The ants go marching Resist the invasion even if the war is lost

Chris Clarke / Contra Costa Times 27jan01

IT'S A COLD WARRIOR'S worst nightmare. You think you're safe in your home, with your double deadbolt locks and security system and gated drive, but the invasion may have begun even as you read this. A highly disciplined army slips past the perimeter, invisible to motion sensors and security guards, and establishes a beachhead. Soon, they're everywhere: eating your food, drinking your water, despoiling your garden, harassing your family.

And worse, it isn't even you they're after. You're just in their way. Their objective: world domination, territorial conquest in the service of their despotic ruler.

Fortunately, they're only an eighth of an inch long.

Still, ants are a significant annoyance to many Californians. Of all household insect pests, only cockroaches and termites prompt more panicked calls to exterminators.

More than 200 species of ants live in California. Most of these are relatively inoffensive, wild species content to live peaceably within a small territory. There, they perform vital ecological services such as aerating the soil and eating other insects. These ants are unlikely to invade your home, and if they do, are easily controlled.

But a few aggressive species, imported from outside the state, give our native ants a bad name.

The fire ant is the best-known of these, with its giant size and large hills and incredibly painful bites. So far, fire ants haven't made it much past the Tehachapis, and the state is embarked on an aggressive eradication campaign. With any luck, the ant world's answer to the killer bee won't ever grace the Bay Area.

However, another pesky exotic ant -- Linepithema humile, the Argentine ant -- is here to stay. If you're currently battling columns of little black ants -- which seem to find every possible entrance to your home -- in your sink, pantry or shower, you're probably dealing with Argentines.

Given their teeny stature, you might be surprised to find out that Argentine ants are one of the most destructive exotic insects ever introduced to California. Medflies and sharpshooters get the front-page coverage, but few insects can match Linepithema's rap sheet. They've even fought fire ants and won.

Part of the reason lies in the Argentine ant's reproductive strategy.

Ant colonies usually reproduce when an existing colony produces an extra queen, who gathers a retinue of males and heads off to found her own colony. If ants from the resulting colony stray into their mother colony's territory, conflict usually results.

Argentine ants, however, have a strategy the entomologists call "unicolonialism," in which such related colonies function as one big happy family. In time, the result can be a very broad swath of territory -- miles -- with what is in effect one horrendously large ant colony on it.

Freed from having to fight each other, Argentine ants can turn their energy to fighting other ants -- you'll find virtually no native ants in an area colonized by Argentines -- eating and breeding. Thus they become a nuisance, in the home and outside it as well.

It's unlikely that Argentines will do much damage in your home. They may get into your sugar bowl, or put mealy bugs on your ficus tree, but they won't eat your siding. They'll bite you, but you'll never know it unless you stick one up your nose. Still, they're an annoyance, and don't we have enough annoyances already? And when the weather hits what passes for extremes here in the Bay Area -- too hot and dry, or too cold and rainy -- they can fill your home like special effects in a science-fiction movie.

And forget about spraying your whole yard with chemicals, despite the blandishments of the Orkin man. If you kill all the ants within your property lines with pesticides, your neighbors' ants will pour over the border as soon as it's safe. Ants develop resistance to chemical pesticides fairly rapidly, so you may find yourself spraying stronger and stronger stuff as successive waves of ants retake their rightful territory.

The time for chemical weapons of mass destruction has passed: Argentine ants are here to stay. We in the Bay Area have lost the war. But we can still win a battle or two. You won't be able to get rid of the ants altogether, but you can keep them away from your kitchen.

You have three weapons in this war: sanitation, physical barriers and precisely targeted, small-dose pesticides.

Sanitation means keeping food sources away from the ants. When you make a peanut butter and jelly sandwich, wash the knife right away rather than letting it drip marmalade onto the counter. Make sure ant-attracting foods are tightly sealed, preferably in glass jars, and don't let dishes sit in the sink -- or dishwasher -- for more than a few minutes. If you keep your kitchen clean, Argentine ants will look outside for their food.

But they'll still come in now and then, especially when they get thirsty during hot, dry summers or when winter rains flood their nests. And when they do invade, it's time to use barriers.

When you see a line of ants marching across your counter, follow it until it ends. If it ends at the cookie your 5-year-old left in a potted plant, follow it the other way. Look until you find their entrance to your home. Search thoroughly! Baseboards and cabinetry can be deceptive.

When you find the entry point, barricade it. There are a few home remedies touted as "ant-proof" barriers, including cinnamon, chile powder, chalk and cucumber peels. Go ahead and try them if you like, though why someone who doesn't want ants in his house wouldn't mind a windowsill full of cucumber peels is beyond me. A more effective method is to physically plug the hole, with caulk or something similar.

But, if you absolutely must go toxic, an efficient and safe way of using pesticides is to allow the ants to do it for you. Hardware stores offer a wide variety of poison baits for ant control, some of which are effective against Argentine ants. The theory behind baits is simple and elegant. When ants find food, they eat a little but carry most of it back to the nest: Poison baits will poison the whole nest. The trick is to put the bait where the ants will get to it. You may need to put the bait directly on an ant trail for it to work. This requires patience and tolerance: It can take several days for the colony to die, which means several days of ant trail across your credenza. It makes sense to put bait stations in cupboards, under sinks and in other places where ants can congregate for a few days without bothering you.

None of these methods is foolproof, nor will they work even close to permanently. But with diligence and patience, you can reduce your household ant infestation to a minimum.

And remember, it could be worse: They could be cockroaches.