Dissertation Research: Evolutionary and Coevolutionary Forces in a Three Trophic Level Interaction

这项研究将首次探索由柳树、柳树、抓茎木蝇、真叶蜂和寄生蜂组成的三个营养级别系统中的共同进化相互作用。对相互作用的每个成员的进化力量将被研究，因为当它们可以被寄生蜂攻击时，它们为茎缩小蜂创造了一个“易受攻击的窗口”。Lathrostizus只能在有限的时间内攻击每个Euura虫胆中的幼虫，这一时间段由虫胆和木蝇的发育速度定义。初步证据表明，不同的柳树基因型和表型具有不同的“窗口”，导致寄生率有很大的差异。实验将回答以下问题：1)瘤性状是否决定了对Lathrostizus攻击的易感性，柳树Euura，柳树，或者两者之间的相互作用？2)真蜂对褐飞虱攻击的脆弱性窗口取决于植物基因吗？3)脆弱性窗口是否可以通过改变植物表型来改变？4)脆弱性窗口是否增加了资源的复杂性，降低了寄生蜂的搜索效率？5)褐飞虱更好吗？适应攻击系统中的其他画廊吗？这些结果将有助于研究三营养相互作用的基本生态学。

This research will explore for the first time coevolutionary interactions in a three trophic level system consisting of willow, Salix lasiolepis, a stem-galling sawfly, Euura lasiolepis, and a parasitoid, Lathrostizus euurae. The evolutionary forces on each member of the interaction will be studied as they create a "window of vulnerability" for the stem- galler when it can be attacked by the parasitoid. Lathrostizus can only attack larvae in each Euura gall for a limited time period defined by the developmental rates of both the gall and the sawfly. Preliminary evidence suggests that different willow genotypes and phenotypes have galls with different "windows," resulting in widely different parasitism rates. Experiments will answer the following questions: 1) Are gall characters determining vulnerability to Lathrostizus attack heritable characters of Euura, the willow, or interaction between the two? 2) Does the window of vulnerability of Euura to Lathrostizus attack depend on plant genotype? 3) Can the window of vulnerability be altered by changing plant phenotype? 4) Does the window of vulnerability increase resource complexity decreasing the searching efficiency of the parasitoid? 5) Is Lathrostizus better adapted to attacking other gallers in the system? Results will contribute to the basic ecology of tritrophic interactions.