Trap-Jaw Ants

Trap-jaws are highly modified, spring-loaded mandibles which snap shut with tremendous speed and power. They are primarily used for prey capture but in some species have a defensive defensive role. The jaws are commonly held in an open position and are released when trigger hairs, which extend forward from the anterior margin of the head capsule, encounter a prey item.

Larabee & Suarez (2014, Fig. 1): Representative trap-jaw ant species. (a) Two species illustrating the extremes of size variation among different line-ages: Odontomachus chelifer, in the subfamily Ponerinae, is one of the largest trap-jaw ant species, whereas Strumigenys sp., in the subfamily Myrmicinae, is one of the smallest. (b) Anochetus faurei. (c) Odontomachus latidens. (d) Myrmoteras iriodum. (e) Strumigenys rogeri. (f) Microdaceton sp. (g) Acanthognathus ocellatus. Images (b - g) © Alex Wild, used by permission.

Trap-jaws have evolved independently several times in ants and are found in the subfamilies and genera:

• Formicinae: Myrmoteras
• Myrmicinae: Acanthognathus, Daceton, Epopostruma, Microdaceton, Orectognathus, Strumigenys (many species)
• Ponerinae: Anochetus, Odontomachus

References

• Larabee, F.J., Gronenberg, W., Suarez, A.V., 2017. Performance, morphology and control of power-amplified mandibles in the trap-jaw ant Myrmoteras (Hymenoptera: Formicidae). Journal of Experimental Biology 220, 3062–3071 (DOI 10.1242/jeb.156513).
• Larabee, F.J., Smith, A.A., Suarez, A.V., 2018. Snap-jaw morphology is specialized for high-speed power amplification in the Dracula ant, Mystrium camillae. Royal Society Open Science 5, 181447 (DOI 10.1098/rsos.181447).
• Larabee, F.J., Suarez, A.V., 2014. The evolution and functional morphology of trap-jaw ants (Hymenoptera: Formicidae). Myrmecological News 20, 25–36.
• Liu, C., Sarnat, E.M., Friedman, N.R., Hita Garcia, F., Darwell, C., Booher, D., Kubota, Y., Mikheyev, A.S., Economo, E.P. 2020. Colonize, radiate, decline: Unraveling the dynamics of island community assembly with Fijian trap‐jaw ants. Evolution 74, 1082–1097 (doi:10.1111/EVO.13983).