Most Wanted: Crazy Ant


November 16, 2015

Photo: Eli Sarnat, PIAkey: Invasive Ants of the Pacific Islands, USDA APHIS ITP,

Photo: Eli Sarnat, PIAkey: Invasive Ants of the Pacific Islands, USDA APHIS ITP,

Also known as the longhorn crazy ant, this Formicid crowds and contaminates. 

Description: Workers are monomorphic and 0.08 to 0.12 in. in length. The head, thorax, petiole and gaster are dark brown to black. Antennae are 12-segmented without a club and have a distinctly long scape. There is one visible petiole node, many body hairs, and legs are out of proportion to the body.

Life Cycle: Complete metamorphosis. Colonies can be large. Alates emerge on warm rainy days from May to September. While still immature, queens’ wings might be removed, and males have been observed not taking flight. Mating might take place near the nest entrance.

⦁ Habitat: Very adaptable — colonies can be in soil, decaying wood, tree hollows, clutter and trash. Crazy ants might forage long distances from the nest, which makes sourcing difficult.

Food: Generally omnivorous and living on dead insects, seeds, fruits, plant secretions, house fly larvae and household food. Workers also secure and replenish honeydew by tending aphids, mealy bugs and scales.

Range: Florida to South Carolina, west to Texas, Arizona and California. They also have been documented in Hawaii, Missouri, Virginia, New York and Massachusetts. Imported crazy ant populations are found within residential, commercial and industrial structures.

Significance: The crazy ant is considered to be the most broadly distributed of any ant species.* Aggressive and wide-ranging foraging habits result in high pest activity or contamination of food areas, medical and veterinary treatment areas, and many other sensitive environments.

*Wetterer, 2008

 Dr. Stuart Mitchell, D.O., Ph.D., M.P.H., B.C.E., a board-certified physician and entomologist, is principal technical specialist for PestWest Environmental, as well as PMP’s Technical Editor. He can be reached at or 515-333-8923.


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