Red imported fire ant impact on native ants and litter removal in the post oak savannah of central Texas

Abstract

I examined the impacts of the invasive red imported fire ant (RIFA, Solenopsis invicta) on native ants (Monomorium minimum, Paratrechina sp., S. krockowi, Pheidole metallescens, Forelius pruinosus, and Camponotus americanus) and litter removal in a post oak savannah community in central Texas. The study site was divided into 3 adjacent areas, and ant-toxic bait was used, along with additional colonies of RIFA, to establish 3 different densities of RIFA (naturally occurring, low, and high). I surveyed the ants in the 3 density areas and calculated the catch per unit effort for each species. Litter baits were placed in the 3 density areas for 14 12-hour trials. The masses of the litter removed were measured, and means were calculated for each speciesdensity/ trial/date/period/bait combination. The average amounts of litter removed by RIFA and native ant were different in the 3 density areas (0.42 g, 0.0 g, and 0.75 g for RIFA in the natural RIFA density area, low RIFA density area, and high RIFA density area, respectively; 0.0 g, 0.16 g, and 0.15 g for native ants in the natural RIFA density area, low RIFA density area, and high RIFA density area, respectively), indicating that RIFA does have an effect on native ant habitat use.