The trap-jaw mechanism in the dacetine ants Daceton armigerum and Strumigenys sp.

Research output: Contribution to journalArticle

54 Citations (Scopus)

Abstract

Ants of three different subfamilies, among them the tribe Dacetini, have evolved very fast snapping mandibles called trap-jaws. The two dacetine genera examined, the large Daceton and the small Strumigenys, employ the same mechanism for their mandible strike. Video analysis reveals that, in Strumigenys sp., the strike takes less than 2.5 ms. It is released within 5 ms by contact of trigger hairs on the labrum. The ants employ a catapult mechanism to generate such a fast movement. Before the strike, the mandibles are opened wide and locked in the open position by the labrum, which functions as a latch. They stay open even when the large slow closer muscles contract. Upon trigger hair stimulation, the labrum is pulled backwards by a small, fast trigger muscle. The mandibles are thus freed from the catch and close rapidly. This reflex is controlled by giant sensory and motor neurones in the labral neuromere that are probably monosynaptically coupled. The short latency of the reflex thus results from the combination of a catapult mechanism, fast trigger muscles, high neuronal conduction velocities and small synaptic delays. Comparison with the trap-jaw mechanism of the ant genus Odontomachus reveals a remarkable example of convergent evolution.

Original languageEnglish (US)
Pages (from-to)2021-2033
Number of pages13
JournalJournal of Experimental Biology
Volume199
Issue number9
StatePublished - Sep 1996
Externally publishedYes

Fingerprint

mandible (bone)
Ants
Jaw
Mandible
jaws
ant
Formicidae
muscle
traps
hair
reflexes
Muscles
muscles
hairs
Reflex
convergent evolution
Odontomachus
sensory neurons
Motor Neurons
Sensory Receptor Cells

Keywords

  • ants
  • Daceton armigerum
  • reflex pathway
  • Strumigenys sp.
  • trap-jaw mechanism

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Agricultural and Biological Sciences (miscellaneous)

Cite this

The trap-jaw mechanism in the dacetine ants Daceton armigerum and Strumigenys sp. / Gronenberg, Wulfila.

In: Journal of Experimental Biology, Vol. 199, No. 9, 09.1996, p. 2021-2033.

Research output: Contribution to journalArticle

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