Reconsidering the taxomony of several Ostrinia species in the light of reproductive isolation: a tale for Ernst Mayr

Abstract

We reconsider the taxonomy of a group of closely related Ostrinia spp., illustrating how useful Mayr's biological spe- cies concept remains for studying speciation patterns and processes. We review and re-analyse recent data on Ostrinia scapulalis , Ostrinia nubilalis , Ostrinia narynensis and Ostrinia orientalis , along with those obtained over > 45 years in the former Soviet Union. The ten species of the 'trilobed uncus' group in the Ostrinia genus are clas- sified into subgroups according to male mid-tibia morphology. However, none of the characters that further discrim- inate between them (female sex pheromones, male genitalia and calling time) varies together with male mid-tibia morphology, and neither do molecular markers. Moreover, male mid-tibia morphology appears to depend on only two diallelic loci and seems to be unrelated to reproductive isolation between Ostrinia taxa. By contrast, reproductive iso- lation is strongly related to host-plant type. In accordance with Mayr's species concept, we thus propose a revision of the trilobed uncus Ostrinia spp. based primarily on host-plant type. We propose that O. narynensis Mutuura & Munroe, 1970 ( syn. nov. ) and O. orientalis Mutuura & Munroe, 1970 ( syn. nov. ) be synonymized with O. scapulalis (Walker, 1859). We further demonstrate that O. nubilalis auctt. pro parte feeding on mugwort, hop, and several other dicotyledons (previously called the ' O. nubilalis mugwort-race' in France) also belongs to O. scapulalis . Consequently, we propose that only O. nubilalis specimens feeding on maize (the former French ' O. nubilalis maize- race') belong to O. nubilalis (Hubner, 1796). The implications of this revision are discussed. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 91 , 49-72. ADDITIONAL KEYWORDS: biological species concept - host-races - Ostrinia furnacalis - Ostrinia narynensis - Ostrinia nubilalis - Ostrinia orientalis - Ostrinia scapulalis - speciation - taxonomy.