APHIDS ALTER THE COMMUNITY-WIDE IMPACT OF FIRE ANTS

Abstract

Positive species interactions have the potential to strongly influence the structure and dynamics of ecological communities, yet surprisingly few studies have documented their general importance. We tested the hypothesis that the mutualistic association between fire ants and aphids enhances the impact of fire ants on the herbivorous and predaceous arthropod community of cotton. We found that the presence of aphids attracted foraging fire ants onto cotton plants. This shift from ground to foliar foraging resulted in more frequent interactions between fire ants and arthropods associated with cotton. The survival of herbivores (caterpillars) and predators (ladybird beetles and lacewings) was lower in the presence of fire ants and aphids compared with fire ants alone in greenhouse experiments. Similarly, fire ants and aphids deterred plant bugs from spending time on cotton foliage. Using large-scale field manipulations of fire ants along with naturally occurring aphid populations, we found that the ant–aphid ...