Bigger Is better: feeding ecology of the giant crayfish in the genus Barbicambarus

The crayfish genus Barbicambarus is comprised of only two species. The genus differs from all other crayfish in possessing unique antennal morphology and in growing considerably larger in body size than most other North American species. Relatively little else is known about their natural history. This study aims to describe the feeding ecology of both B. cornutus and B. simmonsi through stable isotope analysis and gut contents. Individuals as well as other sympatric species were collected from two known sites from each species in the Southeastern United States. Tissues were analyzed for levels of δ15N and δ13C and values were used to calculate trophic position. Results show a consistent positive relationship between trophic position and body size in Barbicambarus species. An analysis of gut-contents also supports this trend. This possibly implies that these species are using their superior size to feed on higher trophic level items. Our data thus suggests a novel feeding behavior among crayfish.