Autothysis

Autothysis (from the Greek roots autos- "self" and thysia "sacrifice") is the process where an animal destroys itself via an internal rupturing or explosion of an organ which ruptures the skin. The term was proposed by Maschwitz and Maschwitz in 1974 to describe the defensive mechanism of Camponotus saundersi, a species of carpenter ant. It is caused by a contraction of muscles around a large gland that leads to the breaking of the gland wall. Some termites (such as the soldiers of Globitermes sulphureus) release a sticky secretion by rupturing a gland near the skin of their neck, producing a tar effect in defense against ants. It is a form of suicidal altruism.

Groups of termite whose soldiers have been found to use autothysis to defend their colonies include: Serritermes serrifer, Dentispicotermes, Genuotermes and Orthognathotermes. Several species of the soldierless Apicotermitinae, for example those of the Grigiotermes and Ruptitermes genera, have workers that can also use autothysis. This is thought to be one of the most effective forms of defense that termites possess as the ruptured workers block the tunnels running into the nest and it causes a one-to-one exchange between attackers and defenders, meaning attacks have a high energy cost to predators.

The soldiers of the neotropical termite family Serritermitidae, have a defense strategy which involves front gland autothysis, with the body rupturing between the head and abdomen. When outside the nest they try to run away from attackers, and only use autothysis when in the nest, to block tunnels up, preventing attackers entering.

Old workers of Neocapritermes taracua develop blue spots on their abdomens that are filled with copper-containing proteins. These react with a secretion from the labial gland upon autothysis to form a mixture which is toxic to other termites.

Some ants belonging to the Camponotus genus have adapted to using autothysis as an altruistic defensive trait to better fight against arthropods and to possibly deter vertebrate predators for the benefit of the colony as a whole. These ants use autothysis as a self-destructive defense to protect their territory, but they use it differently from termites, in that their primary uses for autothysis do not include blocking the tunnels of their territory from attackers, but more so for combat purposes during territorial battles.

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