Jaws that snap: Control of mandible movements in the ant Mystrium

Wulfila Gronenberg, Bert Hölldobler, Gary D. Alpert

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


Ants of the genus Mystrium employ a peculiar snap-jaw mechanism in which the closed mandibles cross over to deliver a stunning blow to an adversary within about 0.5 ms. The mandible snapping is preceded by antennation and antennal withdrawal. The strike is initiated by contact of the adversary with mechanosensory hairs at the side of the mandible, and is powered by large yet slow closer muscles whose energy is stored by a catapult mechanism. Recording of closer muscle activity indicates that the mandibles are not triggered by any fast muscle. Instead, we suppose that activity differences between the left and right mandible muscles imbalance a pivot at the mandible tip and release the strike. The likelihood for the strike to occur can be modulated by an alarm pheromone. The presence of specialized sensilla and for a complex muscle receptor organ shows that the mandibles are also adapted to functions other than snapping and suggests that the force of the mandible can be finely adjusted for other tasks.

Original languageEnglish (US)
Pages (from-to)241-253
Number of pages13
JournalJournal of insect physiology
Issue number3-4
StatePublished - Mar 1998
Externally publishedYes


  • Fast movements
  • Functional morphology
  • Insect mechanoreceptors
  • Motor control

ASJC Scopus subject areas

  • Physiology
  • Insect Science


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