An Australian scientist has discovered an unknown ant species with a particularly unexpected defense weapon. Colobopsis explodens does not hesitate to blow himself up after having trapped his enemy, to project on him a sticky toxic yellowish substance, likely to neutralize it. An extremely rare sacrificial behavior in ants.
Some ants are real kamikazes. Nicknamed “explosive ant”, Colobopsis explodens is indeed able to turn into a real animal bomb when it comes to defeating its enemies. An extraordinary combat strategy revealed during a study published in the journal ZooKeys. At the origin of this discovery, Alice Laciny, doctoral student at the Museum of Natural History in Vienna, responsible for the identification of this species with a particular warrior customs.
To defend themselves, some of these hymenoptera do not hesitate, in a way, to make a hara-kiri: they tear up their abdomen to spread on their enemy, previously trapped, a viscous and yellowish mixture, particularly toxic, and thus able to slow down their opponent enough, or even kill it for good. An extraordinary defense strategy, this secret weapon is very rare in ants, since no other species capable of “exploding” had been discovered since 1935.
It also seems to be reserved for social insects, such as termites or even bees. Flying insects with whom the explosive ants share the common characteristic. “It’s a bit the same mechanism when a bee stings,” says Alice Laciny, kind of like “suicide bombing” against the enemy.
Who explodes and who doesn’t also seems to be connected to the complex social hierarchy of the ants. In Colobopsis explodens, not all individuals are in the same boat. Only second-class workers are able to sacrifice for their community. This feature demonstrates the highly stratified organization of the anthills. “An ant colony should not be treated as a family of individuals, but really as a superorganism, and each ant acts more like a cell in a body and has its own role to play,” Alice Laciny explains.
For some workers, of higher rank, the role of defense turns out to be quite different. Thanks to their oversized head, the head workers ensure the protection of the anthill. “The entrance to their nest is a small hole, about the same diameter as the heads of the female workers,” reveals Alice Laciny. “So they just fix their heads in the hole and close it up, so that nothing can get inside. While simple workers are kamikazes, the chief workers are more passive defenders,” says Alice Laciny.
Other ant species also use this amazing morphological property to defend their nest. But this time, it’s against the elements that insects fight. The Australian ant Camponotus anderseni has a habit of building its nest on the beaches. A special situation that makes them very vulnerable to floods. “Their nests are flooded by the waves with each tidal cycle, so the nest of these ants is immersed for long periods every day. These ants thus block the entrances of the nest not to prevent their enemies from entering, but to prevent water from entering,” says Alan Anderson, an ant ecologist at Charles Darwin University, Australia.
According to scientists, such species could help to better understand the behavior of explosive ants, which seem to hold many secrets. The next discoveries on Colobopsis explodens are sure to be like a bomb.