First molecular phylogeny and species delimitation of West Palaearctic Pollenia (Diptera: Polleniidae)

Cluster flies of the genus Pollenia are known as mass invaders of human dwellings, but are important plant pollinators in the temperate climatic zone. Despite being the most species-rich and widespread genus in Polleniidae, no study to date has tested infrageneric relationships using molecular data. Here we use three molecular markers, COI, Ef-1 alpha and CAD to reconstruct the phylogenetic relationships between 18 West Palaearctic species of Pollenia, representing eight predefined morphological species groups, using both maximum likelihood and Bayesian approaches. We show several instances where morphological and molecular results are congruent, but also instances where they are discordant. We develop a COI barcode reference library for 18 species, containing newly generated data (87 sequences) and sequences retrieved from the Barcode of Life Data System (BOLD). We analyse this dataset using both Automatic Barcode Gap Discovery (ABGD) and Bayesian Phylogenetics & Phylogeography (BPP) methods to validate morphological species hypotheses and delimit species. The results of these species delimitation analyses were, in most cases, identical and aligned with predefined morphological species concepts. Based on the results of our analyses, we synonymize P. moravica (stat. rev.) with P. amentaria and assign 191 unidentified sequences from BOLD to named morphospecies.

Automated summary

This study investigates the phylogenetic relationships and species delimitation of the genus Pollenia using molecular markers and morphological data. The results show a congruence between morphology and molecular results in most cases, providing valuable insights into the species relationships and the importance of cluster flies as plant pollinators.