autothysis

Autothysis is a self-sacrificial defense mechanism observed in a few eusocial insects, most notably in certain ants. In this behavior, an individual agent ruptures its own body, typically the abdomen, to release its contents into or onto an attacker. The act effectively sacrifices the individual to protect the colony by creating a physical barrier, dispersing toxins, or delivering a sticky secretion that deterred predators.

In ants, the best-known example is the Camponotus saundersi, sometimes called the exploding ant. Soldiers perform autothysis by contracting muscles to rupture the gasters, expelling a viscous, glue-like secretion that can trap or discourage would-be predators. The rupture is fatal to the individual, but it can substantially reduce immediate threats to the nest and neighboring colony members. The exact chemical composition of the released substances can vary, and in some species the material includes toxins or irritants produced by specialized glands.

Autothysis is distinct from autotomy, another self-amputation strategy used by some animals to escape capture. In autothysis, the objective is to deter or incapacitate a competitor through the release of defensive contents, whereas autotomy generally provides an escape mechanism without a guaranteed threat to the pursuer. This behavior is relatively rare and often limited to specific species or life stages, reflecting a trade-off between individual mortality and colony-level survival.