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Coexistence In Unisexual-Bisexual Species Complexes Of Poeciliopsis (Pisces: Poeciliidae), William S. Moore, Frances E. Mckay

Biological Sciences Faculty Research Publications

All-female forms of Poeciliopsis rely on males of closely related bisexual species for sperm. The natural habitat of Poeciliopsis in Sonora, Mexico, consists of a variety of small ponds connected by intermittent watercourses. Optimal areas, containing mixed female aggregates, are defended by territorial males. Social structure in natural populations very closely resembles that of laboratory experiments, wherein subordinant males show reduced mate discrimination and inseminate unisexuals.

An equation relating male density to unisexual inseminations is used in a computer simulation model of a population. A stable equilibrium is inherent in unisexual-bisexual species complexes but the level of equilibrium is affected …