Chemical ecology: migration and tritrophic interactions

帝王蝶的季节性迁徙已经有了很好的记录，但我们仍然不知道出生在北美的帝王蝶是如何定位在墨西哥年复一年使用的特定越冬地点的。我们将进行实验，以检验这样一种假设，即前几代蝴蝶留下的化合物积累在寄主树的蜡中作为迁徙的线索，这些化合物是基于通过幼虫和成虫喂养植物获得的化合物。如果这是真的，这不仅将回答与这一令人惊叹的自然现象有关的重要悬而未决的问题之一，而且还将为物种保护提供一个潜在的工具。粘虫是一种季节性迁徙的谷物害虫，我们一直以该物种为模式系统来研究飞蛾的迁徙。我们正在将实验室中卧式迁徙行为下的生理学研究扩展到野外。这项拟议的研究将有助于我们理解迁徙飞蛾的生态生理学，包括迁徙飞行和未来繁殖之间的权衡，并确定觅食基因是否在迁徙中发挥作用。植物在受到食草动物的攻击后会释放挥发物，这是有充分证据的，这些挥发物参与了防御的上调。此外，食草动物的天敌利用这些挥发物作为觅食线索。然而，大多数工作都是在有限的生态条件下进行的，我们没有真正了解这些线索在不同的生态条件下有多重要。利用威斯康星大学生物加速器气候变化研究中心的独特设施，我们将研究一系列不同的气候条件如何影响植物防御系统的上调，因为寄生蜂对由此产生的挥发物的反应。所获得的结果将有助于理解气候变化将如何影响植物防御的诱导，有助于确定落叶植物的挥发物在多大程度上作为有益昆虫的觅食线索，并澄清这些化合物是否真的有可能在综合害虫管理计划中发挥作用。

The seasonal migration of the monarch butterfly has been well documented yet we still do not understand how the monarchs, born in North America, locate the specific overwintering sites, used year after year in Mexico. We will carry out experiments to test the hypothesis that compounds left by previous generations of butterflies accumulate in the waxes of host trees serve as cues for immigrants, and that these are based on compounds acquired from plants through larval and adult feeding. If true, this will not only answer one of important unanswered questions related to this amazing natural phenomenon, but also provide a potential tool for the conservation of the species. The armyworm is a seasonal migrant cereal pest and we have been using this species as a model system to study moth migration. We are extending our studies of the physiology under lying migratory behavior in the laboratory into the field. The propsed research will contribute to our understanding of eco-physiology in migrant moths, including tradeoffs between migratory flight and future reproduction, and determine if a foraging gene plays a role in migration. It has been well documented that plants emit volatiles following attack by a herbivore and that these are involved in the up-regulation of defenses. Furthermore, natural enemies of herbivores use these volatiles as foraging cues. However, most of the work has been carried out under a limited range of ecological conditions and we have no real understanding of the how important these cues are under variable ecological conditions. Using the unique facilities in the Biotron Climate Change Research Center at UWO we will examine how an array of different climatic conditions affect the up-regulation of plant defenses as the responses of parasitoids to the resulting volatiles. The results obtained will help understand how climate change will affect the induction of plant defenses, help determine to what extent volatiles from defoliated plants serve as foraging cues for beneficial insects and clarify whether there really is any potential for these compounds in integrated pest management programs.