Invasive ants have found a new way to spread across the globe

Sneaking aboard a minivan or clinging to the bumper of a delivery truck, small creatures like ants hitch rides on cars every day for long-distance trips across continents.

Tires roll through soil, doors brush against tree limbs, and before anyone notices, a living stowaway is on its way to a brand-new zip code.

Seeds, moth eggs, and even mosquitoes have taken advantage of this free transit, but ants may be the most surprising passengers of all.

Those trips can reshape local nature.

When a species lands far from its old haunts, it meets plants and animals that have never learned to handle its tricks. Some newcomers fizzle out, yet others spread fast and shove resident species aside.

Hitchhiking turns vehicles, built for human convenience, into silent partners in a biological shuffle that plays out across parking lots and interstates.

Ants invading by cars

After watching ants scurry onto car tires in Taipei, entomologist Scotty Yang, an assistant professor in Virginia Tech’s Department of Entomology, decided to document the behavior.

Between 2017 and 2023, he logged nine species hitching rides on everyday vehicles; seven were invasive in the places where they appeared. His notes mark the first systematic look at ants using personal cars as moving vans.

Seeds have hung on for rides of well over 200 miles, and the spongy moth is infamous for planting eggs on freight containers.

Tiger mosquitoes have been spotted inside cars cruising across Spain. Ants add another twist: whole colonies, queen included, can march up a tire and disappear under the chassis before the driver turns the key.

Citizen science on wheels

Yang’s project leaned on social-media posts from drivers around Taiwan who snapped photos of cars suddenly coated in ants.

“We saw social-media posts where people were devastated about finding their cars covered in ants,” Yang said. “Although we felt sorry for them, we wanted to examine whether these events had anything in common.”

Reports poured in about ghost ants, black cocoa ants, and several other species. Observers recorded the month, the weather, the type of car, how long it had been parked, and how many insects they counted.

Patterns emerged.

A successful trip required three conditions: the insects had to climb the vehicle’s surface, the colony needed to be in a restless foraging or nesting mood, and the chosen nook – often a wheel well – had to remain within their preferred temperature range.

When all three boxes were ticked, a family of ants could roll out like seasoned travelers.

Why invasive ants on cars matter

In a new neighborhood, invasive ants tangle with local species for every crumb and hiding place. Native insects often lose those fights, and the dominoes keep falling. Birds, reptiles, and small mammals that rely on the displaced insects go hungry.

Some ants act as bodyguards for plant-sucking pests that drip sugary honeydew, allowing the pests to damage crops longer than usual.

Urban life does not escape the trouble. Large colonies can swarm kitchens, chew insulation, or short-circuit traffic lights.

Farmers face yield losses when ants protect sap-sipping bugs in orchards and fields, while homeowners pay for repairs after surprising electrical outages.

Each unplanned trip in a car, then, is more than an odd anecdote; it is a potential spark for ecological and economic headaches that can stretch for years.

What the team learned

Of the 100 worst invasive species on the planet, five are ants, and two of those – the red imported fire ant and the Argentine ant – are already established in Virginia. Warmer winters over the past decade have let both inch farther north.

Yang warns that casual rides in pickup trucks and family SUVs could speed that push. Personal vehicles, once dismissed as biologically unimportant, might be handing these tough insects fresh territory one rest-area stop at a time.

Virginia’s experience serves as a cautionary note for the broader Eastern United States. If motorists keep arriving from infested zones without checking their fenders and cargo, colonies can pop up beyond their previous limits.

Yang hopes to launch a citizen-science network similar to the Taiwanese project so residents can flag outbreaks early, long before fire ants find a foothold in new counties.

Check your car for ants

Drivers can cut the odds of giving ants a lift. Parking away from overgrown curbs, brushing loose soil from tires, and rinsing wheel wells after off-road jaunts help deny the insects a foothold.

On long trips, a quick inspection during fuel stops catches roving workers before they settle in.

Communities can pitch in, too. Local extension offices may distribute identification cards, while schools host weekend “bug check” events in parking lots.

Early warnings from sharp-eyed citizens let pest managers respond before an ant metropolis takes root. Each small action, repeated by thousands of travelers, keeps one more invasive colony from racing down the highway.

The full study was published in the journal Ecological Entomology.

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