Specimen Showcase | Ants that Go SNAP! In the Woods

Hong Kong Biodiversity Museum
Mar 10
3 min read

Welcome back to the amazing world of ants 🐜! Many ant species around the world have independently evolved towards a particular type of ant predation in which mandibles can first open widely before closing at incredible speed onto their prey. These ants are all known as trap jaw ants, and while most are just a few millimetres long, others like the species of the genus 𝘖𝘥𝘰𝘯𝘵𝘰𝘮𝘢𝘤𝘩𝘶𝘴 (Latreille, 1804) can reach nearly 1 cm, and are found in all tropical and subtropical regions over the globe.

In the pictures here is the species 𝘖𝘥𝘰𝘯𝘵𝘰𝘮𝘢𝘤𝘩𝘶𝘴 𝘮𝘰𝘯𝘵𝘪𝘤𝘰𝘭𝘢 (Emery, 1892), one of the two species recorded in Hong Kong, where it can be found in forested habitats nesting on the forest floor, under leaf litter or within rotten logs. Most 𝘖𝘥𝘰𝘯𝘵𝘰𝘮𝘢𝘤𝘩𝘶𝘴 worker ants hunt alone, which is called solitary foraging, using their powerful mandibles (the ants’ ‘jaws’) to hunt prey such as termites.

Mandibles, which are jaw-like appendages at the front of the ant’s head, not only help ants hunt, but they can also be used to transport other colony members or even care for their young (here larvae)! Although all ants have these, the ones on trap-jaw ants are special – they are very long and have sharp teeth 🦷 on their extremities. Trap-jaw ants can open their mandibles to about 180° and close them extremely rapidly, generating large amounts of force. In 𝘖. 𝘮𝘰𝘯𝘵𝘪𝘤𝘰𝘭𝘢, closing takes only 0.16 ms—one of the fastest known movements in the animal kingdom 💨. To put it into perspective, that’s over 1,000 times faster than the blink of a human eye! The acceleration is so high that the mandibles of trap-jaw ants have evolved to be hollow and lightweight to limit their shock while closing, otherwise they would explode.

The amazing mandibles of trap-jaw ants actually have many different functions. Besides being a powerful weapon for capturing prey, the ants also use them to defend their nests against invaders, injuring or even flinging enemies far away with one strike 🥊! Even more remarkably, trap-jaw ants can strike their mandibles downwards against the ground, sending themselves flying upwards through the air 🤸. But why would they do this? It turns out that this behaviour helps them escape natural predators like antlions, which build unstable pits in the ground to trap and ambush the ants. In a blink of an eye (actually faster), the ant will disappear from this deadly trap.

Mandibles are not the only weapon of trap-jaw ants—they also capture prey using their venomous sting ☠️. Stinging is more frequently used by smaller 𝘖𝘥𝘰𝘯𝘵𝘰𝘮𝘢𝘤𝘩𝘶𝘴 species, or if they are dealing with larger prey items. It can also be used in defense though—so be sure to observe them from a safe distance in the wild, because as the director of the HKBM can attest, their sting is not a pleasant feeling! If you really want to look at these amazing ants up close, come visit the HKBM and in the meantime, have a look at this amazing video of trap jaw ants: https://www.youtube.com/watch?v=29kDUJVAUBU !