Wood ant queen has no egg-laying monopoly

Helsinki, Finland -- Finnish scientists have discovered the reproductive monopoly of the wood ant queen is not as absolute as has been thought.

Heikki Helantera and Professor Lotta Sundstrom of the University of Helsinki investigated worker ovary development and egg laying in nine Northern European wood ant species of the genus Formica, and discovered widespread reproductive endeavors by workers.

Genetic analysis showed workers lay eggs on a large scale -- in one species as many as one of four eggs is laid by workers.

Wood ant colonies range in size to hundreds of thousands of workers, and usually species in such large colonies have very little worker reproduction, the researchers said. That's because the majority of the workers favor the queen as the egg layer, preventing reproduction by egg laying workers.

"It is obvious such surrender has not taken place in wood ants," said Helantera, currently at the University of Sheffield. "The big questions are then why are the workers so persistently trying, and how does this ongoing conflict over reproduction affect colony functioning as a whole."

The study appears in The American Naturalist.

Copyright 2007 by United Press International.