Dissertation Research: Physiological/Biochemical Tradeoffs with Host Specialization: Ecological Implications for Generalist and Specialist Saturniids (Callosamia spp)

很少有昆虫食草动物利用木兰弗吉尼亚（sweetbay）作为一个 寄主植物，一种是甜湾蚕蛾，Callosamia securifera （土星科）。 然而，密切相关的物种遭受100% 这种植物的死亡率。 初步的植物化学研究表明 死亡率是由于至少两种杀虫化合物， 厚朴酚和联苯醚。 这项研究将描述 生理/生化适应C.安全到木兰 通过比较其解毒机制与两种 同类无法耐受宿主的化学物质 体外和 将使用体内实验来鉴定酶 解毒系统 此外，由于三个Callosamia 物种似乎最近已经分化，并有一些重叠， 宿主使用、消化效率的可能权衡以及 解毒酶活性可能有利于寄主植物 将测试属中的专业化。 具体地说， 预测1）专家有更高的消化效率 比通才和2）通才有更高的水平或3）更高 广泛底物特异性解毒活性的诱导 专家们将接受测试。 与详细 特征的特定解毒机制所使用的C。 securifera科普毒素在其主机，它可能是可能的， 提出更好的关于生物化学权衡的假设 与主机专业化相关。

Few insect herbivores utilize Magnolia virginiana (sweetbay) as a hostplant, one being the sweetbay silkmoth, Callosamia securifera (Saturniidae). However, closely related species suffer 100% mortality on this plant. Preliminary phytochemical work indicates that mortality is due to at least two insecticidal compounds, magnolol and biphenyl ether. This study will characterize physiological/biochemical adaptations of C. securifera to Magnolia by comparing its detoxification mechanisms with those of two congeners unable to tolerate this host's chemicals. In vitro and in vivo experiments will be used to identify enzymatic detoxification systems. In addition, because the three Callosamia species appear to have recently diverged and have some overlap in host use, possible tradeoffs in digestive efficiency and detoxification enzyme activity that may have favored hostplant specialization in the genus will be tested. Specifically, predictions that 1) specialists have higher digestive efficiency than generalists and 2) generalists have higher levels or 3) higher inducibility of broad substrate-specificity detoxification activity than specialists will be tested. With the detailed characterization of specific detoxification mechanisms used by C. securifera to cope with toxins in its host, it may be possible to formulate better hypotheses concerning biochemical tradeoffs associated with host specialization.