Dissertation Research: The Evolution of a Host-Parasitoid Association.

9700696根种群分化在物种相互作用进化中的作用没有得到很好的证明。选择可能因种群而异，导致某些领域的共同进化相互作用和其他领域的非互惠进化。豌豆蚜是豆科作物的重要害虫，其寄生蜂是二色蚜茧蜂。在纽约，专门吃苜蓿的豌豆蚜虫比专门吃三叶草的豌豆蚜虫对寄生的抵抗力高出两到三倍。耐药性是由基因决定的，也是基于生理的。它不是寄主植物诱导效应的产物，也不是两种作物上的任何一种昆虫的产物。拟议的研究集中在三个领域。1)对来自另外两个地理区域（马里兰州和法国）的两种作物上的豌豆蚜虫的调查将表明所观察到的相对抗性模式的一般性。2)实验室中的相互移植实验将确定昆虫是否在其地理区域内适应当地环境。3)将进行一项实验，以确定豌豆蚜虫抗性遗传变异的相对大小，从三叶草和苜蓿。这将表明，尽管两种作物都有很强的选择性，但三叶草中较低水平的遗传变异是否会减缓抗性的进化。这项研究是重要的，在提高物种相互作用的演变的基本理解，并将提供洞察物种相互作用的演变对生物控制程序的效力的影响。

9700696 ROOT The role of population differentiation in the evolution of species interactions is not well documented. Selection can differ by population, leading to coevolutionary interactions in some areas and non reciprocal evolution in other areas. The pea aphid, a pest of legume crops, is attacked by the parasitoid, Aphidius ervi. Pea aphids in New York which specialize on alfalfa are two or three times more resistant to parasitism than pea aphids specialized on clover. Resistance is genetically determined and physiologically based. It is not a product of host-plant induced effects or either insect species on the two crops. The proposed research focuses on three areas. 1) A survey of pea aphids on both crops from two other geographical area, Maryland and France, will indicate the generality of the observed pattern of relative resistance. 2) Reciprocal transplant experiments in the lab will determine whether the insects are locally adapted within their geographic region. 3) An experiment will be performed to ascertain the relative magnitude of genetic variation for resistance in pea aphids from clover and from alfalfa. This will indicate if lower levels of genetic variation in clover could be slowing the evolution of resistance despite strong selection in both crops. This research is important in enhancing a basic understanding of the evolution of species interactions, and will provide insight in the effects of the evolution of species interactions on the efficacy of biological control programs.