Washington State University Extension

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written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

One of the few insects that gives me the heebie-jeebies are ants. I don’t know why, but they do. However, despite my aversion to ants I do appreciate their place in the environment.

Ants are a social insect, living together in nests with a hierarchal system. Ant colonies usually start with an inseminated “queen.” The queen’s job is to lay eggs, lots of eggs. The eggs hatch into larvae that later turn into worker ants that are all females. As young workers, their job is to care for the babies (larvae) and the nest.

The older, more mature worker ants are given the job of defending the nest or searching for food for the queen and the many larvae. Their quest for food can take them far away from the nest. To find their way back, they will place down a chemical trail.

Male ants are another caste within the typical ant nest hierarchy. The male’s only purpose (you guessed it) is to mate with winged or breeding females. The inseminated females are new “queens” that start new nests. However, with over 14,000 species of ants in the world their life cycles and food preferences vary.

Two of the most common ants in Washington are the pavement ant and the odorous house ant. The pavement ant feeds on various foods like honeydew, insects, pollen, plant sap, meat, grease, nuts, cheese, bread, and honey. They’re a small ant, 1/8 inch or less, and light to dark brown to black in color. Their nests are found in rotting wood and in exposed soil under stones or pavement… giving them their name.

The odorous house ant is tiny, only about 1/16 inch long, and brown to black in color. They prefer sweet foods, such as flower nectar, honeydew from aphids, and fruit juices, but they’ll also eat dairy products, meat, vegetables, and insects. They get their name because of the rotten odor they emit when disturbed.

Generally, ants found in the garden are considered beneficial or at least inconsequential, but they can become pests when they nest beneath plants, undermining the roots or when they take up residence in childrens’ play areas. In lieu of using pesticides, you can discourage them in the garden by raking down their mounds frequently and keeping the area wet. This won’t kill them, but will encourage them to move somewhere else.

Indoors, try using ant bait traps where ants are a problem. The worker ants foraging for food in the area find the poisoned bait and take it back to their nest, killing the queen and the larvae. If possible, place the bait close to where the ants are coming inside. Don’t wipe off counter surfaces and floors before putting a bait trap down. This removes the chemical trail the ants use to find their way back to the nest. Because different ants have different food preferences, try a another type of bait if the first one doesn’t work. (The odorous house ant favors sweets and may be most attracted to the liquid or gel baits. )

If baits don’t work for you, try locating the nest and directly treating it with a pesticide product labeled for this use. There are separate outdoor and indoor ant sprays and baits. Check the label and select the one that fits your situation. With odorous house ants you may need to look for the nests at night, using a flashlight to follow their trails from your house to their nest. If this fails, contact a licensed pest control operator.

Published: 9/4/2010 12:27 PM



