Imagine returning home after a hard day of work and finding your study teeming with dozens of insects emerging from the baseboard, swarming on the sofa, cavorting on the windowsill. These are disturbing insects, the winged kind that evoke the fear of home destroyers – termites and carpenter ants. Is it time to call the exterminator? Maybe not. A closer examination of these rascals reveals the telltale narrow waist of an ant rather than the wide waist of a termite. The antennae on these insects have the distinct “elbow” joint characteristic of ants rather than the “string of beads” look of antennae found on the termite.
Notice the narrow waist and jointed antenna with long segments that are characteristics of ants.
They are not termites so breathe a small sigh of relief, but could these be carpenter ants? Our most common carpenter ant in the eastern United States is the black carpenter ant, Camponotus pennsylvanicus. This ant is dark brown to black in color with wingless workers about ½ inch in length and winged queens slightly larger. The winged ants crawling on the sofa are reddish – yellow and less than ½ inch in length, not likely to be carpenter ants. The real clincher for this one is its aroma revealed by the “sniff test”.
Termites have a wide waist and antennae that look like a string of beads.
For those unfamiliar with fine art of sniffing insects, it is really very simple. Grasp the insect with your index finger and thumb and gently roll it back and forth between your fingers. Hold the insect about an inch from your nostrils and inhale slowly. Sense the odor. Warning – this technique should not be attempted with stinging insects like bees or wasps or those that spray noxious chemicals like bombardier beetles. A sniff test of this ant revealed a delightful bouquet reminiscent of lemon or citronella, hence, one common name for this ant is the citronella ant. The scent is produced by special glands in the ant and likely used as a defense against its predators. Citronella ants, Acanthomyops interjectus, are also known as large yellow ants. The good news is that citronella ants do not cause structural damage to homes. They nest in soil often along foundations. Sometimes these nests extend under slabs or into crawl spaces beneath living spaces.
Black carpenter ants usually make their home in decaying wood outdoors but they often forage and may establish colonies inside homes.
The workers of this species feed on honeydew produced by ants and mealybugs outdoors and it is unusual to see workers inside the home. However, on a sunny spring day, the new queens may emerge inside a home. The wing-bearing queens are called alates and attempt to find their way outdoors to establish new colonies. This impressive exodus can last several days and is often confused with the swarming of termites. What should you do if you are treated to swarms of large yellow ants in your home? Workers and alates are not attracted to baited traps like the odorous house ants we visited on January 2, 2006 in “A holiday brunch with my ants”. For the alates emerging indoors, simply grab the vacuum, suck them up, and toss the bag out or maybe use it as an air freshener, the citronella scent is marvelous. My intrepid neighbors, who shared their citronella ants for this bug of the week, plan to deal with their ants with a vacuum and a healthy dose of good humor. If you discover a colony of large yellow ants located along the foundation outdoors, it can be eliminated with an insecticide labeled for this purpose. Colonies beneath crawl spaces or slabs may require the help of a professional.
References:
We give special thanks to our good friends Jeff and Linda for sharing their ant infestation for this bug of the week. For more information on yellow ants and carpenter ants, please visit the following web sites.
http://lancaster.unl.edu/pest/ants/LargeYellowAnt.shtml
http://www.hgic.umd.edu/_media/documents/publications/ants_pfv.pdf
http://www.hgic.umd.edu/_media/documents/publications/carpenter_ants_pfv.pdf