Paratrechina longicornis (Latreille) (1925)
(from Creighton 1950)
The crazy ant is found in various parts of the world and is not native to the United States (Smith
1965). It is of Asian or African origin but is found in tropical cities worldwide (Trager 1984). In
the United States the crazy ant can be found from Florida to South Carolina and west to Texas. It
also is found in residences and warehouses over much of the eastern U.S. (Creighton 1950) and
in California and Arizona (Trager 1984).
distribution
The antennae of the crazy ant have 12-segments without a club and are extremely long. The
crazy ant worker is relatively small (2.3-3 mm). All workers in a crazy ant colony are
monomorphic and have only one node between the propodeum and the gaster. The scape, the
basal segment of the antenna, is extraordinarily long with the apex surpassing the posterior
border of the head by at least one-half the scape length. Eyes are elliptical, strongly convex, and
placed close to the posterior border of the head. Legs are extraordinarily long. The petiole is
wedge-shaped, with a broad base, and inclined forward. A small round terminal orifice
surrounded by a fringe of setae, or hairs, the acedipore serves for the application of venom both
in defense and predation. The stinger is lacking but the crazy may bite an intruder and curve its
abdomen forward to inject a formic acid secretion onto the wound. The body has long, coarse,
well scattered, suberect to erect, grayish or whitish setae. The head, thorax, petiole, and gaster
are dark brown to blackish (Creighton, 1950); the body often has faint bluish iridescence.
Lateral View
dorsal view
The crazy ant is extremely easy to identify on sight by observing its rapid and erratic
movements. Confirmation may be made with the aid of a hand lens through which the
extremely long antennal scape, long legs, and erect setae are very apparent. The slender-
bodied, long-legged worker is capable of extremely rapid movement.
Colonies of crazy ants are moderate to very populous. The colonies may raise sexuals at any time
of the year in warmer regions, but in the seasonal climate of north Florida, alate production is
apparently limited to the warm rainy months of May through September (Trager 1984). On warm,
humid evenings, large numbers of males gather outside nest entrances and may mill about
excitedly. Workers patrol vegetation and other structures nearby. Periodically, a dealate queen
emerges. Mating was not observed, but Trager (1984) suggested that it occurred in such
groupings around the nest entrance. Wings of queens are removed while still callow and males
were never observed to fly or use their wings in any way. However, in several cases it has been
observed that males frequently appear at lights (Trager 1984).
The crazy ant has achieved pest status across the United States. It has been found on top floors of
large apartment buildings in New York, hotels and flats in Boston and in hotel kitchens in San
Francisco, California.
Marlatt (1930) observed that the crazy ant is a pest in Florida and the Gulf States. In 1977,
modular units, serving as temporary schoolrooms, were being used by a North Lauderdale
elementary school. The principal reported that the units were so inundated by the ant that students
were constantly in a state of turmoil. The invasion reached such proportions that the students'
sack lunches were kept in closed plastic bags placed on tables with each table leg sitting in a pan
of water as a barrier to the ant.
Workers are omnivorous, feeding on live and dead insects, seeds, honeydew, fruits, plant
exudates, and many household foods. The crazy ant thrives in places such as gasoline stations,
convenience stores, and sidewalk cafes where workers may be seen transporting crumbs and
insects attracted to lights. They apparently have a seasonal preference for a high-protein diet, and
during the summer months may refuse honey or sugar baits. They are attracted to honeydew
producing homopterans in spring and fall. They obtain honeydew by tending aphids, mealybugs,
and soft scales (Smith 1965). Large prey items are carried by a highly concerted group action
(Trager 1984).
The workers are known to gather small seeds of such crops as lettuce and tobacco from seedbeds.
In cold climates, the ants nest in apartments and other buildings where they are potential pests
year round. Workers feed on many household foods such as meats, grease, sweets, fruits,
vegetables, and liquids (Smith 1965).
The crazy ant is highly adaptable, living in both very dry and rather moist habitats. The crazy ant
often nests some distance away from its foraging area. It nests in such places as trash, refuse,
cavities in plants and trees, rotten wood, in soil under objects and also have been found under
debris left standing in buildings for long periods of time (Smith 1965). These ants can nest in a
variety of locations from dry to moist environments. A crazy ant nest site can be found by looking
for workers carrying food back to the nest.
Non-chemical control is based on exclusion through good housekeeping practices and cleanliness
eliminating food sources. Crazy ants nest outdoors so prevention of their entrance by caulking
exterior penetrations and weather-stripping may aid in their control. Indoors chemical controls
are based on baits, dusts, and spot treatments with residual sprays. Outdoor treatments include
chemical formulations as baits, granules, dusts, and sprays. Read and follow label instructions
and precautions before using any insecticide.
Insect Management Guide for ants
Ant Trails: A key to control with baits
- Creighton WS. 1950. The Ants of North America. Bulletin of the Museum of Comparative Zoology 104. 585 p.
- Fasulo TR. (2002). Cockroaches and Pest Ants. Bug Tutorials. University of Florida/IFAS. CD-ROM. SW 157.
- Fasulo TR, Kern W, Koehler PG, Short DE. (2005). Pests In and Around the Home. Version 2.0. University of Florida/IFAS. CD-ROM. SW 126.
- Mallis A. 1997. Handbook of Pest Control. 7th Edition. Franzak & Foster Co. Cleveland. 1990. 1152 p.
- Marlatt CL. 1930. House ants, kinds and methods of control. USDA Farmer's Bulletin 740. 12
p.
- Smith MR. 1965. House-infesting ants of the eastern United States; their recognition, biology,
and economic importance. USDA Technical Bulletin 1326. 105 p.
- Trager JC. 1984. A revision of the genus Paratrechina (Hymenoptera: Formicidae) of the
continental United States. Sociobiology 9: 51-162.
- Wilson EO, Taylor RW. 1967. The ants of Polynesia (Hymenoptera: Formicidae). Pacific Insects Monograph 14. 109 p.
Author: J.C. Nickerson, Florida Department of Agriculture and Consumer Services, Division of
Plant Industry, and Kathryn A. Barbara, University of Florida.
Originally published as DPI Entomology Circular 289. Updated for this publication.
Photographs and illustration: Kathryn A. Barbara and James Castner, University of Florida
Project Coordinator: Thomas R. Fasulo, University of Florida
Publication Number: EENY-142
Publication Date: June 2000. Latest revision: July 2007.
Copyright 2000-2007 University of Florida
Featured Creatures
Department of Entomology and Nematology
Division of Plant Industry
Electronic Data Information Source
