Ants are an expected, albeit unwelcome, guest at any summertime picnic, but how many of us are driving around, giving these unwanted hitchhikers a free ride?
A lot of us, it seems. Like Mara from New Jersey, for example-- whose been conscripted into providing transportation services to an entire colony of six-legged picnic crashers. (Got a few minutes while the boss is away? Take a listen to this classic Car Talk call right here.)
Then again, infestation is a judgment call. One person sees a pair of antennae waving in the refreshing breeze of the a/c vent and calls it an invasion, while another doesn’t bother to notice until s/he is being carried off to the mothership on hundreds of tiny-but-mighty shoulders.
Dr. Mike Merchant, professor and urban entomologist at Texas A&M, told me most ant species don’t nest inside automobiles (fire ants are the exception). The real estate market is all about location, location, location, and a car doesn’t offer the amenities an ant colony looks for when choosing a home.
A continuous influx of immigrants could mimic the appearance of a hostile takeover. It depends somewhat on the ant species involved. Carpenter ants are looking for rotting wood (generally pretty rare in most modern cars). Other species, particularly mound-builders, prefer to live in soil. Some can be found nesting behind the moldings, baseboards, countertops, etc. in a building, these locations tend to be stationary (although not always) and have a steady and handy supply of food and liquids. Not that one would never find something to eat and drink in a car, but it would have to be present when the new queen is looking to establish a colony. Worker ants find their way into some pretty surprising places as they forage but they'll return to the nest with whatever they find and then leave--they don't establish new outposts.
So if the caller is seeing ants in the car on a ongoing basis, and the car is being used regularly, it's highly likely the "invasion" has something to do with where the car is parked. The car may be parked in the shade beneath a carpenter ant nest, or in a garage with a colony in the rafters. As ants leave the nest to forage some will fall or crawl onto the car and find their way inside through an open window or a crack in the weather seals.
Reasoning that all animals need water, Tom and Ray suggested spraying the outside of the car with insecticide—when the ants leave to quench their thirst they go marching through a deadly chemical cocktail. Problem solved.
Not so fast, boys—Dr. Mike says ants get nearly all of the moisture they need from their food.
Ants are attracted to liquids, though, so in a roundabout way the guys were on the right track. Regardless of whether the ants are visiting or squatting, Dr. Mike suggests liquid ant bait placed inside the car. It probably won’t stop them from getting in but Mara and her husband are less likely to be bothered by them.
Car Talk Editor's Note: Ever seen an ant drink? After reading Dr. Kieran's take on this, we realized we never had. Thankfully, there's youtube. 13 seconds of this ant trying to get at the water will make you grateful that your cappuccino is served in a cup!