Section 1

Insect Queen Distributes Birth Control
March 01, 2004

When it comes time to talk about the birds and the bees, an ant colony’s queen sends out a message encoded on her eggs. The surface of the queen’s eggs is coated with a pheromone that prevents worker ants from laying their own eggs. Social insects, like the ant species Camponotus floridanus, live in large colonies and share labor. Each colony includes a fertile queen and her largely infertile offspring, known as workers. If the workers also reproduced, the colony’s productivity might suffer. Pheromones can signal the presence of a fertile queen and thus prevent worker reproduction, but Jürgen Liebig and colleagues wondered how the signal is spread to workers not in direct contact with the queen. The researchers set up several colonies with only workers—no queen—and added various combinations of pupae, larvae, and eggs. Workers in colonies that did not receive queen-laid eggs began to lay their own eggs. When both queen-laid and worker-laid were added to a colony, the ants destroyed the worker-laid eggs. Only the presence of queen-laid eggs inhibited worker reproduction. The authors used chemical analysis to show that the surface of the queen-laid eggs contains a special hydrocarbon blend, very similar to that found on the body of the queen herself. Adding the isolated hydrocarbon blend to the surface of worker-laid eggs prevented the ants from destroying these eggs.

“Surface hydrocarbons of queen eggs regulate worker reproduction in a social insect,” PNAS, March 01, 2004

Abstract © 2004 PNAS

Jürgen Liebig, Biozentrum, Universität Würzburg