Variation in Egg Components: A Study of Maternal Investment and Resource Partitioning in the Nesting Loggerhead Sea Turtle; Estimating Genic Variation and Mapping Genetic Lineage of a Rare Captive Helodermatid Population: Heloderma Horridum Charlesbogerti
Term of Award
Master of Science in Biology (M.S.)
Document Type and Release Option
Thesis (open access)
Department of Biology
David C. Rostal
Committee Member 1
Lance D. McBrayer
Committee Member 2
J. Scott Harrison
Committee Member 3
J. Scott Harrison
Loggerhead sea turtles have the highest egg yields of any oviparous non-avian reptiles. Blood urea nitrogen levels increased as the season progressed while total blood albumen and total protein levels decreased. Wet egg mass (H = 1.7719 df = 2 p = 0.0375*) and albumen mass (H = 6.0507 df = 2 p = 0.0485*) significantly decreased across the nesting season however, wet yolk did not. Analysis of dried egg components showed that dry yolk and albumen did not differ across the nesting season. In addition on no seasonal change in dried egg components, hatchling size was conserved across the nesting season. This study shows that maternal condition declined across the nesting season and this decline correlated with the decrease in egg size, specifically the amount of water allocated to eggs. Late season clutches were incubating at the same time that seasonal rainfall increased (r = -0.7251 df = 2, p = 0.0271*) and were compensated with water from increased rainfall. This study suggests that in loggerhead sea turtles, natural selection favors an optimal hatchling size rather than an optimal egg size.
Heloderma horridum charlesbogerti is the rarest recognized subspecies of H. horridum with approximately 200-250 individuals in the wild. Using five microsatellite markers, we found that the nine wild caught individuals, show very little genetic variation across the microsatellites used. In terms of effective population size, three wild caught females and three males are reproductively active. So far, three of the hatchings were produced by male A06107 and female A06110 in 2003, two were produced by male A06106 and female A06100 in 2006 at the San Diego Zoo. The final hatchling was produced by A06104 and A06105 in 2012 at Zoo Atlanta. Assessments of genetic markers used in this study show a high PID value 0.0792, suggesting a low specificity in terms of identifying individuals by genetic profiles therefore, more genetic markers must be developed to better identify these animals.
Patel, Ketan V., "Variation in Egg Components: A Study of Maternal Investment and Resource Partitioning in the Nesting Loggerhead Sea Turtle; Estimating Genic Variation and Mapping Genetic Lineage of a Rare Captive Helodermatid Population: Heloderma Horridum Charlesbogerti" (2013). Electronic Theses & Dissertations. 42.