Evolutionary co-option of trap-jaw ant mandible strikes: defensive interactions with antlions

Larabee, Fredrick

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https://hdl.handle.net/2142/29470 Copy

Description

Title

Evolutionary co-option of trap-jaw ant mandible strikes: defensive interactions with antlions

Author(s)

Larabee, Fredrick

Issue Date

2012-02-01T00:47:48Z

Director of Research (if dissertation) or Advisor (if thesis)

Suarez, Andrew V.

Department of Study

Entomology

Discipline

Entomology

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Trap-jaw Ants
• Evolutionary Co-Option
• Predator-Prey Interactions
• Predator Avoidance

Abstract

The co-option of existing traits for novel functions is fundamental to many theories of trait evolution, but relatively few studies have examined evolutionary co-option at a behavioral level. Trap-jaw ants in the genus Odontomachus have a rapid and powerful mandible snap that is used during predation to disable fast or dangerous prey. Previous research suggests that some trap-jaw species may have co-opted the high forces generated by the mandibles for escape: in threatening situations ants direct their strikes against the substrate and launch themselves into the air. Until now, no actual predators or competitors have been found in the field against which trap-jaw use their “escape jumps.” Here, I examine the use of mandible snapping behavior in two trap-jaw species (Odontomachus brunneus and Odontomachus relictus) during their interactions with predatory antlions in the genus Myrmeleon. Using behavioral observations, high-speed videography, and traditional bioassays, I describe how trap-jaw ants can use their mandible strikes to escape from antlion pits. Interestingly, while both species use the mandible snap for predation, only O. brunneus use the mandible snap to escape from antlion pits. A comparison of the kinematic properties of mandible strikes suggests that differences in force generation might contribute to the behavioral differences between these species. Taken together, my results indicate that trap-jaw mandible snaps can be used to escape from natural predators, lending support to the idea that this predatory behavior has been evolutionarily co-opted for anti-predator defense.

Graduation Semester

2011-12

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http://hdl.handle.net/2142/29470

Copyright and License Information

Copyright 2011 Fredrick Larabee

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