103
0-8493-1123-3/03/$0.00+$1.50
© 2003 by CRC Press LLC
Critical Approaches
to Sex Determination
in Sea Turtles
Thane Wibbels
CONTENTS
4.1 Introduction .................................................................................................104
4.2 Characteristics of TSD in Sea Turtles ........................................................104
4.2.1 Accuracy of Temperature Estimates ...............................................104
4.2.2 Pivotal Temperatures of Sea Turtles ...............................................105
4.2.3 TRT of Sea Turtles .........................................................................107
4.2.4 Methods for Estimating Pivotal Temperature and TRT in a Sea
Turtle Population ............................................................................109
4.3 Sex Ratios in Sea Turtle Populations .........................................................111
4.3.1 Hatchling Sex Ratios from Nesting Beaches .................................112
4.3.2 Nest Location and Hatchling Sex Ratios .......................................112
4.3.3 Seasonal Variation in Hatchling Sex Ratios ...................................114
4.3.4 Yearly Variation in Hatchling Sex Ratios ......................................114
4.3.5 Sex Ratios in Immature and Adult Portions of a Population ........115
4.3.6 Problems Encountered When Estimating Sex Ratios in a Sea
Turtle Population ............................................................................118
4.3.7 Predicting Hatchling Sex Ratios .....................................................119
4.3.7.1 Direct Methods for Predicting Hatchling Sex Ratios .....119
4.3.7.2 Indirect Methods for Predicting Hatchling Sex Ratios ..120
4.3.7.3 Predicting an Overall Sex Ratio for a Nesting Beach ....121
4.3.8 Manipulation of Hatchling Sex Ratios ...........................................122
4.4 Physiology of TSD .....................................................................................123
4.4.1 Thermosensitive Period and Gonadal Differentiation ....................123
4.4.2 Estrogen Hypothesis .......................................................................124
4.4.3 Genetics of TSD .............................................................................124
Acknowledgments ................................................................................................126
References ............................................................................................................126
4
1123 book.book Page 103 Monday, November 11, 2002 11:11 AM
0-8493-1123-3/03/$0.00+$1.50
© 2003 by CRC Press LLC
Critical Approaches
to Sex Determination
in Sea Turtles
Thane Wibbels
CONTENTS
4.1 Introduction .................................................................................................104
4.2 Characteristics of TSD in Sea Turtles ........................................................104
4.2.1 Accuracy of Temperature Estimates ...............................................104
4.2.2 Pivotal Temperatures of Sea Turtles ...............................................105
4.2.3 TRT of Sea Turtles .........................................................................107
4.2.4 Methods for Estimating Pivotal Temperature and TRT in a Sea
Turtle Population ............................................................................109
4.3 Sex Ratios in Sea Turtle Populations .........................................................111
4.3.1 Hatchling Sex Ratios from Nesting Beaches .................................112
4.3.2 Nest Location and Hatchling Sex Ratios .......................................112
4.3.3 Seasonal Variation in Hatchling Sex Ratios ...................................114
4.3.4 Yearly Variation in Hatchling Sex Ratios ......................................114
4.3.5 Sex Ratios in Immature and Adult Portions of a Population ........115
4.3.6 Problems Encountered When Estimating Sex Ratios in a Sea
Turtle Population ............................................................................118
4.3.7 Predicting Hatchling Sex Ratios .....................................................119
4.3.7.1 Direct Methods for Predicting Hatchling Sex Ratios .....119
4.3.7.2 Indirect Methods for Predicting Hatchling Sex Ratios ..120
4.3.7.3 Predicting an Overall Sex Ratio for a Nesting Beach ....121
4.3.8 Manipulation of Hatchling Sex Ratios ...........................................122
4.4 Physiology of TSD .....................................................................................123
4.4.1 Thermosensitive Period and Gonadal Differentiation ....................123
4.4.2 Estrogen Hypothesis .......................................................................124
4.4.3 Genetics of TSD .............................................................................124
Acknowledgments ................................................................................................126
References ............................................................................................................126
4
1123 book.book Page 103 Monday, November 11, 2002 11:11 AM