DISSERTATION RESEARCH: Genetic and Ecological Bases of Hostplant Specialization.

对于任何生物体来说，帮助生物体适应环境的复杂性状的遗传基础都没有得到很好的理解。当密切相关的物种对环境的适应不同时，这些特征的基础就特别引人入胜了。Heliothis subflexa和Heliothis virescens就是这样一对物种：最近从共同的祖先进化而来，它们99%的基因相似。尽管有这种遗传上的相似性，但它们在取食的寄主植物的数量和多样性上却有根本的不同。Heliothis subflexa是单食的，只以Physalis植物为食，而Heliothis virescens是一个饮食的多面手，以14个植物科为食。本研究的目的是确定多能植物Heliothis virescens对Physalis植物的利用是否受到与Heliothis subflexa相同的染色体的控制，以及对Physalis使用的选择是否有助于宏观进化分化。生态上重要的性状既可以影响基本的生物现象（如物种形成），也可以影响物种之间更高层次的相互作用（如害虫对农业生产的影响）。更好地了解它们的遗传基础可能会对我们理解适应和物种形成之间的关系产生深远的影响。此外，阐明昆虫寄主范围的遗传机制可以为控制重要农业害虫提供新的方法。

The genetic basis of complex traits that help organisms adapt to their environment is not well understood for any organism. The basis of such traits is particularly fascinating when closely related species differ in adaptation to their environment. Heliothis subflexa and Heliothis virescens are one such species pair: recently evolved from a shared ancestor, they are 99% genetically similar. In spite of this genetic similarity, they differ radically in the number and diversity of hostplants fed upon. Heliothis subflexa is monophagous, feeding only on Physalis plants, while Heliothis virescens is a dietary generalist, feeding on 14 plant families. The goal of this proposal is to determine whether use of Physalis plants by the generalist Heliothis virescens is controlled by the same chromosomes as in Heliothis subflexa, and whether selection for use of Physalis contributes to macroevolutionary divergence. Ecologically important traits can affect both basic biological phenomena (e.g., speciation) and higher level interactions between species (e.g., the impact of insect pests on agricultural production). An improved understanding of their genetic bases could have profound impact on our understanding of the relationship between adaptation and speciation. In addition, clarification of the genetic mechanisms underlying insect hostplant range could lead to novel ways of controlling agriculturally important pest species.