Morphological differentiation of closely related species of the genus Bucculatrix Zeller, 1839 (Lepidoptera, Bucculatricidae) with an analysis of their distribution and mechanisms of reproductive isolation

Morphological studies of the representatives of the genus Bucculatrix Zeller, 1839 from the gnaphaliella, albedinella, frangutella, bechsteinella, cidarella, and ulmella species-groups revealed numerous pairs of closely related and almost indistinguishable species. Their delimitation is only possible by the tiny differences in the genitalia structures, which are more clearly expressed in females than in males. Within the cidarella and ulmella species-groups, some species are found to form more compact subgroups. The analysis of distribution shows overlapping of the ranges for the majority of the studied pairs. The reproductive isolation of the examined sibling species may be generated, similarly to several gelechioid families (Momphidae, Cosmopterigidae), not so much by inconspicuous differences in their morphology but rather by the peculiarities of their biology (different host-plants and different life cycles) and ethology (different mechanisms of finding a mating partner).