Genetic and Host Plant Influences in Insect Population Differentiation

专门以某些植物群为食的昆虫是解决进化生物学中两个基本问题的重要实验生物。这些是什么因素影响生物体新品种或新种族的出现？2)什么因素决定了进化的速度和方向？当新的植物被引入或入侵昆虫已经以相关植物为食的地区时，就会发现新的昆虫品种。丁格尔博士建议研究一种以各种相关植物为食的昆虫，这种昆虫在其活动范围的部分地区，已经转变为作为观赏植物引入的植物物种。丁格尔博士将通过检查基因和环境对这种进化的影响来研究分化的进化。丁格尔博士还将研究这两个种群的宿主选择基础，并测试这两个种群是否仍会杂交。通过这种方式，丁格尔博士将试图了解这两个种群是否分化到足以成为不同的物种。对新寄主植物的适应问题具有相当重要的基础和实际意义。大多数重要的农作物都是引进来的，了解昆虫如何适应它们并成为害虫是很重要的。许多外来植物是偶然引进的，可能因此“逃脱”了通常以它们为食的昆虫，成为大量的杂草。为了控制它们，了解新的昆虫如何适应它们并取代它们留下的天敌是有用的。这里研究的这种昆虫特别有用，因为寄主植物的一个开关的影响，即口部结构的巨大变化，是很容易测量和操纵的。由于这种转换，这种昆虫在捕食不同植物的口器结构上发生了进化变化。因此，该研究在尽量减少昆虫对引进作物的损害和最大限度地损害引进杂草方面具有很大的潜力。

Insects which specialize in feeding on only certain groups of plants are important experimental organisms for addressing two fundamental questions in evolutionary biology. These are 1) what factors influence the appearance of new varieties or races of organisms? and 2) what factors determine the rate and direction of evolution? New varieties of insects have been found when new plants are introduced to or invade areas where an insect is already feeding on a related plant. Dr. Dingle proposes to study an insect species that feeds on various species of related plants and has switched in parts of its range to plant species that have been introduced as ornamentals. Dr. Dingle will study the evolution of the differentiation by examining the influence of genes and the environment on this evolution. Dr. Dingle will also examine the basis of host choice in the two populations and test to see if the two populations will still interbreed. In this way Dr. Dingle will attempt to learn if the two populations have differentiated enough to be separate species. The problem of adaptation to new host plants is of considerable basic and practical importance. Most important crop plants are introduced and it is important to know how readily insects can adapt to them and become pests. Many alien plants are accidentally introduced and may thus "escape" the insects which normally feed on them to become abundant weeds. To control them it is useful to know how readily new insects can adapt to them and replace the natural enemies they left behind. The insect studied here is particularly useful because the effect of a switch in host plants, a dramatic change in mouth part structure, is so easy to measure and manipulate. As a result of this switch, the insect has evolved changes in the structure of mouth parts used in feeding on the different plants. The research thus holds great potential for minimizing insect damage to introduced crops and to maximize damage to introduced weeds.