The Reproductive Biology of the Chelonia

ISBN-13: 9783642804168 / Angielski / Miękka / 2011 / 223 str.

Gerald Kuchling

Opis

This book presents a comparative view of chelonian reproduction and discusses ecophysiological implications for their captive breeding. Chelonians, with their protective rigid armour, are a phylogenetically antique group of reptiles which radiated to occupy niches from the open waters of the oceans, to rivers, creeks, swamps, forests, savannahs, and deserts. A few North American turtle species have been well studied, but until recently reproductive data on other chelonian species have been scarce. The way in which chelonians adjust their conservative mode of reproduction to the various requirements of their habitats and life styles is the theme of this book; the physiology of reproduction and its interplay with ecological conditions are its central subjects.

Spis treści

1 Introduction.- 1.1 Phylogeny.- 1.1.1 The Chelonian Bauplan.- 1.1.2 Fossil History and Evolution.- 1.1.3 Systematics and Biogeography.- 1.1.4 Body Size.- 1.2 Chelonian Reproductive Traits Compared with Other Reptiles.- 1.3 Anatomy of the Sexual Organs.- 1.3.1 Males.- 1.3.2 Females.- 1.4 Secondary Sexual Characteristics.- 2 Methods to Study Reproduction.- 2.1 Radiography.- 2.2 Ultra-sound Scanning.- 2.3 Laparoscopy and Biopsies.- 2.4 Blood Sampling.- 2.5 Considerations Regarding Captive Maintenance.- 3 Gonadal Cycles and Gamete Production.- 3.1 Sexual Maturity.- 3.2 Ovarian Cycle and Egg Production.- 3.2.1 Oogenesis and Folliculogenesis.- 3.2.2 Vitellogenesis.- 3.2.3 Oocyte Maturation and Ovulation.- 3.2.4 Luteal Phase.- 3.2.5 Oviducal Period.- 3.2.6 Regression and Follicular Atresia.- 3.3 Testicular Cycle and Sperm Production.- 3.3.1 Germinal Quiescence.- 3.3.2 Gonial Proliferation.- 3.3.3 Spermatocytogenesis.- 3.3.4 Spermiogenesis.- 3.3.5 Spermiation.- 3.3.6 Maturation and Storage of Sperm in the Epididymis.- 3.4 Accessory Secretions and Insemination.- 3.5 Sperm Storage in the Female Genital Tract.- 4 Reproductive Behaviour.- 4.1 Migration.- 4.2 Sexual Behaviour.- 4.2.1 Timing of Mating.- 4.2.2 Finding a Partner.- 4.2.3 Courtship and Copulation.- 4.2.4 Sexual Selection and Sexual Size Dimorphism.- 4.3 Nesting.- 4.3.1 Nesting Area and Selection of Nest Site.- 4.3.2 Conditions for Nesting.- 4.3.3 Preparation of Nest Site.- 4.3.4 Digging the Nest Hole.- 4.3.5 Oviposition.- 4.3.6 Covering the Nest.- 4.3.7 Nest Guarding.- 4.4 Emergence from the Nest.- 5 Reproductive Cycles and Environment.- 5.1 Temperate Zone.- 5.2 Tropical and Subtropical Zone.- 5.3 Multi-Year Reproductive Cycles.- 5.4 Unpredictable Habitats.- 5.5 Conclusions.- 6 Control of Reproduction.- 6.1 Exogenous Factors.- 6.1.1 Temperature and Photoperiod.- 6.1.2 Water Levels, Rain and Moisture.- 6.1.3 Food Availability.- 6.1.4 Social Factors and Population Density.- 6.2 Endogenous Timing Mechanisms.- 6.3 Effects of Stress on Reproduction.- 6.4 Conclusions.- 7 Hormones and Reproduction.- 7.1 Gonadal Steroids.- 7.1.1 Males.- 7.1.2 Females.- 7.2 Gonadotropins.- 7.3 Gonadotropin-Releasing Hormone.- 7.4 Pineal Hormones.- 7.5 Other Hormones.- 7.6 Hormones and Behaviour.- 7.7 Conclusions.- 8 Eggs and Embryonic Development.- 8.1 Egg Characteristics.- 8.1.1 Eggshell.- 8.1.2 Egg Contents.- 8.2 Development and Hatching.- 8.2.1 Development Rates and Incubation Times.- 8.2.2 Descriptive Embryology.- 8.2.3 Pipping and Hatching.- 8.3 Sex Determination.- 8.4 Effect of Incubation Environment on Neonates.- 9 Reproductive Patterns and Life History.- 9.1 Resource Allocation.- 9.1.1 Growth and Maturity.- 9.1.2 Egg Size, Clutch Size and Clutch Frequency.- 9.1.3 Reproductive Effort and Cost of Reproduction.- 9.1.4 Mortality, Longevity and Ageing.- 9.1.5 Somatic Repair.- 9.2 Population Structure and Dynamics.- 10 Threats, Reproduction and Conservation.- 10.1 Environmental Degradation.- 10.1.1 Case Study: Pseudemydura umbrina.- 10.2 Exploitation.- 10.2.1 Case Study: Erymnochelys madagascariensis.- 10.3 Conservation Strategies.- 10.3.1 Conservation of Wild Populations.- 10.3.2 Sustainable Use.- 10.3.3 Conservation in Captivity.- 10.3.4 Case Study: Pseudemydura umbrina.- 10.3.5 Case Study: Erymnochelys madagascariensis.- 10.4 Commercial Captive Breeding Operations.- 10.5 Risk Minimisation in Assessing Reproduction in Live Chelonians.- 10.5.1 Risks and Limitations of Currently Used Methods.- 10.5.2 Routine Screening of Reproductive Condition.- 11 Conclusions and Outlook.- References.- Systematic Index.