Discordant patterns in the genetic, ecological, and morphological diversification of a recently radiated phytophagous beetle clade (Coleoptera: Nitidulidae: Meligethinae)

Molecular analyses on the Brassicogethes coracinus species complex (pollen beetles associated with Brassicaceae) were performed to explore genetic and ecological diversification, and robustness of the current morphologically based classification. Complete COI sequences (1,542 bp) were obtained from 69 individuals assigned to 10 recognized species and from 5 individuals of the designated outgroup (B. aeneus). Mean interspecific divergence within the clade varied from 0.005 to 0.283. The species B. epeirosi, B. subaeneus and B. cantabricus were associated with the tribe Arabideae and found to occupy basal most positions in the phylogeny, whereas all other species, mostly associated with the tribe Hesperideae, grouped together. In the latter group, B. erysimicola and B. coracinus occupied a basal position adjacent to a wider cluster of mixed haplotypes, likely, due to incomplete lineage sorting or past hybridization events. New data based on nuclear genetic markers are currently being collected to pursue a multilocus analysis. © Springer-Verlag 2012