A chromosomal analysis of the Onthophagus similisopacicollis-fracticornis species group (Coleoptera: Scarabaeidae)

Abstract

Plain and C-banded karyotypes of Onthophagus similis, O. opacicollis and O. fracticornis are described and illustrated. All three karyotypes show clear and consistent differences from one another, and show no evidence of hybridisation between O. similis and O. opacicollis where they occur together in central Spain. It is suggested that the apparent exchange of genetic material between some Spanish populations of O. similis and O. opacicollis, inferred from the allozyme studies of Martin-Piera and Boto (1999), may be the result of alteration of gene frequencies by natural selection.