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Herbivore-induced plant volatiles as cues for habitat assessment by a foraging parasitoid

Authors

  • CEDRIC TENTELIER,

    1. Institut National de la Recherche Agronomique, UMR 1112 ‘Réponse des Organismes aux Stress Environnementaux’, 400, Routes des Chappes, BP 167, 06903 Sophia Antipolis Cedex, France
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  • XAVIER FAUVERGUE

    1. Institut National de la Recherche Agronomique, UMR 1112 ‘Réponse des Organismes aux Stress Environnementaux’, 400, Routes des Chappes, BP 167, 06903 Sophia Antipolis Cedex, France
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Cédric Tentelier, Department of Biological and Environmental Sciences, University of Helsinki, PO Box 65, FIN-0014 Helsinki, Finland. Tel.: +358 9 19157697; Fax: +358 9 19157694; E-mail: cedric.tentelier@helsinki.fi

Summary

  • 1Animals usually require information about the current state of their habitat to optimize their behaviour. For this, they can use a learning process through which their estimate is continually updated according to the cues they perceive. Identifying these cues is a long-standing but still inveterate challenge for ecologists.
  • 2The use of plant cues by aphid parasitoids for the assessment of habitat profitability and the adaptation of patch exploitation was studied. Grounding on predictions from optimal foraging theory, we tested whether parasitoids exploited host patches less intensively after visiting heavily infested plants than after visiting plants bearing fewer aphids.
  • 3As predicted, after visiting heavily infested plants parasitoids reduced their residence time and attacked fewer hosts in the next patch. This was the case regardless of whether the aphids were actually present on the first plant, indicating that the cue came from the plant. Moreover, the level of infestation of a plant at some distance from the first plant visited affected parasitoid patch exploitation on the second plant in a similar manner, indicating that the cue was volatile.
  • 4These results highlight a novel role of herbivore-induced volatiles in parasitoid foraging behaviour, different from the widely studied attraction at a distance.

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