Entomologists are claiming they have discovered a new species of so-called ‘exploding ant’ living in the remote rainforests of Borneo, Thailand, and Malaysia. When their colony is threatened by an intruder, minor workers of the new species — named Colobopsis explodens — can tear their own body apart, in order to release toxins and either kill or repel the enemy. Colobopsis explodens is described in a paper published online April 19 in the journal ZooKeys. Watch this video to see the behavior of exploding ants in various settings.
Major worker of Colobopsis explodens with characteristically enlarged head. Image credit: Heinz Wiesbauer.
“Amongst the countless fascinating plants and animals inhabiting the tropical rainforests of Southeast Asia, there are the spectacular ‘exploding ants,’ a group of arboreal, canopy dwelling ants nicknamed for their unique defensive behavior,” explained lead author Dr. Alice Laciny of the Natural History Museum Vienna, Austria, and colleagues.
“When threatened by other insects, minor workers can actively rupture their body wall. Apart from leading to the ants’ imminent death, the ‘explosion’ releases a sticky, toxic liquid from their enlarged glands, in order to either kill or hold off the enemy.”
These ants were first recorded exploding in 1916, but no new species had been described since 1935, due to insufficient evidence.
Instead, entomologists used to simply refer to them as the members of the Colobopsis cylindrica group.
That was until Dr. Laciny and co-authors came together led by their shared fascination with these insects and their extraordinary mechanism of self-sacrifice (also called autothysis) in 2014.
Minor worker of Colobopsis explodens with posterior body raised in a defensive pose. Image credit: Alexey Kopchinskiy.
Colobopsis explodens has been picked as the model species of the group, after the researchers deemed it to be ‘particularly prone to self-sacrifice when threatened by enemy arthropods, as well as intruding scientists.’
“While minor workers of Colobopsis explodens exhibit the ability to ‘explode,’ the other castes have specialties of their own,” Dr. Laciny and colleagues said.
“For example, major workers — also called ‘doorkeepers’ — have big, plug-shaped heads used to physically barricade the nest entrances against intruders.”
“During a sampling trip to Brunei in 2015, we even managed to observe queens and males on a mating flight. We sampled the first males of these ants ever to be seen.”
“We also recorded the ants’ activity schedule and conducted the first experiments on food preferences and exploding behavior.”
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A. Laciny et al. 2018. Colobopsis explodens sp. n., model species for studies on ‘exploding ants’ (Hymenoptera, Formicidae), with biological notes and first illustrations of males of the Colobopsis cylindrica group. ZooKeys 751: 1-40; doi: 10.3897/zookeys.751.22661
