Identification
Description
Tawny crazy ants are recognized by the appearance of many (millions) of uniformly-sized 1/8 inch long, reddish-brown ants in the landscape; foraging occurs indoors from outdoor nests. Under a microscope, a 12-segmented antennae, a petiole (1 node) and an acidopore (circle of hairs at the tip of the abdomen) will be seen, and the ant will be covered with many hairs (macrosetae).
Basic anatomy of a worker
The typical tawny crazy ant is 1/8 inch long; this is a lateral view of a worker
Males are winged and are needed for identification of the species. TCA form loose foraging trails, but will also forage randomly (non-trailing). The workers crawl rapidly and erratically, hence the description "crazy" ant. Ant colonies, where queens with brood (whitish larvae and pupae) live, occur under landscape objects like rocks, timbers, piles of debris, etc. These ants do not build centralized nests beds, or mounds, and do not emerge to the surface from nests through central openings.
Male tawny crazy ants are winged
TCA have hairs (macrosetae) encircling the acidopore at the tip of the abdomen
TCA are recognizable by their large congregations,
at times numbering in the millions
Nesting sites can be found under any object outdoors that can retain moisture
Habitat and Life Cycle
Colonies can be found under or within almost any object or void, including stumps, soil, concrete, rocks, potted plants, etc. Nests primarily occur outdoors, but worker ants will forage indoors, into homes and other structures. Nesting occurs under almost any object that retains moisture.
Few worker ants forage during cooler winter months. In spring, foraging activity begins and colonies grow, producing millions of workers that increase in density dramatically by mid-summer (July-August). Ant numbers remain high through fall (October-November).
Despite the males having wings, no mating (nuptial) flights have been observed in the field. This suggests that colonies spread or propagate by "budding" with breeding possibly occurring at/near the edge of the nest, creating new colonies at the periphery. Annual rate of spread by ground migration is ~20 and ~30m per month in neighborhoods and industrial areas respectively and ~207m/year in rural landscapes.