Non-Host Plant Volatiles Disrupt Sex Pheromone Communication in a Specialist Herbivore.

Fumin Wang,Guoxin Zhou,Lize Shen,Bingbing Ye,Xiaohui Yin,Yonggen Lou,Jianyu Deng,Coby Schal,Zhihong Xu

doi:10.1038/srep32666

Abstract

The ecological effects of plant volatiles on herbivores are manifold. Little is known, however, about the impacts of non-host plant volatiles on intersexual pheromonal communication in specialist herbivores. We tested the effects of several prominent constitutive terpenoids released by conifers and Eucalyptus trees on electrophysiological and behavioral responses of an oligophagous species, Plutella xylostella, which feeds on Brassicaceae. The non-host plant volatile terpenoids adversely affected the calling behavior (pheromone emission) of adult females, and the orientation responses of adult males to sex pheromone were also significantly inhibited by these terpenoids in a wind tunnel and in the field. We suggest that disruption of both pheromone emission and orientation to sex pheromone may explain, at least in part, an observed reduction in herbivore attack in polyculture compared with monoculture plantings. We also propose that mating disruption of both male and female moths with non-host plant volatiles may be a promising alternative pest management strategy.

Highlights

Co-evolution among herbivores and plants shapes communities of specialist and generalist feeders
Sex pheromone blends are generally emitted by sexually receptive females that engage in a species-specific pattern of pheromone emission, termed calling behavior[5]
We speculate that the relative dearth of research on non-host plant volatiles (NHPVs) can be attributed to two reasons: First, while it is relatively easy to define “non-host”, especially for specialist herbivores, the universe of non-hosts is essentially boundless

Summary

Introduction

Co-evolution among herbivores and plants shapes communities of specialist and generalist feeders. Insects use visual and olfactory cues to assess habitat suitability[1], and volatile chemicals emitted by plants play central roles in this assessment[2]. Sex pheromone blends are generally emitted by sexually receptive females that engage in a species-specific pattern of pheromone emission, termed calling behavior[5]. Conspecific males are exquisitely and sensitive to their species-specific pheromone blend and they navigate upwind toward the calling females[6]. Both the emission of pheromone by females and male orientation to females are photoperiodically controlled. Volatile compounds play pivotal roles in direct/constitutive and indirect plant defenses, but they can affect insect reproductive behavior. Compounds considered to be NHPVs may be found in small amounts and under unique conditions in host plants as well

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