Antbird capable of increasing testosterone level when ...( also have been looking at the effect of...)

also have been looking at the effect of testosterone on aggression and sexual desire. Another study involving birds found that male dark-eyed juncos -- a temperate, migrating species -- stray from their mates and care-giving duties when given large doses of the hormone.

"We want to find out how aggression is regulated and what factors influence aggressiveness," Wikelski said. "Birds are good models, because they are easy to observe, as opposed to mammals who display most of their aggression at night or out of sight. We need to understand aggression in natural systems to really understand how aggressiveness is regulated in humans, and what kinds of physiological parameters are important. We know from this study that social challenge plays a role."

Co-authors of the paper were U. of I. colleague Michaela Hau and John G. Wingfield of the University of Washington. Funding came from the National Science Foundation, Alexander Von Humboldt Society, Smithsonian Tropical Research Institute, Deutsche Forschungsgemeinschaft, Deutsche Ornitholgen-Gesellschaft and the Max Planck Gesellschaft.

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Contact: Jim Barlow, Life Sciences Editor
b-james3@uiuc.edu
217-333-5802
University of Illinois at Urbana-Champaign
1-Jun-1999

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