Rain Has Ants on the Move; People Are Crying Uncle
Go to the ant, you sluggard! Consider her ways and be wise.
-- Proverbs 6:6
SACRAMENTO -- They’ve earned a bit part in the Bible, been a hit in Hollywood sci-fi flicks and starred in contemporary computer-generated cartoons. But in the real world, theirs is a humble life, free of fanfare -- until they arrive uninvited in a sugar bowl near you.
Ants are on the march again all over the Golden State, and it’s the weather that made them do it.
With a wet October followed by a frosty November, nature’s workaholics have been showing up early and often, swarming kitchen counters, cupboards, even the toasty innards of a few computers.
“I’m starting to believe Merced is the center of the ant universe,” said Ken Gosting, fresh from repeated jousts with interloping ants in the Central Valley city. “It’s like a chapter of ‘War and Peace.’ But mostly it’s been a lot of war and not much peace.”
The likely culprit, scientists say, is a transplant from far south of the border, the Argentine ant.
Known as Linepithema humile to the entomologically astute, the Argentines arrived surreptitiously a century ago, hitching a ride on coffee and sugar shipments from South America. They landed initially in New Orleans in 1891, as far as scientists can tell, and hit California maybe a decade later.
Ever since, the species has behaved like a Midwest tourist who arrives for the Rose Bowl and never goes home.
Argentine ants blanketed California, crowding out their native cousins and putting pressure on all sorts of other critters, from horned toads on the coast to a few varieties of ground-nesting songbirds.
And, of course, on us.
The state’s native ant population has always been adept at bedeviling human households, but Argentine ants appear to be better bugs. They evolved over the ages to survive on the banks of rivers. When big waters start to flow, they sound a retreat and head for higher ground.
In civilization, that means finding a cozy spot in an insulated wall when the rain and cold hit outside.
“We had quite the early rainfall this year,” noted Philip Ward, a UC Davis professor of entomology. “I think that instigated a movement.”
Mike Pechner, owner of Golden West Meteorology, said October saw many spots in the state hit by triple the normal rainfall. November then turned cold, he said, with Los Angeles more than 5 degrees below normal for the month, while Sacramento and Fresno were 3 degrees cooler.
“It’s a no-brainer why the ants seem on the move early this year,” Pechner said. “You freeze them out or rain them out, and they come inside.”
In case anyone doubted that correlation, Stanford scientists documented it a few years back. A study of 69 households in the heart of Silicon Valley found that cold and wet weather sent the ants inside.
The flip side occurs in summer. Like us, ants scurry inside for cool air and water during heat waves.
And, experts add, there’s little we can do about it.
“Like anyone else, I don’t like ants on the kitchen counter,” said Deborah Gordon, a Stanford ecology professor and ant expert. But pouring pesticides on them doesn’t accomplish much more than a quick fix, she said. “I prefer just wiping down their trails with Windex.”
Hot pepper powder. Chili oil. Lemon extract. Bleach and ammonia and Formula 409. Plugging their holes with silly putty. Let us count the home remedies folks deploy in the battle with the ant.
Marsh Pitman of Merced fought back by mixing a home remedy of boric acid and sugar in a plastic water bottle. The ants grabbed the mix and returned to the nest with what amounted to an entomological dirty bomb. When the cat’s water bowl was overrun, Pitman turned to an old standby: creating a moat by putting the dish in a pie tin filled with soapy water.
Despite the sugar bowl assaults, ants go inside primarily because of the weather, scientists say. That empty Pepsi can they’re swarming on your kitchen counter? It’s a mere side dish of our hospitality.
For the ant-infested who reach their limit, there are the traditional standbys, including pesticide spray and ant-bait traps.
“I’ve tried everything on the market,” said Vaunita Meehan, a neighbor of Pitman’s who recently woke up from a nap to find ants crawling over her arm. “I’ve tried everything, but they keep coming. Sometimes I feel like I’ll drive down my street and see them moving my house over.”
Nearby, retired airline executive Jim Newhoff found ants cascading out of a tiny old nail hole in the bathroom drywall. He bathed them with insecticide, then plugged the hole with some instant-dry glue.
Now he looks at it philosophically. Humans might think they rule the Earth, but when it comes to ants, they may be sadly mistaken.
“We share this environment, but I believe they should stay outside,” Newhoff concluded. “They don’t agree. They get what they want.”
Gordon of Stanford University said the Argentine ant appears to be more persistent than native ants about seeking refuge inside houses. And they work longer hours. They’re also more opportunistic in foraging for food.
To top it off, the nests of Argentine ants feature multiple queens, making it tougher to eliminate the colony by killing off a single top gal with a crown.
The tough-team reputation was burnished by headlines in 2000, when scientists from UC San Diego announced a startling theory that harked back to those old sci-fi flicks.
California, they said, had been seized by one big “super colony” of genetically similar eighth-inch invaders, the presumed progeny of the ones that arrived in the U.S. a century ago.
The genetic similarities, the scientists concluded, were the reason the California brand of ants behaved in a very uncharacteristic way. Most ant colonies are bitter enemies. Even ants of the same species tend to rip one another apart if they come from different nests.
Argentine ants, however, seem to cooperate in California as if they were from one big happy family, the UC San Diego scientists found. With fewer wars among themselves, they’ve more readily spread up and down the state.
But a new study released this year by Gordon and other Stanford biologists has raised doubts about the super colony theory. They say the Argentines here are less genetically similar than originally believed. Looking at ants in a biological preserve astride Stanford’s linear accelerator, a two-mile-long atom smasher, Gordon and company found divergent genes among colonies just 300 feet apart.
Gordon said it may be diet and smell, more than genes, that prompt the California cooperation. What they eat determines how ants smell, and it is smell that most scientists believe triggers aggression among colonies. Switching diet among happy nest mates, a North Carolina State University study found, turned them into nasty combatants.
Gordon suspects that the California bunch of Argentine ants may simply not give a whiff about small differences in smell between colonies.
On the battlefront, Gosting, one of the Merced homeowners, applauds the science but would prefer a foolproof answer.
He recently stood dumbstruck while watering a garden planter. The home’s stucco wall turned black with ants scurrying to escape the torrent. Think of Tippi Hedren and “The Birds” in miniature.
Gosting, an ecologist at heart, said his indoor encounters with ants have caused him to dump old philosophical beliefs. He now readily considers pesticides he once resisted. The sight of ant carcasses gives him a feeling of success.
“Let’s make their life more miserable for what they’ve done to us,” he said, only half in jest.
But one good thing has come of his ant experiences, Gosting said. “At least you don’t have to go to the Sierra to see nature. Just look in your sink.”