The UB research, published last month in Proceedings of the Royal Society: Biological Sciences, opens a new window on the biological diversity of several species of water fleas, including those in the genus Daphnia and the genus Bosmina, that play major roles in freshwater food webs.

It also demonstrates that pesticides that mimic the hormone used in the UB experiments may have much broader effects than initially believed, and could damage populations of fish and other organisms higher up in the food chain.

"Most freshwater fish eat water fleas at some point in their lives," said Derek J. Taylor, Ph.D., associate professor of biological sciences in UB's College of Arts and Sciences and co-author on the paper. "They are an important food source for fish."

Water fleas are nearly microscopic organisms with transparent bodies. Found in lakes, ponds and other bodies of fresh water, they are crustaceans like lobsters and not insects, as their name suggests.

"People use water fleas as aquatic 'coal-mine canaries,'" said Taylor. "They are good indicators of environmental change."

In stable environments, female water fleas generally reproduce asexually, essentially cloning themselves and resulting in populations of females that are practically impossible to tell apart.

Water flea populations grow much faster when they reproduce asexually than when they do so sexually, Taylor explained.

He added that the practice of rarely producing males has likely been conserved for 100 million years or more in a large group of freshwater crustaceans.

In the UB experiments, four distantly related species of water fleas were exposed to methyl farnesoate (MF), a crustacean juvenile hormone that is known to determine sex in some specie
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Contact: Ellen Goldbaum
goldbaum@buffalo.edu
716-645-5000 x1415
University at Buffalo
6-Dec-2005