'Exploding Ants' From Borneo Sacrifice Their Own Bodies For Their Colony

These insects are 'particularly prone to self-sacrifice.'

In order to ensure their survival, the Earth’s species have evolved sticky, prickly, and dangerous defense mechanisms. A rose has thorns, psilocybin mushrooms spew psychedelic compounds, and porcupine fish inflate, all of them tied together in their efforts to avoid being consumed. On Thursday, scientists announced that they discovered a new creature that’s an expert in defense: an exploding ant aptly called Colobopsis explodens.

Discovered in the high rainforest canopy of Borneo, an island in Southeast Asia, the C. explodens belongs to the species called Colobopsis cylindrica. Exploding ants were first recognized by scientists in 1916, but no new species have been formally described since 1935. The newly discovered are just one of the 15 separate species of exploding ants recently found by an international and interdisciplinary research team, and they’re the first within this group to be formally described in a journal. The scientists published their findings on Thursday in the open-access journal ZooKeys.

C. explodens was previously nicknamed “Yellow Goo” — for reasons you’ll see demonstrated below.

The defense mechanisms of this exploding ant aren’t really meant to defend the individual; rather, they’re to defend the colony. “[As] impressive and effective as the detonation is in killing its predators, it is ultimately a suicide defense, for it also explodes the ant’s whole body which ultimately leads to its own demise,” the researchers write.

Essentially, minor workers within this ant group — which are all sterile females — actively and purposefully rupture their body wall when they’re threatened by other insects. They literally tear their own body apart by flexing their abdomens, carefully angling their backsides toward their attacker to let rip a bright yellow gland secretion. If all goes to plan, the sticky and toxic liquid overwhelms the other bug, and the ant has made a sacrifice that protects its colony.

Minor worker of *C. explodens* with its posterior body raised in a defense mode.

Alexey Kopchinskiy

The scientists write that C. explodens is the model species within the group of exploding ants they encountered, explaining that they are “particularly prone to self-sacrifice when threatened by enemy arthropods, as well as intruding researchers.” Co-author and entomologist Alice Laciny, Ph.D., told The Guardian on Friday that her own experiences with the ants gave her the impression that the goo has “a distinct and not unpleasant smell that’s strangely reminiscent of curry.”

These altruistic ants are not alone in the animal kingdom. Other creatures perform suicidal self-sacrifice as well. For example, pea aphids will explode themselves in an effort to scare off predators, some times doing so in the very moment after they’re consumed. A species of termites found in French Guiana are also prone to explosion; throughout their lives, worker termites grow a sac of toxic blue liquid on their backs and, when invading termites attack, the oldest termites in the group will rupture their body walls and release the chemical towards the invaders.

This weird, suicidal behavior is called autothysis, and the researchers behind this new ant study says their plan is to continue to study the phenomenon in other exploding ants — many of which they say they expect to describe in the near future.

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