Impact of temperature and season on ant foraging activity of two invasive species in a Mediterranean urban area

Abstract

Invasive species often have harmful effects on human activities and biodiversity. The Tapinoma nigerrimum complex includes three species that exhibit invasive traits and the ability to form supercolonies, including Tapinoma magnum and Tapinoma darioi. While these species are native to the Mediterranean basin, they have recently been reported as invasive in more northern regions of Europe. However, T. magnum and T. darioi show different invasion patterns in Europe, suggesting differences in thermal preferences between these species. We aimed to determine whether there was any difference in activity pattern depending on temperature or season between the two Tapinoma species and between Tapinoma and co‐occurring native Mediterranean ants. We measured ambient temperature and ant foraging activity around the nest entrances of T. darioi and T. magnum in urbanised sites around Montpellier, southern France, over almost 1 year. We did not detect differences in activity between the two species according to temperature, but T. magnum was more active than T. darioi in winter. Compared to the co‐occurring native species, the two Tapinoma species were more active at low temperatures and earlier in the year. These results suggest that the difference in invasion success between T. magnum and T. darioi may not be explained by temperature preference. The difference in activity between native Mediterranean species and invasive Tapinoma suggests a coexistence through niche partitioning. In addition, our results suggest that control measures against invasive Tapinoma species would be more effective if applied at the end of winter.