Wilson J Keaton, Woods H Arthur
Center for Insect Science, University of Arizona, 1007 E Lowell Street, P.O. Box 210106, Tucson, AZ 85721
Organismal Biology, Ecology and Evolution, Division of Biological Sciences, University of Montana, 32 Campus Drive HS104, Missoula, MT 59812.
J Insect Sci. 2016 Dec 13;16(1). doi: 10.1093/jisesa/iew108. Print 2016.
Parasitoid insects face the fundamental problem of finding a suitable host in environments filled with competing stimuli. Many are deft sensors of olfactory cues emitted by other insects and the plants they live on, and use these cues to find hosts. Using olfactory cues from host-plants is effective because plants release volatile organic compounds (VOCs), in response to herbivory or oviposition, that contain information about the presence of hosts. However, plant-produced cues can also be misleading because they are influenced by a variety of stimuli (abiotic variation, infection and multiple sources of induction via herbivory or oviposition). Flexible behavior is one strategy that parasitoids may use to cope with variation in olfactory cues. We examine the innate and learned responses of a natural population of wasp egg parasitoids (Trichogramma deion and Trichogramma sathon) using a series of laboratory and field Y-olfactometer experiments. Wasps typically attack eggs of the hawkmoth Manduca sexta and Manduca quinquemaculata on native Datura wrightii plants in the southwestern United States. We show that Trichogramma wasps responded innately to VOCs produced by D. wrightii and could distinguish plants recently attacked by M. sexta from non-attacked plants. Furthermore, adult Trichogramma wasps were able to learn components of the VOC blend given off by D. wrightii, though they did not learn during exposure as pupae. By further exploring the behavioral ecology of a natural population of Trichogramma, we gain greater insight into how egg parasitoids function in tri-trophic systems.
寄生性昆虫面临着在充满竞争刺激的环境中找到合适宿主的基本问题。许多寄生性昆虫是其他昆虫及其所栖息植物释放的嗅觉线索的灵敏感知者，并利用这些线索来寻找宿主。利用来自宿主植物的嗅觉线索是有效的，因为植物会因食草动物取食或产卵而释放挥发性有机化合物（VOCs），这些化合物包含有关宿主存在的信息。然而，植物产生的线索也可能具有误导性，因为它们受到多种刺激（非生物变化、感染以及通过食草动物取食或产卵产生的多种诱导源）的影响。灵活的行为是寄生性昆虫可能用来应对嗅觉线索变化的一种策略。我们通过一系列实验室和野外Y型嗅觉仪实验，研究了黄蜂卵寄生蜂（Trichogramma deion和Trichogramma sathon）自然种群的先天和学习反应。黄蜂通常会在美国西南部原生的曼陀罗属植物上攻击烟草天蛾（Manduca sexta）和番茄天蛾（Manduca quinquemaculata）的卵。我们发现，赤眼蜂对曼陀罗属植物产生的挥发性有机化合物有先天反应，并且能够区分最近被烟草天蛾攻击的植物和未被攻击的植物。此外，成年赤眼蜂能够学习曼陀罗属植物释放的挥发性有机化合物混合物的成分，尽管它们在蛹期接触时并未学习。通过进一步探索赤眼蜂自然种群的行为生态学，我们对卵寄生蜂在三营养系统中的功能有了更深入的了解。
