Distribution of Hybrid Imported Fire Ants (Hymenoptera: Formicidae) and Some Native Ant Species in Relation to Local Environmental Conditions and Interspecific Competition in Mississippi Forests

Abstract

Studies of interactions between imported fire ants and other ant species (Hymenoptera: Formicidae) have generally addressed populations in open areas where imported fire ant densities are highest. Forest habitats harbor a different assemblage of ant species and interactions between ant species in forests are occurring under different environmental conditions. We have asked three questions about the distribution of hybrid imported fire ants and native ant species in a Mississippi forest: 1) Is their distribution influenced primarily by interspecific competition or by local conditions? 2) Are the communities at locations with and without hybrid imported fire ants different? and 3) Which native ant species are using the same resources as hybrid imported fire ants? To answer these questions, ant species were collected at baits, along with the metrics for a set of local conditions, over a representative sample of forest habitats. Data were analyzed using permutation tests comparing the observed characteristics of the ant community to those expected by random processes. The community of ant species collected at baits was not structured competitively and their distribution was strongly associated with the distribution of local conditions. The assemblage of ant species was different at locations with hybrid imported fire ants from the assemblage at locations without them, but the two groups of locations were equal in richness when samples were standardized by rarefaction. Of the 28 species collected, 14 occurred with hybrid imported fire ants. One species, Aphaenogaster carolinensis Wheeler, was negatively associated, and another, Monomorium minimum (Buckley), was positively associated with hybrid imported fire ant occurrence.