Allochronic speciation, reproductive character displacement, and sexual selection in periodical cicadas (Magicicada spp)

周期蝉独特的生物地理格局和生活史特征导致了不寻常的物种形成事件和物种关系。每一次同步周期的蝉羽化被认为包含最多三种：13年的七叶蝉、三叶蝉和七叶蝉；或17年的七叶蝉、七叶蝉和七叶蝉。我们的遗传、生物地理和行为研究导致了1998年发现了一个新物种，它的生命周期为13年，即Magicicada new tredecm。这个新物种似乎起源于一个类似的物种，生命周期为17年。新天牛被分成两个不同年份出现的主要地理类群；因此，虽然新天牛上一次出现是在1998年，但另一个种群将在2002年出现。在下一次羽化过程中，将绘制物种分布图，获取用于遗传分析的样本，评估杂交的潜力，并评估种间相互作用对交配行为的影响。新灰蝉及其与其他类似物种的相互作用的研究为了解这一独特的物种复合体、生活史变化的机制以及同一生命周期的种群变得不同步的方式提供了有价值的信息。对这些机制的理解将为物种形成过程和物种边界的维持提供一般性的见解，这两个过程都是现代进化生物学的重要焦点。

Simon9982039Unique biogeographic patterns and life history traits of periodical cicadas have brought about extraordinary speciation events and species relationships. Each synchronized periodical cicada emergence was thought to contain up to three species: 13-year Magicicada tredecim, Magicicada tredecassini and Magicicada tredecula; or 17-year Magicicada septendecim, Magicicada cassini, and Magicicada septendecula. Our genetic, biogeographical and behavioral research led to the 1998 discovery of a new species with a 13-year life cycle, Magicicada neotredecim. This new species appears to have originated from a similar species with a 17- year life cycle. Magicicada neotredecim is divided into two major geographic groups that emerge in different years; thus, although Magicicada neotredecim last emerged in 1998, another population will emerge in 2002. During the next emergence, species distributions will be mapped, samples for genetic analysis obtained, the potential for interbreeding assessed, and the effect of interspecific interactions on mating behaviors evaluated.Study of Magicicada neotredecim and its interactions with other similar species provides valuable information about this unique species complex, the mechanisms by which life cycles change, and the ways in which populations of the same life cycle become asynchronous. The understanding of these mechanisms will provide general insights into the speciation process and the maintenance of species boundaries, both important foci of modern evolutionary biology.