Hyperparasitoids exploit herbivore-induced plant volatiles during host location to assess host quality and non-host identity

Antonino Cusumano*, Jeffrey A. Harvey, Marcel Dicke, Erik H. Poelman

*Corresponding author for this work

    Research output: Contribution to JournalArticleAcademicpeer-review

    Abstract

    Although consumers often rely on chemical information to optimize their foraging strategies, it is poorly understood how top carnivores above the third trophic level find resources in heterogeneous environments. Hyperparasitoids are a common group of organisms in the fourth trophic level that lay their eggs in or on the body of other parasitoid hosts. Such top carnivores use herbivore-induced plant volatiles (HIPVs) to find caterpillars containing parasitoid host larvae. Hyperparasitoids forage in complex environments where hosts of different quality may be present alongside non-host parasitoid species, each of which can develop in multiple herbivore species. Because both the identity of the herbivore species and its parasitization status can affect the composition of HIPV emission, hyperparasitoids encounter considerable variation in HIPVs during host location. Here, we combined laboratory and field experiments to investigate the role of HIPVs in host selection of hyperparasitoids that search for hosts in a multi-parasitoid multi-herbivore context. In a wild Brassica oleracea-based food web, the hyperparasitoid Lysibia nana preferred HIPVs emitted in response to caterpillars parasitized by the gregarious host Cotesia glomerata over the non-host Hyposoter ebeninus. However, no plant-mediated discrimination occurred between the solitary host C. rubecula and the non-host H. ebeninus. Under both laboratory and field conditions, hyperparasitoid responses were not affected by the herbivore species (Pieris brassicae or P. rapae) in which the three primary parasitoid species developed. Our study shows that HIPVs are an important source of information within multitrophic interaction networks allowing hyperparasitoids to find their preferred hosts in heterogeneous environments.

    Original languageEnglish
    Pages (from-to)699-709
    Number of pages11
    JournalOecologia
    Volume189
    Issue number3
    Early online date5 Feb 2019
    DOIs
    Publication statusPublished - Mar 2019

    Funding

    Acknowledgements The authors thank Léon Westerd, André Gidding and Frans van Aggelen for culturing insects and the experimental farm of Wageningen University (Unifarm) for rearing plants. Field assistance by Gabriel Joachim was appreciated. AC acknowledges funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Grant agreement No. 655178. EHP was supported by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant agreement No. 677139).

    FundersFunder number
    Horizon 2020 Framework Programme655178, 677139
    European Research Council

      Keywords

      • Fourth trophic level organisms
      • Hyperparasitoid foraging behavior
      • Multitrophic interactions
      • Non-host parasitoid species
      • Plant-based food web

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