Some aging fish may switch mating habits

Ohio University scientists say they have determined that as female swordtail fish age, they change their mating habits.

Lead researcher Molly Morris, an associated professor of biological sciences at the Athens, Ohio, school, said as the females grow older and larger, they spend more time with asymmetrically striped males than with symmetrical males, when offered a choice.

The findings are the first to contradict previous studies indicating females tend to prefer males with symmetrical markings, which in this case are black bars on each side of the body. Scientists have suggested symmetrical markings are a sign of genetic fitness.

The study provides evidence that visual cues are not the only thing driving mate selection. The findings also suggest "females may not have the same mating preferences throughout their lives," Morris said.

Co-authors of the study were post-doctoral fellow Oscar Rios-Cardenas and undergraduate student Mary Scarlett Tudor.

Funded by the National Science Foundation and the Research Challenge Program at Ohio University, the paper has been published online in Biology Letters and will appear in next month's print edition.

Copyright 2005 by United Press International