Sept. 12, 2006 — Clusters of blister beetle larvae mimic female bees in an act of deception so successful that male bees try to mate with them and bring them back to the nest. There the larvae live in the lap of bee luxury by receiving free food and shelter, according to a new study.
Scientists believe the behavior is the first known example of cooperative, aggressive mimicry among insects. Cooperation is involved since the larvae stack up on top of each other and work as a unit to mimic just one female bee. The act is aggressive because, once in the bee’s nest, the sneaky parasites either eat the egg or the bees' hard-won food.
The act of mimicry goes beyond appearances, explained Leslie Saul-Gershenz, who worked on the study, published in the Proceedings of the National Academy of Sciences.
"The blister beetle larvae cooperate to emit a pheromone of sufficient signal strength that mimics the female bee," she said.
Saul-Gershenz, director of conservation at the Center for Ecosystem Survival in San Francisco, and coauthor Jocelyn Millar studied the insects at Kelso Dunes in California’s Mojave National Preserve. The act of seductive mimicry, they found, happens in four steps.
The worm-like larvae first emerge from eggs at the base of plants, such as grass blades, and then pile into a ball before shinnying up the plant.
The insects then release their secret weapon — a chemical similar to the female bee pheromone — and wait. With the release of this "perfume" plume, the baby beetles reach out toward any nearby male bee.
"The larvae extend out the upper part of their body and their front legs, which have specialized claws that are adapted for grasping," Saul-Gershenz explained to Discovery News.
