Special features of helminth fauna of Mustelidae in the Polistovsky National Nature Reserve and development factors

The purpose of the research is to study the species composition of helminths of the Mustelidae family taking into account biotopic and trophic factors in the Polistovsky National Nature Reserve.Materials and methods. Faeces of Mustela putorius, Neovison vison, Lutra lutra and Martes martes were studied to determine a helminth fauna composition in the Mustelidae family and the factors affecting its development. Helminth eggs were detected using coproovoscopy. For detection of nematode eggs in the feces, the Forate sugar solution flotation method was used; for detection of trematode and cestode eggs, the successive washing method was used. Sexually mature nematodes of the genus Eucoleus were obtained from the pine marten by the method of B. V. Romashov. Species diagnostics of helminth eggs was carried out according to determinants, monographic and other works. The morphometric study of eggs was carried out using the Screen Meter computer program with an accuracy of 0.001 mm. The final diagnostics was carried out by comparing eggs from the faeces of predators and eggs from mature helminths. To study the trophic factor in helminth fauna development, the faeces composition was studied.Results and discussion. The studied mustelids were infected by nematodes Eucoleus sp., Eucoleus aerophilus and Capillaria putorii, and trematodes Isthmiophora melis and Opisthorchiidae sp. Helminth eggs were found in 42.3% samples. The helminth eggs prevail in the material from the polecat and American mink (60.5%) over that from the otter (30.5%). Stenobionts, stenophagy and morphophysiology determine a low infection rate in the otter versus the mink and polecat. Mixed coniferous-small-leafed forest shows a richer list of helminths than the marsh. The obtained data evidences limited helminth circulation in high moor. It is not possible to differentiate eggs of E. aerophilus and E. trophimenkovi according to the previously proposed shape index due to the high individual variability of eggs. High moor as a specific biotope reduces biodiversity including helminths.