Navigation Links
Does including parasites upset food web theory? Yes and no, says new paper
Date:6/14/2013

Parasites comprise a large proportion of the diversity of species in every ecosystem. Despite this, they are rarely included in analyses or models of food webs. If parasites play different roles from other predators and prey, however, their inclusion could fundamentally alter our understanding of how food webs are organized.

In the journal PLOS Biology this week, Santa Fe Institute Professor Jennifer Dunne and collaborators test this assertion and show that including parasites in ecological datasets does alter the structure of food webs, but that most changes occur because of an increase in diversity and complexity rather than from unique characteristics of parasites.

"Current food web models and theory were developed with data for free-living species," says Dunne. "We wanted to understand whether including parasites alters network structure in unique ways, or if observed changes are consistent with the addition of any types of species and links to a food web."

The group of researchers, which included parasitologists and food web ecologists, analyzed highly resolved datasets for seven coastal estuary and marine food webs. They compared three versions of each food web dataset: webs without parasites; webs that included parasites and all of their links to other species; and an intermediate case that included parasites but excluded the "concomitant" links between a predator and the parasites of its prey.

The team found that including parasites altered many aspects of network structure, such as the distribution of feeding links per species, the average shortest feeding chain between pairs of species, and the proportion of species that are omnivores or cannibals. But a closer look suggested that most of these changes were generic effects of increasing the overall diversity and complexity of the network, rather than unique effects attributable to the parasites' roles in food webs.

"Our analyses show that in many ways parasites are similar to other species in terms of their effects on food web organization," says Dunne.

However, the team did find two cases where parasites seem to play special roles that alter aspects of food web structure. One case is when a parasite is eaten along with its host. "The physical intimacy between a parasite and its host is not found as frequently between free-living predators and prey," Dunne says. "The fact that predators incidentally feed on the parasites of their prey can alter certain patterns of interactions among species."

The other case appears to result from the complex life cycles of many of the parasites in these food webs. Parasites can shift hosts in a dramatic fashion, for example by starting out with a cricket as a host, but later requiring a fish host. This results in a more structurally complex feeding niche than is seen for most free-living predators.

"Our research extends the generality of food web theory and provides a more rigorous framework for assessing the impact of any species on trophic organization," says Dunne. "However, it also reveals limitations of current food web models when they are applied to the more diverse and highly resolved data that researchers are increasingly compiling."


'/>"/>

Contact: Dr. Jennifer Dunne
jdunne@santafe.edu
Santa Fe Institute
Source:Eurekalert

Related biology news :

1. Study helps managers identify regions with multiple threat potential, including wildfires
2. Geosphere features top geoscience technology, including LiDAR, EarthScope, CHIRP, ALSM, and IODP
3. Team including UC Riverside entomologist honored for research leading to healthier potato chips
4. New research underscores the health benefits of fibers, including bone health
5. Do parasites upset food web theory?
6. Young malaria parasites refuse to take their medicine, may explain emerging drug resistance
7. Parasites of Madagascars lemurs expanding with climate change
8. Belgian scientists develop way to detect superparasites
9. Single-cell parasites co-opt ready-made genes from host: UBC research
10. Elsevier launches International Journal for Parasitology: Parasites and Wildlife
11. T cells hunt parasites like animal predators seek prey, a Penn Vet-Penn Physics study reveals
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/17/2017)... NXT-ID, Inc. (NASDAQ: NXTD ) ("NXT-ID" or the ... Annual Report on Form 10-K on Thursday April 13, 2017 with ... ... Relations section of the Company,s website at http://www.nxt-id.com  under "SEC ... . 2016 Year Highlights: Acquisition ...
(Date:4/11/2017)... 11, 2017 Crossmatch®, a globally-recognized leader ... today announced that it has been awarded a ... Activity (IARPA) to develop next-generation Presentation Attack Detection ... "Innovation has been a driving force within Crossmatch ... allow us to innovate and develop new technologies ...
(Date:4/11/2017)... April 11, 2017 NXT-ID, Inc. (NASDAQ: ... company, announces the appointment of independent Directors Mr. Robin ... its Board of Directors, furthering the company,s corporate governance and ... Gino Pereira ... look forward to their guidance and benefiting from their considerable ...
Breaking Biology News(10 mins):
(Date:9/20/2017)... ... September 20, 2017 , ... The award-winning producers ... (Koch) to feature new innovations aimed at helping farmers solve the problem of ... Farmer airs Tuesdays at 8:30aET on RFD-TV. Check your local listings for more ...
(Date:9/20/2017)... ... , ... Diversity focused business accelerator, The Refinery , announced today they ... the top technology-driven, women-led startups in Boston, MA, New Haven/Hamden, CT, and Newark, NJ. ... going on that week – in Boston, it will be part of the City ...
(Date:9/20/2017)... ... September 20, 2017 , ... ... Huron Digital Pathology , a provider of whole slide imaging solutions, are ... conference . The workshop, entitled “Successfully Deploying a Best-in-Class Strategy for Digital Pathology,” ...
(Date:9/20/2017)... ... September 20, 2017 , ... From industry leaders, sports stars, ... standard medicine failed. Many of these people had lost all hope. Their ... Free Download (pdf) , “Neil takes readers on a riveting journey ...
Breaking Biology Technology: