Xenobiosis

Xenobiosis, also referred to as compound nests or guest ants, occurs when two species of ants live together in the same nest but keep their broods separate and they show minimal actual interaction with each other. Details of the relationship among the partners in a xenobiotic nest vary considerably. In some cases, the species involved are essentially equal partners with little indication of either species being a "guest" or a "host" (parabiosis and plesiobiosis). In other cases, the guest species form small colonies (up to a hundred individuals) in the nesting material or nest walls of the host and are normally much smaller than their host (cleptobiosis and lestobiosis). The guest maintains its nest well separated from the brood chambers of their host and they tend their own brood. They are dependent upon the hosts for nutrition and often shelter and some xenobiotic species may solicit regurgitated food directly from a host worker or participate in food exchange (trophallaxis) between two host workers.

The biology of Formicoxenus nitidulus provides natural history information about one representative guest ant.

Xenobiotic species generally fall into one of 4 subtypes:
 * Cleptobiosis: stealing food from other species; a mutual relation in which members of one species habitually steal food from another.
 * Lestobiosis: stealing brood; cleptobiosis in which covert thievery replaces aggressive plundering.
 * Parabiosis: sharing nests and trails.
 * Plesiobiosis: casual or regular nesting in close vicinity; casual association of two or more colonies.