Megalomyrmex adamsae

Uneasy relationship: a Mycetomoellerius fungus-growing ant (left) encounters a Megalomyrmex adamsae that is a parasite of her nest. Panama; captive colony at the University of Texas

Megalomyrmex adamsae & Mycetomoellerius

Ant nests present a rich concentration of resources for organisms that can get past the ants' defenses. Nests often contain parasites, and one of the more intriguing cases of parasitism in the new world tropics involves another ant species, the parasite Megalomyrmex adamsae (the smaller ant at center-left). These solenopsidine ants inhabit nests of fungus-growing attine ants and feed on the brood and gardens of their hosts. Panama; captive colony at the University of Texas

Megalomyrmex adamsae

Panama; captive colony at the University of Texas

Polyergus mexicanus

A dulotic colony of the slave-raiding ant Polyergus mexicanus and its host, the silver field ant Formica argentea. Sagehen Creek, California, USA

Polyergus mexicanus

Polyergus mexicanus nest. Note the presence of both host (black) and parasite (red) workers. Urbana, Illinois, USA

Polyergus mexicanus & Formica subsericea

At the entrance of a Polyergus mexicanus slave-raiding ant colony, a Formica subsericea worker carries excavated soil from the nest. The parasitic Polyergus workers do not perform those sorts of tasks. Urbana, Illinois, USA

Polyergus mexicanus

Polyergus mexicanus workers return from a successful raid with captured pupae of the host species, Formica subsericea. Urbana, Illinois, USA

Polyergus mexicanus

Polyergus mexicanus workers return from a successful raid with captured pupae of the host species, Formica subsericea. Urbana, Illinois, USA

Polyergus mexicanus

A queen Polyergus mexicanus with a host Formica argentea worker. Sagehen Creek, California, USA

Polyergus mexicanus

Polyergus mexicanus slave-raiding ant with its Formica argentea host. Notice the difference in mandible shape in the two species- the sharp tines in the slave-raider for carrying pilfered host brood, and the broad working mandibles in the host. Sagehen Creek, California, USA

Polyergus montivagus

Champaign, Illinois, USA

Polyergus lucidus

Formica incerta field ant (left) with a social parasite, the slave-raiding ant Polyergus lucidus. East Brooklyn, Illinois, USA

Polyergus montivagus

Polyergus montivagus. The sickle-shaped mandibles are used primarily for transporting host pupae, as these ants perform few, if any, other duties. Champaign, Illinois, USA

Polyergus mexicanus

A kidnapper ant carries a Formica field ant pupa. Champaign, Illinois, USA

Polyergus mexicanus

Champaign, Illinois, USA

Lasius claviger

Lasius (Acanthomyops) claviger is a nest-founding parasite. Following this young queen's mating flight, she will attempt to enter the nest of a Lasius species, kill the resident queen, and coopt the Lasius worker force to raise out her own offspring. South Bristol, New York, USA

Formica pergandei & Formica glacialis

Formica pergandei (red) is a social parasite that kidnaps brood from other ant species to use as labor. Here, guards from a target Formica glacialis colony put up a tough enough fight that the kidnappers failed to breach the nest. South Bristol, New York, USA.

Formica pergandei & Formica glacialis

Formica pergandei (red) is a social parasite that kidnaps brood from other ant species to use as labor. Here, guards from a target Formica glacialis colony put up a tough enough fight that the kidnappers failed to breach the nest. South Bristol, New York, USA.

Formica subintegra

Formica subintegra with a queen pupa they have stolen during an afternoon slave-raid. South Bristol, New York, USA

Formica gynocrates with Formica vinculans

A slave-raiding ant Formica gynocrates (right) with its host, Formica vinculans. Urbana, Illinois, USA.

Aphaenogaster tennesseensis

This parasitic queen has just penetrated a nest of her host species, Aphaenogaster rudis. She is highly attractive to her victims, who unknowingly tend her and begin raising her eggs as their own. The original host queen killed, this colony will gradually turn into a full nest of A. tennesseensis. Manhattan, Kansas, USA

Aphaenogaster tennesseensis

This parasitic Aphaenogaster tennesseensis queen has just penetrated a nest of her host species, Aphaenogaster rudis. She is highly attractive to her victims, who unknowingly tend her and begin raising her eggs as their own. The original host queen killed, this colony will gradually turn into a full nest of A. tennesseensis. Manhattan, Kansas, USA

Aphaenogaster tennesseensis

Socially parasitic ants are usually discernable by their relatively small queens, as ants that start new colonies by infiltrating existing nests do not need large body reserves. The queen of Aphaenogaster tennesseensis- a temporary nest-founding parasite of several other woodland Aphaenogaster- is scarcely larger than her own workers. Urbana, Illinois, USA

Aphaenogaster tennesseensis

Portrait of a social parasite, Aphaenogaster tennesseensis. Urbana, Illinois, USA

Dorymyrmex reginicula

Dorymyrmex reginicula (at left), a socially parasitic species, is harassed by a worker of its host Dorymyrmex elegans. Workers of the two species coexist in a single nest for a period after the parasite queen has assumed reproduction and before the last remaining host workers die off. The transition period is not entirely smooth, as evidenced by this aggressive interaction. Archbold Biological Station, Florida, USA