Insect brain, behavior evolution studied

Nov. 15, 2006 at 5:06 PM
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SEATTLE, Nov. 15 (UPI) -- U.S. research suggests brain and behavior relationships may have significantly changed as larger, more complex insect societies evolved.

Sean O'Donnell, a University of Washington associate professor of psychology, and colleagues from the University of Texas found a key region in the brain of a primitively social paper wasp is better developed in dominant females than in subordinate ones.

"This finding, the first of its kind, contrasts with most of the prior work on social insect brain development," said O'Donnell. "Earlier studies, including one of ours, were done on highly social species with large colony sizes. Among these species, age plays an important role in task performance and workers that leave the nest to forage generally have better-developed brains.

"We found the opposite pattern with a primitively social wasp. Here, the stay-at-home dominant females had better brain development. In this species, direct dominance interactions among the females dictate task performance," he said. "Dominance and social interactions were more important than foraging tasks in explaining brain development."

Co-authors of the study, published in the Journal of Neurobiology, were Theresa Jones, a University of Texas associate professor of psychology, and Nicole Donlan, a University of Texas research technician.

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