Population Genetic Structure of the Crazy Ant, Paratrechina longicornis, in Biosphere 2
Emily A. Matthews1, Volker Witte2, James K. Wetterer3, and Michael A. D. Goodisman1. (1) Biology, Georgia Institute of Technology, Atlanta, GA 30332, (2) Biology, Ludwig-Maximilians-Universität München, Martinsried, Germany, (3) Biology, Florida Atlantic University, Jupiter, FL 33458
Invasive ants dramatically disturb both local ecosystems and human activities. The crazy ant, Paratrechina longicornis, is an invasive pest ant that has reached high densities in several localities around the world. We used genetic methods to understand the population and social structure of P. longicornis on both global and local scales. P. longicornis workers were sampled from 12 global sites located in the Caribbean islands, Pacific islands, and the United States, as well as from 18 sites all within the Biosphere 2 project in the United States. We developed DNA microsatellite markers to understand patterns of gene flow among workers collected from the sampled sites. The microsatellite markers displayed unusual banding patterns suggesting a recent genome duplication event. Regardless, 9 of the 12 microsatellite loci were variable. The island populations displayed significant genotypic differentiation and showed evidence for genetic isolation by distance. Our data also suggested a common source for the Florida and Fiji populations. Ants from within Biosphere 2 showed no significant genetic structure, which suggested a lack of colony structure consistent with supercoloniality. Overall, our results suggest that the ant P. longicornis forms supercolonies, as is the case with other invasive ants. In addition, the strong genetic differentiation among the global samples suggests that distinct populations were likely founded by small groups of ants. Further population analysis should yield additional insights into the methods by which invasive ants colonize new habitats.