Positive association between densities of the red imported fire ant, Solenopsis invicta (Hymenoptera: Formicidae), and generalized ant and arthropod diversity


The invasive ant, Solenopsis invicta Buren, is a threat to native arthropod biodiversity. We compared areas with naturally varying densities of mostly monogyne S. invicta and examined the association of S. invicta density with three diversity variables: (1) the species richness of ants, (2) the species richness of non-ant arthropods, and (3) the abundance of non-S. invicta ants. Pitfall traps were used to quantify S. invicta density and the three diversity variables; measurement of mound areas provided a complementary measure of S. invicta density. We sampled 45 sites of similar habitat in north central Florida in both the spring and autumn of 2000. We used partial correlations to elucidate the association between S. invicta density and the three diversity variables, extracting the effects of temperature and humidity on foraging activity. Surprisingly, we found moderate positive correlations between S. invicta density and species richness of both ants and non-ant arthropods. Weaker, but usually positive, correlations were found between S. invicta density and the abundance of non-S. invicta ants. A total of 37 ant species, representing 16 genera, were found to coexist with S. invicta over the 45 sites. These results suggest that S. invicta densities as well as the diversities of other ants and arthropods are regulated by common factors (e.g., productivity). Many invaded communities may be more resistant to S. invicta than generally believed, or possess an unexpected resilience for recovery if S. invicta can be permanently suppressed.

Document Type





Arthropod diversity, Invasive species, Partial correlation, Solenopsis invicta

Publication Date


Journal Title

Environmental Entomology