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.
The trap-jaw mechanism in the dacetine ants Daceton armigerum and Strumigenys sp.
W Gronenberg; The trap-jaw mechanism in the dacetine ants Daceton armigerum and Strumigenys sp.. J Exp Biol 1 September 1996; 199 (9): 2021–2033. doi: https://doi.org/10.1242/jeb.199.9.2021
Download citation file:
Advertisement
Cited by
In the field: an interview with Harald Wolf
(update)-Conversation.jpg?versionId=3667)
In our new Conversation, Harald Wolf talks about his fieldwork experiences working with desert ants in Tunisia to understand their navigation.
Propose a new Workshop
-GSWorkshop.png?versionId=3667)
Our Workshops bring together leading experts and early-career researchers from a range of scientific backgrounds. Applications are now open to propose Workshops for 2024, one of which will be held in a Global South country.
Julian Dow steps down and John Terblanche joins the JEB team
-NewEditor.png?versionId=3667)
After 15 years with the journal, Julian Dow from University of Glasgow, UK, is stepping down as a Monitoring Editor. We wish Julian all the best for the future and welcome John Terblanche, Stellenbosch University, South Africa, who is joining the team. Julian talks about his long association with The Company of Biologists and the journal and John tells us about his life and career in this News article.
Ecotourism affecting iguana glucose tolerance
-Iguanas.jpg?versionId=3667)
Ecotourists feeding grapes on skewers to north Bahamian rock iguanas may be doing the reptiles more harm than good as the sugar charged diet is giving the animals high blood sugar.
Evolution of metabolic plasticity
-MetabolicPlasticity.png?versionId=3667)
In their Commentary, Frank Seebacher and Julian Beaman propose that metabolic plasticity originated in prebiotic protocells and that it was a pre-requisite for effective transfer of genetic material across generations – the hallmark of Darwinian evolution.