Carpenter Ant: Scientific name: Camponotus nearcticus

 

Description:  Carpenter ants are a nuisance by their presence when found in parts of the home such as the kitchen, bathroom, living room and other quarters. When 20 or more large winged and/or wingless ants are found indoors, in the daytime near one location, it is possible that the colony is well established in the home and the nest may have been extended into sound wood, sometimes causing structural damage. They do not eat wood, but often remove quantities of it to expand their nest size. However, if only one to two large wingless ants are erratically crawling, they may simply be foraging for food with the nest located outside. Outdoors, they are frequently seen running over plants and tree trunks or living in moist, partly rotten wood stumps.

 

Identification: Carpenter ants are among the largest ants found in homes and live in colonies containing three castes consisting of winged and wingless queens, winged males and different sized workers. Winged males are much smaller than winged queens. Wingless queens measure 5/8 inch, winged queens 3/4 inch to the tips of their folded brownish wings, small minor workers 1/4 inch and large major workers 1/2 inch. Workers have some brown on them while queens are black. Workers have large heads and a small thorax while adult    swarmers have a smaller head and large thorax. Carpenter ants have a smoothly rounded arched (convex) shape to the top of the thorax when viewed from the side and a pedicel between the thorax and abdomen consisting of only one segment or node. They have constricted waists, elbowed antennas and the reproductive’s forewings are larger than the hindwings, transparent or brownish and not easily removed. Adults are usually black with some species red, brown or yellow occurring on parts of the body and legs. Eggs are about 1/8-inch long, cream colored and oval. Larvae are legless and grub-like, later pupating in tough silken, tan-colored cocoons erroneously referred to as "ant eggs." Winged male and female carpenter ants (swarmers) emerge from mature colonies usually from March to July.    After mating, males die and newly fertilized females (mated for life), establish a new colony in a small cavity in    wood, under bark, etc. and each lays 15 to 20 eggs in 15 days. The egg stage takes about 24 days, larval stage 21 days and pupal stage 21 days or about 66 days from egg to adult at 70 to 90 degrees F. Cool weather may lengthen this period up to 10 months. The colony does not produce swarmers until about three years later. A mature colony, after three to six years, has 2,000 to 4,000 individuals. During the first brood, larvae are fed entirely by a fluid secreted from the queen’s mouth where she does not take food, but uses    stored fat reserves and wing muscles for her nourishment. The few workers emerging from the first brood assume duties of the colony, collecting food, excavating galleries to enlarge the nest and tending the eggs, larvae and pupae of the second generation. Workers regurgitate food for nourishment of the developing larvae and queen. She has few duties except to lay eggs. In later generations, workers of various sizes are produced (polymorphism) into major and minor workers, that are all sterile females. Males formed are winged swarmers. Larger "major" workers guard the nest, battle    intruders, explore and forage for food while smaller "minor" workers expand the nest and care for the young workers, when disturbed, carry off the larvae and pupa, which must be fed and tended or they die. In a mature colony, there is usually one queen with 200 to 400 winged individuals produced as swarmers. Workers have strong jaws and readily bite (sharp pinch) when contacted.

 Nests are usually established in soft, moist (not wet), decayed wood or occasionally in an existing wood cavity or void area in a structure that is perfectly dry. Workers cut galleries in the wood, expanding the nest size for the enlarging colony. Galleries are irregular, usually excavated with the wood grain (sometimes across the grain) into softer portions of the wood. The walls of the nest are smooth and clean (sandpapered appearance) with shredded sawdust-like wood fragments, like chewed up toothpicks (frass), carried from the    nest and deposited outside. These piles of wood fragments, often found beneath special openings (windows) or nest openings, may contain portions of insects, empty seed coats, etc. Carpenter ants do not eat wood but excavate wood galleries to rear their young ants and carry aphids to plants, placing them on leaves for the production of honey dew. The food diet is of great variety (omnivorous) of both plant and animal origin such as plant juices, fresh fruits, insects (living or dead), meats, syrup, honey, jelly, sugar, grease, fat, honey dew (aphid excrement), etc. They feed readily on termites and usually never co-exist with them in a home. Workers are known to forage for food as far as 100 yards from their nest.

 

Prevention: Homeowners should trim all trees and bushes so branches do not touch or come in contact with the house. Correct moisture problems such as leaking roofs, leaking chimney flashing, or plumbing, poorly ventilated attics or crawl spaces and blocked gutters. Replace rotted or water-damaged wood and eliminate wood to soil contact. Remove dead stumps within 50 feet of the house, if practical, and repair trees with damage at broken limbs, and holes in the trunk. Seal cracks and crevices in the foundation, especially where utility    pipes and wiring occur from outside. Be sure to store firewood off the ground away from the house and bring in only enough firewood (first examining it) to be used quickly. Consider non-organic mulches near the house in heavily infested ant areas. High moisture conditions must be eliminated to help control carpenter ants, prevent future attacks and prevent "wood decay" fungus infection.

   

Acknowledgement: Much of the information on this page was first published in New South Wales Department of Agriculture Entomology Branch Insect Pest Bulletin 111, 1977.