Mate selection is costly to female iguanas

For some female iguanas such activity saps strength they might have used for finding food, escaping predators or producing eggs, said Princeton University graduate student Maren Vitousek, the study's lead investigator.

The behavior -- which offers some of the first evidence that selecting a desirable partner is energetically costly for females -- is surprising because scientists often assume choosiness demands comparatively little exertion from females.

However, the scientists say avoiding energetic, but unwanted, males is itself exhausting and can result in smaller eggs whose young might be less likely to survive. The team found that during a month-long mating period, particularly choosy females lost as much as 25 percent of their body weight -- far more than the 14 percent lost by the average female.

The study, which also included scientists from Louisiana State University and the University of Birmingham, England, appeared in the June 27 online issue of the journal PLoS One, a publication of the Public Library of Science.

Copyright 2007 by United Press International