d i f f e r by as much as 300 m e t e r s t o s t a r t w i t h ; by '1500 m e t e r s t h i s n o r t h - s o u t h s l o p e d i f f e r e n c e i s up t o 500 45 m e t e r s ( H u x l e y , 1 9 6 7 ) . As M i c r o t u s a r v a l i s i s p r i m a r i l y h e r b i -v o r o u s ( T a b l e X V I g : page 6 1 ) , i t may be a f f e c t e d by t h i s d i f -f e r e n c e . Y e t no c o l l e c t o r s p e c i f i e d w h e t h e r t h e a n i m a l was t r a p p e d on a s o u t h e r n o r n o r t h e r n s l o p e . 1.2.1.2. Ques t_io na b _1 e_meas u rem en t_s A c c o r d i n g t o G r e e n ( 1 9 3 2 ) s k u l l m e a s u r e m e n t s i n mammals a r e l i t t l e a f f e c t e d by e x t r a n e o u s i n f l u e n c e s . I f t h i s were s o , t h e 27 c r a n i a l and m a n d i b u l a r d i m e n s i o n s m e a s u r e d i n t h i s s t u d y w o u l d n o t be s u i t a b l e i n d i c e s f o r m a r k i n g an a l t i t u d i n a l c l i n e . B u t many m a m m a l o g i s t s a p p a r e n t l y do n o t a g r e e w i t h G r e e n ' s s t a t e m e n t as s k u l l m e asurements c o n t i n u e t o f e a t u r e i n t h e i r s t u d i e s on g e o g r a p h i c v a r i a t i o n (W.B. D a v i s , 1938; D a l e , 1940; S n y d e r , 1 954; D o t t r e n s , 1 9 6 2 ; R e e s , 1969; C l a u d e , 1970; R o b i n s o n and H o f f m a n n , 1 9 7 5 ) . E x t e r n a l body m e a s u r e m e n t s a r e a l s o u s e d t o gauge s i z e v a r i a t i o n i n mammals ( D a l e , 1940; D o t t r e n s , 1 962; D e l a n y and H e a l y , 1964; C l a u d e , 1970; J o n e s , 1 9 7 0 ) . As n o t e d i n t h e meth-o d o l o g y s e c t i o n , t h e e x t e r n a l d i m e n s i o n s i n t h i s s t u d y may n o t have been a c c u r a t e enough f o r p r e c i s e a n a l y s i s due t o t h e num-b e r o f c o l l e c t o r s and p o s s i b l e t e c h n i q u e s i n v o l v e d . The mea-s u r e m e n t s a l s o may have been a f f e c t e d by t h e f o l l o w i n g . 1.2.1.3. Pop ul. a t i o n_cy_c 1_ i n g _ M i c r o t u s a r v a l i s , l i k e many m i c r o t i n e s , u n d e r g o e s p o p u l a -t i o n c y c l e s i n w h i c h t h e r e i s a p o p u l a t i o n b u i l d up, a peak and a d e c l i n e ( T a b l e X V I h : page 6 2 ) . (A c o m p r e h e n s i v e r e v i e w o f t h i s phenomenon i n s m a l l mammals c a n be f o u n d i n K r e b s and M y e r s , 1 9 7 4 ) . D u r i n g peak p o p u l a t i o n y e a r s i n M. a r v a l i s , 46 S t e i n ( 1 9 5 7 ) d o c u m e n t e d an a d u l t i n c r e a s e i n body w e i g h t , and Zimmermann ( 1 9 5 5 ) r e p o r t e d an i n c r e a s e i n m a n d i b l e l e n g t h among a d u l t s . The c h a n g e i n a d u l t body s i z e w h i c h a c c o m p a n i e s t h e m i c r o t i n e c y c l e i s c a u s e d by d i f f e r i n g g r o w t h r a t e s o f i n d i v i d -u a l s , n o t by c h a n g e s i n age s t r u c t u r e o f t h e p o p u l a t i o n ( K r e b s , 1964) . S i n c e t h e museum s p e c i m e n s i n t h i s t h e s i s were c o l l e c t e d o v e r a p e r i o d o f 40 y e a r s i t i s p r o b a b l e t h a t some o f t h e a d u l t s p e c i m e n s were t a k e n a t peak p o p u l a t i o n t i m e s and t h u s may have been l a r g e r t h a n n o r m a l . T h i s means t h a t i f by c h a n c e most o f t h e a d u l t s f r o m 2500 m e t e r s were c o l l e c t e d a t non peak p h a s e s and most o f t h e a d u l t s f r o m 1000 m e t e r s were c o l l e c t e d a t peak t i m e s , t h e l a t t e r g r o u p , b e i n g l a r g e r t h a n u s u a l , w o u l d i n f a c t a p p e a r s i m i l a r i n s i z e t o t h e f o r m e r g r o u p . 1.2.2. Sej^ectj.o_n p r e s s u r e s 1.2.2.1. C e n t e r _ o _ f d i s t r _ i b u t _ i o n _ The r e p r e s e n t a t i v e s " o f a g i v e n s p e c i e s i n c r e a s e i n s i z e t o w a r d i t s h y p o t h e t i c a l c e n t e r o f d i s t r i b u t i o n , w h i c h i s i n most c a s e s d o u b t l e s s a l s o i t s o r i g i n a l c e n t e r o f d i s p e r s a l " ( A l l e n , 1906:page 3 7 8 ) . M i c r o t u s a r v a l i s b e l o n g s t o t h e o r d e r R o d e n t i a s a i d t o be o f n o r t h e r n o r i g i n ( A l l e n 1 9 0 6 ) , t o t h e f a m i l y C r i c e t i d a e c o n s i d e r e d t o be o f n o r t h e r n o r i g i n ( M a t -thew, 1 9 1 5 ) , t o t h e s u b f a m i l y M i c r o t i n a e d e s c r i b e d t o be o f n o r t h e r n and c e n t r a l A s i a n o r i g i n ( H i n t o n , 1 9 6 2 ) , and t o t h e genus M i c r o t u s whose H o l a r c t i c d i s t r i b u t i o n i n d i c a t e s a B o r e a l o r i g i n ( D a l e , 1 9 4 0 ) . 47 A l t h o u g h o p i n i o n s were n o t f o u n d on t h e h y p o t h e t i c a l c e n -t e r o f o r i g i n and d i s p e r s a l o f M i c r o t u s a r v a l i s , i t may s h a r e t h e n o r t h e r n o r i g i n s o f i t s g e n u s , s u b f a m i l y , f a m i l y and o r d e r . I f A l l e n ' s ( 1 9 0 6 ) s i z e - c e n t e r o f o r i g i n h y p o t h e s i s were i n f l u -e n c i n g v a r i a t i o n i n t h e common v o l e , a b e t t e r a p p r o a c h t o m o n i -t o r c h a n g e s i n body s i z e w o u l d have been a l a t i t u d i n a l s t u d y i n v o l v i n g b r o a d e r n o r t h t o s o u t h d i s t a n c e s r a t h e r t h a n an a l t i -t u d i n a l s t u d y r e s t r i c t e d t o a n a r r o w band o f l a t i t u d e . 1.2.2.2. _n£luence £f_c_ima_e_ S t u d i e s on l a t i t u d i n a l and a l t i t u d i n a l s i z e v a r i a t i o n u s u -a l l y a t t e m p t t o c o r r e l a t e t h e m e a surements w i t h c l i m a t i c d a t a s u c h as t h e mean o f t e m p e r a t u r e o r s n o w f a l l o r r a i n f a l l o r f r o s t f r e e d a y s . These d a t a a r e u s u a l l y s u p p l i e d by l o c a l w e a t h e r s t a t i o n s . T h e r e a r e two d e f i c i e n c i e s i n h e r e n t i n t h i s a p p r o a c h . The f i r s t i s t h a t t h e r e i s r a r e l y a w e a t h e r s t a t i o n i n t h e e x a c t l o c a l i t y f r o m w h i c h e a c h s p e c i m e n comes and r e s e a r c h e r s a r e f o r c e d t o u s e c l i m a t i c i n f o r m a t i o n a v a i l a b l e f r o m t h e n e a r e s t o r most e q u i v a l e n t l o c a l i t y ( R u i b a l , 1 9 5 7 ) . The s e -c o n d i s t h a t t h e c o n d i t i o n s o f c l i m a t e t o w h i c h young g r o w i n g p l a n t s and a n i m a l s t h a t a r e r e s t r i c t e d t o t h e p r o x i m i t y o f t h e s u r f a c e , o r t h a t l i v e on t h e g r o u n d a r e e x p o s e d , c a n n o t be de-d u c ed d i r e c t l y f r o m t h e f i g u r e s f o r c l i m a t e p u b l i s h e d by t h e n e t w o r k o f o f f i c i a l s t a t i o n s . M e t e o r o l o g i c a l i n s t r u m e n t s h e l -t e r s a r e p l a c e d a t . two m e t e r s above t h e l e v e l o f t h e g r o u n d , t h u s e l i m i n a t i n g t h e c h a n c e i n f l u e n c e s o f t h e p o s i t i o n s e l e c t -e d . Then t h e n a t u r e and t h e s t a t e o f t h e g r o u n d , and t h e v e g e t a t i o n g r o w i n g on i t , no l o n g e r p l a y a s i g n i f i c a n t r o l e . 48 The m e t e r o l o g i c a l s t a t i o n i s t h u s r e p r e s e n t a t i v e o f a w i d e r s u r r o u n d i n g a r e a , and t h e c l i m a t e t h u s measured i s t h a t e x p e r i -e n c e d by a p e r s o n w a l k i n g u p r i g h t , o r human c l i m a t e , as i t i s s o m e t i m e s t e r m e d . I n t h e a i r l a y e r b e l o w t h i s a g r e e d l e v e l o f a b o u t two m e t e r s s u b s t a n t i a l l y d i f f e r e n t c o n d i t i o n s w i l l , i n g e n e r a l , be f o u n d ( G e i g e r , 1 9 7 3 ) . The o f f i c i a l m e t e o r o l o g i c a l n e t w o r k i n S w i t z e r l a n d was n o t e x t e n s i v e enough t o p r o v i d e e v e n c l o s e l o c a l i t y d a t a f o r t h e y e a r s n eeded i n t h e m a j o r i t y o f c a s e s , so t h e i n f l u e n c e o f g r o s s c l i m a t i c c o n d i t i o n s on t h e s i z e o f M i c r o t u s a r v a l i s c o u l d n o t be e v a l u a t e d . W h i l e i t w o u l d have been d e s i r a b l e t o a t t e m p t t o gauge t h e e f f e c t s o f c l i m a t e on s i z e i n t h e common v o l e , G e i g e r ' s ( 1 9 7 3 ) work d e m o n s t r a t e d t h a t t h e d a t a g a t h e r e d by s t a n d a r d m e t e o r o l o g i c a l s t a t i o n s w o u l d n o t have been s u i t -a b l e i n d i c e s i n any c a s e o f t h e e c o c l i m a t e t o w h i c h t h e s p e c i -mens had been e x p o s e d . 1.2.2.3. Burrowi^nci T h e r e a r e d i f f e r e n t d e g r e e s t o w h i c h a n i m a l s c a n be f o s s o -r i a l and t h e d e g r e e may a f f e c t s i z e v a r i a t i o n . At one end o f t h e s c a l e i s an a n i m a l s u c h as t h e : p o c k e t g o p h e r (Geomys b u r -s a r i u s ) w h i c h l i v e s i n c l o s e d b u r r o w s y s t e m s and f o l l o w s a s i z e - l a t i t u d e g r a d i e n t (McNab, 1 9 7 1 ) . At t h e o t h e r end o f t h e s c a l e i s a s u p e r f i c i a l b u r r o w e r s u c h a s t h e g r e y - s i d e d v o l e ( C I e t h r i o n o m y s r u f o c a n u s ) w h i c h o v e r w i n t e r s u n d e r t h e snow b u t i n o v e r g r o u n d n e s t s . I t , t o o , f o l l o w s a s i z e - l a t i t u d e g r a d i e n t ( K a l e l a , 1 9 5 7 ) . 49 Somewhere i n t h e m i d d l e i s M i c r o t u s a r v a l i s . I t d o es not l i v e i n a c l o s e d b u r r o w s y s t e m , b u t i t d o e s have e x t e n s i v e t u n -n e l s y s t e m s and b e l o w s u r f a c e f o o d s t o r a g e c h a m b e r s . I t s n e s t s a l s o c a n be u n d e r g r o u n d ( T a b l e X V I e , f and n: p a g e s 59, 60 and 68, r e s p e c t i v e l y ) . The common v o l e o v e r w i n t e r s u n d e r g r o u n d b u t makes f o r a y s above g r o u n d f o r f o o d , n o t r e l y i n g t o t a l l y on p r o -v i s i o n s i n t h e s t o r a g e c h a m b e r s . As s u c h , M i c r o t u s a r v a l i s may q u a l i f y as one o f t h e b u r r o w i n g mammals w h i c h " a l m o s t c o n s i s -t e n t l y f a i l t o obey Bergmann's R u l e " ( M a y r , 1963:page 3 2 3 ) . F o r t h e s e a n i m a l s t h e amount o f snow c o v e r , o r t h e amount o f f o o d a v a i l a b l e i n w i n t e r o r t h e d e p t h o f t h e s o i l may be t h e d e c i s i v e f a c t o r i n d e t e r m i n i n g body s i z e (W.B. D a v i s , 1938; M a y r , 1 9 6 3 ) . 1.2.2.4. _ o m p _ t i t _ o _ G e o g r a p h i c v a r i a t i o n c a n be s t r o n g l y i n f l u e n c e d by t h e k i n d s o f c o m p e t i t o r s p r e s e n t . Two c l o s e l y r e l a t e d s p e c i e s a r e d i s t i n c t where t h e y o c c u r t o g e t h e r - t h e y ' d i s p l a c e ' one a n o t h -e r i n one o r more c h a r a c t e r s - b u t where one member o f t h e p a i r o c c u r s a l o n e i t c o n v e r g e s t o w a r d t h e s e c o n d , e v e n t o t h e e x t e n t o f b e i n g n e a r l y i d e n t i c a l w i t h i t i n some c h a r a c t e r s . The c h a r a c t e r s i n v o l v e d c a n be m o r p h o l o g i c a l , e c o l o g i c a l , b e h a v i -o u r a l , o r p h y s i o l o g i c a l ; t h e y a r e assumed t o be g e n e t i c a l l y b a s e d (Brown and W i l s o n , 1 9 5 6 ) . I n t e r a c t i o n i n t h e f o r m o f c o m p e t i t i o n b e t w e e n c l o s e l y r e -l a t e d s y m p a t r i c s p e c i e s i s i m p l i c i t i n t h i s t h e o r y o f c h a r a c t e r d i s p l a c e m e n t . T h e r e i s no u n a n i m i t y c o n c e r n i n g t h e p r e c i s e de-f i n i t i o n o f c o m p e t i t i o n , y e t i t a l w a y s means t h a t two o r more 50 i n d i v i d u a l s , p o p u l a t i o n s o r s p e c i e s s e e k s i m u l t a n e o u s l y an e s -s e n t i a l e n v i r o n m e n t a l r e s o u r c e , s u c h as f o o d , o r a p l a c e t o l i v e , t o h i d e , o r t o b r e e d t h a t i s i n l i m i t e d s u p p l y (Brown and W i l s o n , 1956; Mayr, 1 9 6 3 ) . T h r o u g h o u t i t s r a n g e i n S w i t z e r l a n d , t h e common v o l e p r o b a b l y i s s y m p a t r i c w i t h a t l e a s t one o t h e r c o n g e n e r i c s p e c i e s - e i t h e r t h e f i e l d v o l e , M. a g r e s t i s (up t o 1000 m e t e r s ) , o r t h e snow v o l e , M. n i v a l i s ( a b o v e 1800 m e t e r s ) , o r b o t h ( f r o m 1000 m e t e r s t o 1800 m e t e r s ) . F i g u r e 8 i l l u s t r a t e s t h e a l t i t u d e r a n g e s o f t h e s e t h r e e s p e c i e s f r o m d a t a i n T a b l e XVIb ( p a g e 5 6 ) , and t h e S w i s s a l t i t u d e s f r o m w h i c h t h e 422 M^ _ a r v a l i s s p e c i m e n s were t a k e n . W hether t h i s ' w edding c a k e ' d i a g r a m i s an a c c u r a t e r e f l e c t i o n o f t h e f r e q u e n c y d i s t r i b u t i o n o f t h e common v o l e o r t h e f r e q u e n c y d i s t r i b u t i o n o f t h e c o l l e c t o r s i s unknown. However, as M i c r o t u s a r v a l i s i s p r i m a r i l y an a n i m a l o f c u l t i v a t e d l a n d s and p a s t u r e s ( T a b l e X V I c : page 5 7 ) , and as t h e a v a i l a b i l i t y o f t h i s k i n d o f h a b i t a t d e c r e a s e s w i t h a l t i t u d e , g i v i n g way t o l e s s a r a b l e l a n d and more r o c k y z o n e s , i t i s p o s s i b l e t h a t t h e museum s p e c i m e n s do g i v e a t r u e p i c t u r e o f t h e v o l e ' s f r e q u e n -cy d i s t r i b u t i o n i n S w i t z e r l a n d . T h e r e i s , o f c o u r s e , no way t o f i n d d i r e c t e v i d e n c e o f i n -t e r s p e c i f i c c o m p e t i t i o n among t h e t h r e e r e s i d e n t s p e c i e s o f v o l e s f r o m museum c o l l e c t i o n s o f M. a r v a l i s . A l i t e r a t u r e r e -v i e w , h o w e v e r , c a n p r o v i d e c e r t a i n c l u e s . T a b l e XVI co m p a r e s FIGURE 8: ALTITUDE RANGES OF THREE SPECIES OF MICROTUS 14 43 74 87 97 107 M. AGRESTIS M. ARVALIS M. NIVALIS NUMBER OF SPECIMENS IN SWITZERLAND IN EACH ALTITUDE GROUP OF 400 METERS t h e l i f e h i s t o r i e s o f t h e t h r e e s p e c i e s i n 29 c a t e g o r i e s - 20 non r e p r o d u c t i v e ( T a b l e X V I a t o k: pages 55 t o 65) and n i n e r e -p r o d u c t i v e ( T a b l e X V I I t o q: pages 66 t o 7 1 ) . T h e r e a r e t h r e e c a t e g o r i e s w h i c h may r e f l e c t c o m p e t i t i o n t h r o u g h a c t u a l o r p o t e n t i a l c h a r a c t e r d i s p l a c e m e n t : d a i l y a c -t i v i t y r h y t h m s ( T a b l e X V I i : page 6 3 ) , p o p u l a t i o n c y c l i n g ( T a b l e X V I h : page 62) and h a b i t a t s e l e c t i o n ( T a b l e X V I c : page 5 7 ) . 1 .2 .2 .4 .1 . 2 a i ^ y . a - c JLiy_ i JLy_ r ! !y . t n m . s „ M. a r v a l i s i s c h i e f l y c r e p u s c u l a r o r n o c t u r n a l ( D e l o s t , 1955b; B r i n k , 1967; S a i n t G i r o n s , 1 9 7 3 ) . I n t h e w i l d , M. a g r e s t i s was r e p o r t e d t o be more d i u r n a l t h a n M. a r v a l i s ( B r i n k , 1967) b u t i n l a b o r a t o r y c o n d i t i o n s , i t was more a c t i v e a t n i g h t (D.H.S. D a v i s , 1 9 3 3 ) . T h i s change i n r h y t h m may have been an a b e r r a t i o n i n c a p t i v i t y o r i t may have i n d i c a t e d a b i o -r h y t h m p l a s t i c i t y , an a b i l i t y t o change i n r e s p o n s e t o one o r s e v e r a l v a r i a b l e s , s u c h as s e a s o n , ( E r k i n a r o , 1969) r e p r o d u c -t i v e c o n d i t i o n , a g e , p r e s e n c e o f c o m p e t i t o r s o r p r e d a t o r s . O p i n i o n was d i v i d e d on t h e peak a c t i v i t y p e r i o d s o f M. n i v a l i s . B r i n k ( 1 9 6 7 ) and S a i n t G i r o n s ( 1 9 7 3 ) c o n s i d e r e d t h e snow v o l e a p r i n c i p a l l y d i u r n a l c r e a t u r e , w h e r e a s i t was l a b e l -l e d c r e p u s c u l a r o r n o c t u r n a l a f t e r f i e l d o b s e r v a t i o n s by K o w a l -s k i ( 1957) and Le L o u a r n and J a n e a u (1975) and a f t e r l a b o r a -t o r y o b s e r v a t i o n s by B i e n k o w s k i and M a r s z a l e k ( 1 9 7 4 ) . As i n t h e c a s e o f M. a g r e s t i s , t h e s e c o n t r a d i c t i o n s i n M. n i v a l i s may r e f l e c t a b e h a v i o u r a l p l a s t i c i t y . 53 1.2.2.4.2. P ° £ u A a _ i o r i _ _ c _ c _ i n g _ a g r e s t i s was r e p o r t e d t o u n d e r g o p o p u l a t i o n c y c l e s i n B r i t a i n (Summerhayes, 1 9 41; D. C h i t t y , 1952 and 1954; H. C h i t t y and D. C h i t t y , I 9 6 0 ; C o r b e t , 1 9 6 6 ) ; i n S c a n d i n a v i a ( C u r r y -L i n d a h l , 1956; K a n e r v o and M y l l y m a k i , 1 9 7 0 ) ; and on t h e c o n t i n -e n t ( E l t o n , 1 9 6 5 ; S a i n t G i r o n s , 1 9 7 3 ) . M. a r v a l i s c y c l e s i n a l l t h e c o u n t r i e s o f c e n t r a l E u r o p e and R u s s i a ( E l t o n , 1 9 6 5 ) . (The common v o l e does n o t o c c u r i n S c a n d i n a v i a o r m a i n l a n d B r i t a i n . ) B r i n k ( 1 9 6 7) s t i p u l a t e d , h o w e v e r , t h a t M. a g r e s t i s i n c r e a s e s i n number t o p l a g u e p r o p o r t i o n s o n l y where M. a r v a l i s d o e s n o t o c c u r , i m p l y i n g t h a t M. a r v a l i s s u p p r e s s e s t h e p o p -u l a t i o n c y c l i n g d y n a m i c s o f M. a g r e s t i s when t h e two s p e c i e s a r e s y m p a t r i c . T h e r e i s no i n f o r m a t i o n on w h e t h e r M. n i v a l i s i s s u b j e c t t o p o p u l a t i o n c y c l i n g , e x c e p t f o r F r a n c e where a p p a r e n t l y i t i s n o t ( S a i n t G i r o n s , 1 9 7 3 ) . 1.2.2.4.3. H a b i t a t s _ e l e c t i o n H a b i t a t a p p e a r s w e l l d i f f e r e n t i a t e d among t h e t h r e e s p e c -i e s o f v o l e s - M. a g r e s t i s a w o o d l a n d o r wet g r a s s l a n d s p e c i e s ( R e g n i e r and P u s s a r d , 1926; E l t o n , 1965; C o r b e t , 1966; B r i n k , 1967; T a p p e r , 1 9 7 6 ) ; M. a r v a l i s a c u l t i v a t e d l a n d s p e c i e s ( B e r n a r d , 1 9 5 3 ; C o r b e t , 1966; B r i n k , 1 9 6 7 ) ; M. n i v a l i s a r o c k y a l p i n e zone s p e c i e s ( C o r b e t , 1966; B r i n k , 1967; Le L o u a r n and J a n e a u , 1 9 7 5 ) . I n d e e d a l t h o u g h some have s u g g e s t e d t h a t M. a g r e s t i s was n o t a b l e t o t o l e r a t e human c u l t i v a t i o n p r o -c e s s e s ( B e r n a r d , 1953) o r r e q u i r e d d e n s e g r o u n d c o v e r ( S c h i n d -l e r , 1 955; C o r b e t , 1966; Ashby, 1 9 6 7 ) , B r i n k ( 1 9 6 7 ) and S a i n t 54 G i r o n s ( 1 9 7 3 ) commented t h a t i n a r e a s where M. a r v a l i s was a b s e n t , M. a g r e s t i s t o o k o v e r i t s h a b i t a t . Le L o u a r n and J a n e a u ( 1 9 7 5 ) r e m a r k e d t h a t i f M. n i v a l i s were s t i l l f o u n d a t low a l t i t u d e s i n t h e M e d i t e r r a n e a n zone i n F r a n c e , i t w o u l d be due t o t h e a b s e n c e o f M. a r v a l i s . S a i n t G i r o n s ( 1 9 7 3 ) w r o t e t h a t t h e more p r o l i f i c s p e c i e s o f M i c r o t u s f o r c e d M. n i v a l i s i n t o t h e m o u n t a i n s and t h e l a t t e r i s a b l e t o e s t a b l i s h i t s e l f a t t h e l o w e r a l t i t u d e s o n l y i f M. a r v a l i s and M. a g r e s t i s a r e a b s e n t o r r a r e . In g e n e r a l i t seems i t i s t h e p r e s e n c e o r a b s e n c e o f M. a r v a l i s t h a t p r o d u c e s e t h o l o g i c a l c h a n g e s i n M. a g r e s t i s and M. n i v a l i s r a t h e r t h a n t h e r e v e r s e . T h i s may be due t o t h e more a g g r e s s i v e n a t u r e o f M i c r o t u s a r v a l i s ( B e r n a r d , 1953) o r s i m p l y to i t s o u t n u m b e r i n g t h e o t h e r two s p e c i e s ( B e r n a r d , 1953; S a i n t G i r o n s , 1 9 7 3 ) . W h a t e v e r t h e r e a s o n , i t a p p e a r s t h a t i f s i z e were t o v a r y a l s o as a r e s u l t o f c o m p e t i t i o n , i t w o u l d do so i n t h e snow v o l e a n d / o r t h e f i e l d v o l e b u t n o t i n t h e common v o l e . 2. S u b s p e c i a t i o n I t i s n o t r e l e v a n t t o t h i s d i s c u s s i o n on s u b s p e c i a t i o n and i n f r a s p e c i f i c v a r i a t i o n t o embark upon a h i s t o r y o f t h e d e b a t e s on t h e c o n c e p t and d e f i n i t i o n o f s p e c i e s . A c c o r d i n g t o S c u d d e r ( 1 9 7 4 : p a g e 1124) " i t i s p r o b a b l y i n h e r e n t l y i m p o s s i b l e t o f rame a s i n g l e r e a l l y p r e c i s e , f u l l y m e a n i n g f u l s p e c i e s d e f i n i -t i o n w h i c h ca n be a p p l i e d w i t h o u t q u e s t i o n t o a l l o r g a n i s m s i n n a t u r e and w h i c h can be a c c e p t e d by t a x o n o m i s t s and TABLE XVIa: LIFE HISTORIES OF THREE SPECIES OF MICROTUS ASPECT BODY (PLUS HEAD) LENGTH (MM) TAIL LENGTH (MM) MICROTUS AGRESTIS 85-130 (Saint Girons, 1973) 95-133 (Brink, 1967) 110-130 ( D i d i e r and Rode, 1939) 25-46 (Sa i n t Girons, 1973) 27-46 (Brink, 1967) 30-45 ( D i d i e r and Rode, 1939) MICROTUS ARVALIS 82.5-122 (Saint Girons, 1973) 95-110 (Regnier and Pussard, 1926) 95-110 ( D i d i e r and Rode, 1939) 95-120 (Brink, 1967) 100-111 ( M i l l e r , 1912) MICROTUS NIVALIS 97-136.5 ( S a i n t Girons, 1973) 117-140 ( B r i n k , 1967) 120-140 ( D i d i e r and Rode, 1939) 23-39 (Sa i n t Girons, 1973) 44-71 ( S a i n t Girons, 1973) 30-35 (Regnier and Pussard, 1926) 50-75 ( D i d i e r and Rode, 1939) 30-40 ( D i d i e r and Rode, 1939) 50-75 (B r i n k , 1967) 30-45 (Brink, 1967) 35-45 ( M i l l e r , 1912) 15- 21 (Saint Girons, 1973) 13-18 (S a i n t Girons, 1973) 18.3-21.5 ( S a i n t Girons, 1973) 16- 20.5 (Brink, 1967) 14-18 (Regnier and Pussard, 1926) 18.5-22 ( B r i n k , 1967) HIND FOOT LENGTH (MM) 17-20 ( D i d i e r and Rode, 1939) 15-16 ( M i l l e r , 1912) 19-22 ( D i d i e r and Rode, 1939) 15- 18.5 ( B r i n k , 1967) 16- 18 ( D i d i e r and Rode, 1939) TABLE XVIb: LIFE HISTORIES OF THREE SPECIES OF MICROTUS ASPECT EAR LENGTH (MM) WEIGHT (GR) MICROTUS AGRESTIS MICROTUS ARVALIS 8- 10 ( D i d i e r and Rode, 1939) 7-9 ( D i d i e r and Rode, 1939) 9- 14 (Saint Girons, 1973) 8-12.3 (Saint Girons, 1973) MICROTUS NIVALIS 11.4-17.8 (Sa i n t Girons, 1973) 15-17 ( D i d i e r and Rode, 1939) 19- 52 (Brink, 1967) 14-46 (Brink, 1967) 38-50 (Brink, 1967) 20- 47.6 ( S a i n t Girons, 1973) 15-35 (Regnier and Pussard, 1926) 42-62 ( S a i n t Girons, 1973) 30-35 ( D i d i e r and Rode, 1939) 16.2-51 (Saint Girons, 1973) 25-30 ( D i d i e r and Rode, 1939) DISTRIBUTION ALTITUDE RANGE (M) A l l Europe-from Scandinavia i n the north to the Alps i n the south and from F i n l a n d i n the east to England, France, Pyrenees, P o r t u g a l i n the west and southwest ( D i d i e r and Rode, 1939) Greater part of Europe and part of Asia c h i e f l y between 45° and 55° north l a t i t u d e ( E l t o n , 1965) In France-to 1800 (Saint Girons, 1973) In Switzerland-to 1800 (G d l d i , 1914) In France-to 2800 ( S a i n t Girons, 1973) In Switzerland-to 2350 ( G d l d i , 1914) In Switzerland-to 2436 (Dottrens, 1962) S i e r r a de Gredos, Spain; Pyren-ees; Alps; C e n t r a l Appenines; p a r t s of the Balkans; Carpath-i a n s ; Tatra (Corbet, 1966) In Alps-1000 to 4000 (Saint G i r -ons, 1973) In Alps-1500 to 2600 (Le Louarn and Janeau, 1975) In A l p s - t o 3500 ( A l l e e and Schmidt, 1962) In France-to 3600 ( D i d i e r and Rode, 1939) In Switzerland-1600 to 2600 (Cor-bet, 1966) TABLE XVIc: LIFE HISTORIES OF THREE SPECIES OF MICROTUS ASPECT MICROTUS AGRESTIS In Belgium-fallow land; f o r -ested areas (Bernard, 1953) In B r i t a i n - p u r e grassland ( E l t o n , 1965) In B r i t a i n - c o v e r c o n s i s t s mainly of grasses and i s dense at ground l e v e l (Ash-by, 1967) HABITAT In B r i t a i n - o p e n , grassy area (Tapper, 1976) In France-woods and p l a n t a -t i o n s (Regnier and Pussard, 1926) In Scandinavia-open h a b i t a t s (Curry-Lindahl, 1956) In General-grassland; wet ground with rushes and sedge (Corbet, 1966). In General-moist areas; open woods (Brink, 1967) MICROTUS ARVALIS In Belgium-cultivated land (Bernard, 1953) In France-grassland with or without shrubs (Le Louarn, S p i t z and D a s s o n v i l l e , 1970) In Mediterranean area-growths of rushes (Rey, 1973) In General-pastures; meadows (Corbet, 1966) In General-pastures; meadows; f i e l d s ; c u l t i v a t e d land ( B r i n k , 1967) MICROTUS NIVALIS In France-alpine and subalpine meadows with rocks l a r g e r than 20 cm (Le Louarn and Janeau, 1975) In General-above t r e e l i n e ; mixture loose rock and grass; open mountain woodland (Corbet, 1966) In General-high mountains; rocky slopes; stoney meadows; open woods (Brink, 1967) TABLE XVId: LIFE HISTORIES OF THREE SPECIES OF MICROTUS ASPECT MICROTUS AGRESTIS For Females-27 m i n length (Brown, 1966) For Males-36 m i n length (Brown, 1966) In General-greatest distance across seldom more than 9-13.5 m (D. C h i t t y , 1952) In General-smaller than 210 HOME sq m (Godfrey, 1954) RANGE In General-size and shape i n SIZE summer f l u c t u a t e s ; depends on gradual changes i n vegetation and c u l t i v a t i o n methods (Curry-Lindahl, 1956) MICROTUS ARVALIS MICROTUS NIVALIS For Females-10-20 m i n d i a -meter i n breeding season (Frank, 1957) For Females-300-500 sq m i n c o n i f e r p l a n t a t i o n (Reich-s t e i n , 1960b) For Females-smaller than 7 m i n length (Dub, 1971a) For Females-1/4 of 146-600 sq m ( N i k i t i n a , K a r u l i n and Zen'Kovich, 1972) For Maies-40-100 m i n diameter i n winter (Frank, 1957) For Males-1200 to 1500 sq m i n c o n i f e r p l a n t a t i o n (Reich-s t e i n , 1960b) For Males-smaller than 13 m i n length (Dub 1971b) For Males-1/4 of 828-1008 sq m ( N i k i t i n a , K a r u l i n and Zen'Kovich, 1972) In General-each f a m i l y occu-pies only a few sq m (Bernard, 1959) In General-smaller than 10 m ( S p i t z , 1963b) In General-decrease i n s i z e with increase i n d e n s i t y i n summer ( S p i t z , 1970a) In General-a few sq m around burrow ( S a i n t Girons, 1973) In General-7.5-9 m ( S p i t z et a l , 1974) TABLE XVIe: LIFE HISTORIES OF THREE SPECIES OF MICROTUS ASPECT MICROTUS AGRESTIS MICROTUS ARVALIS MICROTUS NIVALIS RUNWAY SYSTEMS In Britain-extremely compli-cated, extensive systems (Summerhayes, 1941) In Britain-surface systems (Tapper, 1976) In General-prominent systems through grass (Corbet, 1966) In General-systems above ground but well hidden (Brink, 1967) In B r i t a i n (Orkney Islands)-well marked systems (Turner, 1965) In General-systems connect tunnels on surface (Brink, 1967) TUNNERL SYSTEMS In France-systems s u p e r f i c i a l (Saint Girons, 1973) In General-systems rarely ex-tensive (Corbet, 1966) In General-systems near sur-face (Brink, 1967) In Belgium-systems at depths varying with s o i l conditions; usually a few cm from the surface (Dalimier, 1955) In B r i t a i n (Orkney Islands)-short to complex systems (Turner, 1965) In France-entrances to systems beside rocks (Le Louarn and Janeau, 1975) In General-systems with several openings (Brink, 1967) In France-very deep systems (Saint Girons, 1973) In Poland-100-150 cm long systems at 35 cm depth (Cech-owicz and Pucek, 1961) In General-extensive, complex, shallow systems (Corbet, 1966) TABLE XVIf: LIFE HISTORIES OF THREE SPECIES ASPECT MICROTUS AGRESTIS In B r i t a i n - s t o r e s grass seed (Baker and Ranson, 1932b) In France-stores c e r e a l s , grass, seeds of composites ( D i d i e r and Rode, 1939) In General-has food storage chambers (Brink, 1967) FOOD STORAGE MICROTUS MICROTUS ARVALIS MICROTUS NIVALIS In Belgium-2 kinds of storage chambers: autumn one f o r seeds, g r a i n s ; winter one f o r r o o t s , bulbs, t u b e r c l e s (Dalimier, 1955) In France-oval storage cham-bers, 10-12 cm from s u r f a c e ; i n winter stores 2-3 kg of rhizomes, bulbs, t u b e r c l e s , roots of w i l d p l a n t s (Regnier and Pussard, 1926) In France-stores seeds of c e r -e a l s , lucern grass, apples Delost, 1955b) In USSR-stores 2.5-3.3 kg of food such as bulbs (Gladkina and Chentsova, 1971) In General-stores food i n underground chambers ( B r i n k , 1967) TABLE XVIg: LIFE HISTORIES OF THREE SPECIES OF MICROTUS ASPECT MICROTUS AGRESTIS MICROTUS ARVALIS MICROTUS NIVALIS DIET In Britain-stems, leaves, roots of rough grasses of a l l kinds; certain herbaceous plants (Ranson, 1934) In Britain-herbaceous vegeta-t i o n ; trees only attacked when vole numbers very high (Sum-merhayes, 1941) In Britain-grasses (Godfrey, 1953b and 1955) In Britain-green stems and leaves; not seeds and f r u i t (Elton, 1965) In France-young shoots, green parts of plants (Saint Girons, 1973) In General-almost entirely herbivorous: i n summer, stems, leaves of grasses, rushes, sedges; i n winter, roots, rhizomes, bark (Corbet, 1966) In Belgium-seeds of cu l t i v a t e d cereals, wild plants; i n cap-t i v i t y small insects ( D a l i -mier, 1955) In France-seeds s t i l l green; i n c a p t i v i t y , invertebrates (Saint Girons, 1973) In Switzerland-green parts of plants, not the roots (Goldi, 1914) In General-nuts; bark of l i v -ing trees; seeds of clover, lucern, wheat, oats, rye, barley, corn; potato tubers (Elton, 1965) In France-seeds, roots, flowers, leaves of alpine plants (Didier and Rode, 1939) In France-roots, seeds of alpine plants especially b i l b e r r y (Saint Girons, 1973) In General-grasses, herbs, especially b i l b e r r y (Corbet, 1966) TABLE XVIh: LIFE HISTORIES OF THREE SPECIES OF MICROTUS ASPECT MICROTUS AGRESTIS MICROTUS ARVALIS MICROTUS NIVALIS In Britain-chief agent of tree damage (Elton, 1965) PEST In Scandinavia-chief agent of STATUS damage to ornamental plants, f r u i t trees, forest planta-tions, seed plantations (Kan-ervo and Myllymaki, 1970) In most of Europe and European USSR-chief agent of damage to crops; k i l l s trees, shrubs by gnawing bark; destroys tree seeds (Elton, 1965) In Bulgaria-source and transmitter to wil d and domestic mountain grazers of p a r a s i t i c worms, espe-c i a l l y smaller fluke (Peshev, 1970) In Britain-cycles (Summer-hayes, 1941; D. Chitty, 1952 and 1954; H. Chitty and D. Chitty, 1960; Corbet, 1966) POPULATION On Continent-cycles (Elton, CYCLING 1965) In France-cycles (Saint Girons, 1973) In Scandinavia-cycles (Curry Lindahl, 1956; Kanervo and Myllymaki,1970) In Belgium-cycles (Bernard, 1953 and 1959) In Bulgaria-cycles (Straka and Gerasimov, 1971) In France-cycles (Spitz, 1967; Saint Girons, 1973) In Germany-cycles (Frank, 1957) In a l l the countries of cen-t r a l Europe and Russia-cycles (Elton, 1965) In France-does not cycle (Saint Girons, 1973) ro TABLE X V I i : LIFE HISTORIES OF THREE SPECIES OF MICROTUS ASPECT MICROTUS AGRESTIS MICROTUS ARVALIS MICROTUS NIVALIS DAILY RHYTHM OF ACTIVITY In C a p t i v i t y - 2 - 4 hour rhythm of feeding a c t i v i t y and long-er 24 hour rhythm; peak f o l -lowing sunset; more a c t i v e at night (D.H.S. Davis, 1933) In General-more d i u r n a l than M. a r v a l i s ( B r i n k , 1967) In General-active day and nig h t ; 2 p r i n c i p a l times: s u n r i s e and sunset ( S a i n t Girons, 1973) In General-active at night during summer; a c t i v e during day i n winter (Erkinaro, 1969) In C a p t i v i t y - 8 - 1 0 periods of a c t i v i t y during 24 hours (Durup, 1956) In C a p t i v i t y - 7 - 8 periods of a c t i v i t y during 24 hours ( N i k i t i n a , K a r u l i n and Zen'kovich, 1972) In General-mainly a c t i v e at dusk ( B r i n k , 1967) In General-mainly nocturnal (Delost, 1955b) In General-active day and night; mainly a c t i v e at night i n summer (Saint Girons, 1973) In General-active at night during summer; a c t i v e during day i n winter ( E r k i n a r o , 1969) In C a p t i v i t y - b i p h a s i c patterns of a c t i v i t y ; mainly nocturnal (Bienkowski and Marszalek. 1974) In General-active mainly at night (Kowalski, 1957) In General-active mainly at sunset (Le Louarn and Janeau, 1975) In General-apoears o f t e n by day (B r i n k , 1967)' In General-diurnal ( S a i n t G i r -ons, 1973) VOCALIZATIONS Low pitched p o l y s y l l a b i c c a l l (Frank, 1953b) Conspicuous c a l l (Corbet, 1966) Low and c h a t t e r i n g c a l l ( B r i n k , 1967) Noisy when handled (Dienske, 1969) High monosyllabic c a l l (Frank, 1953b) Less vocal than M. a g r e s t i s (Corbet, 1966; Brink, 1967) High c h i r p i n g squeak ( B r i n k , 1967) More s i l e n t than M. a g r e s t i s when handled (Dienske, 1969) Abrupt and pe n e t r a t i n g c a l l ; u s u a l l y s i n g l e notes; i n breed-i n g season a continuous chat-t e r i n g ( B r i n k , 1967) TABLE X V I j : LIFE HISTORIES OF THREE SPECIES ASPECT MICROTUS AGRESTIS In B r i t a i n - v e r y l o c a l i n move-ments (D. C h i t t y , 1952) In Scandinavia-regular autumn m i g r a t i o n from open f i e l d s to f o r e s t borders and sometimes to f o r e s t ; i n s p r i n g back to summer quarters, (Curry-L i n d a h l , 1956) MIGRATION MICROTUS MICROTUS ARVALIS In Czechoslovakia-manmade mi-g r a t i o n : d u ring autumn c u l t i -v a t i o n measures, r e s i d e n t voles emigrate t o adjacent h a b i t a t s (Dub, 1971b) In F r a n c e - l o c a l migrations (Regnier and Pussard, 1926) In F r a n c e - l o c a l m i g r a t i o n s : i n s p r i n g to l u c e r n , c l o v e r , g r a i n f i e l d s ; i n summer to rye and wheat f i e l d s ; i n winter to t h i c k e t s , orchard borders ( D e l o s t , 1955b) In Poland-seasonal m i g r a t i o n : during and immediately a f t e r harvest, leave the c u l t i v a t e d f i e l d s ; end of September when ploughing terminated, r e t u r n m i g r a t i o n (Cechowicz and Pucek, 1961) In G e n e r a l - l o c a l migrations ( B r i n k , 1967) MICROTUS NIVALIS In France-long migrations September t o A p r i l ; sedentary a f t e r A p r i l (Le Louarn and Janeau,1975) In Poland-migrations up moun-t a i n s i n summer (Kowalski, 1957) In S w i t z e r l a n d - p o s s i b l e ver-t i c a l seasonal migrations (Dottrens, 1962) TABLE XVIk: LIFE HISTORIES OF THREE SPECIES OF MICROTUS ASPECT MICROTUS AGRESTIS MICROTUS ARVALIS MICROTUS NIVALIS In France-weasels v i p e r s , noc-t u r n a l and d i u r n a l r a p t o r s ( D i d i e r and Rode, 1939) In France-carnivores, v i p e r s , PREDATORS r a p t o r s (Saint Girons, 1973) In General-stoats, weasels, p o l e c a t s , martens, foxes, c a t s , buzzards, eagles, har-r i e r s , short earred owls, barn owls, snowy owls (Corbet, 1966) In Belgium-foxes, badgers, p o l e c a t s , ermines, weasels, grass snakes, v i p e r s , r a p t o r s ( D a l i m i e r , 1955) In France-weasels, martens, v i p e r s , r a p t o r s (Delost, 1955b) In France-carnivores, v i p e r s , r a p t o r s ( S a i n t Girons, 1973) In France-carnivores c o r v i d s , d i r u n a l r a p t o r s ( S a i n t Girons, 1973) In F r a n c e - r e p t i l e s , c a r n i v o r e s (Le Louarn and Janeau, 1975) A few months from weaning (Corbet, 1966) 7-8 months ( L e s l i e and Ranson, 1940) LIFE F u l l y grown males of 1 year do EXPECTANCY not l i v e over to the next year (Baker and Ranson, 1933) 18 months maximum (Wasilewski, 1956) I f born February to May: 2-4 months (M a r t i n e t , 1967) I f born March to June: 2 months ( S p i t z , 1967) I f born J u l y t o October; 7-9 months ( S p i t z , 1967) More than 2 years (Delost, 1955b) 2-3 years (Regnier and Pussard, 1926) TABLE XVII: LIFE HISTORIES OF THREE SPECIES OF MICROTUS ASPECT MICROTUS AGRESTIS MICROTUS ARVALIS MICROTUS NIVALIS BREEDING SEASON In B r i t a i n - M a r c h to September (Baker and Ranson, 1933) In B r i t a i n - M a r c h to October, (Brambell and H a l l , 1939) In Britain-February/March to September/October ( A s d e l l , 1964) In B r i t a i n - f r e q u e n t l y an e a r l y end to breeding i n a peak year (D. C h i t t y , 1954) In France-February t o De-cember; can be year round ( S a i n t Girons, 1973) In Belgium-February/March/ A p r i l to August/September/ October/November; beginning and end i n f l u e n c e d by i n t e r n a l f a c t o r s dominated by e x t e r n a l f a c t o r s such as c l i m a t e , food, p o p u l a t i o n d e n s i t y (Bernard, 1964) In France-March t o October (Delost, 1955b) In France-can be year round ( M a r t i n e t , 1967) In France-February to October; can be year round (Le Louarn, S p i t z and G r o l l e a u , 1970) In France-January/February to October; length v a r i e s depend-i n g on c l i m a t i c , n u t r i t i o n a l , s o c i a l c o n d i t i o n s ( S a i n t G i r -ons, 1973) In France-spring and summer (S a i n t Girons, 1973) In France ( i n high A l p s ) - A p r i l to August (Le Louarn and Janeau, 1975) In France ( a t 1500 m) - A p r i l t o September (Le Louarn and Janeau, 1975) In Germany-February/March to October/November; under favour-able c o n d i t i o n s can be year round (Frank, 1957) CTv TABLE XVIm: LIFE HISTORIES OF THREE SPECIES OF MICROTUS ASPECT MICROTUS AGRESTIS MICROTUS ARVALIS MICROTUS NIVALIS AGE AT FIRST BREEDING For Females-21 days: i n lab-oratory (Baker and Ranson, 1933; L e s l i e and Ranson, 1940) For Males-6 weeks: i n labora-tory (Leslie and Ranson, 1940) For Males-6 to 8 weeks: i n laboratory (Baker and Ranson, 1933) For Both-6 weeks (Corbet, 1966) For Both-in wild: i f born la t e i n season attain puberty following spring (Brambell and H a l l , 1939) For Females-15 to 20 days: i n laboratory (Bashenina, 1953) For Females-17 to 21 days: i n laboratory (Bernard, 1964) For Females-20 days or e a r l i e r : i n laboratory (Frank and Zimmermann, 1957a) For Females-20 to 25 days: i n laboratory and i n wi l d (De-l o s t , 1956) For Females-21 days: i n labor-atory (Martinet, 1967) For Females-in Germany, i n wi l d : i f born during and after September do not reach sexual maturity i n same year (Frank, 1957) For Both-in w i l d : growth stops with f i r s t snow but continues i n April/May when sexually mature (Le Louarn and Janeau 1975) For Males-35 days: i n laboratory (Bashenina, 1953; Martinet, 1967) For Males-35 days: i n wild; 40 days: i n laboratory (Delost, 1956) For Both-2 to 2 1/2 months (Regnier and Pussard, 1926) For Both-in France, i n wild: i f born February to May reach sex-ual maturity quickly; i f born after June, do not reach sexual maturity the year of b i r t h (Mar-t i n e t , 1967) TABLE XVIn: LIFE HISTORIES OF THREE SPECIES OF MICROTUS ASPECT MICROTUS AGRESTIS MICROTUS ARVALIS MICROTUS NIVALIS NEST In B r i t a i n - n e a r l y a l l nests found between May and Septem-ber b u i l t above ground i n s l i g h t excavation i n s o i l ; g l o b u l a r i n shape, of f i n e l y shredded dry grass (Godfrey, 1953a) In France-at the surface, sometimes under the s h e l t e r of a rock ( S a i n t Girons, 1973) In General-usually c o n s t r u c t -ed above ground; under a stone or l o g ; sometimes s l i g h t l y below ground l e v e l (Corbet, 1966) In Generai-often above ground; of grass (Brink, 1967) In Belgium-spherical nests l i n e d with dry grass or straw; sometimes i n summer surface nests under cover such as hay stack ( D a l i m i e r , 1955) In B r i t a i n (Orkney I s l a n d s ) -subterranean chambers l i n e d with r o o t s , grass; surface nests i n long grass and heather (Turner, 1965) In France-surface and under-ground nests; 8-10 cm i n d i a -meter; of d r i e d grass on out-s i d e , straw on i n s i d e ; 5-15 cm below ground i n summer, deeper i n winter (Regnier and Pussard, In General-nest chambers of hay and s t a l k s often j u s t below sur-face ( B r i n k , 1967) 1926) In Poland-nest chambers with 2-3 o u t l e t s ; 15 cm i n diameter; 7-12 cm high (Cechowicz and Pucek, 1961) In General-underground nest chambers or nest can be b u i l t above ground of grass and s t a l k s ( B r i n k , 1967) <7> 03 TABLE XVIo: LIFE HISTORIES OF THREE SPECIES OF MICROTUS ASPECT MICROTUS AGRESTIS MICROTUS ARVALIS MICROTUS NIVALIS Post partum (Ranson, 1934; Post partum (Saint Girons, (Brambell and H a l l , 1939; 1973) Corbet, 1966) OESTROUS 2 kinds of c y c l e s : a t y p i c a l short c y l c e or prolonged per-iods of an oestrous s t a t e (H. C h i t t y and A u s t i n , 1957) Spontaneous (Brambell and H a l l , 1939) OVULATION Induced (Breed, 1967) Spontaneous and induced (H. C h i t t y , 1957) Spontaneous (Delost, 1955d; A s d e l l , 1964) GESTATION PERIOD 18-20 days ( D i d i e r and Rode, 1939) 20-21 days (H. C h i t t y , 1957) 21 days (Ranson, 1934; Les-l i e and Ranson, 1940; Corbet, 1966; Sain t Girons, 1973) 16-24 days (Frank and Zimmermann, 1957a) 16-25 days ( R e i c h s t e i n , 1964) 20 days (Regnier and Pussard, 1926) 20-21 days (Delost, 1955b and 1955d) 21 days ( M a r t i n e t , 1967; S a i n t Girons, 1973) 21 days (Sa i n t Girons, 1973) Length of g e s t a t i o n p e r i o d de-pends on s i z e of l i t t e r - more embryos, shorter length of time ( R e i c h s t e i n , 1964) TABLE XVIp: LIFE HISTORIES OF THREE SPECIES ASPECT MICROTUS AGRESTIS 3 l i v e b i r t h s per l i t t e r ; number decreases as age of mother increases ( L e s l i e and Ranson, 1940) 3-6 (Corbet, 1966) 3- 8 ( S a i n t Girons, 1973) 4 average (Ranson, 1934) 4- 7 ( D i d i e r et a l , 1939) LITTER SIZE L i t t e r s i z e may be greater i n a peak year than i n any other (D. C h i t t y , 1954) - MICROTUS MICROTUS ARVALIS 3-5: i n l a b o r a t o r y (Delost, 1955d) 3-7: i n w i l d (Delost, 1955a) 3-7 ( S a i n t Girons, 1973) 3- 8: i n w i l d ( S t e i n , 1957) 4.36 average: i n la b o r a t o r y Frank and Zimmermann, 1957a) 4- 6 ( D a l i m i e r , 1955; Le Louarn, S p i t z and G r o l l e a u , 1970) 5- 6 (Regnier and Pussard, 1926) L i t t e r s i z e depends on i n h e r -i t a n c e , age and s i z e of mother, season; modified by q u a l i t y and q u a n t i t y of food (Frank, 1957) L i t t e r s i z e depends on q u a l i t y of food, age of mother (Ber-nard, 1964) L i t t e r s i z e depends on food, s i z e and age of mother, f r e -quency of l i t t e r s , length of days, i n t e n s i t y of l i g h t , pop-u l a t i o n d e n s i t y ( R e i c h s t e i n , 1964) L i t t e r s i z e maximum (> 6) i n April/May, minimum (3) Novem-ber t o February ( S p i t z , 1967) L i t t e r s i z e v a r i e s i n r e l a t i o n to season, age of mother (Wojciechowska, 1970) MICROTUS NIVALIS 2-4 (Le Louarn and Janeau, 2- 7 (S a i n t Girons, 1973) 3- 7 ( D i d i e r and Rode, 1939) TABLE XVIq: LIFE HISTORIES OF THREE SPECIES OF MICROTUS ASPECT MICROTUS AGRESTIS MICROTUS ARVALIS MICROTUS NIVALIS LACTATION PERIOD 12-16 days (Godfrey, 1953a) 14 days (Ranson, 1934; Leslie and Ranson, 1940; Clarke, 1955) Fewer than 21 days (Corbet, 1966) More than 2 weeks (Dalimier, 1955) 15 days (Spitz, 1970b) 15-18 days (Regnier and Pussard, 1926) 15-20 days (Delost, 1955d) 17 days (Wojciechowska, 1970) 6-8 (Didier and Rode, 1939) 2 usually (Spitz, 1967) 2 probably (Kowalski, 1957) NUMBER Succession of l i t t e r s (Cor- 3-5 (Dalimier, 1955) 2: f i r s t l i t t e r i n June, OF bet, 1966) second l i t t e r mid July to LITTERS 4-5 (Regnier and Pussard, 1926) mid August Several l i t t e r s (Saint Gir- (Le Louarn and Janeau, 1975) ons, 1973) Varies according to quality 2-3 (Didier and Rode, 1939) of food (Bernard, 1964) 72 e v o l u t i o n i s t s " . Y et some d e f i n i t i o n o f t h e t e r m s p e c i e s i s n e c e s s a r y t o e s t a b l i s h a c o n t e x t w i t h i n w h i c h s u b s p e c i a t i o n can be d i s c u s s e d . M a y r ' s ( 1 9 6 9 : p a g e 26) b i o l o g i c a l s p e c i e s d e f i n i t i o n i s a d e q u a t e f o r t h e p u r p o s e s o f t h i s s t u d y -s p e c i e s a r e " g r o u p s o f i n t e r b r e e d i n g n a t u r a l p o p u l a t i o n s t h a t a r e r e p r o d u c t i v e l y i s o l a t e d f r o m o t h e r s u c h g r o u p s " . M i c r o t u s a r v a l i s i s a p o l y t y p i c s p e c i e s - a s p e c i e s t h a t c o n t a i n s two o r more s u b s p e c i e s ( M a y r , 1 9 6 9 ) . "A s u b s p e c i e s i s an a g g r e g a t e o f p h e n o t y p i c a l l y s i m i l a r p o p u l a t i o n s o f a s p e c i e s , i n h a b i t i n g a g e o g r a p h i c s u b d i v i s i o n o f t h e r a n g e o f a s p e c i e s , and d i f f e r i n g t a x o n o m i c a l l y f r o m o t h e r p o p u l a t i o n s o f t h e s p e c i e s " ( M a y r , 1969:page 4 1 ) . The s u b s p e c i e s i s t h e l o w e s t t a x o n o m i c c a t e g o r y r e c o g n i z e d i n t h e I n t e r n a t i o n a l Code o f Z o o l o g i c a l N o m e n c l a t u r e . S u b s p e c i e s i s , h o w e v e r , a non-o b l i g a t e c a t e g o r y and need n o t , e v e n i n p r i n c i p l e , be u s e d t h r o u g h o u t t h e whole o f a c l a s s i f i c a t i o n ( S i m p s o n , 1 9 6 1 ) . M e y l a n ( 1 9 6 6 ) l i s t e d two s u b s p e c i e s o f M i c r o t u s a r v a l i s i n S w i t z e r l a n d : M. a. r u f e s c e n t e f u s c u s ( S c h i n z , 1845) and t h e n o m i n a t e s u b s p e c i e s M. a. a r v a l i s ( P a l l a s , 1 7 7 9 ) . (The n o m i n -a t e s u b s p e c i e s c o n t a i n s t h e t y p e o f t h e s u b d i v i d e d h i g h e r t a x o n and b e a r s t h e same name.) As m e n t i o n e d p r e v i o u s l y b o t h D o t t r e n s ( 1 9 6 2 ) and J o n e s ( 1 9 7 0 ) c o n c l u d e d i n t h e i r p a p e r s t h a t t h e v o l e s f r o m t h e l o w e s t a l t i t u d e s ( 4 0 5 m and 750 m r e s p e c t i v e l y ) b e l o n g e d t o t h e n o m i n a t e s u b s p e c i e s M. a. a r v a l i s , w h ereas t h e v o l e s f r o m t h e mid and h i g h e s t a l t i t u d e s r e p r e s e n t e d t h e s u b s p e c i e s M. a. r u f e s c e n t e f u s c u s . I t was t h e a b s e n c e o f a l t i t u d i n a l v a r i a t i o n a c c o r d i n g t o Bergmann's R u l e t h a t p r o m p t e d b o t h r e s e a r c h e r s t o t u r n t o s u b s p e c i a t i o n as a p o s s i b l e e x p l a n a t i o n f o r t h e s i z e t r e n d s r e c o r d e d . Y e t , as o u t l i n e d i n t h e f i r s t p a r t o f t h i s d i s c u s s i o n s e c t i o n , a d h e r e n c e i n n a t u r e t o Bergmann's t h e o r y o g e o g r a p h i c v a r i a t i o n i n homeotherms, may be more t h e e x c e p t i o n t h a n t h e r u l e . R e a s o n s o t h e r t h a n s u b s p e c i a t i o n were e n u m e r a t ed why t h i s may be p a r t i c u l a r l y t r u e i n M i c r o t u s a r v a l i s . S u b s p e c i e s a r e named on t h e b a s i s o f t h e i r m o r p h o l o g i c a l d i f f e r e n t i a t i o n ( D u r r a n t , 1954) and t h e y i n h a b i t d e f i n i t e g e o g r a p h i c s u b d i v i s i o n s o f t h e r a n g e o f t h e s p e c i e s , ' t h e d i s t r i b u t i o n d e t e r m i n e d l a r g e l y by c o r r e l a t i o n b e t ween t h e d i a g n o s t i c m o r p h o l o g i c a l c h a r a c t e r s and t h e e n v i r o n m e n t ( M a y r , 1 9 6 3 ) . T h e r e f o r e , any a n a l y s i s o f g e o g r a p h i c v a r i a t i o n i n te r m s o f s u b s p e c i a t i o n i n t h e common v o l e i n S w i t z e r l a n d must (1 ) d e m o n s t r a t e m o r p h o l o g i c a l v a r i a t i o n s u f f i c i e n t l y d i s t i n c t f r om a l l o t h e r p o p u l a t i o n s o f M. a r v a l i s t o w a r r a n t t h e popu-l a t i o n ' s b e i n g a s s i g n e d t o a d e f i n i t e t a x o n o m i c c a t e g o r y ; and (2) d e l i m i t t h i s m o r p h o l o g i c a l v a r i a t i o n w i t h i n a d e f i n i t e r a n g e . 2.1. Mor_pho_og_ica_ Va_i_t._on_ Mayr ( 1 9 4 2 : p a g e 36) c a u t i o n e d t h a t " a b s o l u t e s i z e i s an i m p o r t a n t t a x o n o m i c c h a r a c t e r o n l y i f i t i s n o t s u b j e c t t o t o o much i n d i v i d u a l v a r i a t i o n " . The a v e r a g e r a n g e i n mammals and b i r d s o f p u r e l y i n d i v i d u a l v a r i a t i o n i n g e n e r a l s i z e and i n t h e s i z e o f d i f f e r e n t p a r t s i s f r o m 8 t o 15 t o 20 p e r c e n t o f t h e a v e r a g e s i z e f o r t h e s p e c i e s ( A l l e n , 1 9 0 6 ) . I n d i v i d u a l v a r i a t i o n i n a s p e c i e s l i k e M i c r o t u s a r v a l i s c o u l d be much h i g h e r as i t i s a v e r y p l a s t i c s p e c i e s and t h e s i z e a t t a i n e d by a d u l t s d e p e n d s on numerous f a c t o r s , n u t r i t i o n -a l as w e l l as s o c i a l ( S a i n t G i r o n s , 1 9 7 3 ) . S a i n t G i r o n s ( 1 9 7 3 ) warned t h a t u n d e r t h e s e c i r c u m s t a n c e s one must be v e r y c a r e f u l b e f o r e r e c o g n i z i n g t h e v a l i d i t y o f s u b s p e c i e s i n M i c r o t u s a r -v a l i s b a s e d e n t i r e l y on d i m e n s i o n s . B o t h D o t t r e n s ( 1 9 6 2 ) and J o n e s ( 1 9 7 0 ) b a s e d t h e i r montane s u b s p e c i e s h y p o t h e s i s e n t i r e -l y on e x t e r n a l d i m e n s i o n s . T a b l e X V I I c o m p a r e s t h e mean body l e n g t h s i n M. a r v a l i s r e c o r d e d by D o t t r e n s , J o n e s and t h i s s t u d y . To t h e r i g h t o f t h e d o u b l e l i n e a r e t h e means w h i c h a c -c o r d i n g t o D o t t r e n s and J o n e s s h o u l d a p p l y t o t h e montane morph. The l a r g e r a n g e among t h e means r u l e s o u t any c o n c l u -s i v e d e m o n s t r a t i o n o f t h e e x i s t e n c e o f a montane morph. TABLE X V I I : COMPARISON OF BODY LENGTHS WITH ALTITUDE IN MICROTUS ARVALIS (DOTTRENS, 1 9 6 2 ; JONES, 1970; THIS THESIS) 400-800 METERS' 1200-1500 METERS 1900+ METERS REFERENCE N MEAN BODY : N MEAN BODY N MEAN BODY LENGTH (MM)| LENGTH (MM) LENGTH (MM) D o t t r e n s 17 97.8 | ? 105.1 . ? 95.8 (1 9 6 2 ) J o n e s 39 94.4 60 92.7 II 24 101.1 ( 1 9 7 0 ) T h i s t h e s i s 85 92.9 36 91.2 11 93.4 T h e r e a r e a t l e a s t t h r e e p r o c e d u r e s w h i c h i f i m p l e m e n t e d i n s u b s p e c i f i c c l a s s i f i c a t i o n , p a r t i c u l a r l y i n t h e c a s e s o f s p e c i e s w i t h h i g h l y v a r i a b l e g r o w t h l i k e M. a r v a l i s , m i g h t a m e l i o r a t e what W i l s o n and Brown ( 1 9 5 3 ) c a l l e d t h e most c r i t -i c a l and d i s o r d e r l y a r e a o f modern s y s t e m a t i c t h e o r y . The f i r s t i s t o t r y f o r as c o m p l e t e a p i c t u r e as p o s s i b l e o f v a r i a t i o n t r e n d s o f i n d i v i d u a l c h a r a c t e r s w i t h i n t h e w h o l e s p e c i e s , u n c o m p l i c a t e d by l a t i n i z e d names, and a c c o m p a n i e d by some e v a l u a t i o n o f t h e d e g r e e and p o s s i b l e s i g n i f i c a n c e o f any c o n c o r d a n c e t h a t may a p p e a r (Brown and W i l s o n , 1954) . A f t e r s u c h an o v e r v i e w i t w o u l d become a p p a r e n t i f a need s t i l l e x -i s t e d f o r f o r m a l t a x o n o m i c i n f r a s p e c i f i c c l a s s i f i c a t i o n . As Mayr ( 1 9 6 3 ; p a g e 3 4 8 ) , h o w e v e r , r e m a r k e d " t h e b e t t e r t h e g e o -g r a p h i c v a r i a t i o n o f a s p e c i e s i s known, t h e more d i f f i c u l t i t becomes t o d e l i m i t s u b s p e c i e s " . The s e c o n d i s t o e x p a n d t h e d i a g n o s t i c c h a r a c t e r s whereby s u b s p e c i e s a r e c l a s s i f i e d , b eyond p r i m a r i l y m o r p h o l o g i c a l c h a r a c t e r s w h i c h c a n be h i g h l y v a r i a b l e , t o i n c l u d e p h y s i o l o g i c a l , e c o l o g i c a l and e t h o l o g i c a l c h a r a c t e r s w h i c h a r e u s e d i n c l a s s i f i c a t i o n a t t h e s p e c i e s l e v e l and may p r o v e a more s t r i n g e n t t e s t . The t h i r d i s t o e s t a b l i s h w o r k i n g c r i t e r i a on s a m p l e s i z e and p e r c e n t r u l e s . T h e r e i s no a b s o l u t e c r i t e r i o n as t o what c o n s t i t u t e s an a d e q u a t e s a m p l e f o r t a x o n o m i c p u r p o s e s ( S i m p -s o n , 1 9 4 3 ) . T h e r e a r e s e v e r a l p e r c e n t r u l e s u s e d i n s u b s p e c i -f i c c l a s s i f i c a t i o n - t h e 50 p e r c e n t r u l e ( E d w a r d s , 1 9 5 4 ) , t h e 75 p e r c e n t r u l e ( M a y r , 1 9 6 9 ) , and t h e 84 p e r c e n t r u l e ( S i m p s o n and Roe, 1939). Even t h e i r a p p l i c a t i o n i s not s t a n d a r d i z e d . For example, i n the case of the 75 percent r u l e , some taxono-mists judge a p o t e n t i a l subspecies on whether 75 percent of i t s i n d i v i d u a l s d i f f e r from 75 percent o f the i n d i v i d u a l s o f a p r e -v i o u s l y r e c o g n i z e d subspecies (Edwards, 1954); others on wheth-er 75 per c e n t o f i t s i n d i v i d u a l s d i f f e r from 97 per c e n t o f a p r e v i o u s l y r e c o g n i z e d subspecies (Mayr, 1969). 2.2. Geog_a_h_c_Ran_e The range of Microtus a r v a l i s covers the g r e a t e r p a r t of Europe and A s i a c h i e f l y between 45° and 55° north l a t i t u d e ( E l -ton, 1965). Burt (1954) recommended t h a t c o n t i n e n t a l s p e c i e s with more or l e s s continuous ranges would be b e t t e r understood i f the s u b s p e c i f i c d e s i g n a t i o n s were d i s c a r d e d and e f f o r t s were concentrated on the morphological and b e h a v i o u r a l v a r i a t i o n s a c c o r d i n g to geography. J u s t as the o v e r a l l c o n t i n e n t a l d i s t r i b u t i o n of M. a r v a l i s i s more or l e s s continuous, so i s there d i s t r i b u t i o n a l c o n t i n u -i t y i n S w i t z e r l a n d . G o l d i (1914) r e p o r t e d the common v o l e was found up to 2350 meters, Dottrens (1962) up to 2436 meters. The specimens i n c l u d e d i n t h i s study represented an a l t i t u d e range from 385 meters to 2538 meters. I f there were a montane morph a t what a l t i t u d e would i t be found? Dottrens (1962) suggested a lower range l i m i t of 1200 m to 1500 m because h i s b i g g e s t n o n - j u v e n i l e specimens came from t h a t a l t i t u d e . Jones (1970) s a i d t h a t the range of the mon-tane subspecies began around 1900+ m, but even Jones' 77 l a r g e s t group, a t 1940 m, was s m a l l e r than Dottrens' l a r g e s t group a t 1200 m to 1500 m. The subadult and a d u l t specimens i n t h i s study showed no s i z e - a l t i t u d e c o r r e l a t i o n and gave no evidence of a montane morph (Table XVII: page 74). I t i s i n t e r e s t i n g to note t h a t the type l o c a l i t y o f the montane subspecies of M. a r v a l i s d e s c r i b e d by Schinz i n 1845 was the v a l l e y of Urseren, near S t . Gotthard, U r i , S w i t z e r l a n d ( a l t i t u d e was u n s p e c i f i e d but i t c o u l d have been i n the range of 1500 m) and the type l o c a l i t y of the montane subspecies of M. a r v a l i s d e s c r i b e d by Selys-Longchamps i n 1841 was near the summit of St. Gotthard Pass, U r i , S w i t z e r l a n d (again a l t i t u d e was not s p e c i f i e d but i t c o u l d have been i n the range of 2000 m to 2100 m) . To date a d e f i n i t e range f o r a montane morph has s t i l l t o be d e f i n e d . 2.3. Nomenclature Although Dottrens (1962), Lehmann (1967) and Jones (1970) c a l l t h e i r montane subspecies M i c r o t u s a r v a l i s r u f e s c e n t e f u s -cus, there i s another name by which a Swiss montane subspecies of M. a r v a l i s i s c a l l e d i n the l i t e r a t u r e - M i c r o t u s a r v a l i s  i n c e r t u s . T a bles XVIII and XIX l i s t b r i e f nomenclatural h i s -t o r i e s . TABLE XVIII: BRIEF NOMENCLATURAL HISTORY OF MICROTUS ARVALIS RUFESCENTEFUSCUS NOMENCLATURE APPLIED Hypudaeus rufescentefuscus Synonymized with A r v i c o i a a g r e s t i s fusca DISTRIBUTION Type l o c a l i t y : v a l l e y of Urseren, U r i , Switz-e r l a n d ^ 6 0 0 m i n Swiss Alps REFERENCE Schinz (1845) F a t i o (1900) Synonymized with Pitymus subterraneus subterraneus Belgium and northern France eastward through Switzerland to T r a n s y l -vania France, Belgium. Swit-zerla n d , to Yugoslavia and Transylvania M i l l e r (1912) Ellerman and Scott (1946) Synonymized with Microtus a r v a l i s rufescentefuscus y 1200 m i n Swiss Alps y 11900 m i n Swiss Alps Dottrens (1962) Meylan (1966) Lehmann (1967) Jones (1970) Referred to Microtus a r v a l i s Corbet (1978) TABLE XIX: BRIEF NOMENCLATURAL HISTORY OF MICROTUS ARVALIS INCERTUS NOMENCLATURE APPLIED A r v i c o l a i n c e r t u s DISTRIBUTION Type l o c a l i t y : near summit of S t . Gotthard Pass, U r i , Switzerland REFERENCE Selys-Longchamps (1841) Synonymized with A r v i c o l a a r v a l i s f u l v a F a t i o (1869) Synonymized with Microtus i n c e r t u s Mountains of Switzerland and Ty r o l from the c e n t r a l Alps eastward Mountains of Switzerland and Try o l M i l l e r (1912) Regnier and Pussard (1926) Ellerman (1940) Synonymized with Microtus a r v a l i s i n c e r t u s Switzerland ( p a r t ) , to T y r o l Ellerman and Scott (1946) Synonymized with Pitymus subterraneus i n c e r t u s Dottrens (1961) CONCLUSIONS 80 S i z e - a l t i t u d e v a r i a t i o n was n o t i n e v i d e n c e i n t h e 422 museum s p e c i m e n s o f M i c r o t u s a r v a l i s e x a m i n e d f o r t h i s t h e s i s . The l a c k o f g e o g r a p h i c v a r i a t i o n e n c o u n t e r e d may have been t h e r e s u l t o f d e f i c i e n c i e s i n t h e d a t a . A more l i k e l y e x p l a n a t i o n i s t h a t m o r p h o l o g i c a l f e a t u r e s i n t h e common v o l e a r e i n f l u -e n c e d by so many f a c t o r s t h a t v a r i a t i o n e x p r e s s e d by c l e a r c u t m o r p h o l o g i c a l p a t t e r n s may o c c u r o n l y r a r e l y , i f a t a l l , i n t h i s s p e c i e s . I f a montane s u b s p e c i e s o f M i c r o t u s a r v a l i s does e x i s t i n S w i t z e r l a n d , n e i t h e r i t s m o r p h o l o g i c a l d i a g n o s t i c c h a r a c t e r n o r i t s d i s t r i b u t i o n has been d e m o n s t r a t e d c o n c l u -s i v e l y t o d a t e . T h e r e i s d i s a g r e e m e n t among b i o l o g i s t s on e v e r y m a j o r a s p e c t o f t h e s i z e t r e n d c a l l e d Bergmann's R u l e - on t h e g r o u p ( s ) o f o r g a n i s m s t o w h i c h i t a p p l i e s , on t h e t a x o n o m i c l e v e l ( s ) a t w h i c h i t a p p l i e s , ' o n i t s p h y s i o l o g i c a l o r n o n -p h y s i o l o g i c a l i n t e r p r e t a t i o n ( s ) , on i t s r e g u l a r i t y . U n t i l t h e s e m a j o r c o n f l i c t s a r e r e s o l v e d and a c l e a r d e f i n i t i o n o f t h e t r e n d i s f o r m u l a t e d , and a m a j o r i t y o f t h e t a x o n ( o r t a x a ) t o w h i c h t h e r e v i s e d d e f i n i t i o n a p p l i e s i s shown t o a d h e r e t o t h e t r e n d , t h e a p p e l l a t i o n " r u l e " s h o u l d be d i s c a r d e d . APPENDIX 1 NAMES OF INSTITUTIONS, THEIR ADDRESSES, KEY PERSONNEL AND THE NUMBER OF SPECIMENS OF MICROTUS ARVALIS FROM EACH 1. i . S t a t i o n F e d e r a l e de R e c h e r c h e s A g r o n o m i q u e s Nyon, CH-1260, S w i t z e r l a n d D r . A. M e y l a n , Head, V e r t e b r a t e D e p a r t m e n t i i . 189 S p e c i m e n s 2. i . Musee d ' H i s t o i r e N a t u r e l l e Geneve, CH-1211 , S w i t z e r l a n d Dr. F. Baud, Head, B i r d s and Mammals D e p a r t m e n t i i . 99 S p e c i m e n s 3. i . B u n d n e r N a t u r h i s t o r i s c h e s und N a t i o n a l p a r k m u s e u m C h u r , CH-7000, S w i t z e r l a n d Dr. J. M u l l e r , D i r e c t o r i i . 63 S p e c i m e n s 4. i . N a t u r h i s t o r i s c h e s Museum B e r n B e r n , CH-3000, S w i t z e r l a n d Dr. P. L u p s , D i r e c t o r i i . 52 S p e c i m e n s 5. i . Z o o l o g i s c h e s Museum d e r U n i v e r s i t a t Z u r i c h Z u r i c h , CH-8006, S w i t z e r l a n d Dr. C. C l a u d e , D i r e c t o r i i . 15 S p e c i m e n s 6. i . Z o o l o g i s c h e s F o r s c h u n g s i n s t i t u t und Museum A l e x a n d e r K o e n i g 5300 Bonn 1, Germany Dr. R. H u t t e r e r , D i r e c t o r i i . 4 S p e c i m e n s APPENDIX TABLE l a : MEASURING ACCURACY SPECIMENS IN MEAN OF 3 MEASUREMENTS COEFFICIENT OF DESCENDING (IN MM) 4 STANDARD ERROR: VARIATION MAGNITUDE OF TOTAL LENGTH OF SKULL (IN PERCENT) THE COEFFICIENT OF VARIATION 1. GR321 20.200 4 .076 .655 2. GR33 22.400 4 .058 .446 3. GR472 22.000 4 .050 .394 4. GR314 22.683 * .044 .337 5. GR485 23.233 ± .044 .329 6. GR364 22.317 4 .034 .259 7. 5248 23.533 4 .034 .245 8. GR36 20.650 4 .029 .242 9. GR297 21.950 4 .029 .228 10. 5252 23.050 4 .029 .217 11. 5246 24.600 4 .029 .203 12. 5245 24.650 4 .029 .203 13. 5251 25.550 4 .029 .196 14. GR514 23.217 4 .017 .124 15. GR223 23.683 4 .017 .122 16. 5247 23.617 4 .017 .122 17. 5249 24.117 4 .017 .120 18. 5307 24.083 4 .017 .120 19. 344 24.017 4 .017 .120 20. 5305 24.133 4- .017 .120 21. 5308 24.267 * .017 .119 22. 589 25.133 4 .017 .115 23. 586 25.767 4 .017 .112 24. GR39 23.950 * .000 .000 25. 588 23.450 4 .000 .000 APPENDIX TABLE l b : MEASURING ACCURACY SPECIMENS IN DESCENDING MAGNITUDE OF THE COEFFICIENT OF VARIATION 1. 586 2. 3. 4. 5. MEAN OF 3 MEASUREMENTS (IN MM) 4 STANDARD ERROR: NASAL WIDTH 7. 8. 9. 5246 GR297 GR485 5308 GR472 GR39 GR36 589 10. 5248 11. GR364 12. 5247 13. 5307 14. 5305 15. 5245 16. 5251 17. GR223 18. GR33 19. GR314 20. 588 21. 5249 22. GR514 23. 344 24. GR321 25. 5252 2.467 ± 2.683 i 2.400 4 2.367 * 2.400 * 2.233 * 2.367 4 2.383 * 2.750 * 2.433 * 2.333 4 2.383 * 2.433 4 2.433 * 2.483 4 2.667 4 2.450 * 2.217 * 2.333 * 2.433 i 2.517 4 2.583 * 2.583 4 2.000 4 2.150 * .102 .093 .076 .060 .050 .044 .044 .044 .050 .044 .034 .034 .034 .034 .034 .034 .029 .017 .017 .017 .017 .017 .017 .000 .000 COEFFICIENT OF VARIATION (IN PERCENT) 7.119 5.990 5.512 4.398 3.608 3.420 3.227 3.205 3.149 3.139 2.474 2.423 2.373 2.373 2.325 2.165 2.041 1.302 1.237 1.185 1.147 1.118 1.118 0.000 0.000 APPENDIX TABLE l c : MEASURING ACCURACY SPECIMENS IN DESCENDING MAGNITUDE OF THE COEFFICIENT OF VARIATION 5307 MEAN OF 3 MEASUREMENTS (IN MM) ± STANDARD ERROR: ROSTRUM WIDTH 1. 2. 3. 4. 5. 6. 7. 8. 9. GR472 5252 5247 GR485 344 GR321 5248 5246 10. GR36 11. GR297 12. GR223 13. GR514 14. 5249 15. 589 16. GR314 17. GR33 18. 5245 19. GR364 20. 586 21. GR39 22. 5308 23. 588 24. 5305 25. 5251 4.167 i 3.850 4 3.733 i 3.983 4 4.117 4 4.250 4 3.733 ± 3.867 4 4.500 i 3.983 4 4.017 4 4.067 4 4.167 ± 4.267 4 4.567 4 3.933 4 4.067 4 4.183 4 3.850 ± 4.483 4 4.200 4 4.250 4 4.167 ± 4.283 4 4.433 * .120 .087 .060 .060 .060 .058 .044 .044 .050 .044 .044 .044 .044 .044 .044 .034 .034 .034 .029 .034 .029 .029 .017 .017 .017 COEFFICIENT OF VARIATION (IN PERCENT) 4.996 3.896 2.788 2.613 2.528 2.353 2.046 1.975 1.925 1.917 1.902 1.878 1.833 1.790 1.673 1.468 1.420 1.380 1.299 1.288 1.191 1.177 0.693 0.674 0.651 APPENDIX TABLE Id: MEASURING ACCURACY SPECIMENS IN MEAN OF 3 MEASUREMENTS COEFFICIENT OF DESCENDING (IN MM) i STANDARD ERROR: VARIATION MAGNITUDE OF ZYGOMATIC WIDTH (IN PERCENT) THE COEFFICIENT OF VARIATION 1. GR39 13.450 i .076 .984 2. 5245 13.550 ± .076 .976 3. 5305 13.117 i .073 .959 4. GR297 12.333 4 .067 .936 5. 5246 14.067 * .067 .821 6. 588 13.933 ± .060 .747 7. GR321 10.817 ± .044 .706 8. GR485 12.650 4 .050 .685 9. 5248 12.700 4 .050 .682 10. GR314 12.367 * .044 .618 11. GR514 13.483 4 .044 .567 12. 5247 13.233 4 .034 .436 13. 5249 13.583 4 .034 .425 14. GR364 12.050 4 .029 .415 15. GR472 12.200 4 .029 .410 16. GR33 12.500 i .029 .400 17. 5307 13.550 4 .029 .369 18. 5251 14.250 4 .029 .351 19. 589 14.850 i .029 .337 20. 5252 12.267 4 .017 .235 21. GR223 13.217* .017 .218 22. 5308 13.683 4 .017 .211 23. 586 14.833 4 .017 .195 24. GR36 11.200 * .000 .000 25. 344 13.000 * .000 .000 APPENDIX TABLE l e : MEASURING ACCURACY SPECIMENS IN DESCENDING MAGNITUDE OF THE COEFFICIENT OF VARIATION 589 MEAN OF 3 MEASUREMENTS (IN MM) * STANDARD ERROR: LEAST INTERORBITAL WIDTH 1. 2. 3. 4. 5. 6. 7. 586 GR297 GR485 5251 5249 GR36 8. 5248 9. 5252 10. GR472 11. GR39 12. 588 13. GR223 14. 5246 15. 5247 16. GR514 17. 5308 18. 5245 19. GR33 20. 5307 21. 344 22. GR314 23. GR321 24. GR364 25.. 5305 3.100 4 3.317 4 3.200 4 2.967 4 3.067 t 3.117 4 2.767 4 3.033 4 3.117 4 3.183 4 2.850 4 3.333 4 2.900 sr 2.950 4 2.950 4 3.000 4 3.100 4 3.250 4 2.983 4 3.017 4 3.017 4 3.217 4 3.100 4 3.000 4 3.200 4 .104 .060 .058 .044 .044 .044 .034 .034 .034 .034 .029 .034 .029 .029 .029 .029 .029 .029 .017 .017 .017 .017 .000 .000 .000 COEFFICIENT OF VARIATION (IN PERCENT) 5.815 3.138 3.125 2.575 2.491 2.451 2.087 1.903 1.853 1.814 1.754 1.732 1.724 1.695 1.695 1.667 1.613 1.539 0.968 0.957 0.957 0.897 0.000 0.000 0.000 APPENDIX TABLE I f : MEASURING ACCURACY SPECIMENS IN DESCENDING MAGNITUDE OF THE COEFFICIENT OF VARIATION MEAN OF 3 MEASUREMENTS (IN MM) 4 STANDARD ERROR: BRAINCASE WIDTH 1. 2. 3. 4. 5. 6. 7. 8. 9. GR33 GR314 5246 GR39 588 GR485 5249 589 586 10. GR364 11. 5251 12. GR297 13. 5305 14. 5308 15. 344 16. 5247 17. GR472 18. GR514 19. GR36 20. GR321 21. 5248 22. 5252 23. GR223 24. 5307 25. 5245 9.950 ± 10.083 t 10.717 ± 10.167 i 9.717 4 9.783 ± 10.200 i 10.700 - i 11.150 4 10.183 4 10.883 4 10.033 4 10.183 ± 10.417 i 10.667 4 9.850 4 10.150 4 10.550 4 9.317 4 9.333 4 9.883 4 10.083 4 10.133 * 10.483 * 10.783 * .076 .073 .073 .067 .060 .060 .058 .058 .050 .044 .044 .034 .034 .034 .034 .029 .029 .029 .017 .017 .017 .017 .017 .017 .017 COEFFICIENT OF VARIATION (IN PERCENT) i.330 1.248 1.174 1.136 1.071 1.064 0.980 0.935 0.777 0.750 0.702 0.575 0.567 0.554 0.541 0.508 0.493 0.474 0.310 0.309 0.292 0.286 0.285 0.275 0.268 APPENDIX TABLE l g : MEASURING ACCURACY SPECIMENS IN DESCENDING MAGNITUDE OF THE COEFFICIENT OF VARIATION MEAN OF 3 MEASUREMENTS (IN MM) 4 STANDARD ERROR: POST ZYGOMA WIDTH COEFFICIENT OF VARIATION (IN PERCENT) 1. GR364' 8.783 t .093 1.830 2. 5308 9.933 4 .083 1.453 3. GR36 8.783 ± .073 1.433 4. GR485 8.883 ± .073 1.417 5. GR297 9.033 ± .060 1.152 6. 5305 9.483 4 .060 1.098 7. GR472 9.350 4 .058 1.070 8. 5248 9.500 ± .058 1.053 9. 5245 10.200 4 .058 0.980 10. GR39 9.300 4 .050 0.931 11. 5307 9.700 4 .050 - 0.893 12. 586 9.900 4 .050 0.875 13. 5246 10.150 i .050 0.853 14. 5247 9.317 i .044 0.820 15. 5252 9.317 4 .044 0.820 16. GR314 9.333 4 .044 0.818 17. 589 9.933 4 .044 0.769 18. 344 9.967 4 .044 0.765 19. 5251 10.167 ± .044 0.751 20. GR223 9.133 4 .034 0.632 22. GR321 8.650 4 .029 0.578 22. 588 9.050 4 .029 0.553 23. GR514 9.700 4 .029 0.516 24. GR33 9.333 * .017 0.309 25. 5249 9.633 •4 .017 0.300 APPENDIX TABLE l h : MEASURING ACCURACY SPECIMENS IN DESCENDING MAGNITUDE OF THE COEFFICIENT OF VARIATION 589 MEAN OF 3 MEASUREMENTS (IN MM) 4 STANDARD ERROR: MASTOID WIDTH 1. 2. 3. 4. 5. 6. 7. 8. 9. 344 5307 5308 5245 588 5248 5251 5249 10. GR472 11. GR321 12. GR364 13. 586 14. GR485 15. GR223 16. 5305 17. 5247 18. 5246 19. GR314 20. GR36 21. GR297 22. GR33 23. 5252 24. GR514 25. • GR39 9.500 4 9.967 4 9.567 4 9.967 4 10.217 4 9.100 4 9.667 4 10.083 4 10.083 i 8.850 4 8.117 4 8.783 4 9.833 4 8.767 4 8.933 4 9.667 4 9.817 4 10.233 4 9.150 4 8.833 4 8.833 4 9.083 4 9.233 4 9.317 * 9.317 4 .087 .073 .067 .067 .067 .058 .060 .060 .060 .050 .044 .044 .044 .034 .034 .034 .034 .034 .029 .017 .017 .017 .017 .017 .017 COEFFICIENT OF VARIATION (IN PERCENT) 1.579 1.263 1.207 1.159 1.130 1.099 1.077 1.032 1.032 0.979 0.941 0.870 0.777 0.659 0.646 0.597 0.588 0.564 0.546 0.327 0.326 0.318 0.313 0.310 0.310 APPENDIX TABLE l i : MEASURING ACCURACY SPECIMENS IN DESCENDING MAGNITUDE OF THE COEFFICIENT OF VARIATION 586 MEAN OF 3 MEASUREMENTS (IN MM) i STANDARD ERROR: FORAMEN MAGNUM HEIGHT 1. 2. 3. 4. 5. 6. 7. 8. 9. GR472 GR314 GR485 GR364 5249 5248 588 5252 10. GR297 11. 5246 12. GR39 13. GR321 14. 5305 15. 5308 16. 5307 17. 344 18. GR36 19. 5247 20. 5251 21. 5245 22. GR33 23. GR514 24. 589 25. GR223 3.233 4 3.167 4 3.633 4 2.900 4 3.117 4 3.000 4 3.267 4 3.367 4 3.533 4 3.350 4 3.167 4 3.317 4 3.317 4 2.933 4 3.033 4 3.083 4 3.217 4 2.800 4 3.283 4 3.100 4 3.100 4 3.200 4-3.500 4 3.650 4 3.400 ± .093 .088 .088 .058 .060 .058 .060 .060 .060 .050 .044 .044 .044 .034 .034 .034 .034 .029 .034 .029 .029 .029 .029 .029 .000 COEFFICIENT OF VARIATION (IN PERCENT) 4.971 4.824 4.204 3.448 3.340 3.333 3.186 3.092 2.946 2.585 2.412 2.303 2.303 1.969 1.903 1.873 1.795 1.786 1.758 1.613 1,613 1.563 1.429 1.370 0.000 APPENDIX TABLE l j : MEASURING ACCURACY SPECIMENS IN DESCENDING MAGNITUDE OF THE COEFFICIENT OF VARIATION GR485 MEAN OF 3 MEASUREMENTS (IN MM) * STANDARD ERROR: FORAMEN MAGNUM WIDTH 1. 2. 3. 4. 5. 6. 7. 8. 9. 10 GR223 5248 GR33 GR321 GR36 GR39 586 5252 5245 11. GR472 12. 5305 13. GR514 14. 5251 15. 5249 16. GR314 17. GR364 18. 5247 19. 589 20. 588 21. 5307 22. GR297 23. 5246 24. 344 25. 5308 3.400 i 3.650 i 3.500 * 3.667 4 3.833 4 3.650 i 3.517 i 3.567 a 3.833 4 3.583 4 3.667 4 3.600 4 3.833 i 3.567 4 3.683 4 3.867 4 3.033 4 3.333 4 3.667 4 3.450 4 3.600 i 3.750 4 3.850 * 3.567 4 3.583 4 .100 .104 .087 .088 .088 .076 .073 .067 .067 .060 .060 .058 .060 .044 .044 .044 .034 .034 .034 .029 .029 .029 .029 .017 .017 COEFFICIENT OF VARIATION (IN PERCENT) 5.094 4.940 4.286 4.166 3.985 3.624 3.578 3.238 3.012 2.905 2.839 2.778 2.715 2.141 2.074 1.975 1.903 1.732 1.575 1.450 1.389 1.333 1.299 0.809 0.806 APPENDIX TABLE l k : MEASURING ACCURACY SPECIMENS IN DESCENDING MAGNITUDE OF THE COEFFICIENT OF VARIATION 5252 MEAN OF 3 MEASUREMENTS (IN MM) 4 STANDARD ERROR: SKULL HEIGHT 5246 5251 5248 5307 GR36 GR472 8. GR514 9. 5308 10. 588 11. GR321 12. GR364 13. GR223 14. 5247 15. 586 16. 589 17. 344 18. GR297 19. GR485 .20. GR39 21. 5245 22. GR314 23. GR33 24. 5305 25. 5249 6.450 i 6.850 i 7.350 4 6.600 4 5.983 4 6.650 4 6.283 4 6.417 4 7.183 4 5.583 4 5.683 4 6.033 4 6.333 4 6.967 4 7.033 4 7.033 4 6.100 4 6.200 4 6.300 4 6.500 4 6.950 4-6.283 4 6.367 4 6.883 4 7.017 4 .076 .076 .058 .050 .044 .050 .044 .044 .044 .034 .034 .034 .034 .034 .034 .034 .029 .029 .029 .029 .029 .017 .017 .017 .017 COEFFICIENT OF VARIATION (IN PERCENT) 2.051 1.931 1.361 1.312 1.302 1.034 1.276 1.216 1.190 1.063 1.016 0.957 0.912 0.829 0.821 0.821 0.820 0.807 0.794 0.769 0.719 0.459 0.453 0.419 0.411 APPENDIX TABLE 11: MEASURING ACCURACY SPECIMENS IN MEAN OF 3 MEASUREMENTS COEFFICIENT OF DESCENDING (IN MM) i STANDARD ERROR: VARIATION MAGNITUDE OF CONDYLOBASAL LENGTH (IN PERCENT) THE COEFFICIENT OF VARIATION 1. 5251 25.150 4 .050 .344 2. GR485 22.983 4 .044 .332 3. GR36 19.917 i .034 .290 4. GR33 21.717 i .034 .266 5. GR314 22.167 4 .034 .261 6. 5248 23.133 4 .034 .250 7. GR39 23.467 4 .034 .246 8. 5308 23.633 4 .034 .244 9. 5252 22.350 4 .029 .224 10. 5247 23.100 4-. 029 .217 11. GR321 19.717 4 .017 .146 12. GR297 21.517 4 .017 .134 13. GR364 21.717 4 .017 .133 14. GR514 22.817 4 .017 .127 15. GR223 22.933 4 .017 .126 16. 588 23.133 4 .017 .125 17. GR297 23.767 4 .017 .122 18. 5305 23.667 4 .017 .122 19. 5246 23.933 4 .017 .121 20. 589 24.517 4 .017 .118 21. 586 25.183 4 .017 .115 22. GR472 21.145 4 .000 .000 23. 5249 23.800 4 .000 .000 24. 5307 23.600 4 .000 .000 25. 5245 24.150 4 .000 .000 APPENDIX TABLE lm: MEASURING ACCURACY SPECIMENS IN MEAN OF 3 MEASUREMENTS COEFFICIENT OF DESCENDING (IN MM) 4 STANDARD ERROR: VARIATION MAGNITUDE OF BASAL LENGTH (IN PERCENT) THE COEFFICIENT OF VARIATION 1. GR33 20.617 ± .093 .780 2. 5307 21.933 i .088 .696 3. GR472 20.150 4 .076 .657 4. 586 23.733 4 .073 .530 5. 5245 22.617 4 .067 .511 6. 5252 20.800 4 .058 .481 7. 5248 21.683 4 .060 .480 8. GR321 . 18.450 4- .050 .469 9. 344 21.900 4 .058 .457 10. 5251 23.650 4 .058 .423 11. GR314 20.800 4 .050 .416 12. GR514 21.400 4 .050 .405 13. 588 21.700 4 .050 .399 14. 5249 22.250 4 .050 .389 15. 5246 22.750 4 .050 .381 16. 589 23.100 * .050 .375 17. 5305 22.167 4 .044 .345 18. GR36 18.850 * .029 .265 19. GR485 21.550 4 .029 .232 20. 5308 22.200 4 .029 .225 21. GR297 20.333 4 .017 .142 22. GR364 20.617 4 .017 .140 23. 5247 21.783 4 .017 .133 24. GR223 21.867 * .017 .132 25. GR39 21.950 4 .000 .000 APPENDIX TABLE I n : MEASURING ACCURACY SPECIMENS IN DESCENDING MAGNITUDE OF THE COEFFICIENT OF VARIATION MEAN OF 3 MEASUREMENTS (IN MM) 4 STANDARD ERROR: BASILAR LENGTH 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 5246 5251 5248 GR39 GR364 586 GR36 GR321 5307 5252 11. 5249 12. GR297 13. GR33 14. 5305 15. 5308 16. GR472 17. 588 18. 5245 19. GR314 20. GR514 21. GR485 22. 5247 23. GR223 24. 344 25. 589 21.500 4 22.583 i 20.650 4 20.633 * 19.817 4 22.750 4 17.883 4 17.700 4 20.767 4 19.800 4 21.183 4 19.600 4 19.750 i 21.000 4 21.100 4 19.383 4 20.717 4 21.383 4 20.067 4 20.567 4 20.517 ± 20.717 4 20.800 4 20.967 4 21.883 * .132 .093 .076 .073 .067 .076 .060 .058 .067 .058 .060 .050 .050 .050 .050 .044 .044 .044 .034 .034 .034 .034 .029 .017 .017 COEFFICIENT OF VARIATION (IN PERCENT) 1.066 0.712 0.641 0.610 0.583 0.582 0.582 0.565 0.556 0.505 0.491 0.442 0.439 0.412 0.410 0.394 0.369 0.357 0.288 0.281 0.281 0.279 0.240 0.138 0.132 APPENDIX TABLE l o : SPECIMENS IN DESCENDING MAGNITUDE OF THE COEFFICIENT OF VARIATION 1. GR364 2. 5246 3. GR33 4. GR485 5. 588 6. 5308 7. 5307 8. 5245 9. 5252 10. GR514 11. GR223 12. 5247 13. 5249 14. 5305 15. GR472 16. 344 17. 5248 18. GR321 19. GR36 20. GR297 21. GR314 22. GR39 23. 589 24. 586 25. 5251 MEASURING ACCURACY MEAN OF 3 MEASUREMENTS COEFFICIENT OF (IN MM) 4 STANDARD ERROR: VARIATION PALATAL LENGTH (IN PERCENT) 12.183 4 .060 .854 13.900 4 .058 .719 12.350 4 .050 .701 13.100 4 .050 .661 13.017 4 .044 .587 13.317 4 .044 .574 13.617 4 .044 .561 13.767 4 .044 .555 12.367 4 .034 .467 12.567 4 .034 .459 13.167 4 .034 .439 13.183 4 .034 .438 13.417 ± .034 .430 13.683 4 .034 .422 12.200 4 .029 .410 12.950 4 .029 .386 13.150 4 .029 .380 11.117 4 .017 .260 11.517 4 .017 .251 11.883 4 .017 .243 12.317 4 .017 .234 13.117 4 .017 .220 13.617 4 .017 .212 14.217 •4 .017 .203 14.433 •4- .017 .200 APPENDIX TABLE l p : MEASURING ACCURACY SPECIMENS IN DESCENDING MAGNITUDE OF THE COEFFICIENT OF VARIATION GR223 MEAN OF 3 MEASUREMENTS (IN MM) 4 STANDARD ERROR: PALATAL BRIDGE LENGTH 9. 10. 11. GR321 5246 GR39 5305 5251 589 GR33 GR364 5247 588 12. GR485 13. 586 14. GR472 15. GR297 16. 5249 17. 5308 18. 5245 19. 5307 20. 5252 21. 344 22. GR36 23. GR314 24. 5248 25. GR514 5.133 i 4.567 4 5.233 4 4.933 4 5.417 4 5.700 4-5.067 4 4.450 4 4.500 ± 4.783 4 4.917 4 4.750 4 5.733 4 4.483 4 4.533 4 5.317 t 5.317 i 5.117 4 5.367 4 4.700 4 5.000 4 4.283 4 4.667 4 5.233 4 5.000 4 .109 .093 .073 .067 .073 .076 .067 .058 .058 .060 .060 .050 .060 .044 .044 .044 .044 .034 .034 .029 .029 .017 .017 .017 .000 COEFFICIENT OF VARIATION (IN PERCENT) 3.688 3.520 2.404 2.341 2.323 2.321 2.279 2.247 2.222 2.176 2.117 1.823 1.815 1.704 1.685 1.437 1.437 1.128 1.076 1.064 1.000 0.674 0.619 0.552 0.000 APPENDIX TABLE l q : MEASURING ACCURACY SPECIMENS IN MEAN OF 3 MEASUREMENTS COEFFICIENT OF DESCENDING (IN MM) 4 STANDARD ERROR: VARIATION MAGNITUDE OF PALATAL FORAMEN LENGTH (IN PERCENT) THE COEFFICIENT OF VARIATION 1. GR297 3.650 4 .076 3.624 2. 5249 3.850 4 .076 3.436 3. GR364 3.733 4 .073 3.371 4. GR485 4.167 4 .067 2.771 5. 5248 4.300 4 .058 2.326 6. GR472 3.850 4 .050 2.249 7. GR33 3.950 4 .050 2.193 8. GR223 3.917 4 .044 1.950 9. GR39 4.133 4 .044 1.848 10. GR514 3.817 4 .034 1.513 11. 344 3.817 4 .034 1.513 12. 5252 4.067 4 .034 1.420 13. 5245 4.283 4 .034 1.348 14. GR314 3.850 * .029 1.299 15. 5251 4.567 4 .034 1.264 16. 586 4.550 4 .029 1.099 17. GR36 3.483 4 .017 0.829 18. GR321 3.483 4 .017 0.829 19. 5308 4.017 4 .017 0.719 20. 5247 4.367 4 .017 0.661 21. 5307 4.417 4 .017 0.654 22. 5246 4.417 4 .017 0.654 23. 589 4.483 4 .017 0.644 24. 588 4.000 4 .000 0.000 25. 5305 4.200 4 .000 0.000 APPENDIX TABLE l r : MEASURING ACCURACY SPECIMENS IN DESCENDING MAGNITUDE OF THE COEFFICIENT OF VARIATION 1. GR364 2. 3. 4. 5. 6. 7. 8. 9. 10 MEAN OF 3 MEASUREMENTS (IN MM) 4 STANDARD ERROR: PALATAL FORAMEN WIDTH 5249 GR36 5308 5246 5251 GR472 GR321 GR39 5305 11. 589 12. GR485 13. 5252 14. GR223 15. 5247 16. GR33 17. GR314 18. 5245 19. 5248 20. 588 21. 5307 22. GR514 23. GR297 24. 344 25. 586 0.633 4 0.850 i 0.817 i 0.833 4 0.917 4 0.883 4 0.883 4 0.750 4 0.667 4 0.933 4 0.900 4 0.800 ± 0.717 4 1.000 4 0.783 4-0.817 4 0.833 4 0.867 4 0.867 4 0.600 4 1.033 4 0.700 4 0.850 4 0.817 ± 0.833 4 .060 .076 .067 .067 .073 .067 .060 .050 .044 .060 .058 .050 .044 .058 .044 .044 .044 .044 .044 .029 .044 .029 .029 .017 .017 COEFFICIENT OF VARIATION (IN PERCENT) 16.434 15.563 14.139 13.856 13.727 13.072 11.783 11.547 11.456 11.152 11.111 10.825 10.657 10.000 9.750 9.352 9.165 8.813 8.813 8.333 7.391 7.143 5.882 3.535 3.464 APPENDIX TABLE I s : SPECIMENS IN DESCENDING MAGNITUDE OF THE COEFFICIENT OF VARIATION 1. GR36 2. 5245 3. GR223 4. 5252 5. 5247 6. 586 7-. GR297 8. GR472 9. 5248 10. 588 11. 5249 12. 5307 13. GR321 14. GR33 15. GR364 16. GR485 17. 5308 18. GR39 19. 344 20. 5246 21. 5251 22. GR314 23. GR514 24. 589 25. 5305 MEASURING ACCURACY MEAN OF 3 MEASUREMENTS COEFFICIENT OF (IN MM) i STANDARD ERROR: VARIATION MAXILLARY DIASTEMA LENGTH (IN PERCENT) 6.217 4 .093 2.585 7.233 4 .102 2.428 7.217 4 .073 1.744 6.333 4 .060 1.643 7.000 4 .058 1.429 7.967 4 .060 1.307 6.367 4 .044 1.200 6.433 4 .044 1.188 6.883 4 .044 1.110 6.917 4 .044 1.104 6.917 4 .044 1.104 7.067 .044 1.081 5.750 4 .029 0.870 6.733 4 .034 0.858 6.767 4 .034 0.853 7.067 ± .034 0.817 6.550 4 .029 0.763 7.050 4 .029 0.709 7.100 i .029 0.074 7.350 4 .029 0.680 7.550 4 .029 0.662 6.483 4 .017 0.445 6.883 4 .017 0.419 7.617 4 .017 0.379 7.150 4 .000 0.000 APPENDIX TABLE I t : MEASURING ACCURACY SPECIMENS IN DESCENDING MAGNITUDE OF THE COEFFICIENT OF VARIATION GR39 MEAN OF 3 MEASUREMENTS (IN MM) 4 STANDARD ERROR: MAXILLARY TOOTH ROW LENGTH 1. 2. 3. 4. 5. 6. 7. 5308 GR485 GR297 5247 5307 5248 8. 5245 9. GR33 10. GR314 11. GR514 12. 5252 13. 589 14. GR364 15. 5246 16. GR223 17. GR321 18. 588 19. 5251 20. 5305 21. 5249 22. 344 23. GR36 24. GR472 25. 586 5.333 4 5.767 4 4.917 4 5.217 * 5.333 4 5.617 4 5.683 4 5.867 4 5.117 4 5.317 4 5.467 4 5.467 4 5.633 4 4.900 4 5.733 4 5.100 i 5.150 4 5.200 4 6.133 4 5.550 4 5.750 4 5.750 4 4.917 * 5.217 4 5.467 4 .067 .067 .044 .044 .044 .044 .044 .044 .034 .034 .034 .034 .034 .029 .034 .029 .029 .029 .034 .029 .029 .029 .017 .017 .017 COEFFICIENT OF VARIATION (IN PERCENT) 2.165 2.002 1.553 1.464 1.432 1.360 1.344 1.302 1.128 1.086 1.056 1.056 1.025 1.020 1.007 0.980 0.971 0.962 0.941 0.901 0.870 0.870 0.587 0.553 0.528 APPENDIX TABLE l u : MEASURING ACCURACY SPECIMENS IN DESCENDING MAGNITUDE OF THE COEFFICIENT OF VARIATION MEAN OF 3 MEASUREMENTS (IN MM) * STANDARD ERROR: MAXILLARY OUTER MOLAR WIDTH 1. 2. 3. 4. 5. 6. 7. 8. 9. 5247 344 5248 5245 GR364 5308 GR297 GR472 5251 10. 5249 11. GR36 12. 588 13. GR321 14. GR39 15. 589 16. GR485 17. 5305 18. GR33 19. GR314 20. GR223 21. GR514 22. 5307 23. 586 24. 5246 25. 5252 4.117 ± 4.017 4 4.083 ± 4.183 4 3.533 ± 4.100 4 3.817 4 3.917 4 4.217 4 4.317 ± 3.567 i 3.967 4 3.650 4 3.650 4 4.267 i 3.800 i 4.000 i 3.683 4 3.717 4 3.883 4 3.917 4 3.967 4 4.017 4 4.167 4 3.750 4 .093 .088 .060 .060 .044 .050 .044 .044 .044 .044 .034 .034 .029 .029 .034 .029 .029 .017 .017 .017 .017 .017 .017 .017 .000 COEFFICIENT OF VARIATION (IN PERCENT) 3.904 3.803 2.549 2.488 2.162 2.112 2.001 1.950 1.811 1.769 1.619 1.456 1.370 1.370 1.353 1.316 1.250 0.784 0.777 0.743 0.737 0.728 0.719 0.693 0.000 APPENDIX TABLE l v : MEASURING ACCURACY SPECIMENS IN DESCENDING MAGNITUDE OF THE COEFFICIENT OF VARIATION 1. 5252 MEAN OF 3 MEASUREMENTS (IN MM) i STANDARD ERROR: MAXILLARY INNER MOLAR WIDTH 2. 3. 4. 5. 6. 7. 8. GR36 5249 GR314 GR485 344 GR297 589 9. GR364 10. 5248 11. GR39 12. GR321 13. 5307 14. 5251 15. 5305 16. GR514 17.. GR33 18. 588 19. 586 20. GR223 21. 5245 22. 5308 23. 5246 24. GR472 25. 5247 2.033 i 2.067 4 2.267 4 2.000 ± 2.083 4 2.050 4 2.067 4 2.083 4 1.867 4 2.033 ± 2.067 4 1.800 4 2.167 4 2.217 i 2.233 4 2.200 4 1.833 4 2.017 4 2.017 4 2.083 4 2.283 4 2.317 4 2.383 4 2.000 4 2.300 4 .093 .073 .073 .058 .060 .058 .044 .044 .034 .034 .034 .029 .034 .034 .034 .029 .017 .017 .017 .017 .017 .017 .017 .000 .000 COEFFICIENT OF VARIATION (IN PERCENT) 7.905 6.089 5.551 5.000 4.996 4.878 3.696 3.666 3.093 2.840 2.794 2.778 2.665 2.605 2.588 2.273 1.575 1.432 1.432 1.386 1.264 1.246 1.211 0.000 0.000 APPENDIX TABLE lw: MEASURING ACCURACY SPECIMENS IN DESCENDING MAGNITUDE OF THE COEFFICIENT OF VARIATION MEAN OF 3 MEASUREMENTS (IN MM) 4 STANDARD ERROR: MANDIBLE LENGTH 1. 2. 3. 4. 5. 6. 7. 8. 9. GR485 5252 5251 52A7 GR31A GR33 GR297 586 GR36 10. 5308 11. 3AA 12. 52A9 13. GRA72 IA. GR39 15. 5307 16. GR51A 17. 588 18. GR223 19. 52A5 20. 589 21. GR36A 22. 52A8 23. 5246 24. GR321 25. 5305 13.167 * 13.567 i 14.783 i 13.867 * 13.467 4 12.900 i 13.000 4 15.233 4 12.100 4 14.200 4 13.783 4 14.367 4 13.133 4 13.367 4 13.967 * 13.800 4 14.000 * 14.200 ± 14.450 4 14.550 4 12.683 4 13.383 4 14.567 4 12.150 4 14.050 * .088 .088 .093 .073 .067 .058 .058 .067 .050 .050 .044 .044 .034 .034 .034 .029 .029 .029 .029 .029 .017 .017 .017 .000 .000 COEFFICIENT OF VARIATION (IN PERCENT) 1.160 1.126 1.087 0.907 0.858 0.775 0.769 0.758 0.716 0.610 0.554 0.532 0.440 0.432 0.413 0.362 0.357 0.352 0.346 0.344 0.228 0.216 0.198 0.000 0.000 APPENDIX TABLE l x : MEASURING ACCURACY SPECIMENS IN DESCENDING MAGNITUDE OF THE COEFFICIENT OF VARIATION 5307 MEAN OF 3 MEASUREMENTS (IN MM) 4 STANDARD ERROR: JAW LENGTH 1. 2. 3. 4. 5. 6. 7. 5251 344 5308 5252 5247 5249 8. 5248 9. 589 10. GR33 11. GR514 12. 588 13. 5305 14. GR314 15. GR321 16. 5246 17. 586 18. 5245 19. GR472 20. GR297 21. GR223 22. GR36 23. GR364 24. GR39 25. GR485 9.050 4 9.533 4 9.417 i 9.533 4 8.600 4 8.700 4 9.383 4 9.167 4 9.367 i 8.583 4 8.917 4 9.050 4 8.750 i 8.800 4 8.233 4 9.417 4 9.833 4 9.217 4 8.450 4 8.650 4 9.050 4 8.083 4 8.117 4 8.667 4 8.700 ir .104 .109 .088 .088 .076 .076 .073 .067 .067 .060 .060 .058 .050 .050 .044 .044 .044 .034 .029 .029 .029 .017 .017 .017 .000 COEFFICIENT OF VARIATION (IN PERCENT) 1.992 1.986 1.622 1.602 1.538 1.521 1.341 1.260 1.233 1.213 1.168 1.105 0.990 0.984 0.928 0.811 0.777 0.626 0.592 0.578 0.553 0.357 0.356 0.333 0.000 APPENDIX TABLE l y : MEASURING ACCURACY SPECIMENS IN DESCENDING MAGNITUDE OF THE COEFFICIENT OF VARIATION 1. 5251 MEAN OF 3 MEASUREMENTS (IN MM) 4 STANDARD ERROR: MANDIBULAR TOOTH ROW LENGTH GR514 GR297 GR314 GR36 GR364 5307 8. 5248 9. 5252 10. 5305 11. 586 12. 5249 13. GR33 14. GR321 15. GR472 16. GR223 17. GR39 18. 5247 19. 20. 5246 589 21. 5245 22. GR485 23. 588 24. 5308 25. 344 6.100 4 5.467 4 5.233 4 5.317 4 4.700 4 4.850 4 5.633 4 5.767 4 5.400 4 5.450 4 5.500 4 5.750 4 5.067 4 5.117 4 5.167 4 5.183 4 5.283 4 5.367 4 5.667 4 5.733 4 5.833 4 5.000 4 5.300 4 5.900 4 6.000 * .050 .044 .034 .034 .029 .029 .034 .034 .029 .029 .029 .029 .017 .017 .017 .017 .017 .017 .017 .017 .017 .000 .000 .000 .000 COEFFICIENT OF VARIATION (IN PERCENT) 1.420 1.397 1.103 1.086 1.064 1.031 1.025 1.001 0.926 0.917 0.909 0.870 0.570 0.564 0.559 0.557 0.546 0.538 0.509 0.504 0.495 0.000 0.000 0.000 0.000 APPENDIX TABLE 2a; SEXUAL DIMORPHISM AND CORRELATION COEFFICIENT FOR ALTITUDE AND MEASUREMENTS MEAN OF MEASURE- T-VALUE FOR CORRELATION NAME OF NUMBER OF NUMBER SEX AGE ME NT (IN MM) * DIFFERENCE BETWEEN COEFFICIENT FOR MEASUREMENT SPECIMENS MEASURABLE GROUP STANDARD ERROR MEANS (WITH ITS ALTITUDE AND DEGREES OF FREEDOM) MEASUREMENT 17 15 F Juvenile 20.660 4 .288 -.071 (26) -.000070 To t a l 18 13 M Juvenile 20.739 4 .306 -.000028 Length of 128 109 F Subadult 22.665 i .979 .093 (181) -.000002 Sku l l 81 74 M Subadult 22.573 4 . 110 -.000004 72 64 F Adult 24.284 i . 108 -.538 (87) 000004 31 25 M Adult 24.740 4 .162 .000013 17 16 F Juvenile 2.369 * .045 -.157 (32) .000079 18 18 M Juvenile 2.408 * .072 -.000202 Nasal 128 122 F Subadult 2.561 .209 -.021 (198) -.000005 Width 81 78 M Subadult 2.565 4 .024 -.000020 72 70 F Adult 2.810 * .034 .236 (98) .000005 31 30 M Adult 2.745 4 .046 .000013 17 15 F Juvenile 3.947 4 .053 -.304 (30) .000180 18 17 M Juvenile 4.015 * .058 -.000106 Rostrum 128 119 F Subadult 4.223 .257 .237 (196) .000001 Width 81 79 M Subadult 4.158 * .029 -.000018 72 69 F Adult 4.392 * .028 -.192 (97) -.000018 31 30 M Adult 4.435 * .038 .000060 APPENDIX TABLE 2b^ SEXUAL DIMORPHISM AND CORRELATION COEFFICIENT FOR ALTITUDE AND MEASUREMENTS NAME OF MEASUREMENT NUMBER OF NUMBER SEX AGE SPECIMENS MEASURABLE GROUP MEAN OF MEASURE-MENT (IN MM) i STANDARD ERROR T-VALUE FOR DIFFERENCE BETWEEN MEANS (WITH ITS DEGREES OF FREEDOM) CORRELATION COEFFICIENT FOR ALTITUDE AND MEASUREMENT 17 16 F Juvenile 11.513 * .151 -.001 18 15 M Juvenile 11.513 .181 Zygomatic 128 113 F Subadult 12.760 * . 716 .306 Width 81 76 M Subadult 12.540 .074 72 67 F Adult 13.771 .074 -,430 31 30 M Adult 14.037 * . 119 17 16 F Juvenile 3.206 4 .050 -.055 Least 18 18 M Juvenile 3.219 % . 070 I n t e r o r b i t a l 128 121 F Subadult 3.184 ± . 161 .034 Width 81 76 M Subadult 3. 178 .019 72 72 F Adult 3.156 i .028 -.154 31 31 M Adult 3.189 .031 17 14 F Juvenile 9. 936 * . 102 .277 18 12 M Juvenile 9.833 * . 110 Braincase 128 112 F Subadult 10.225 4 .351 . 172 Width 81 75 M Subadult 10.161 i .043 72 65 F Adult 10.496 4 .048 219 31 29 M Adult 10.412 ir . 069 -.000089 -.000049 .000000 -.000006 .000007 .000044 .000236 .000138 .000009 .000018 .000013 .000102 .000135 .000136 .000006 .000016 .000000 .00002 5 APPENDIX TABLE 2a SEXUAL DIMORPHISM AND CORRELATION COEFFICIENT FOR ALTITUDE AND MEASUREMENTS MEAN OF MEASURE- T-VALUE FOR CORRELATION NAME OF NUMBER OF NUMBER SEX AGE MENT (IN MM) 4 DIFFERENCE BETWEEN COEFFICIENT FOR MEASUREMENT SPECIMENS MEASURABLE GROUP STANDARD ERROR MEANS (WITH ITS ALTITUDE AND DEGREES OF FREEDOM) MEASUREMENT 17 10 F Juvenile 9. 185 4 . 133 .341 (15) -.000147 Post 18 7 M Juvenile 9.050 * . 135 -.000296 Zygoma 128 84 F Subadult 9.492 * .044 . 141 (133) -.000011 Width 81 51 M Subadult 9.440 4 .043 -.000044 72 48 F Adult 9.564 4 .045 -.042 (63) -.000003 31 17 M Adult 9.577 * .075 -.000094 17 13 F Juvenile 8. 912 * .099 .284 (23) -.000230 18 12 M Juvenile 8. 792 4 .040 -.000135 Mastoid 128 105 F Subadult 9.388 4 .397 -.020 (172) -.000013 Width 81 69 M Subadult 9.396 4- .048 -.000025 72 63 F Adult 9.598 •4 .045 -.454 (83) -.000017 31 22 M Adult 9. 766 4 .088 -.000022 17 10 F Juvenile 3.200 * .088 -.399 (19) .000063 Foramen 18 11 M Juvenile 3.305 4 .075 -.000152 Magnum 128 100 F Subadult 3.219 * .026 .407 (163) .000011 Height 81 65 M Subadult 3.119 *• .028 .000006 72 56 F Adult 3.266 4- .034 .376 (77) .000019 31 23 M Adult 3.174 4 .046 -.000007 APPENDIX TABLE 2d; SEXUAL DIMORPHISM AND CORRELATION COEFFICIENT FOR ALTITUDE AND MEASUREMENTS NAME OF NUMBER OF NUMBER MEASUREMENT SPECIMENS MEASURABLE MEAN OF MEASURE-SEX AGE MENT (IN MM) * GROUP STANDARD ERROR T-VALUE FOR CORRELATION DIFFERENCE BETWEEN COEFFICIENT FOR MEANS (WITH ITS ALTITUDE AND DEGREES OF FREEDOM) MEASUREMENT 17 11 F Juvenile 3.573 * .072 -.424 (19) .000134 Foramen 18 10 M Juvenile 3.655 * .041 -.000070 Magnum 128 103 F Subadult 3.619 . 187 . 103 (171) -.000000 Width 81 70 M Subadult 3.598 .028 -.000000 72 57 F Adult 3.660 4 .024 .269 (80) -.000002 31 25 M Adult 3. 612 * .033 -.000101 17 13 F Juvenile 6.162 i .074 -.122 (25) -.000317 18 14 M Juvenile 6.204 4. . 108 -.000102 Sku l l 128 111 F Subadult 6. 678 * .339 .280 (183) -.000010 Height 81 74 M Subadult 6.574 4 .046 -.000029 72 66 F Adult 7.029 4 .052 -.160 (92) -.000016 31 28 M Adult 7.093 4 .065 -.000004 17 14 F Juvenile 20.311 * .311 .117 (25) -.000064 18 13 M Juvenile 20.173 4 .327 -.000033 Condylobasal 128 109 F Subadult 22.214 4- 1.013 .093 (179) -.000003 Length 81 72 M Subadult 22.118 .125 -.000006 72 64 F Adult 23.795 4 . 106 -.553 (87) .000000 31 25 M Adult 24.250 *• . 150 .000004 APPENDIX TABLE 2e; SEXUAL DIMORPHISM AND CORRELATION COEFFICIENT FOR ALTITUDE AND MEASUREMENTS MEAN OF MEASURE- T-VALUE FOR CORRELATION NAME OF NUMBER OF NUMBER SEX AGE MENT (IN MM) * DIFFERENCE BETWEEN COEFFICIENT FOR MEASUREMENT SPECIMENS MEASURABLE GROUP STANDARD ERROR MEANS (WITH ITS ALTITUDE AND DEGREES OF FREEDOM) MEASUREMENT 17 14 F Juvenile 18.896 t .306 -.316 (24) -.000067 18 12 M Juvenile 19.296 * .402 -.000044 Basal 128 101 F Subadult 21.006 41.005 .190 (167) -.000002 Length 81 68 M Subadult 20.818 * . I l l -.000005 72 61 F Adult 22.562 * .111 -.513 (83) .000004 31 24 M Adult 22.996 4 .161 .000003 17 13 F Juvenile 17. 808 *• .331 -.294 (23) -.000060 18 12 M Juvenile 18.183 4 .394 -.000042 B a s i l a r 128 96 F Subadult 19.932 4 . 101 .199 (158) -.000002 Length 81 64 M Subadult 19.738 . 120 -.000004 72 61 F Adult 21.419 * . I l l -.471 (83) .000005 31 24 M Adult 21.829 * . 180 .000006 17 13 F Juvenile 11.596 4- .206 -.116 (25) -.000084 18 14 M Juvenile 11.679 * .181 -.000037 P a l a t a l 128 119 F Subadult 12.704 * .591 .201 (191) -.000001 Length 81 74 M Subadult 12.577 4- .0 71 -.000008 72 69 F Adult 13.618 4 .065 -.477 (96) .000009 31 29 M Adult 13.881 4 .105 .000038 APPENDIX TABLE 2f; SEXUAL DIMORPHISM AND CORRELATION COEFFICIENT FOR ALTITUDE AND MEASUREMENTS NAME OF NUMBER OF NUMBER MEASUREMENT SPECIMENS MEASURABLE MEAN OF MEASURE-SEX . AGE MENT (IN MM) * GROUP STANDARD ERROR T-VALUE FOR CORRELATION DIFFERENCE BETWEEN COEFFICIENT FOR MEANS (WITH ITS ALTITUDE AND DEGREES OF FREEDOM) MEASUREMENT 17 13 F Juvenile 4.827 t .099 . 113 (24) -.000140 18 13 M Juvenile 4.785 % . 107 -.000044 Pa l a t a l 128 119 F Subadult 5. 151 i .332 . 137 (189) -.000007 Bridge 81 72 M Subadult 5.103 i .040 -.000018 Length 72 68 F Adult 5.416 .063 .045 (94) -.000011 31 28 M Adult 5.395 * .068 .000025 17 17 F Juvenile 3.335 .099 .266 (33) -.000197 18 18 M Juvenile 3.222 * .104 -.000085 Pa l a t a l 128 123 F Subadult 3.762 * .319 -.011 (199) -.000016 Foramen 81 78 M Subadult 3.765 * .036 -.000023 Length 72 70 F Adult 4.110 * .035 -.721 (98) -.000018 31 30 M Adult 4.305 * .038 -.000154 17 17 F Juvenile .906 .035 -.427 (33) .000151 18 18 M Juvenile .972 * .039 -.000330 P a l a t a l 128 123 F Subadult .897 * . 102 -.117 (199) -.000025 Foramen 81 78 M Subadult . 910 * .013 -.000041 Width 72 70 F Adult .931 * .014 .090 (98) -.000051 31 30 M Adult .920 .022 -.000263 APPENDIX TABLE 2g: SEXUAL DIMORPHISM AND CORRELATION COEFFICIENT FOR ALTITUDE AND MEASUREMENTS NAME OF MEASUREMENT MEAN OF MEASURE-NUMBER OF NUMBER SEX AGE MENT (IN MM) t SPECIMENS MEASURABLE GROUP STANDARD ERROR T-VALUE FOR DIFFERENCE BETWEEN MEANS (WITH ITS DEGREES OF FREEDOM) CORRELATION COEFFICIENT FOR ALTITUDE AND MEASUREMENT Maxillary 17 17 F Juvenile 5.859 * .092 -.306 (33) -.000188 18 18 M Juvenile 5.997 *• .121 -.000011 Diastema 128 122 F Subadult 6.592 .391 .019 (199) .000006 Length 81 79 M Subadult 6.584 4 .044 .000005 72 71 F Adult 7.250 * .056 -.279 (99) .000020 31 30 M Adult 7.378 4- .078 .000076 Maxillary 17 17 F Juvenile 5.079 * .069 . 140 (32) -.000143 18 17 M Juvenile 5.041 * .064 -.000212 Tooth 128 127 F Subadult 5.395 4 .263 .031 (205) -.000022 Row 81 80 M Subadult 5.386 4 .032 -.000041 Length 72 72 F Adult 5. 645 T .034 -.047 (99) -.000017 39 31 M Adult 5.659' * .055 -.000030 17 17 F Juvenile 3.891 *- .065 -.325 (32) -.000029 Maxillary 18 17 M Juvenile 3.985 4 .075 -.000219 Outer 128 126 F Subadult 4.015 * .211 -.113 (205) -.000014 Molar 81 81 M Subadult 4.041 *• .025 -.000039 Width 72 71 F Adult 4.151 4 .030 -.005 (96) -.000023 31 27 M Adult 4.152 4 .048 -.000032 APPENDIX TABLE 2h; SEXUAL DIMORPHISM AND CORRELATION COEFFICIENT FOR MEAN OF MEASURE NAME OF NUMBER OF NUMBER SEX AGE MENT (IN MM) * MEASUREMENT SPECIMENS MEASURABLE GROUP STANDARD ERROR 17 17 F Juvenile 2.077 4 .036 Maxillary 18 17 M Juvenile 2.124 * .043 Inner 128 125 F Subadult 2.082 4 . 149 Molar 81 78 M Subadult 2.137 * .018 Width 72 71 F Adult 2.170 *• .023 31 27 M Adult 2.194 •i .042 17 17 F Juvenile 1. 818 •i .051 18 17 M Juvenile 1.862 .068 128 125 F Subadult 1. 930 * . 180 81 78 M Subadult 1.905 * .025 72 71 F Adult 1. 981 4 .032 31 27 M Adult 1. 957 * .037 17 16 F Juvenile 12.556 *• . 169 18 16 M Juvenile 12.653 * .161 Mandible 128 120 F Subadult 13.552 * .684 Length 81 78 M Subadult 13.397 .058 72 66 F Adult 14.464 * .080 31 29 M Adult 14.402 *• . 123 ALTITUDE AND MEASUREMENTS T-VALUE FOR DIFFERENCE BETWEEN MEANS (WITH ITS DEGREES OF FREEDOM) -.289 (32) -.336 (201) -.123 (96) CORRELATION COEFFICIENT FOR ALTITUDE AND MEASUREMENT .000020 .000012 -.000029 -.000032 -.000006 -.000000 .178 (32) .125 (201) .094 (96) -.000064 -.000274 .000000 -.000025 -.000016 -.000052 .147 (30) .233 (196) .095 (93) -.000099 -.000046 .000000 .000015 .000000 .000026 APPENDIX TABLE 2 i ; SEXUAL DIMORPHISM AND CORRELATION COEFFICIENT FOR ALTITUDE AND MEASUREMENTS NAME OF MEASUREMENT MEAN OF MEASURE-NUMBER OF NUMBER SEX AGE MENT (IN MM) * SPECIMENS MEASURABLE GROUP STANDARD ERROR T-VALUE FOR DIFFERENCE BETWEEN MEANS (WITH ITS DEGREES OF FREEDOM) CORRELATION COEFFICIENT FOR ALTITUDE AND MEASUREMENT 17 15 F Juvenile 8.380 4 .090 -.294 (28) -.000124 18 15 M Juvenile 8.477 * .080 -.000241 Jaw 128 121 F Subadult 8. 825 .375 .085 (198) -.00000 7 Length 81 79 M Subadult 8.791 .041 -.000022 72 69 F Adult 9.317 .045 .059 (97) -.000008 31 31 M Adult 9.295 i .072 .000024 17 14 F Juvenile 3.321 •i .055 -.236 (27) .000061 Mandibular 18 15 M Juvenile 3.373 .060 -.000181 Diastema 128 121 F Subadult 3.438 * .202 -.077 (198) .000006 Length 81 79 M Subadult 3.456 * .028 -.000008 72 68 F Adult 3.670 *• .034 -.119 (95) .000011 31 29 M Adult 3.705 *• .061 .000013 17 15 F Juvenile 5.067 * .076 -.130 (28) -.000214 Mandibular 18 15 M Juvenile 5.103 *• .070 -.000182 Tooth 128 125 F Subadult 5.384 * .269 .170 (202) -.000016 Row 81 79 M Subadult 5.335 .030 -.000036 Length 72 70 F Adult 5. 641 * .032 .186 (97) -.000025 31 29 M Adult 5.591 .048 .000034 APPENDIX TABLE 2 j ; SEXUAL DIMORPHISM AND CORRELATION COEFFICIENT FOR ALTITUDE AND MEASUREMENTS NAME OF MEASUREMENT MEAN OF MEASURE-NUMBER OF NUMBER SEX AGE MENT (IN MM) 4 SPECIMENS MEASURABLE GROUP STANDARD ERROR T-VALUE FOR DIFFERENCE BETWEEN MEANS (WITH ITS DEGREES OF FREEDOM) CORRELATION COEFFICIENT FOR ALTITUDE AND MEASUREMENT 17 15 F Juvenile 73.267 2.184 .028 (30) .000000 Body 18 17 M Juvenile 73.058 1.620 .000004 (Plus 128 106 F Subadult 90.019 4 4.735 .258 (176) .000000 Head) 81 72 M Subadult 88.667 4 .630 -.000000 Length 72 46 F Adult 104.065 1.706 -.432 (66) .000000 31 22 M Adult 108.364 % 1.024 .000002 17 15 F Juvenile 27.333 4 . 814 .009 (30) -.000010 18 17 M Juvenile 27.294 4 1.274 -.000009 T a i l 128 106 F Subadult 32.293 4 3.814 -.220 (176) .000000 Length 81 72 M Subadult 33.167 4 .477 -.000000 72 .46 F Adult 33.804 * . 788 .898 (66) .000000 31 22 M Adult 38.455 * 1.018 .000000 17 15 F Juvenile 14.467 * . 133 -.555 (30) -.000045 Hind 18 17 M Juvenile 15.000 4 .298 -.000051 Foot 128 107 F Subadult 14.851 4 .859 -.527 (176) .000002 Length 81 71 M Subadult 15.282 4 .083 .000000 72 47 F Adult 17.255 4 . 163 -.272 (66) .000002 31 22 M Adult 15.546 4 .205 .000008 APPENDIX TABLE 2k; SEXUAL DIMORPHISM AND CORRELATION COEFFICIENT FOR ALTITUDE AND MEASUREMENTS MEAN OF MEASURE-NAME OF NUMBER OF NUMBER SEX AGE MENT (IN MM) * MEASUREMENT SPECIMENS MEASURABLE GROUP STANDARD ERROR 17 10 F Juvenile 9.900 * . 180 18 15 M Juvenile 10.267 * . 300 Ear 128 67 F Subadult 10.776 * . 129 Length 81 44 M Subadult 10.546 * . 132 72 34 F Adult 11.588 * . 208 31 16 M Adult 11.500 i . 354 T-VALUE FOR DIFFERENCE BETWEEN MEANS (WITH ITS DEGREES OF FREEDOM) -.376 (23) .233 (109) -.069 (48) CORRELATION COEFFICIENT FOR ALTITUDE AND MEASUREMENT -.000129 -.000049 .000000 .000005 -.000002 .000005 17 14 F Juvenile 12.643 4- .958 (gr) 18 12 M Juvenile 12.167 * .953 (gr) 128 97 F Subadult 18.794 * .466 (gr) 81 67 M Subadult 17.343 * .484 (gr) 72 36 F Adult 25.583 4 .906 (gr) 31 19 M Adult 29.737 4 1.140 (gr) .138 (24) -.000025 -.000011 Weight 4  r) > 3 3 5 ( 1 6 2 ) -.000000 -.000002 -.788 (53) .000000 -.000004 APPENDIX TABLE 3a; AGE DIFFERENCES NAME OF NUMBER OF NUMBER AGE MEASUREMENT SPECIMENS MEASURABLE GROUP Tota l 49 Length of 226 Skull 114 42 Juvenile 200 Subadult 100 Adult Nasal 49 Width 226 114 48 Juvenile 217 Subadult 111 Adult Rostrum 49 46 Juvenile Width 226 215 Subadult 114 108 Adult Zygomatic 49 Width 226 114 42 Juvenile 203 Subadult 105 Adult Least 49 I n t e r o r b i t a l 226 Width 114 48 Juvenile 212 Subadult 113 Adult Braincase 49 36 Juvenile Width 226 201 Subadult 114 105 Adult "'Significant at .001 le v e l MEAN OF MEASUREMENT (IN MM) 4 STANDARD ERROR T-VALUE FOR DIFFERENCE BETWEEN MEANS (WITH ITS DEGREES OF FREEDOM) 20.705 * .017 11. 622*(240) 22.647 4 .677 24.428 .086 15. 704*(298) 2.382 .032 4. 977*(263) 2.561 i . 154 2. 781 4 .255 7. 816*(326) 3.999 4 .034 4. 782*(305) 4.201 * .181 4.391 4 .218 6. 388*(321) 11.570 * .097 9. 549*(243) 12.694 .496 13.845 4 .599 14. '152*(306) 3.207 4 .033 906 (258) 3.181 4- . 117 3.159 4 . 195 -1. 007 (323) 9.929 *• .057 3. 970*(235) 10.192 4 .261 10.485 * .379 5. 878*(304) 00 APPENDIX TABLE 3b; AGE DIFFERENCES NAME OF MEASUREMENT Post Zygoma Width NUMBER OF NUMBER SPECIMENS MEASURABLE 49 226 114 25 145 71 AGE GROUP Juvenile Subadult Adult Mastoid Width 49 226 114 34 185 92 Juvenile Subadult Adult Foramen 49 Magnum 226 Height 114 29 Juvenile 176 Subadult 88 Adult Foramen 49 Magnum 226 Width 114 30 Juvenile 184 Subadult 92 Adult S k u l l 49 36 Juvenile Height 226 200 Subadult 114 103 Adult Condylobasal 49 Length 226 114 40 Juvenile 196 Subadult 100 Adult "'Significant at .001 level MEAN OF MEASUREMENT (IN MM) i STANDARD ERROR T-VALUE FOR DIFFERENCE BETWEEN MEANS (WITH ITS DEGREES OF FREEDOM) 9. 168 4 .066 9. 468 * .302 9. 573 * .037 •3.873*(168) 2.097 (214) 8.874 4 .069 6.968*(217) 9.394 *• .294 9.635 .039 4.830 (275) 3.224 * .046 -.955 (203) 3.177 * .184 3.232 4 .027 1.703 (262) 3. 585 * .037 3. 605 * . 153 3. 637 * .018 .489 (212) 1.276 (274) 6. 214 T .057 6.375*(234) 6. 634 * .260 7. 028 * .387 8.607*(301) 20.346 * .165 22.189 * .718 23.939 * .084 10.495*(234) 14.958*(294) APPENDIX TABLE 3c; AGE DIFFERENCES NAME OF NUMBER OF NUMBER AGE MEASUREMENT SPECIMENS MEASURABLE GROUP Basal 49 40 Juvenile Length 226 183 Subadult 114 96 Adult B a s i l a r 49 Length 226 114 39 Juvenile 173 Subadult 95 Adult P a l a t a l 49 Length 226 114 39 Juvenile 209 Subadult 109 Adult Pal a t a l 49 Bridge 226 Length 114 38 Juvenile 207 Subadult 107 Adult P a l a t a l 49 Foramen 226 Length 114 49 Juvenile 218 Subadult 111 Adult Pal a t a l Foramen Width 49 226 114 49 218 111 Juvenile Subadult Adult "'Significant at .001 level MEAN OF MEASUREMENT (IN MM) * STANDARD ERROR T-VALUE FOR DIFFERENCE BETWEEN MEANS (WITH ITS DEGREES OF FREEDOM) 19.039 * .196 20.941 * .716 22.694 * .087 17. 962 * .197 19.862 4 .724 21. 550 4 .091 11. 669 * . 103 12. 672 4 .425 13. 705 -4 .525 4. 791 *• .055 5. 135 •4 .241 5. 397 4- .450 3. 2 64 *• .058 3. 767 •4 .230 4. 167 4- .264 10.662*(221) 10.635*(210) 9.290*(246) 5.657*(243) 9.004-(2 65) 14.947*(277) 14.223*(266) 14.774*(316) 5.644*(312) 10.698*(327) .918 * .022 .903 * .074 .928 4 .114 -.838 (265) 1. 878 (327) APPENDIX TABLE 3d.- AGE DIFFERENCES NAME OF NUMBER OF MEASUREMENT SPECIMENS Maxillary 49 Diastema 226 Length 114 NUMBER AGE MEASURABLE GROUP 49 Juvenile 218 Subadult 112 Adult Maxillary 49 Tooth Row 226 Length 114 48 Juvenile 224 Subadult 112 Adult Maxillary 49 Outer Molar 226 Width 114 Maxillary 49 Inner Molar 226 Width 114 48 Juvenile 223 Subadult 108 Adult 48 Juvenile 219 Subadult 108 Adult Maxillary 49 Molar 226 Width 114 48 Juvenile 219 Subadult 108 Adult Mandible Length 49 226 114 45 214 105 Juvenile Subadult Adult '•'Significant at .001 level MEAN OF MEASUREMENT (IN MM) * STANDARD ERROR T-VALUE FOR DIFFERENCE BETWEEN MEANS (WITH ITS DEGREES OF FREEDOM) 5. 904 4 .062 6. 587 t .274 7. 285 4 .425 5. 081 4: .042 5. 396 4 . 191 5. 640 * .267 3. 902 4 .039 4. 021 4 . 154 4. 140 4- .237 2. 037 •i .027 2. 095 4- . 116 2. 170 . 190 1. 867 * .034 1. 925 4 . 138 1. 970 4 .236 10.545*(265) 6.922*(270) 3.140 (269) 2.103 (265) 1.746 (265) 14.298*(328) 7.396*(334) 4.317*(329) 3.564*(325) 1.751 (325) 12.652 * .103 13.505 * .447 14.452 * .619 7.883*(257) 12.294*(317) APPENDIX TABLE 3e; AGE DIFFERENCES NAME OF MEASUREMENT Jaw Length NUMBER OF NUMBER SPECIMENS MEASURABLE 49 226 114 44 216 110 AGE GROUP Juvenile Subadult Adult Mandibular Diastema Length 49 226 114 43 216 108 Juvenile Subadult Adult Mandibular Tooth Row Length 49 226 114 44 220 110 Juvenile Subadult Adult Body 49 (Plus Head) 226 Length 114 33 Juvenile 179 Subadult 69 Adult T a i l Length 49 226 114 33 179 69 Juvenile Subadult Adult Hind 49 Foot 226 Length 114 34 Juvenile 180 Subadult 70 Adult - vSignificant at .001 level MEAN OF MEASUREMENT (IN MM) * STANDARD ERROR T-VALUE FOR DIFFERENCE BETWEEN MEANS (WITH ITS DEGREES OF FREEDOM) 8.414 * 8.810 * 9.297 * .047 .262 ,354 6.427*(258) 10.942*(324) 3.326 * .031 3.195 (257) 3.446 *• . 156 3.676 * .284 7.689*(322) 5.091 * .042 5.849*(262) 5.363 * .190 5.618 * .249 7.934*(328) 73.242 * 1.277 15.221*(210) 89.453 * 3.925 105.464 * 1.202 16.358*(246) 27.364 * .742 6.932*(210) 32.643 * 2.969 35.362 * .668 4.293*(246) 14.882 *- .206 15.022 * .625 15.357 * .128 .827 (212) 2.622 (248) APPENDIX TABLE 3f; AGE DIFFERENCES NAME OF MEASUREMENT Ear Length NUMBER OF NUMBER SPECIMENS MEASURABLE 49 226 114 27 111 50 49 26 Weight 226 164 114 55 AGE GROUP Juvenile Subadult Adult Juvenile Subadult Adult "'Significant at .001 le v e l MEAN OF MEASUREMENT (IN MM) * STANDARD ERROR 10.074 *• .185 10.685 * .941 11.560 4 - . 178 T-VALUE FOR DIFFERENCE BETWEEN MEANS (WITH ITS DEGREES OF FREEDOM) 2.890 (136) 4.748*(159) 12.423 * .666 (gr) 18.201 * 3.418 (gr) 27.018 4 .755 (gr) 6.427*(188) 12.017*(217) APPENDIX TABLE 4: PROPORTIONAL RELATIONSHIPS WITH AGE IN CRANIAL MEASUREMENTS OF MICROTUS ARVALIS NAMES OF NUMBER OF NUMBER AGE MEASUREMENTS SPECIMENS MEASURABLE GROUP M a x i l l a r y Diastema 49 48 M a x i l l a r y Tooth Row 226 224 114 112 MEAN OF PROPORTION T-VALUE FOR DIFFERENCE (IN MM) 4 BETWEEN MEANS (WITH STANDARD ERROR ITS DEGREES OF FREEDOM) Juv e n i l e 1. 168 * . O i l Subadult 1. 179 4 .162 Adult 1. 282 4 .148 .308(270) 4.099(334) I n t e r o r b i t a l Width 49 48 Ju v e n i l e .619 4 .015 -2.847(270) M a x i l l a r y Tooth Row 226 224 Subadult .554 4 .101 114 112 Adult .556 4 .066 I n t e r o r b i t a l Width 49 44 Ju v e n i l e .372 4 .009 -.224(258) Jaw Length 226 216 Subadult .340 4 .061 114 110 Adult .337 4 .039 115(334) -.272(324) S k u l l Height 49 42 Ju v e n i l e .422 4 .035 Zygomatic Width 226 203 Subadult .483 4 .098 114 105 Adult .475 4 .128 2.306(243) -.516(306) Zygomatic Width 49 40 Ju v e n i l e .527 4 .024 Condylobasal Length 226 196 Subadult .543 4 .091 114 100 Adult .551 4 .013 .691(234) .510(294) LITERATURE CITED 125 A d a m c z e w s k a - A n d r z e j e w s k a , K.A. and L. N a b a g l o . 1977. Demograph-i c p a r a m e t e r s and v a r i a t i o n s i n numbers o f t h e common v o l e . A c t a T h e r i o l o g i c a , 2 2 ( 3 1 ) : 4 3 1 - 4 5 7 . A l l e e , W.C., 0. P a r k , A.E. Emerson, T. 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