From Host Races to Species: Systematics of the Rhagoletis pomonella Species Complex in the Southern United States

农业植物的害虫往往表现出在新的、以前未受感染的植物物种上形成新种群的趋势。苹果蛆蝇就是一个例子，这是一种本地昆虫，最初会感染本地山楂树的果实，但大约在125年前开始感染苹果。根据过去20年的研究结果，很明显，原来的山楂蝇种群和苹果上的新种群在基因上是不同的。这一发现对农业和进化生物学都有重要意义。进化生物学预测，新的食用植物种群，如苹果蝇蛆的种群，可能会继续积累遗传差异，最终成为不同的物种。这一预测的依据是，有许多苹果蛆蝇的近亲生活在蓝莓、雪莓、山茱萸浆果和其他植物上。目前研究的目的是确定在美国南部实际存在多少种与苹果蛆蝇有关的物种，并确定它们与苹果蛆蝇的遗传相似性。这一点之所以重要，有两个原因。首先，南方物种与苹果蛆蝇极其相似，这将揭示新物种进化的第一步。其次，在南方，蓝莓和其他水果的产量正在增加，而对这些作物的果蝇的控制由于目前对这些果蝇的数量和基本生物学的无知而受到阻碍。

Insect pests of agricultural plants often show a tendency to form new populations on new, previously uninfested plant species. An example is the apple maggot fly, which is a native insect that originally infested fruits of native hawthorn trees but began infesting apples about 125 years ago. As a result of research carried out over the last 20 years, it has become clear that the original hawthorn fly populations and the new populations on apple are genetically different from one another. This finding has important implications for both agriculture and evolutionary biology. Evolutionary biology predicts that populations on new food plants, like the apple population of the apple maggot fly, may continue to accumulate genetic differences and eventually become different species. This prediction is suggested by the observation that there are many close relatives of the apple maggot fly living on fruits such as blueberry, snowberry, dogwood berries, and other plants. The purpose of the current research is to determine how many species related to the apple maggot fly actually exist in the southern United States, and determine their genetic similarity to the apple maggot fly. This is important for two reasons. First, the southern species are extremely similar to the apple maggot fly, and will reveal the first steps in the evolution of new species. Second, production of blueberries and other fruit is increasing in the South and control of the fruit flies of these crops is impeded by current ignorance of the number and basic biology of these flies.