Harvester Ants
Pogonomyrmex spp., Formicidae, HYMENOPTERA


DESCRIPTION

Adult -- The harvester ants are large ants 5 to 6 mm in length and different species can vary in color from reddish-brown to yellow or black. The pedicel (or stalk) between the abdomen and thorax has two segments. They have elaborate fringes of hairs underneath the head. As is the case with other ants, adults may be winged males or females, or workers (wingless females). Winged ants have two pairs of wings, the anterior pair being much larger than the second pair.

Egg -- The eggs are minute, less than 0.5 mm long, white and elliptical in shape.

Larvae -- The larvae are white and legless. The body is covered with short hairs and is shaped like a crookneck squash or gourd with a small distinct head.

Pupa -- Found in a cocoon, the pupa resemble the larva except that the body is straight and rigid with legs and wings visible.


BIOLOGY

Distribution -- The so-called harvester ants occur west of the Mississippi except for one species. The two most common species are the Texas harvester ant and Western harvester ant.

Host Plants -- The harvester ants do not consume grass for food but denude areas around mounds and along trails. Their principal source of food is seeds of various grasses and the flesh of arthropods.

Damage -- The harvester ants not only construct large mounds which cause loss of grass but also clear areas of grass around the next and along the forage trails radiating from the central nest. Cleared areas around the nest may be 7 m or more in diameter. Generally, nests are constructed in open areas and are a real problem on golf courses, recreational areas and occasionally in lawns. It is also thought that they may hinder reseeding of different grasses by collecting seed. In addition, they can sting viciously. At least three small children have died from their stings in Oklahoma.

Life History -- The harvester ants are social insects and live together in colonies. Winged males and females swarm from the parent colony, pair off, and mate. The males die soon after mating. The female loses her wings, finds a suitable nesting site in the soil, and begins laying a few eggs. After hatching, the queen feeds and cares for the young larvae. The larvae mature and change to pupae, then to adult workers. The adult workers then begin taking care of the queen as well as eggs and larvae of future generations.


CONTROL

If only a few mounds occur, it is preferable to treat each mound individually. If numerous mounds are found, it is preferable to treat the whole area. For specific chemical control recommendations, consult the agricultural extension service.