Comparison of plant preference hierarchies of male and female moths and the impact of larval rearing hosts

Authors

  • Gunda Thöming,

    Corresponding author
    1. Swedish University of Agricultural Sciences, Department of Plant Protection Biology, Division of Chemical Ecology, Box 102, SE-23053 Alnarp, Sweden
    • Present address: Norwegian Institute for Agricultural and Environmental Research–Bioforsk, Division of Plant Health and Plant Protection, Høgskoleveien 7, NO-1432 Ås, Norway. E-mail: gunda.thoeming@bioforsk.no

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  • Mattias C. Larsson,

    1. Swedish University of Agricultural Sciences, Department of Plant Protection Biology, Division of Chemical Ecology, Box 102, SE-23053 Alnarp, Sweden
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  • Bill S. Hansson,

    1. Swedish University of Agricultural Sciences, Department of Plant Protection Biology, Division of Chemical Ecology, Box 102, SE-23053 Alnarp, Sweden
    2. Max Planck Institute for Chemical Ecology, Department of Evolutionary Neuroethology, Hans-Knöll-Strasse 8, DE-07745 Jena, Germany
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  • Peter Anderson

    1. Swedish University of Agricultural Sciences, Department of Plant Protection Biology, Division of Chemical Ecology, Box 102, SE-23053 Alnarp, Sweden
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  • Corresponding Editor: J. A. Rosenheim.

Abstract

Selection of a suitable host plant is essential for the fitness of herbivorous insects. For polyphagous insects the underlying proximate mechanisms for host plant selection, including phenotypic plasticity, remain only partially understood. We established an experimental protocol evaluating preferences to five plant species in males and females of the polyphagous moth Spodoptera littoralis. Female preference hierarchies were assessed by oviposition decisions; those of males were assessed by the attraction to female sex pheromones in background odors of different plant species. The experiments revealed clear preference hierarchies in both males and females, which were partly overlapping in spite of the different behavioral contexts of the respective assays. Furthermore, we demonstrated strong effects of the larval rearing host on adult plant preference, where the larval host plant species was generally elevated to the most preferred plant in both sexes, without otherwise affecting the overall preference hierarchy. Our results suggest that both sexes are involved in host plant choice and that experience-based convergent intersexual plant preferences may confer selective advantages. The host plant choice is guided by a stable plant preference hierarchy, which can be modified by the larval rearing host, permitting fast adaptation to variation in local conditions and to novel environments. It may also provide a mechanism for reducing costs associated with polyphagy by functional plasticity in plant choice.

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