Molecular identification of the potentially forensically relevant cluster flies Pollenia rudis (Fabricius) and Pollenia vagabunda (Meigen) (Diptera: Polleniidae) - non-recorded species in Algeria

Cluster flies are represented by the genus Pollenia Robineau-Desvoidy, 1830 of the family Polleniidae Brauer and Bergenstamm, 1889. Their larvae are known to be internal parasites or predators of earthworms. Herein, we report for the first time the occurrence of the cluster flies Pollenia rudis Fabricius, 1794 and Pollenia vagabunda (Meigen, 1826) (Diptera: Polleniidae) on carcasses in Algeria and identify them through DNA barcoding. A region of the mitochondrial cytochrome c oxidase I gene (COI) was amplified and sequenced. Genetic distances were determined. A phylogenetic tree was constructed with the maximum parsimony method using 10 000 bootstrap replicates. A total number of 157 adults of P. rudis were collected together with 325 adults of Pollenia vagabunda. The occurrence of Pollenia on animal carcasses does not seem to be correlated with a particular stage of decomposition. All the sequences were correctly identified using the BLASTn tool from the GenBank database and the BOLD identification engine. Intra- and interspecific sequence divergence values were less than 1% and greater than 3%, respectively. COI barcodes obtained from this study were robust enough to identify and distinguish unambiguously between P. rudis and P. vagabunda. In the tree-based analysis, the cluster flies were all assigned to their respective species separately from each other confirming the morphological identification. These results provide DNA barcodes that contribute to the growth of reference databases and allow fast and accurate identification.