Young fire ants play dead when attacked

TAMPA, Fla., April 14 (UPI) -- U.S. biologists say playing dead is an effective self-defense strategy adopted by young fire ant workers under attack from neighboring colonies.

University of South Florida Associate Professor Deby Cassill and colleagues found that tactic makes the young ants four times more likely to survive aggression than older workers who either flee or fight back. As a result, the young workers are able to contribute to brood care and colony growth to ensure the survival and fitness of their queen.

The researchers discovered the age of the victims was a predictor of their response to aggressors. Days-old workers responded to the attacks by pretending to be dead. Weeks-old workers responded by fleeing and months-old workers fought back.

The scientists posit that by feigning death, young workers were avoiding physical aggression when they are not yet adequately developed and are most certain to fail or by feigning death the young workers are spared, allowing them to increase colony growth, which is essential to the survival and fitness of the colony queen.

The study is reported online in the journal Naturwissenschaften.