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Cursorial spiders retard initial aphid population growth at low densities in winter wheat

Författare:
  • Klaus Birkhofer
  • E. Gavish-Regev
  • K. Endlweber
  • Y.D. Lubin
  • K. Von Berg
  • David H. Wise
  • Stefan Scheu
Publiceringsår: 2008
Språk: Engelska
Sidor: 249-255
Publikation/Tidskrift/Serie: Bulletin of Entomological Research
Volym: 98
Nummer: 3
Dokumenttyp: Artikel
Förlag: Cambridge University Press

Sammanfattning

Generalist predators contribute to pest suppression in agroecosystems. Spider communities, which form a substantial fraction of the generalist predator fauna in arable land, are characterized by two functional groups: web-building and cursorial (non-web-building) species. We investigated the relative impact of these two functional groups on a common pest (Sitobion avenae, Aphididae) in wheat by combining a molecular technique that revealed species-specific aphid consumption rates with a factorial field experiment that analyzed the impact, separately and together, of equal densities of these two spider functional groups on aphid population growth. Only cursorial spiders retarded aphid population growth in our cage experiment, but this effect was limited to the initial aphid-population growth period and low-to-intermediate aphid densities. The molecular analysis, which used aphid-specific primers to detect aphid DNA in predator species, detected the highest proportion of aphid-consuming individuals in two cursorial spiders: the foliage-dwelling Xysticus cristatus (Thomisidae) and the ground-active Pardosa palustris (Lycosidae). The results suggest that manipulating the community composition in favour of pest-consuming functional groups may be more important for improving biological control than fostering predator biodiversity per se. Agricultural management practices that specifically foster effective species or functional groups (e.g. mulching for cursorial spiders) should receive more attention in low-pesticide farming systems.

Disputation

Nyckelord

  • Biology and Life Sciences
  • aphids
  • Araneae
  • biological control
  • generalist predators
  • functional group diversity
  • DNA-based gut content analysis
  • natural enemies
  • Sitobion avenae

Övriga

Published
Yes
  • ISSN: 0007-4853 (Print)
  • ISSN: 1475-2670 (Online)

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