Meeting Abstract
High speed power-amplification mechanisms have evolved independently in many groups of organisms across the tree of life, including multiple times in ants (Hymenoptera: Formicidae). “Trap-jaw” ants possess spring loaded mandibles that allow them to swiftly incapacitate or kill elusive prey. Trap-jaw ants have the potential to serve as model organisms for studies on the relationship between morphological and functional diversity and the evolution of power-amplification mechanisms, but to date the feasibility of these studies is limited by a lack of performance data for many groups of trap-jaw ants. Here we use high speed videography and micro-CT to describe the strike kinematics and functional morphology of Acanthognathus brevicornis, a trap-jaw ant from the neotropics that possesses a morphologically distinct trap-jaw mechanism. Acanthognathus brevicornis workers have enlarged basal processes on their highly elongated mandibles that interlock when the mandibles are opened, allowing elastic energy to be stored within the head capsule as the mandible closer muscles contract. A modified section of closer muscle rotates the mandible dorsally, disengaging the basal processes and releasing the mandibles. High speed videography revealed that A. brevicornis mandibles close in less than 0.08 ms, reaching an average maximum velocity of 30 m/s and an average maximum acceleration of 1.2e6 m/s2 over the course of a strike. Comparisons to other trap-jaw ant species revealed that A. brevicornis strikes conform to scaling relationships seen across trap-jaw ant groups. This study is the first to quantify the strike performance of Acanthognathus and is part of a larger project examining the biomechanics and evolution of power-amplified mandibles ants.
