Term of Award

Fall 2011

Degree Name

Master of Science in Biology (M.S.)

Document Type and Release Option

Thesis (open access)

Department

Department of Biology

Committee Chair

David C. Rostal

Committee Member 1

John Scott Harrison

Committee Member 2

Denson McLain

Abstract

Characterizing the mating system of a species is important for understanding demography and population dynamics and can contribute information to conservation efforts. Mating systems can impact the ecology, evolution, effective population size and genetic variability of a species. Polyandry, resulting in multiple paternity can influence the maintenance of genetic variation within a population. Within Testudines, the frequency of multiple paternity varies extensively among species (0-100% of nests). Previous studies on the loggerhead turtle (Caretta caretta) have shown that within the large management unit of peninsular Florida, multiple paternity occurs in approximately 30% of nests. This study examines nests from the smaller and more endangered northern management unit. The primary objectives of this study are to determine if multiple paternity exists in Georgia's smaller nesting population and determine if the percentage of nests with multiple fathers differs significantly from previous studies. Secondary objectives are to compare the incidence of multiple paternity over multiple years, determine if multiple paternity varies over the course of the nesting period. Our final objectives were to determine the relationship between the number of fathers per nest and female size (straight carapace length), as well as hatching success and to determine how many males are actually contributing to this nesting population. Mothers and offspring (up to 20) were initially sampled from more than 90 nests over three nesting seasons on Wassaw Island, GA (2008-2010). We found that multiple fathers contribute to 75% of nests over the three years. There is a difference in number of fathers per nest with relation to the year, but there is no relationship between the number of fathers per nest and the nesting period. There is a positive relationship between female size (SCL) and the number of fathers per nest. There is no relationship between the number of fathers contributing to a clutch and hatching success. Finally I found a total of 195 male genotypes over the course of the study, resulting in a sex ratio of 2.7 males per 1 nesting female. Every male genotype that I discovered only contributed to one nest over the three years samples, indicating there is a large number of males contributing to this nesting population.

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