This study quantified the foraging patterns of polygyne red imported fire ants Solenopsis invicta. Ants in colonies were mass-marked a unique color and sampled at olive oil-bait stations in a 10 x 10m grid (61 bait locations) in 10 field sites (n=610 baits total). Regression analyses show that the distance to food resources, colony size, and average internidal (between nest) spacing were good predictors of the degree and extent of foraging. Model predictions show that some foraging areas overlap, yet most of the marked ants (90%) foraged within approximately 4m of the colony. Chi-square analyses show that there was a significant difference between the observed foraging distribution of colonies on individual baits and the expected distribution calculated from the regression model. We developed a chi-square statistic to test whether the differences on baits were due to a single colonies ability to numerically dominate that bait to the exclusion or reduction of foragers from neighboring colonies. Results show that the presence of high numbers of ants on a bait from a given colony has a negative effect on the numbers of ants from neighboring colonies on that bait. Resource use by polygyne fire ants may be adaptive to an invasive life history, where food resources are quickly dominated and utilized efficiently among competing colonies of the same and native species. Interference competition among colonies may occur when ants from one colony arrive first at a food item and competitively exclude ants from another colony by recruiting many workers.
Species 1: Hymenoptera Formicidae Solenopsis invicta (red imported fire ant)
Keywords: foraging
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