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

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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.