Will fire ants conquer The Bahamas?: The impact of habitat type on competitive interactions between alien fire ants and ant species assemblages on San Salvador, The Bahamas

Presented by Daniel Kjar and Zachory Park

Zachory Park and Daniel Kjar

The imported red fire ant (Solenopsis invicta) and the tropical fire ant (Solenopsis geminata) are both common, introduced ants throughout most tropical areas in the world. These ants appear to prefer disturbed habitats and frequently interact with humans. These ants are very aggressive, and will attack and sting any animal that disturbs their large nests. The presence of fire ants reduces populations of ground nesting birds, lizards, and mammals. They will also attack ground nesting bees, wasps, and other insects. Our studies on San Salvador Island, The Bahamas, examine the habitat preference and competitive interactions of fire ants with other native and introduced ant species. We observed ant interactions at 136 baits across two field seasons (June 2014 and June 2015) and in 3 different habitat types (Blackland, Palmetto, and plantations). We found 27 ant species at our baits across both years of this study. Across all habitats, 51% of ant visits observed at baits were not native species. The Blacklands had the highest number of native ant species and plantations had the lowest number of native species. Competitive interactions at the baits were relatively predictable within each habitat. When alien fire ants were present at baits they would dominate the bait with few exceptions. Many studies have demonstrated that both S. invicta and S. geminata prefer disturbed habitats and are not frequently found in native undisturbed habitats. We have observed this on San Salvador, however, the presence of fresh water may allow fire ants to move into and dominate habitats that are relatively undisturbed. Clearing of Blacklands may increase the pressure on native ant species from encroachment of alien fire ants.