Assessing the multivariate evolutionary responses of phenological differentiation of sibling species: biosystematics in the Macrosteles fascifrons complex (Homoptera: Cicadellidae)

A brief history of the concept of the Macrosteles fascifrons (Staal) complex (aster leafhoppers) in the literature is given. Taxonomic problems are discussed involving the use of the name M. fascifrons for vector work in the lower Nearctic, the origin of the holotype of Macrosteles severini Hamilton, 1983, and the taxonomic status of long-winged and short-winged Macrosteles cultures at the University of California, Berkeley. A method is presented for distinguishing, quantifying, and comparing the biologically inherent seasonal phenological differentiation between these two laboratory-reared sibling species in the complex. The results can be used in taxonomic decisions. Morphometric traits are used after variance information associated with species level differentiation is removed.