Meeting Abstract

P3-37   -   Skull Shape Divergence Across Three Species of Louisiana Bats with Similar Diets Sheehy, ET*; Rummel, AD; Schachner, ER; Hedrick, BP; Tulane University, New Orleans LA; Brown University, Providence RI; LSUHSC, New Orleans LA; LSUHSC, New Orleans LA erinsheehy405@gmail.com

Resource partitioning is an evolutionary process that partly defines community structure and regulates the co-existence of species that live in sympatry. We conducted geometric morphometric shape analyses comparing the crania and mandibles of three vespertilionid bats in Louisiana, Lasiurus borealis, L. seminolus, and Nycticeius humeralis. These species live in sympatry and are known to have ecologically similar diets. Given recent work demonstrating that bat species commonly specialize in a single diet and perform resource partitioning when in sympatry with other insectivorous bats, we examined whether potential dietary divergence among these three species impacted skull morphology, both intra- and interspecifically. For our intraspecific analyses, we found significant sexual size dimorphism in all species, with females being the larger sex. Sexual shape dimorphism was not a large component of shape variation. In our interspecific analyses, we observed considerable overlap in the skull shape of two species (L. borealis and L. seminolus) in all configurations. In contrast, N. humeralis cranial configurations were entirely distinct in shape from the other two species, although mandible shape separation was observed to be less distinct among the three species. This may be an example of many-to-one mapping where there are multiple solutions (e.g., different skull shape configurations) that evolve to solve the same problem (e.g., eating similar diets). However, given the similarity between the two Lasiurus species, it is likely there is also a strong phylogenetic component to this and thus drift may be leading to shape divergence rather than selection for different prey items indicative of resource partitioning. This work is a step towards improved understanding of the degree of inter- and intraspecific morphological variation of bats that live in sympatry in the southeastern United States.