( The good news if you’re grazing normal...)Parasites' impact goes beyond host to affect ecosystem

The research, published in this week’s Proceedings of the National Academy of Sciences Early Edition (http://www.pnas.org/papbyrecent.shtml), suggests that parasites can not only substantially affect their hosts ?altering their growth, behavior, nutritional status, reproductive abilities, and even their mortality ?but also the hosts?entire ecosystem.

In the article, "Parasites alter community structure," lead author Chelsea Wood, then a Dartmouth College undergraduate, and UNH associate professor of zoology James Byers, working at the Shoals Marine Lab off the coast of New Hampshire, looks at parasitism by the trematode Cryptocotyle lingua in Littorina littorea, a snail known as the common periwinkle and the dominant herbivore in the intertidal zone. "We wanted to find out what was this parasite’s impact on the community," says Byers, who advised Wood during the research, which she conducted in summer 2005 as part of the highly competitive Research Experience for Undergraduates at the Shoals Marine Lab (SML).

Byers and Wood hypothesized that since L. littorea was the intertidal zone’s most voracious eater of green, weedy algae, and the flatworm C. lingua infects L. littorea and damages its digestive system, then perhaps C. lingua infection could alter the abundance of this ephemeral macroalgae.

The Shoals Marine Laboratory, located seven miles off the coast of Portsmouth on Appledore Island and operated jointly by UNH and Cornell University, provided the ideal setting for such an experiment. While C. lingua infects approximately 10 percent of L. littorea living on the mai
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Source:University of New Hampshire