Sympatry in the Culicoides variipennis complex (Diptera : Ceratopogonidae): a taxonomic reassessment

We report sympatry among larval populations of the Culicoides variipennis c omplex in widespread and diverse aquatic habitats throughout the United Sta tes. Six sites in California, Nevada, New Mexico, and Texas were co-inhabit ed by C. v. occidentalis and C. v. sonorensis, whereas 8 sites in Florida, Georgia, Louisiana, Maryland and Texas were co-occupied by C. v. sonorensis and C. v. variipennis. No intermediate forms were identified either electr ophoretically or morphologically in adults reared from field-collected larv ae and pupae. The absence of intergrades in zones of sympatry represents su fficient evidence to confirm species status for Culicoides variipennis (Coq uillett) and Culicoides occidentalis Wirth & Jones, and to elevate Culicoid es sonorensis to species rank (NEW STATUS). Culicoides v. albertensis Wirth & Jones is a synonym of C. sonorensis (NEW SYNONYMY); C. v. australis Wirt h & Jones also is confirmed as a synonym of C. sonorensis. We also demonstr ated a correlation between population taxonomic status as determined by ele ctrophoresis and adult morphology.