A laboratory observation of nuptial flight and mating behaviour of the parasite ant Acromyrmex ameliae (Hymenoptera: Formicidae)

Abstract

Nuptial flight is a critical phase in the reproduction of most ant species. Here, we describe the nuptial flight and mating behaviour of Acromyrmex ameliae, a leaf-cutting ant social parasite. We observed a nuptial flight of this parasite in a parasitized colony of Acromyrmex subterraneus subterraneus – known as a host of the social parasite in nature – and we registered the initial and final times of copula as well as the time the male dispended attempting to mate. Mating flight occurred after the beginning of the light phase in the laboratory. Agitation of host workers preceded the nuptial flight, without aggression between host workers and sexuals. Alates were attracted to the light bulbs of the room and formed couples that dropped to the ground immediately after their formation. Copula lasted on the average 1.6 ± 0.6 min. During mating attempts, the male put his forelegs on the female's abdomen while she remained walking on the ground. Copula normally occurred when the female stopped or slowed her movement. No attempt at remating was observed. Dealate females were offered to colonies of Acromyrmex subterraneus molestans, a taxon not known as a host of the social parasite in nature, and were promptly accepted by these colonies. The sex ratio value (males:females) was 1:1.83, another factor suggesting that females mate with only one male.