Genetic, ecological and morphological differences among populations of the cactophilic Drosophila mojavensis from southwestern USA and northwestern Mexico, with descriptions of two new subspecies

Abstract

A variety of molecular markers have consistently shown that little gene flow occurs among the geographically isolated populations of the cactophilic Drosophila mojavensis Patterson and Crow of southwestern USA and northwestern Mexico. The molecular studies support previous subspecies designations of D. mojavensis (D. m. mojavensis from the Mojave Desert and D. m. baja from the Baja California peninsula) and, in addition, suggest that two additional subspecies should be recognized (D. m. sonorensis from Sonora and Sinaloa, Mexico to southern Arizona and D. m. wrigleyi from Santa Catalina Island, California). Here we review evidence from studies on population genetics, ecology and behaviour that supports the subspecies assignments in D. mojavensis, and provide descriptions of D. m. sonorensis and D. m. wrigleyi. We also provide redescriptions of D. m. mojavensis and D. m. baja. Morphologically, the four subspecies are similar in external appearance, but showed differences in the male genitalia.