Meeting Abstract

81.6  Wednesday, Jan. 6  Examination of Residual Yolk Utilization in Hatchling Smooth Softshell Turtles, Apalone mutica VAN DYKE, J/U*; BEAUPRE, S/J; PLUMMER, M/V; University of Arkansas; University of Arkansas; Harding University juvandy@uark.edu

Sufficient postnatal provisioning is presumed critical for survival before neonate animals successfully forage. While parents do not feed offspring in most lineages, nearly all lecithotrophic vertebrates retain a residual portion of yolk which was not used during embryogenesis. Hypothesized uses of residual yolk are diverse and include postnatal development, catabolic fuel for nest emergence, and nutritional sustenance for maintenance, activity, or hibernation. However, few studies have tested hypothetical uses of residual yolk and our understanding of consequences of different uses remains limited. We investigated the ability of unfed hatchling Smooth Softshell Turtles (Apalone mutica) to allocate residual yolk to postnatal growth, and determined whether residual yolk served as a significant energy source for nest emergence. We also tested whether yolk catabolism contributed to neonatal metabolic rate. Comparisons of growth trajectories between control and yolkectomized turtles were not significantly different. Both treatments exhibited 100% survival rates until residual yolk was absorbed in control turtles. Shell size and wet mass increased significantly after hatching in all treatments, but dry mass did not. Comparisons of crude protein and crude fat content between freshly laid egg yolk and residual yolk were not different. Metabolic rates of control and yolkectomized turtles were not significantly different. Nest emergence did not significantly reduce residual yolk dry mass. In summary, post-hatch growth in mass and shell size appear to be dependent on water uptake rather than residual yolk. Short-term survival was not dependent on residual yolk, and residual yolk did not fuel nest emergence activity. Our results suggest that residual yolk does not fulfill many of the hypothetical uses of postnatal provisioning in A. mutica.