Necrophoresis

Necrophoresis is a behavior found in social insects – such as ants, bees, wasps, and termites – in which they carry the dead bodies of members of their colony from the nest or hive area.[1] This acts as a sanitary measure to prevent disease or infection from spreading throughout the colony. Although any member of a colony can carry the bodies, it is usually done by designated 'undertakers'. Ant undertakers have a slightly altered development cycle, and are much more likely than other ants to handle corpse removal. They are not restricted to performing only this task, but they do exhibit different behavioral and movement patterns than other members of the colony, which assist them in this task.[2] Non-undertaker ants may also remove dead bodies, but do so with much less consistency. Differentiating between dead and living insects is accomplished by detecting their chemical signature. Depending on the species, this can be communicated by either the absence of chemicals that are present when they are alive,[3] or by those released in decaying corpses. [4] Corpses will either be taken to a random point a certain distance away from the nest, or placed in a refuse pile closer to the nest, along with other waste.

A black garden ant (Lasius niger) engaging in necrophoresis

The removal of corpses carrying infectious disease is crucial to the health of a colony. Efforts to eliminate colonies of fire ants, for instance, include introducing pathogens into the population, but this has limited efficacy where the infected insects are quickly separated from the population. However, certain infections have been shown to delay the removal of dead bodies or alter where they are placed.[5] Although placing corpses farther away reduces the risk of infection, it also requires more energy. Burial and cannibalism are other recorded methods of corpse disposal among social insects. Termites have been shown to use burial when they cannot afford to devote workers to necrophoresis, especially when forming a new colony.[6]

Although in mature ant colonies only workers feature undertaking behaviours, the queen ants from the Lasius niger species undertake deceased co-founders.[7]