Meeting Abstract

64.3  Friday, Jan. 6  Evolution of jaw-morphology and kinematics in ponerine trap-jaw ants SPAGNA, J.C.*; LARABEE, F.J.; SUAREZ, A.V.; William Paterson University; University of Illinois, Urbana-Champaign; University of Illinois, Urbana-Champaign

Trap-jaw ants in the genus Odontomachus and Anochetus are known for their oversized jaws that can be cocked and rapidly released in the form of devastating strikes on prey or enemies. In some species, these strikes have been co-opted for locomotion; by striking their jaws against hard surfaces, the ants can launch themselves many body-lengths into the air. Though trap-jaw morphology is polyphyletic, the subfamily Ponerinae includes both Odontomachus and Anochetus, covering a broad range of body size, morphological variation, and ecological variation. As a basis for comparative hypothesis-testing on these species, we developed a multi-gene molecular phylogeny for the ponerine ants. We sequenced the genes wingless, Cytochrome oxidase 1, long-wavelength rhodopsin, histone H3, 28S rDNA, and 18S rDNA from a total of 40 species (20 Odontomachus, 9 Anochetus, and 11 exemplars of potential ponerine outgroup genera) to produce the matrix, which was analyzed using partitioned Bayesian analysis. Ultra-high speed videography (50,000-120,000 frames per second) was used to estimate maximum angular jaw velocities for a subset of these species, which was used to model maximum jaw momentum during a strike. Mapping kinematic capabilities onto the phylogeny and performing comparative analyses demonstrated that kinematic variation is tied primarily to jaw and body size, and controlling for phylogenetic effects has a small influence when modeling jaw strikes based on animal size within each genus.