Origin:
This is a native species in Texas and south into Mexico.
Biology:
Leafcutting ants feed only on a fungus that grows on bits of vegetation they gather and store in their underground colonies. However, these ants are active enough to cause serious defoliation of trees and shrubs that they have chosen as their resource in an area. Swarming by males and females occurs in mid to late spring and the winged adults may come to lights at night. New colonies are then established by these newly mated females and may grow and survive for many years, ultimately containing up to 2 million workers and with galleries up to 20 feet deep in the soil. Many entrances to the nest may be found at the soil surface with the surface around them somewhat cleared of vegetation. Foraging is primarily at night with workers traveling up to 600 feet or more from the colony. The foliage of virtually any plant is susceptible, including conifers.
Identification:
The workers of this species may be confused with harvester ants, as they are reddish-brown and up to ½ inch long, but instead of the single pair of spines present on harvester ants the leafcutting ants have 3 pairs of spines on the thorax. The winged reproductive female is unmistakable, being up to ¾ inch long and with a very large thorax and abdomen.
Characteristicts Important to Control:
These ants rarely accept standard insect baits due to their specialized diet. Special ant baits may exist that are formulated for them, but even if accepted by the ants rebaiting will be necessary on a regular basis. Temporary protection of valuable plants can be obtained using residual insecticides sprayed or dusted onto the foliage. Direct injection of the nest openings, particularly with an active ingredient that can be transported further into the colony, can provide some effectiveness.
