A University of Iowa researcher has discovered that a "Goldilocks" effect applies to the reproductive output of a tiny New Zealand snailconsidered a troublesome species in many countriesthat may one day help environmentalists control their spread.
Known in the United States as the "New Zealand mud snail," the freshwater snail (Potamopyrgus antipodarum) grows to a length of about one-quarter inch in U.S. rivers and lakes, and up to one-half inch in its native New Zealand.
The snails were first discovered in the Pacific Northwest in the 1980s and have since spread widely throughout the West, including Yellowstone National Park, as well as east to the Great Lakes. Parts of the Snake River in Idaho have been reported to contain more than 100,000 snails per square meter.
The snail study, conducted by Maurine Neiman, assistant professor in the University of Iowa Department of Biology, appears in the Nov. 21 issue of the journal PLOS ONE. Her co-author, Nicholas Zachar, received his undergraduate degree from the UI in 2013 and currently is studying documentary filmmaking at American University, Washington, D.C. You can view the paper online, titled "Profound Effects of Population Density on Fitness-Related Traits in Invasive Freshwater Snail," at: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0080067
Neiman says her research has shown that although the species is resilient and prolific, certain boundaries may restrict its ability to grow and reproduce.
"The snails are incredibly sensitive to their environment," she says. "For example, we discovered that increasing population size from seven to eight snails results in a striking drop in reproductive output, with the snails in the eight-snail populations producing only half as many embryos as snails in the seven-cup populations. Altogethe
|Contact: Gary Galluzzo|
University of Iowa