The correspondence between the physiological cold tolerance and the distribution border of Mediterranean sandflies in Southeast Europe.

Abstract

Background objectives: The distribution of sandflies is influenced by several climatic factors, like winter temperature limits, summer humidity, and drought. Only a few studies were performed to search for the connection between the physiological tolerance of sandflies and the result of the Climate Envelope Models projected distribution borders.

Methods: It was studied how the depth of rodent burrows could determine the occurrence of five European Phlebotomus species based on their known physiological cold tolerances.

Results: The modelled distributions based on the monthly minimum temperatures showed notable differences by soil depth and species. The observed and modelled European distribution areas of sandflies according to - 20 cm soil depth showed good coincidence with the observed occurrences of Phlebotomus neglectus , Ph. papatasi , and Ph. perfiliewi in East-Central, Southeast, and East Europe. Also, a good coincidence was found in the case of the modelled and observed occurrences of Phlebotomus perniciosus in Western Europe.

Interpretation conclusion: It can be concluded that in their north-eastern distribution borders, sandflies can overwinter in rabbit and rodent burrows at depths of - 20 cm below the surface. The physical cold tolerance of Ph. ariasi could be underestimated. In more than - 50 cm of depth, the stable and continuously cold environment of the shelters (mean temperature less than 10°C) could inhibit the post-winter diapause activation of sandflies in the northern regions.