The study revealed 52 cases of “active ant hitchhiking,” the researchers wrote, with ants making their way into cars’ interiors and even engines. Researchers counted nine species overall, seven of which were invasive. Reports grew during warmer months and dropped off during colder months. Cars parked near trees were particularly likely to attract ants, the researchers found, probably due to ants’ ability to climb onto the cars using hanging tree branches and leaves.

The successful invaders may have something in common, the researchers speculate: heat tolerance that allows them to withstand the high temperatures inside closed passenger vehicles and on painted surfaces. Tree-dwelling ants are likelier to successfully hitch rides than ground-dwellers, the researchers surmise, because the same features that allow them to climb trees make them better able to cling to the slippery paint on cars.

Now that scientists know ants can hitch rides on private vehicles, too, they can use the discovery to further study how invasive species expand their habitats. The researchers call for more surveillance efforts and the development of a framework for predicting ant behavior in an attempt to better manage ant invasions.