Tawny Crazy Ants

Facts, Identification & Control

Scientific Name

Nylanderia fulva

Appearance & Identification

castner ant

The tawny crazy ant, also known as the rasberry crazy ant, is an invasive species that was brought to the U.S. from South America. They are about 1/8 of an inch long; have long antennae; and legs that are reddish-brown in color. Like with other ant species, they have complete metamorphosis (four life stages: egg, larvae (grub), pupae and adult). A typical colony will consist of multiple egg-laying queens.

Behavior, Diet & Habits

The simplest way to describe tawny crazy ant behavior is disorganized, chaotic foraging by worker ants, and colonies with queens who possess enormously abundant reproductive potential. The homeowner who has well developed, healthy colonies on or near their property, is almost certain to see huge numbers of worker ants, all being the same size and shape foraging in a quick, haphazard manner with seemingly little or no pattern to their movements; thus, warranting the common name, crazy ant.

Tawny crazy ants are omnivores – meaning they will consume just about any sweet or protein substances. Sweets commonly eaten are honeydew (excretions produced by aphids and other insects), sweet portions of plants, over-ripe fruits and honey from beehives. Protein sources include small insects and small mammals that are overcome by the numerous workers that attack. The workers are most active and plentiful in the early spring, while foraging is limited in the winter months. Colonies will produce millions of workers by mid-summer and continue to thrive throughout the fall. Crazy ants build nests under almost any object or inside any void that remains moist. Favored locations may be stumps, damp soil, rocks, landscape timbers, potted plants and piles of debris, compost and garbage.

One of the more fascinating aspects of tawny crazy ant behavior is their habit of infesting electronic equipment in such large numbers that they create short-circuits that render the equipment unusable. These ants are unlike other frequently encountered ant species since they do not possess a stinging mechanism used for protection. So, rather than sting, the tawny crazy ant emits chemical compounds that protect them from attack by other insects. While capable of inflicting a bite, most people report the bite is mildly painful and quickly diminishes. Another behavioral phenomenon is the tendency for tawny crazy ant populations to replace other ant populations. Field observations show that crazy ants can out-compete and replace fire ant populations when both species occupy the same territory.

More Information

While the ant’s official name is tawny crazy ant, it is also known as a Rasberry crazy ant after Tom Rasberry who identified the ant in 2002 in Texas.

While prevention is always important to reduce suitable ant habitats, this is one pest that should never be controlled by using do-it-yourself strategies. If you have tawny crazy ants, contact an experienced pest management professional right away. Get ahead of the ants by seeking the advice, recommendations and expertise of your pest specialist and begin the ant management program before the population explodes in the warmer months. In addition, if the control program is only partially effective, the ant populations will more than likely rebound and continue to create problems.