Sibling species delimitation and nomenclature of the Merodon avidus complex (Diptera: Syrphidae)

A study of the relationships between 21 southern European, Moroccan and Turkish populations of the Merodon avidus species complex was carried out. Based on a parallel study of type material from several museums, documented diagnostic morphological characters, season of adult activity and geographical distribution, the authors justify the use of the following names for three closely related taxa in this complex: M. avidus, M. moenium, and M. ibericus. A cluster analysis of DNA barcoding sequences clearly separated M. ibericus, but not M. avidus and M. moenium, even though the lack of shared haplotypes, analysis of molecular variance, pairwise Φ^sub st^ values together with allozyme and ecological niche analyses revealed statistically significant percentage of variation among all three species in the Merodon avidus complex. Analysis of 5 diagnostic enzyme loci revealed the presence of genetic differentiation among the M. avidus/moenium complex populations investigated and species-specific alleles were found at the AAT locus.