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.
