If the weather is hot, ants may find your home an attractive spot to hunker down. But relax, there's not a lot you can do about it.
Those are the findings of a California study that confirms what homeowners have long suspected about ants.
But the study has two pieces of good news: The home invaders normally won't hurt anybody, and they'll eventually get homesick for the outdoors.
"When the weather changes, the ants leave," says lead study author Deborah M. Gordon, professor of biology at Stanford University.
Gordon, an expert in ant behavior, undertook the study to find out if ants head indoors when the weather turns hot and dry.
"People have certainly suspected, but we just couldn't find any data on it, so we decided to do this survey," she said.
Much of Northern Nevada is plagued by the Argentine ant, which was first introduced to the United States about a century ago.
The ants spread in imported sugar. Argentine ants are also common in other warm areas like Australia, the Mediterranean coastline, the coast of South Africa and Hawaii.
Ants seldom bite, aren't harmful to the house, and are just generally a pest. Unless the ant plague is interferring with dining or sleeping, just brush them into the wastebasket, unless you're Buddhist. But that's another problem.
There are plenty of ant sprays in the stores, but be careful using them around the house. Spray a stream of ants on a wall, and you've got to scrub it down with soap and water. You can use pesticides effectively on the perimeter of the house by dousing the ant hills, thus stopping any infestations.
Ants appear to be drawn by moisture in hot periods, and seek dryness and warmth during wet periods, Gordon said. Also, because ants eat almost anything, their search for food may bring them indoors. Nothing the people in her study did seemed to help, she said. Some used over-the-counter bug sprays and poisoned bait; others used homemade solutions made of strong substances like hot pepper, chili oil and vinegar. No one reported calling an exterminator, however.
"It's not a question of whether these things actually kill bugs on the spot. They all do," Gordon said. "The question is whether their use changes the amount of time that bugs are in the house." The answer, she said, is no. However, Gordon said other species of ants may act differently.
Due to their biology, some may be more interested in moisture, while others seek food, said Greg Baumann of the National Pest Management Association, an exterminator trade group.
"The industry would probably agree that they are one of the peskiest pests to get rid of." Only termites are as hard to eradicate, he said.
If ants do decide to move in, experts say you shouldn't get too alarmed. Unlike termites, they won't make your house fall down, and they probably won't spread germs either. "There's no evidence that these ants pose any health risk," Gordon said. "I don't like having ants on my kitchen counter either, but they're not dangerous. For the most part, people don't like them because they're icky."