Food web structure of three guilds of natural enemies: predators, parasitoids and pathogens of aphids

A - Papers appearing in refereed journals

Van Veen, F. J. F., Muller, C. B., Pell, J. K. and Godfray, H. C. J. 2008. Food web structure of three guilds of natural enemies: predators, parasitoids and pathogens of aphids. Journal of Animal Ecology. 77 (1), pp. 191-200. https://doi.org/10.1111/j.1365-2656.2007.01325.x

AuthorsVan Veen, F. J. F., Muller, C. B., Pell, J. K. and Godfray, H. C. J.
Abstract

1. Most communities of insect herbivores are unlikely to be structured by resource competition, but they may be structured by apparent competition mediated by shared natural enemies. 2. The potential of three guilds of natural enemies (parasitoids, fungal entomopathogens and predators) to influence aphid community structure through indirect interactions is assessed. Based on the biology, we predicted that the scope for apparent competition would be greatest for the predator and least for the parasitoid guilds. 3. Separate fully quantitative food webs were constructed for 3 years for the parasitoid guild, 2 years for the pathogen guild and for a single year for the predator guild. The webs were analysed using standard food web statistics designed for binary data, and using information-theory-based metrics that make use of the full quantitative data. 4. A total of 29 aphid, 24 parasitoid, five entomopathogenic fungi and 13 aphid specialist predator species were recorded in the study. Aphid density varied among years, and two species of aphid were particularly common in different years. Omitting these species, aphid diversity was similar among years. 5. The parasitoid web showed the lowest connectance while standard food web statistics suggested the pathogen and predator webs had similar levels of connectance. However, when a measure based on quantitative data was used the pathogen web was intermediate between the other two guilds. 6. There is evidence that a single aphid species had a particularly large effect on the structure of the pathogen food web. 7. The predator and pathogen webs were not compartmentalized, and the vast majority of parasitoids were connected in a single large compartment. 8. It was concluded that indirect effects are most likely to be mediated by predators, a prediction supported by the available experimental evidence.

KeywordsEcology; Zoology
Year of Publication2008
JournalJournal of Animal Ecology
Journal citation77 (1), pp. 191-200
Digital Object Identifier (DOI)https://doi.org/10.1111/j.1365-2656.2007.01325.x
PubMed ID17986208
Open accessPublished as non-open access
FunderBiotechnology and Biological Sciences Research Council
Funder project or codeCentre for Sustainable Pest and Disease Management (PDM)
ISSN00218790
PublisherWiley
Grant IDBB/E010857/1

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