Colony and population genetic structure of the newly invasive white-footed ant (Technomyrmex difficilis) in the U.S.

Ants are some of the most successful invasive organisms in the world. The success of invasive ants may relate to their high plasticity in breeding structure (multiple queens) and colony organization (forming supercolonies). Technomyrmex difficilis (white-footed ant) is one such invasive ant thought to display these hallmark invasive characteristics (polygyny, unicoloniality), with colonies capable of reaching 3,000,000 individuals. Originating from Madagascar, this ant was first found in the U.S. in 1986 in Florida. More recently in 2019, an infestation was detected in Texas. These ants are prominent urban pests and are commonly found infesting manmade structures. Better knowledge of their colony and population structure may help IPM efforts to limit further expansion of this pest. Here, we combine behavioral and genetic data to clarify their colony structure in the invasive U.S. range. First, aggression assays were conducted between colonies in each state to test for supercoloniality. Interestingly, we found high aggression levels in the Florida population (6 collection points separated by at least 4 km) but low aggression levels in the Texas population (9 collection points separated by only 5 m). To complement the behavioral data, 10 microsatellite markers will also be used to investigate their population genetic structure in Florida and Texas. This study will inform us about the colony social organization and population genetic structure of the newly invasive difficult white-footed ant in the U.S..