Social Control over the Survival and Selection of Winged Virgin Queens in an Ant without Nuptial Flight: Iridomyrmex humilis

Abstract

AbstractLaboratory and field experiments show that the number of winged virgin queens of the Argentine ant Iridomyrmex humilis allowed to remain alive in the nest is under social control. When reared in their natal nest, survival of virgin queens depends on the presence of males. In the presence of mature alate males or even male pupae only 20% of the gynes are executed before they are 4 days old. By contrast, if pupal and adult males are absent, about 55% of the gynes are executed. The workers tend to kill the lightest ones. Although the Argentine ant is a unicolonial species exhibiting complete acceptance of foreign conspecific workers and mated queens, regardless of whether the recipient nest is queenright or queenless, the acceptance of gynes is variable: they are executed by foreign queenless workers but widely accepted in queenright nests. These results are discussed with regard to possible existence of queen and gyne pheromones allowing recognition and to the lack of nuptial flight in this species.