Oviposition process of Solenopsis invicta (Hymenoptera: Formicidae) Queens

Abstract

The oviposition process of the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), is described as a succession of four events forming one egg-laying cycle. Each time an egg is laid, the vulva opens and the sting is fully extended. When the vulva closes, the egg is forced to the base of the sting, whereupon the sting is usually retracted across the egg. This phenomenon has been consistently observed for queens from monogynous and polygynous S. invicta colonies. Zero to four eggs can be laid for each opening of the vulva. Multiple egg deposition is more frequent for monogyne queens, and it generally follows an oviposition cycle in which no egg is laid. The egg-laying cycles were evenly distributed during the observation periods, regardless of the total number of eggs laid, thereby suggesting that oviposition is a continuous process in S. invicta.