Fredrick Larabee

Department of Entomology, University of Illinois, Urbana-Champaign

My general research interests are centered on comparative physiology and behavioral ecology of insects. Currently, my research focuses on the structure–function relationships involved in the rapid mandible strike of trap-jaw ants and the evolutionary cooption of their predatory strike for defense.

Trap-jaw ants are specialized predators that have elongated mandibles that snap shut at incredibly high speeds. The mandible strike of ants in the genus Odontomachus, for example, are some of the fastest animal movements ever recorded and generate forces over 400 times the ant's body mass. These strikes allow trap-jaw ants to adeptly capture fast or dangerous prey, but also allow some species to use ballistic jaw propulsion to escape dangerous situations. Odontomachus ants can orient their mandibles against the ground and launch themselves many centimeters into the air. Even more remarkable, the trap-jaw mechanism has independently evolved at least four times in the subfamilies Ponerinae, Formicinae, Myrmicinae, and Amblyoponinae.

For my dissertation research, I am examining the morphological and material adaptations that allow trap-jaw mandibles to maintain their structural integrity during a strike. I am also measuring the variation in strike performance (velocity, acceleration, and force) within and between species of trap-jaw ants to explore how these high-performance behaviors have evolved.

The other half of my research is focused on trap-jaw ants' use of ballistic jaw propulsion in the field during defensive interactions. I am currently identifying potential competitors and predators against which trap-jaw ants use this behavior and characterizing these interactions. I am also interested in surveying the prevalence of the escape jump behavior among the Ponerine genera of trap-jaw ants to learn how this complex behavior has been evolutionarily coopted.

<odontomachus brunneus>

Odontmachus brunneus Photo by Alex Wild

trap jaw ants

Trap-jaw ants Photos from