Most Wanted: Crazy Ants

By: Albert Lee

The
 crazy ant is believed to be a native of Asia. It has become a cosmopolitan
species due to world trade, and is now well-established in many towns 
and cities along the Gulf Coast of the United States, especially Florida.
They are sporadically distributed in the North and inland. In these areas,
they are primarily a pest in hotels, greenhouses and apartment buildings.
Crazy ants get their common name because the workers often run in a haphazard
manner.

The workers range from 2.2 mm to 3 mm in length. Only one node is present
on the pedicel. The thorax is not evenly rounded, and the antenna has
12 segments and lacks a club. The stalk (scape) of the antenna is very
long and about twice the length of the head. The eyes are large and strongly 
convex.

These ants have long and slender legs, which allow for rapid movements.
 Their dark brown to black bodies contain long, coarse, grayish-white hairs
that are well scattered.

The crazy ant is highly adaptable, living in both dry and moist habitats. The
 colonies themselves typically contain about 2,000 workers and have anywhere
 from 8 to 40 queens. A single colony consists of a number of satellite colonies
connected by foraging trails. It is unknown whether separate colonies are antagonistic
toward each other, and whether neighboring colonies are capable of integration.
Crazy ant colonies are very mobile and can move to new locations when environmental
conditions become unfavorable. New colonies are formed through budding from
the original colony. Winged reproductives swarm mainly during the summer months, 
but in southern Florida, they swarm throughout the year.

Eating preferences

Crazy ants are omnivorous, feeding on live and dead insects, seeds, fruits,
honeydew and household foods. Their keen sense of smell enables them to
locate food rapidly. They are attracted to honeydew-producing insects
during the spring and the fall. They apparently have a seasonal preference
for high-protein diets during the summer months.

Despite their erratic movements, these ants form foraging trails, following
structural guidelines such as sidewalks and the edge of buildings. They are
capable of foraging for more than 100 feet. Crazy ants forage both outside and
inside structures with relative ease. Common nesting sites outdoors include
areas under heavy vegetation, landscape vegetation that lies against a solid
surface, trash, rotting wood, potted plants and plant and tree cavities.

 Outdoor colonies will readily forage indoors, while indoor colonies tend to
nest inside wall voids and under items on the floor that have not been moved
in a long time.

Treatment methods

In areas where the crazy ants have established themselves, complete eradication
is nearly impossible. However, there are things that can be done to manage
them.

One of the most effective methods is to correct favorable conditions by practicing
good housekeeping and eliminating food sources within the structure. Tree branches
and shrubbery should be removed if they are in contact with the structure. Cracks
on the outside of the structure should be sealed to prevent entry.

Outdoor colonies can be treated with residual insecticides. When the ants are
already inside the structure, however, a chemical treatment is often necessary.
Drilling a hole in the wall and treating the voids with an aerosol or dust can
eliminate crazy ants nesting in walls. Because of the ants’ varied feeding
habits, commercial ant baits are not usually effective.

It is important to remove debris on top of colonies for maximum effectiveness.
 Satellite colonies can reinfest, so all satellite colonies must be located and
treated.