Evidence of a Dietary Shift in Female Barbour's Map Turtle (Graptemys barbouri) to Exploit an Exotic Mollusk

Abstract

Barbour's map turtle (Graptemys barbouri) is the species of map turtle with the highest degree of sexual dimorphism, with females attaining larger body sizes and having much greater head widths than males. Accordingly, females and males also feed on different riverine prey, with females historically feeding on native gastropods and bivalves and males predominantly feeding on soft-bodied macroinvertebrates. Here, we report on a diet shift in female Barbour's map turtle from native prey to an invasive mollusk, the Asian clam (Corbicula fluminea), in southwestern Georgia.