Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA.
Proc Biol Sci. 2013 Feb 27;280(1757):20130020. doi: 10.1098/rspb.2013.0020. Print 2013 Apr 22.
Plant volatiles serve as key foraging and oviposition cues for insect herbivores as well as their natural enemies, but little is known about how genetic variation within plant populations influences volatile-mediated interactions among plants and insects. Here, we explore how inbred and outbred plants from three maternal families of the native weed horsenettle (Solanum carolinense) vary in the emission of volatile organic compounds during the dark phase of the photoperiod, and the effects of this variation on the oviposition preferences of Manduca sexta moths, whose larvae are specialist herbivores of Solanaceae. Compared with inbred plants, outbred plants consistently released more total volatiles at night and more individual compounds-including some previously reported to repel moths and attract predators. Female moths overwhelmingly chose to lay eggs on inbred (versus outbred) plants, and this preference persisted when olfactory cues were presented in the absence of visual and contact cues. These results are consistent with our previous findings that inbred plants recruit more herbivores and suffer greater herbivory under field conditions. Furthermore, they suggest that constitutive volatiles released during the dark portion of the photoperiod can convey accurate information about plant defence status (and/or other aspects of host plant quality) to foraging herbivores.
植物挥发物是昆虫食草动物及其天敌觅食和产卵的关键线索，但人们对植物种群内的遗传变异如何影响植物和昆虫之间的挥发性介导的相互作用知之甚少。在这里，我们探讨了来自三种本地杂草（Solanum carolinense）母系的自交和杂交植物在光周期的暗期释放挥发性有机化合物的情况有何不同，以及这种变化对其幼虫是茄科专食性食草动物的烟夜蛾 Manduca sexta 产卵偏好的影响。与自交植物相比，杂交植物在夜间持续释放更多的总挥发物和更多的单个化合物，包括一些先前报道的能驱赶飞蛾和吸引捕食者的化合物。雌蛾压倒性地选择在自交（而非杂交）植物上产卵，即使在没有视觉和接触线索的情况下呈现嗅觉线索，这种偏好仍然存在。这些结果与我们之前的发现一致，即自交植物在野外条件下招募更多的食草动物并遭受更多的食草侵害。此外，它们表明，在光周期的暗期释放的组成型挥发物可以向觅食的食草动物传达有关植物防御状态（和/或宿主植物质量的其他方面）的准确信息。
