Trophallaxis is the transfer of food or other fluids among members of a community through mouth-to-mouth (stomodeal) or anus-to-mouth (proctodeal) feeding. It is most highly developed in social insects such as ants, termites and bees. The word was introduced by the entomologist William Morton Wheeler in 1918. The behaviour was used in the past to support theories on the origin of sociality in insects.
In ants, individual colony members store food in their crops and regularly exchange it with other colony members and larvae to form a sort of "communal stomach" for the colony. In termites and cockroaches, proctodeal trophallaxis is crucial for replacing the gut endosymbionts that is lost after every molt. This should not be confused with coprophagia. Some vertebrates such as birds also feed their young through trophallaxis.
Trophallaxis is also performed by members of the dog family. In the wild, a hunting dog will regurgitate food gorged while far from its lair in order to feed its puppies. These puppies lick the face of the adult in order to trigger trophallaxis. Domestic dogs are tame because of arrested development of their wild tendencies and will treat certain humans, in particular their owner, as lifelong 'parents'. Therefore, when a dog licks your face, it may be that he's manifesting a vestigial feeding instinct.
Trophallaxis serves as a means of communication, at least in bees and ants. In some species of ants, it may play a role in spreading the colony odour that identifies members.
trophallaxis in German: Trophallaxis
trophallaxis in Spanish: Trofalaxis
trophallaxis in French: Trophallaxie
trophallaxis in Lithuanian: Trofalaksis
trophallaxis in Polish: Trofalaksja
trophallaxis in Portuguese: Trofalaxia