Department of Plant and Soil Sciences, University of Vermont, 63 Carrigan Dr, Burlington, VT, 05405, USA.
Department of Entomology, Rutgers The State University of New Jersey, 96 Lipman Dr, New Brunswick, NJ, 08901, USA.
Sci Rep. 2019 Jul 23;9(1):10621. doi: 10.1038/s41598-019-47094-8.
Specialist insect herbivores are constrained by highly specific odor recognition systems to accept suitable host plants. Given that odor recognition leads specialist insects to accept a limited range of plants, we hypothesized that phylogenetically distant plants produce odors that are physicochemically different from host odors and would be less attractive or even repellent to a specialist herbivore. We tested this hypothesis by examining behavioral and ovipositional responses of swede midge (Contarinia nasturtii, Diptera: Cecidomyiidae), a specialist of brassicas, to broccoli sprayed with non-host essential oils. Specifically, we asked: (1) How do essential oils from different plant species influence host-seeking and oviposition behaviors of swede midge? (2) Do odors from non-host plants that are not phylogenetically related or physicochemically similar to host plants affect host-seeking or ovipositional behavior of swede midge? In oviposition assays, we found that non-host odors varied in their ability to modify female midge behavior and that phylogenetic relatedness was negatively correlated with larval density. In y-tube assays, we found that female midges most frequently avoided non-host odors that were more similar to brassica odors. Females were less likely to oviposit on or choose any treated host plants, but particularly avoided garlic, spearmint, thyme, eucalyptus lemon, and cinnamon bark treatments. Overall, we found that plant phylogenetic relatedness and odor similarity are related to repellency. Therefore, altering the diversity of plant odors by explicitly accounting for plant phylogenetic distance and odor similarity, relative to host plants, may be an important, underexploited tactic for sustainably managing challenging pests.
专业的昆虫食草动物受到高度特异性气味识别系统的限制，只能接受合适的宿主植物。鉴于气味识别使专业昆虫接受有限范围的植物，我们假设进化上相距较远的植物产生的气味在物理化学上与宿主气味不同，对专业食草动物的吸引力较小，甚至可能具有驱避性。我们通过检查小菜蛾（Contarinia nasturtii，双翅目：瘿蚊科）的行为和产卵反应来检验这个假设，小菜蛾是十字花科的专食者，小菜蛾被喷洒了非宿主精油的西兰花。具体来说，我们提出了以下问题：（1）来自不同植物物种的精油如何影响小菜蛾的寻宿主和产卵行为？（2）与宿主植物在进化上不相关或在物理化学上不相似的非宿主植物的气味是否会影响小菜蛾的寻宿主或产卵行为？在产卵测定中，我们发现非宿主气味在改变雌性小菜蛾行为的能力上存在差异，并且进化关系与幼虫密度呈负相关。在 Y 型管测定中，我们发现雌性小菜蛾最常回避与十字花科气味更相似的非宿主气味。雌虫不太可能在任何处理过的宿主植物上产卵或选择产卵，而是特别回避大蒜、留兰香、百里香、柠檬桉树和肉桂树皮处理。总的来说，我们发现植物进化关系和气味相似性与驱避性有关。因此，通过明确考虑植物进化距离和气味相似性相对于宿主植物来改变植物气味的多样性，可能是可持续管理具有挑战性的害虫的一种重要但尚未充分利用的策略。
