Genetic and phenotypic diversity patterns in Merodon albifrons Meigen, 1822 (Diptera: Syrphidae): evidence of intraspecific spatial and temporal structuring

Molecular and phenotypic diversities of Merodon albifrons (Diptera, Syrphidae) of the Aegean islands (Greece) were assessed and compared with the Aegean (Greece) island and island versus mainland sites (Volos, Greece; Alicante, Spain). The complementary use of molecular markers of nuclear and mitochondrial genomes and the study of phenotypic traits (wing size and shape) were found to be powerful tools for revealing hidden temporal (spring versus autumn generation) and spatial (Iberian versus Greek clade, within the Greek clade) diversity within M.albifrons. First, wing size and shape differences discriminated the Spanish M.albifrons clade from the Greek populations, implying the presence of an evolutionarily independent lineage. Wing measurements also revealed hidden temporal (spring versus autumn) phenotypic diversity. By contrast to the mitochondrial cytochrome c oxidase I gene diversity observed in Lesvos (seven haplotypes), Naxos (three haplotypes), and Volos (five haplotypes), only one haplotype was registered in both spring and autumn generations from Chios. The observed allelic and genotypic uniqueness at nuclear allozyme loci indicates temporal (spring versus autumn) and spatial (within and between Chios and Lesvos islands) patterns of genetic diversity. By contrast to the genetic homogeneity found among samples from Chios Island, population structure was found to characterize Lesvos Island. Based on individual relatedness, spatial analysis across islands clustered particular populations of both generations from Lesvos compared to others, which is in agreement with the barriers identified by the software ALLELES IN SPACE.(c) 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 110, 257-280.