The reproductive biology of two small southern African mammals, the spiny mouse, Acomys spinosissimus (Rodentia: Muridae) and the Eastern rock elephant- shrew, Elephantulus myurus (Macroscelidea: Macroscelididae) by Katarina Medger Submitted in partial fulfilment of the requirements for the degree Doctor of Philosophy In the Faculty of Natural and Agricultural Sciences University of Pretoria Pretoria December, 2010 © University of Pretoria II Table of Contents List of tables .............................................................................................................. vii List of figures ............................................................................................................ viii Acknowledgements ..................................................................................................... x Declaration ................................................................................................................ xii SUMMARY ............................................................................................. 1 GENERAL INTRODUCTION .................................................................. 3 Seasonal reproduction ....................................................................................... 3 Temperate vs. sub-tropical and tropical regions ....................................................... 3 Food quantity and quality .......................................................................................... 4 Seasonal vs. opportunistic breeding strategies ......................................................... 4 Other environmental factors ..................................................................................... 6 Photoperiod .............................................................................................................. 7 The hypothalamo-pituitary-gonadal axis and kisspeptin .................................... 9 Study objectives ............................................................................................... 11 Study species ................................................................................................... 12 The spiny mouse, Acomys spinosissimus ................................................................12 The Eastern rock elephant-shrew, Elephantulus myurus .........................................14 Thesis organisation .......................................................................................... 16 References ....................................................................................................... 18 CHAPTER 1 .......................................................................................... 33 SEASONAL REPRODUCTION IN THE MALE AND FEMALE SPINY MOUSE (ACOMYS SPINOSISSIMUS) FROM SOUTH AFRICA Abstract ............................................................................................................ 34 Introduction ...................................................................................................... 35 Materials and Methods ..................................................................................... 36 General ...................................................................................................................36 Histology .................................................................................................................38 Hormone analysis ....................................................................................................39 Relative age classes ................................................................................................40 © University of Pretoria TABLE OF CONTENTS III Data analysis ...........................................................................................................41 Results ............................................................................................................. 42 Climate data ............................................................................................................42 Body mass ...............................................................................................................42 Males .......................................................................................................................42 Females ..................................................................................................................43 Discussion........................................................................................................ 45 Acknowledgements .......................................................................................... 50 References ....................................................................................................... 50 Tables .............................................................................................................. 56 Figure legends ................................................................................................. 60 Figures ............................................................................................................. 61 CHAPTER 2 .......................................................................................... 66 SEASONAL REPRODUCTION IN MALE AND FEMALE EASTERN ROCK ELEPHANT-SHREWS (ELEPHANTULUS MYURUS) FROM SOUTH AFRICA Abstract ............................................................................................................ 67 Introduction ...................................................................................................... 68 Materials and Methods ..................................................................................... 70 General ...................................................................................................................70 Histology .................................................................................................................71 Hormone analysis ....................................................................................................73 Relative age classes ................................................................................................74 Data analysis ...........................................................................................................75 Results ............................................................................................................. 76 General ...................................................................................................................76 Body mass ...............................................................................................................77 Months ....................................................................................................................78 Relative age classes ................................................................................................79 Month and relative age class ...................................................................................80 Discussion........................................................................................................ 81 Acknowledgements .......................................................................................... 87 References ....................................................................................................... 87 Tables .............................................................................................................. 93 © University of Pretoria TABLE OF CONTENTS IV Figure legends ................................................................................................. 98 Figures ........................................................................................................... 100 CHAPTER 3 ........................................................................................ 109 REPRODUCTIVE PHOTORESPONSIVENESS IN MALE SPINY MICE (ACOMYS SPINOSISSIMUS) FROM SOUTH AFRICA Abstract .......................................................................................................... 110 Introduction .................................................................................................... 111 Materials and Methods ................................................................................... 113 Histology ............................................................................................................... 114 Testosterone analysis ............................................................................................ 115 Data analysis ......................................................................................................... 115 Results ........................................................................................................... 115 Discussion...................................................................................................... 116 Acknowledgements ........................................................................................ 121 References ..................................................................................................... 121 Figure legends ............................................................................................... 127 Figures ........................................................................................................... 128 CHAPTER 4 ........................................................................................ 130 REPRODUCTIVE RESPONSES TO PHOTOPERIOD IN MALE EASTERN ROCK ELEPHANT-SHREWS