Featured Research

from universities, journals, and other organizations

Parasites' Impact Goes Beyond Host To Affect Ecosystem

Date:
May 15, 2007
Source:
University of New Hampshire
Summary:
New research 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.

Cryptocotyle lingua, the dominant trematode parasite infecting the snail Littorina littorea. Infected snails graze less ephemeral algae with resultant effects on intertidal community composition.
Credit: Chelsea Wood and James E. Byers

The good news, if you're grazing normally on algae in the rocky intertidal zone of the North Atlantic, is that you may not be infected by a parasite. But the better news is, according to new research from the University of New Hampshire, that you might have more to eat if plenty of your neighbors are infected.

Related Articles


The research, published in this week's Proceedings of the National Academy of Sciences Early Edition, 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 mainland, approximately half the snails on Appledore Island are infected. That's because L. littorea is just one of three hosts in the life cycle of C. lingua, which first lives in the snails' gonads then moves to a fish as its second host. Shorebirds -- more prevalent on Appledore than on the mainland -- are the final hosts, contracting infection by eating infected fish, then in their feces excreting the eggs of C. lingua, which are in turn eaten by the snails.

"The parasite's life cycle is a really amazing strategy for an organism that doesn't have a brain," says Byers, who predicts that anywhere gulls are prevalent, the C. lingua trematode would also be prevalent.

A laboratory experiment confirmed Wood's and Byers' hypothesis: snails infected with the parasite ate 40 percent less macroalgae than uninfected snails. In the field, where researchers measured the macroalgae in three types of bottomless cages -- with no snails (control), uninfected snails, and infected snails -- they similarly saw less reduction of ephemeral algae by infected snails.

But when researchers isolated ephemeral, or edible, algae, "we saw dramatic change," says Byers. Edible algae account for a small proportion of macroalgae on rocky shorelines -- just about seven percent -- but they are an important food and habitat resource for a variety of organisms. Over the three-and-a-half-week field experiment, ephemeral algae increased 186 percent in the no-snails control cage and 59 percent in the cage of infected snails; it decreased by six percent in the uninfected snails treatment.

"Whatever controls that edible algae controls a lot," says Byers, noting that other snails, isopods, and possibly near-shore fish feed on ephemeral algae. "It's suggestive that these non-lethal impacts of parasites have influential effects that can trickle down to affect other residents of the ecosystem."

Byers' and Wood's study signals an increasing appreciation for parasites in ecological studies. "Parasitism is the most common lifestyle out there," says Byers. "It's playing a role in larger ecosystems."


Story Source:

The above story is based on materials provided by University of New Hampshire. Note: Materials may be edited for content and length.


Cite This Page:

University of New Hampshire. "Parasites' Impact Goes Beyond Host To Affect Ecosystem." ScienceDaily. ScienceDaily, 15 May 2007. <www.sciencedaily.com/releases/2007/05/070514174251.htm>.
University of New Hampshire. (2007, May 15). Parasites' Impact Goes Beyond Host To Affect Ecosystem. ScienceDaily. Retrieved April 21, 2015 from www.sciencedaily.com/releases/2007/05/070514174251.htm
University of New Hampshire. "Parasites' Impact Goes Beyond Host To Affect Ecosystem." ScienceDaily. www.sciencedaily.com/releases/2007/05/070514174251.htm (accessed April 21, 2015).

Share This


More From ScienceDaily



More Plants & Animals News

Tuesday, April 21, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Going Ape: Sierra Leone Chimpanzees Hail Ebola Retreat

Going Ape: Sierra Leone Chimpanzees Hail Ebola Retreat

AFP (Apr. 21, 2015) As money runs out at Tacugama Chimpanzee Sanctuary in Sierra Leone, around 85 chimps are facing homelessness. The centre closed when the Ebola epidemic was ravaging the country but now that closure is beginning to look permanent. Video provided by AFP
Powered by NewsLook.com
Blue Bell Recalls All Products

Blue Bell Recalls All Products

AP (Apr. 21, 2015) Blue Bell Creameries voluntary recalled for all of its products after two samples of chocolate chip cookie dough ice cream tested positive for listeria, a potentially deadly bacteria. Blue Bell&apos;s President and CEO issued a video statement. (April 21) Video provided by AP
Powered by NewsLook.com
Deepwater And Dolphins: The Oil Spill's Impact 5 Years On

Deepwater And Dolphins: The Oil Spill's Impact 5 Years On

Newsy (Apr. 20, 2015) Five years on, the possible environmental impact of the Deepwater Horizon spill includes a sustained die-off of bottlenose dolphins, among others. Video provided by Newsy
Powered by NewsLook.com
Five Years Later, the BP Oil Spill Is Still Taking Its Toll

Five Years Later, the BP Oil Spill Is Still Taking Its Toll

AFP (Apr. 20, 2015) On April 20, 2010, an explosion and fire on the Deepwater Horizon rig in the Gulf of Mexico started the biggest oil spill in US history. BP recently reported the Gulf is recovering well, but scientists paint a different picture. Duration: 02:36 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins