Long-term dynamics of species composition and numbers of helminthes of the marsh frog Pelophylax ridibundus (Pallas, 1771) in the conditions of Tambov region

The species composition and numbers of parasitic worms of 214 specimens of marsh frog Pelophylax ridibundus caught in 2006–2008 and 2012–2014 in the Tsna River near Tambov were studied. Totally 28 species from two classes were found: Trematoda (23), Nematoda (5). A significant decrease of species diversity of worms in 2012–2014 in comparison with 2006–2008 was detected. A significant reduction of extensity of invasion by 7 species — Diplodiscus subclavatus, Opisthioglyphe ranae, Pneumonoeces asper, Skrjabinoeces similis, Pleurogenes сlaviger, Pleurogenoides medians, Prosotocus confuses, and variations of this character in Pneumonoeces variegatus in some years were registered. Refs 12. Tables 1