The detection of cryptic species in complexes that have undergone recent speciation is often difficult, since many standard nuclear markers have not yet accumulated differences between closely related taxa, and differences in mitochondrial markers can be leveled out due to mitochondrial introgressions. In these cases, the use of derived chromosomal characters such as non-ancestral chromosomal numbers and/or unusual karyotype features may be a solution to the species delimitation problem. However, non-ancestral but similar karyotypes may arise secondarily as a result of homoplastic evolution, and their interpretation as homologies may lead to incorrect taxonomic conclusions.
View Article and Find Full Text PDFThe need for multi-gene analysis in evolutionary and taxonomic studies is generally accepted. However, the sequencing of multiple genes is not always possible. For various reasons, short mitochondrial DNA barcodes are the only source of molecular information for some species in many genera, although multi-locus data are available for other species of the same genera.
View Article and Find Full Text PDFThe Polyommatus (Agrodiaetus) damone (Eversmann, 1841) species complex comprises from 5 to 8 species distributed in southeastern Europe and southern Siberia. Here we used chromosomal and DNA-barcode markers in order to test the taxonomic hypotheses previously suggested for this complex. We revealed that all taxa within this group demonstrate chromosomal stasis and share the same or very similar haploid chromosome number (n = 66 or n = 67).
View Article and Find Full Text PDFChromosomal and molecular analyses of rapidly evolving organisms such as Latreille, 1804 blue butterflies are essential for understanding their taxonomy and evolutionary history, and the studies of populations from their type localities are crucially important for resolving problems of nomenclature and species identity. Here we present data on the topotypical population of the blue butterfly species described as Lycaena damone var. cyanea Staudinger, 1899.
View Article and Find Full Text PDFThe karyotype of Polyommatus (Agrodiaetus) eriwanensis Forster, 1960 from the type locality ("Eriwan" [Yerevan, Armenia]) and other localities in Armenia was investigated. The number of chromosomal elements (bivalents+ multivalents) observed in male meiosis I was found to vary from 29 to 34. In individuals with n = 34, all observed elements were represented by bivalents.
View Article and Find Full Text PDFThe karyotype of the blue butterflies from the Angarskiy Pass (Crimea), previously attributed to Polyommatus (Agrodiaetus) poseidon (Herrich-Schäffer, 1851), was re-examined. In all 19 studied individuals, we found the haploid chromosome number n = 26, including 7 pairs of relatively large and 19 pairs of relatively small chromosomes. According to the chromosome number and karyotype structure, the studied population does not differ from P.
View Article and Find Full Text PDFFinding a new species is a rare event in easy-to-see and well-studied organisms like butterflies, especially if they inhabit well-explored areas such as the Western Palaearctic. However, even in this region, gaps in taxonomic knowledge still exist and here we report such a discovery. Using a combined analysis of chromosomal and molecular markers we demonstrate that blue populations from Daghestan (South Russia), previously identified as , represent in fact a new species which is described here as We also show that the enigmatic described as a form of and later considered as an entity similar to or is conspecific with a taxon previously known as .
View Article and Find Full Text PDFThe species-rich subgenus Polyommatus (Agrodiaetus) has become one of the best studied groups of Palearctic blue butterflies (Lepidoptera, Lycaenidae). However, the identity and phylogenetic position of some rare taxa from Iran have remained unclear. An enigmatic, recently described Central Iranian species Polyommatus (Agrodiaetus) shirkuhensis ten Hagen et Eckweiler, 2001 has been considered as a taxon closely related either to Polyommatus (Agrodiaetus) eckweileri ten Hagen, 1998 or to Polyommatus (Agrodiaetus) baltazardi (de Lesse, 1962).
View Article and Find Full Text PDFThe reinforcement model of evolution argues that natural selection enhances pre-zygotic isolation between divergent populations or species by selecting against unfit hybrids or costly interspecific matings. Reinforcement is distinguished from other models that consider the formation of reproductive isolation to be a by-product of divergent evolution. Although theory has shown that reinforcement is a possible mechanism that can lead to speciation, empirical evidence has been sufficiently scarce to raise doubts about the importance of reinforcement in nature.
View Article and Find Full Text PDFButterflies in the large Palearctic genus Agrodiaetus (Lepidoptera: Lycaenidae) are extremely uniform and exhibit few distinguishing morphological characters. However, these insects are distinctive in one respect: as a group they possess among the greatest interspecific karyotype diversity in the animal kingdom, with chromosome numbers (n) ranging from 10 to 125. The monophyly of Agrodiaetus and its systematic position relative to other groups within the section Polyommatus have been controversial.
View Article and Find Full Text PDFWe have investigated the nature of highly ordered bivalent arrangement in lepidopteran spermatocytes by analysing and comparing the patterns of bivalent distribution in intact metaphase I plates of 24 closely related species of the genus Agrodiaetus (Lycaenidae). The studied species greatly differed in haploid chromosome numbers (from n = 13 to n = 90) and in the structure of their karyotypes. We found that the larger the bivalent, the closer to the centre of the metaphase plate it was situated.
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