Molecular Characterization of Lipoptena fortisetosa from Environmental Samples Collected in North-Eastern Poland

SIMPLE SUMMARY: Lipoptenafortisetosa is an invasive, hematophagous insect, which lives on cervids and continues to spread across Europe. The species originated from the Far East and eastern Siberia. Besides wild animals, these ectoparasites can attack humans, companion animals, and livestock. These insects may also play a role in transmitting infectious diseases. The objective of this study was to confirm the presence of L. fortisetosa in north-eastern Poland and to characterize the examined population with the use of molecular methods. Deer keds were collected from six natural forests in the region of Warmia and Mazury. DNA of L. fortisetosa was extracted and subjected to molecular studies. Two species of deer keds (Lipoptena cervi and L. fortisetosa) were obtained in each location during field research. There were no differences in the sex distribution of these two ectoparasite species. During the research, more L. cervi than L. fortisetosa specimens were obtained. The studied insects were very closely related to specimens from Lithuania, the Czech Republic, and Japan. Our study indicates various ectoparasite lineages, and such research contributes to the improvement of basic knowledge on the distribution, genetic structure, and variability of the invasive ked fly L. fortisetosa. ABSTRACT: Recent years have witnessed an increase in the population of Lipoptena fortisetosa in Central Europe. The genetic profile of this ectoparasite has not been studied in Poland to date. The aim of the present study was to confirm the presence of L. fortisetosa in north-eastern Poland and to characterize the examined population with the use of molecular methods. Deer keds were collected between June and July 2019 in six natural, mixed forests. A fragment of the rRNA 16S gene was used as a marker to identify L. fortisetosa by polymerase chain reaction (PCR). DNA samples were sequenced in the last step. Six new locations of L. fortisetosa were confirmed. No significant differences were observed in the sex ratios of L. cervi and L. fortisetosa (L. cervi p-value = 0.74; L. fortisetosa p-value = 0.65). Significant differences were noted between the total size of L. cervi and L. fortisetosa populations (p-value < 0.001). The similarity to GenBank sequences ranged from 95.56% to 100%. The obtained nucleotide sequences were very closely related to L. fortisetosa sequences from Lithuania, the Czech Republic, and Japan. Molecular analyses revealed considerable genetic diversity, which could indicate that various ectoparasite lineages have spread throughout Europe.