With the doldrums of winter a distant memory, Bug of the Week is busier than ever. Lightening bugs have made an early appearance and a strange sawfly larva was seen devouring dogwoods, but these played second fiddle to the vast number of inquiries from viewers this week about small ants swarming inside homes. My personal invasion began at dusk as dozens of winged reproductive ants laid siege to my home, discovering tiny rents around my well-sealed windows, and swarming over my computer screen and stacks of white papers that clutter my desk. Light streaming from the window was an obvious attractor as scores of kings and queens cued up to gain entry. These ants were not on the usual "pillage the kitchen mission" carried out by workers. The ants entering my home were winged adults, new kings and queens venturing from their natal home in large numbers to establish new colonies. Odorous house ants have become a perennial guest at Bug of the Week as these small brown ants invade homes throughout our region each spring. This ant earns its name by virtue of the distinctive smell it makes when crushed between your fingers or on a counter. The odor is reminiscent of slightly fermented coconuts. How and why does this invasion reappear each year? After passing the chilly months of winter and early spring in a state of relative inactivity, the return of warm weather sends worker ants into an unending search for sugars, proteins, and fats to feed the burgeoning colony. In the wild, plants and other insects provide these foods. When ants locate a rich larder such as the sugary honeydew produced by a colony of aphids like the ones we visited in a few weeks ago, they establish a trail marked by chemicals called pheromones. The trail leads other workers from the nest to the bounty. Outdoors odorous house ants nest beneath stones or fallen logs. I usually have several colonies in my yard in a woodpile. However, odorous house ants are very opportunistic and will occasionally enter homes to set up shop. I have discovered colonies of these rascals in my wall voids and in electrical appliances including a surge protector beneath my desk. Their quest for food brings them into homes and a few grains of sugar on the counter, a pet dish on the floor, or a leaky bottle of pancake syrup in the pantry, will often initiate a full-scale invasion. If you find ants and their telltale trails on counters or along baseboards, try to locate the source of food and then follow the trail back to the point of entry into your home. To foil these raiders, first eliminate as many sources of food as possible. Clean the counters, mop up drips, and get pet food off the floor. Be sure that no syrup or sweets are spilled or leaking in your cupboards. Disrupt ant trails on the counter or floor by spraying them with household cleansers or other solutions. You can buy ant traps or purchase tubes of liquid or gelatin ant baits. Place ant traps or baits at locations indicated on the label. I usually place one near the point of entry into my home and several others around my counters and near their raiding columns. The traps and baits contain a lure that attracts ants searching for sweets or fatty foods. The lure contains poison. Workers ingest the toxin and are killed or in some cases they carry the toxic treat back to the colony and feed the deadly meal to the queens and their nest mates and, voilà, the royals are assassinated and the colony with them. A few well-placed bait stations usually put an end to the ant trails in a matter of days. To be effective, the bait must attract ants. If you purchase a bait or ant trap, and the ants eschew your invitation, well, get yourself another type of trap or bait. Whenever you use a product containing an insecticide, be sure to follow precisely the instructions on the label. Never apply pesticides directly to surfaces used for food preparation or consumption like countertops or tables. To stem the flow of the jolly reproductives that invaded my study, I dosed the lights that attracted them in the first place. Early the next morning, I located a raucous ant trail emerging from the corner of a basement window immediately below my study. Several generous portions of ant bait soon had jillions of workers carrying the lethal meal back to their colony. Within two days of baiting, the ant trail deteriorated to an anemic trickle and by day three nary an ant could be found. Illumination returned to the study and no swarming reproductives returned. Many species of ants can become visitors or residents in our homes. Large black ants in the home, especially ones with wings, may be carpenter ants and a sign of more serious problems than just a little sugary larceny. If you have concerns or questions regarding the identity or management of any six-legged vandals, contact your local extension office for advice.
References
Bug of the Week thanks Al Wilson for the inspiration to this week’s episode. To learn more about odorous house ants and other ants inside homes, please visit the following web sites.
http://www.msstate.edu/org/mississippientmuseum/Researchtaxapages/Formicidaepages/genericpages/Tapinoma.sessile.htm
http://www.hgic.umd.edu/_media/documents/AntsandTheirControlhg7pfv.pdf