Meeting Abstract

102.5  Sunday, Jan. 6  Effects of scaling on bite force and suction index in the Eastern Hellbender (Cryptobranchus alleganiensis) LARGHI, N.P.*; DEBAN, S.M.; Univ. of South Florida, Tampa; Univ. of South Florida, Tampa nlarghi@gmail.com

In 1950, AV Hill developed a series of predictions on how animal movements should scale with body size. Since this pivotal paper, many studies have been published regarding animal locomotion and scaling, but few have focused on feeding mechanisms and scaling. The hellbender (Cryptobranchus alleganiensis), is a salamander that grows over a large range of body sizes (18-74 cm TL) making it an ideal organism for examining scaling effects. Morphology can be expected to change as an organism grows larger, and because morphology and performance are closely linked, this morphological change can result in a change in feeding ability. C. alleganiensis are primarily aquatic salamanders and utilize both suction feeding and biting behaviors while feeding. We hypothesized that bite force would increase with positive allometry due a to a possible dietary shift in diet during ontogeny in which larger Cryptobranchus favor crayfish, which are hard shelled and aggressive when confronted by a predator. Suction potential is hypothesized to scale with negative allometry because it would be advantageous for smaller animals to rely on suction due to consumption of smaller prey items and a lower absolute bite force. Preserved specimens (11.9-34.5 cm SVL) were used to investigate the effects of scaling on suction potential and bite force. Bite force was calculated by use of a 3D static equilibrium model and suction potential was calculated as suction index. Bite force scaled with positive allometry allowing the animals to bite relatively harder with increasing body size, yet suction index showed no effect of body size.