Strutturazione genetica e filogeografia di specie del genere Mylabris (Coleoptera, Meloidae) negli Appennini centrali

In this study we have used sequence polymorphisms of a fragment of the mitochondrial DNA region encoding for the Cytochrome Oxidase I gene (COI; 637 base pairs) to analyze intra- and inter-specific genetic variability and divergence in three species of the blister beetle genus Mylabris (M. flexuosa, M. pusilla, M. variabilis). Samplings have been conducted in the Central Apennines and included three main mountain massifs (Velino-Sirente, Gran Sasso and Majella). The study includes nine populations for a total of 125 individuals sequenced. These 125 sequences defined a total of 16 unique haplotypes (3 for M. flexuosa; 11 for M. pusilla and 2 for M. variabilis). Genetic data and phylogenetic analyses confirmed the previous placement (based on morphology as well as mitochondrial and nuclear genes and mtDNA and nDNA sequences) of M. flexuosa and M. pusilla in a different subgenus (Micrabis) from M. variabilis (subgenus Mylabris). Intra-specific genetic divergence is lower in M. variabilis and M. flexuosa (0.1-0.2 6 0.09%) than in M.pusilla (1.3 6 0.8%). Results of multiple mismatch analyses suggest that M. flexuosa experienced a sudden demographic expansion during the last Quaternary glacial maxima while M. pusilla did not. Such a different pattern in the past demography of the two species can be explained in light of differences in their ecological requirements