Navigation Links
Parasites' impact goes beyond host to affect ecosystem

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.

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 mai nland, 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 e cological studies. "Parasitism is the most common lifestyle out there," says Byers. "It’s playing a role in larger ecosystems."

Source:University of New Hampshire

Related biology news :

1. Researchers reveal the infectious impact of salmon farms on wild salmon
2. Measuring the impact of post-genomics on Mediterranean populations
3. Second messenger NAADP shows fast, dose-related impact on satiety cycle
4. The first impact factor for PLoS Biology ?13.9
5. Open Access journals get impressive impact factors
6. OHSU research shows vitamin C counteracts some negative impacts of smoking on unborn babies
7. York scientists warn of dramatic impact of climate change on Africa
8. Old drug, new tricks: Prospects for slashing the impact of malaria
9. Breath of the dragon: ERS-2 and Envisat reveal impact of economic growth on Chinas air quality
10. Amazon trees much older than assumed, raising questions on global climate impact of region
11. Health of Acehnese reefs in the wake of the tsunami shows human impacts more harmful

Post Your Comments:

(Date:11/10/2015)... Nov. 10, 2015  In this report, ... basis of product, type, application, disease indication, ... this report are consumables, services, software. The ... safety biomarkers, efficacy biomarkers, and validation biomarkers. ... are diagnostics development, drug discovery and development, ...
(Date:11/4/2015)... 4, 2015 --> ... published by Transparency Market Research "Home Security Solutions Market - ... 2015 - 2022", the global home security solutions market is expected ... 2022. The market is estimated to expand at a ... to 2022. Rising security needs among customers at homes, ...
(Date:10/29/2015)... Oct. 29, 2015 Daon, a global leader ... has released a new version of its IdentityX ... North America have already installed IdentityX ... includes a FIDO UAF certified server component ... to activate FIDO features. These customers include some of ...
Breaking Biology News(10 mins):
(Date:11/24/2015)... DIEGO , Nov. 24, 2015 Halozyme Therapeutics, Inc. ... Healthcare Conference in New York on Wednesday, ... Helen Torley , president and CEO, will provide a corporate ... New York at 1:00 p.m. ET/10:00 a.m. PT ... and investor relations, will provide a corporate overview. --> ...
(Date:11/24/2015)... /PRNewswire/ - Aeterna Zentaris Inc. (NASDAQ:  AEZS) (TSX: AEZ) (the ... the Toronto Stock Exchange, confirms that as of the ... developments that would cause the recent movements in the ... --> About Aeterna Zentaris Inc. ... Aeterna Zentaris is a specialty biopharmaceutical company engaged in ...
(Date:11/24/2015)... ... ... The Academy of Model Aeronautics (AMA), led by its Executive Council, has officially ... to represent the First–Person View (FPV) racing community. , FPV racing has exploded in ... racing and several new model aviation pilots have joined the community because of their ...
(Date:11/24/2015)... , Nov. 24, 2015 /PRNewswire/ - Aeterna ... announced today that the remaining 11,000 post-share consolidation ... Purchase Warrants (the "Series B Warrants") subject to ... exercised on November 23, 2015, which will result ... After giving effect to the issuance of such ...
Breaking Biology Technology: