Variations in the population structure of Phlebotomine sandflies (Diptera: Psychodidae) in relation to the presence of potential dog hosts

The seasonal and circadian population dynamics of Phlebotomine sandflies depend on many environmental factors, especially temperature and humidity. However, the factors that influence fluctuations in species composition are more uncertain. During the regular monitoring of arthropod vectors in the Slovenian coastal region, an interesting change in the population dynamics of these insects was observed, depending on the presence or absence of domestic dogs. To investigate the changes in species composition, we set traps for adult flies at two different locations (Medljan and Cetore) in the Coastal-Karst region (Izola, Slovenia). The collections were carried out in June and July 2017 and 2018. In total, 632 specimens of four species (Phlebotomus papatasi, P. neglectus, P. perniciosus and P. mascittii) were collected in the study area in both years. The females of all sandfly species were examined for the presence of Leishmania parasites in both years, but no Leishmania DNA was detected. The relocation of hunting dogs as potential reservoir hosts from Cetore to another location in early 2018 significantly changed the species composition of the sandflies. Two species, P. neglectus and P. perniciosus, were no longer present at this site. Changes in the species composition and population dynamics of phlebotomine sandflies are probably related to the presence or absence of the Leishmania reservoir host.