A gamergate (/ˈɡæmərˌɡeɪt/) is a mated worker ant that is able to reproduce sexually, i.e. lay fertilized eggs that will develop as females. Gamergates are restricted to taxa where the workers have a functional sperm reservoir ('spermatheca'). In various species, gamergates reproduce in addition to winged queens (usually upon the death of the original foundress), while in other species the queen caste has been completely replaced by gamergates. In gamergate species, all workers in a colony have similar reproductive potentials, but as a result of physical interactions, a dominance hierarchy is formed and only one or a few top-ranking workers can mate (usually with foreign males) and produce eggs. Subsequently however, aggression is no longer needed as gamergates secrete chemical signals that inform the other workers of their reproductive status in the colony.
Depending on the species, there can be one gamergate per colony (monogyny) or several gamergates (polygyny). Most gamergate species have colonies with a few hundred or fewer workers.
The term "gamergate" here is not "gamer-gate" but "gam-ergate" and derives from the Greek words γάμος (gámos) and ἐργάτης (ergátēs) and means "married worker". It was coined in 1983 by geneticist William L. Brown and was first used in scientific literature by entomologists Christian Peeters and Robin Crewe in a 1984 paper published in Naturwissenschaften. The definition typically found in entomological dictionaries is "mated, egg-laying worker", and is drawn from the glossary of Bert Hölldobler and E. O. Wilson's 1990 book, The Ants.
There are 100–200 different species in which gamergates reproduce (roughly 1% of all ants), most of which fall within the poneromorph subfamilies. Whereas workers (which are all females) in most ant species are morphologically incapable of storing sperm, in gamergate species one or several workers mate and have active ovaries. Gamergate lifespan is short compared to queens in queenright colonies, but gamergates can be replaced by other dominant workers in the colony without risking colony survival. Reproductive investment in gamergate females is thus optimized because non-differentiated gamergates (i.e. reproductively inactive workers) function as laborers.