Sympatric Speciation via Host or Habitat Specialization: An Experimental Test

生物学中一个有争议的问题是，当没有地理屏障将早期物种分开时，物种形成（即一个物种分裂成两个物种）是否会发生。据推测，没有地理隔离的物种形成发生在以寄主为交配地点的植食性昆虫中：如果一个种群分化成两个以不同寄主为食的种群，那么产生的种群将不再相遇。提出的工作将调查宿主偏好的差异和随之而来的交配隔离是否会发生在普通果蝇的实验室种群中，果蝇。在每一代中，未交配的苍蝇将被允许在两个需要不同苍蝇属性的宿主之间进行选择，以成功繁殖。交配只会发生在选择同一寄主的苍蝇之间。将监测实验种群分成具有不同寄主偏好的两个种群的程度。这些结果将有助于生物学家了解植物食性昆虫的物种形成机制，昆虫是地球上最多样化的生物群体之一。研究结果还将揭示以非作物物种为食的昆虫物种如何以作物物种为食形成新种族的机制。

A contentious issue in biology is whether speciation, the splitting of one species into two, can occur when no geographic barrier separates the incipient species. Speciation without geographic isolation has been hypothesized to occur in plant-feeding insects that use the host as a rendezvous for mating: if a population diverges into two populations that feed on different hosts, the resulting populations will no longer encounter each other. The proposed work will investigate whether divergence in host preference and consequent mating isolation can occur in a laboratory population of the common fruit fly, Drosophila melanogaster. In each generation, unmated flies will be allowed to choose between two hosts that require different fly attributes for successful breeding. Mating will take place only between flies that chose the same host. The extent to which the experimental population splits into two populations with different host preferences will be monitored.The results will aid biologists' understanding of the mechanisms of species formation in plant-feeding insects, one of the most diverse groups of organisms on earth. The results will also shed light on the mechanisms by which insect species that feed on non-crop species can form new races on crop species.