Vol 57, No 6 (2023)

Fundamental aspects in the evolution of nematodes parasitizing woody plants are reviewed. 1) Nematode faunal lists of natural refigia are useful to predict the risks of opportunistic pathogens becoming true pathogens in the forest and park communities. 2) Nematode composition in natural refugia gives a chance to identify nematode antagonists of insect vectors of dangerous fungal and nematode infections, which can be potentially used as of the biological agents for woody plants’ protection. 3) Dauers of the ancestors of wood-inhabiting nematodes played a role as a survival stage in the detritus decomposition succession, and they later acquired the functions of dispersion and adaptations for transmission using insect vectors. 4) When inspecting wilted trees, it is necessary to use dauers for diagnostics, as sexually mature nematodes may absent in tree tissues. 5) Plant parasitic nematodes originated from members of the detritus food web and retained a detritivorous phase in the life cycle as a part of the propagative generation. 6) Vectors in the life cycles of plant parasitic nematodes are inherited from the ancestral detritivorous nematode associations, rather than inserted in the dixenic life cycle of the ‘nematode-fungus-plant’ association. 7) Despite the significant difference in the duration of the nematode-tree and nematode-vector phases of the life cycle, the actual parasitic nematode specificity is twofold: firstly to the vector and secondly to the natural host plant (as demonstrated in phytotests excluding a vector).

This paper reports on the first record of Helicometra fasciata (Rudolphi, 1819) complex (Opecoelidae) maritae from black-striped pipefish, Syngnathus typhle Linnaeus, 1758, in the Black Sea. Ten fish specimens caught near the Kerch Strait (north-eastern part of the Black Sea) in July 2007 were examined and one of them was found to be parasitized by a single H. fasciata complex ovigerous marita. Description and drawing of the trematode found are given. S. typhle and fish of the Syngnathidae family as a whole are believed to be accidental definitive hosts of H. fasciata complex. Cases of Helicometra spp. ovigerous maritae records in fresh waters are discussed. The expansion of H. fasciata complex definitive host range in the Black Sea ( S. typhle is its 33d known fish host from here) reflects a complexity of food webs in the shelf zone of this sea.

The fish from 11 lakes and 4 rivers of four regions of the south of Western Siberia (Novosibirsk, Tomsk, Kemerovo and Omsk regions), were examined from May to November 2015. A total of 817 specimens 14 fish species to five families: Coregonidae (1 species), Thymallidae (1), Cyprinidae (8), Lotidae (1), Percidae (3) were inspected for ectoparasites and endoparasites were infestation. In the present study taxonomic composition of ectoparasites includes representatives of four families of crustaceans (Lernaeopodidae, Lernaeidae, Argulidae and Ergasilidae) and leeches (Glossiphoniidae). Monogeneans were represented by three families: Dactylogyridae, Tetraonchidae and Diplozoidae. Cestodes of two families Ligulidae and Dilepididae were discovered. Fish infected with сestodes family Diphyllobothriidae were no found. The species composition of trematodes is the most diverse (7 genera to 4 families). Metacercariae of the families Diplostomatidae (genera Diplostomum , Posthodiplostomum , Tylodelphys ), Bucephalidae (genus Rhipidocotyle ), Prohemistomatidae (genus Paracoenogonimus ), and Opisthorchiidae (genus Metorchis and Opisthorchis ) were identified. Opisthorchis felineus , and Metorchis bilis , are two opisthorchiid species potentially perilous to human health, and domestic pets (cats, dogs) were found. Metacercariae of O. felineus , in all regions (Novosibirsk, Tomsk, Kemerovo and Omsk), in all surveyed rivers: Kiya, Tom, Irtysh and Ob were found. The opisthorchiid metacercariae potentially perilous to human health in three species (dace, ide, roach) out of eight studied (Cyprinidae) were found. The trematodes of the family Diplostomatidae were found in 8 fish species. The highest rates of infection were observed in roach and pike perch.