Parasites Dominate Food Web Links

Parasitism is the most common animal lifestyle, yet food webs rarely include parasites. The few earlier studies have indicated that including parasites leads to obvious increases in species richness, number of links, and food chain length. A less obvious result was that adding parasites slightly red...

Full description

Saved in:
Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2006-07, Vol.103 (30), p.11211-11216
Main Authors: Lafferty, Kevin D., Dobson, Andrew P., Kuris, Armand M.
Format: Article
Language:English
Subjects:
Animal behavior
Animals
Biodiversity
Biological Evolution
Biological Sciences
Biomass
Ecology - methods
Ecosystem
Ecosystems
Food Chain
Food chains
Food webs
Hyperlinks
Models, Biological
Parasite hosts
Parasites
Parasites - physiology
Parasitism
Predators
Predatory Behavior
Salt marshes
Snails
Trophic levels
Trophic relationships
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Parasitism is the most common animal lifestyle, yet food webs rarely include parasites. The few earlier studies have indicated that including parasites leads to obvious increases in species richness, number of links, and food chain length. A less obvious result was that adding parasites slightly reduced connectance, a key metric considered to affect food web stability. However, reported reductions in connectance after the addition of parasites resulted from an inappropriate calculation. Two alternative corrective approaches applied to four published studies yield an opposite result: parasites increase connectance, sometimes dramatically. In addition, we find that parasites can greatly affect other food web statistics, such as nestedness (asymmetry of interactions), chain length, and linkage density. Furthermore, whereas most food webs find that top trophic levels are least vulnerable to natural enemies, the inclusion of parasites revealed that mid-trophic levels, not low trophic levels, suffered the highest vulnerability to natural enemies. These results show that food webs are very incomplete without parasites. Most notably, recognition of parasite links may have important consequences for ecosystem stability because they can increase connectance and nestedness.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.0604755103