Researchers place infected larvae on the fire ant mound. Ants adopt and raise infected larvae. The disease spreads to workers and the queen.

In the queen, the disease multiplies, causing the abdomen to shrink. This is a healthy queen, left, and a diseased queen, right.

Diseased queens have dark cysts in their ovaries and produce 90 percent fewer eggs. These queens are dissected to show healthy ovaries, left, and diseased ovaries, right.

The few eggs the queen produces are diseased. Only a few larvae and workers develop. The workers in the healthy colony, left, greatly outnumber workers in the diseased colony.

A diseased, weak, colony cannot defend itself. Stronger, raiding colonies, left, carry off and adopt the diseased larvae.

Strong colonies which produce many winged ants, left, eventually become diseased and weak, producing only a few winged ants, so ant infestations do not spread.

Areawide cooperators have successfully established Thelohania solenopsae
throughout the imported fire ants' range within the United States.