Atrazine and the African clawed frog

Wisconsin's Water Library's AskWater email reference service often responds to questions about frogs. Cricket frogs, Spring Peeper frogs, Northern Leopard frogs, and, of course, Bullfrogs, there are many species found throughout Wisconsin. From flooded prairie to ephemeral pond, our state provides many habitats for a peaceful evening of frog song.

But frogs also play an important roll as indicator species. Their abundance and overall health often reflect the health of whole ecosystems. Frogs are being carefully watched by scientists.

A new study published by the National Academy of Science analyzes atrazine and it's affect on the African clawed frog. A popular corn herbicide, atrazine is one of the most commonly applied pesticides in the world. And, as a result, it's often found in ground and surface waters. In Wisconsin, for example, a 2005 DATCP survey of 16,000 private wells showed that almost 40% tested positive for it (FY 2009 Groundwater Coordinating Council Report to the Legislature, p. 74).

According to the new study, this is bad for frogs.

Atrazine-exposed males were both demasculinized (chemically castrated) and completely feminized as adults. Ten percent of the exposed genetic males developed into functional females that copulated with unexposed males and produced viable eggs. Atrazine-exposed males suffered from depressed testosterone, decreased breeding gland size, demasculinized/feminized laryngeal development, suppressed mating behavior, reduced spermatogenesis, and decreased fertility.

If you'd like to know more, read the study here.
Or, check out the Wisconsin's Water Library's recommended reading list on frogs.