NUPTIAL FLIGHT OF MYRMICARIA-OPACIVENTRIS (HYMENOPTERA, FORMICIDAE, MYRMICINAE)

We examined nuptial night in the ant Myrmicaria opaciventris. Swanning takes place after the first rains, or between March and April. Swanni ng occurs after a strong rain, between 8 a.m. and 11:30 a.m. Before fl ight, some females mate several times on the nest with several differe nt males. After flight, the males form a swarm around an open site whe re they fly at shrub level. They mate with females who cross the swarm . The structure of the male gaster, whose underside is concave, permit s it to be wed to the convex dorsal face of the female's gaster. It al so enables the male to move over the female, and to cling to her in a way which facilitates mating. The mating posture is described and the means by which males and females mate and several factors influencing their survival are discussed. Females coming from different nests can land at the same time in the same place. Those who do not take flight, return to their nests at the end of swarming, without being attacked. We observed the presence of inseminated alate females in the nest (6% ), leaving the nest (80%), and preparing to take flight (90%). An the females recorded at the landing site were inseminated. During swarming , a great number of females were captured by birds and ants, including nestmates. Sexuals who fell not far from their source nest or another nest (at a distance of less than 10 m), were drawn and quartered on s ite before being carried off.