Meeting Abstract

90.7  Thursday, Jan. 7  Mechanisms of bite force production and their relationship with diet in Neotropical leaf-nosed bats SANTANA, S.E.*; DUMONT, E.R.; DAVIS, J.L.; UMass Amherst; UMass Amherst; UMass Amherst ssantana@bio.umass.edu

In terms of cranial morphology and diet, Neotropical leaf-nosed bats (family Phyllostomidae) are one of the most diverse groups of mammals. This morphological diversity translates into variation in biting performance (bite force), which corresponds with some aspects of their dietary ecology. However, relatively little is known about the morphological determinants of bite force production among phyllostomids, and whether these determinants vary among dietary groups. Here we investigate morphological predictors of bite force across 25 species of phyllostomids that are commonly described as insectivores, frugivores, nectarivores, omnivores, and sanguivores. We built a 3D static bite force model based on cranial and muscle data from individual specimens whose bite force was measured in the field. We used the model to predict bite force during canine and molar biting, and to investigate variation among dietary groups. The predicted bite forces were significantly correlated with our in vivo bite force data, although r ² values were relatively low. Based on the relative contribution of the cranial muscles to the total moment about the temporomandibular joint (TMJ), species fall into groups that appear to reflect dietary hardness. The temporalis is the main contributor to rotation about the TMJ in all the bats we studied, but its relative contribution is highest within the group composed of durophagous frugivores and carnivores. In contrast, the medial pterygoid makes a greater relative contribution to rotation about the TMJ in bats that specialize in liquid diets (nectarivores and sanguivores). Our results suggest that variation in the morphology of phyllostomid skulls reflects mechanical specializations to variation in the physical properties of their diets.