Vol 57, No 3 (2023)

Metacestode infestation of Semibalanus balanoides and Balanus crenatus, collected in the Barents and White Seas and in the northern part of the Sea of Okhotsk in 2020 and 2021, correspondingly, has been studied. 313 S. balanoides from Mogilnaya Bay of Kildin Island (Barents Sea) and isolated mature wrinkled barnacles B. crenatus, 2 and 4 specimens from the Pechora Sea and Kandalaksha Bay of the White Sea, respectively, were examined in 2020. Metacestodes Fimbriarioides intermedia (Fuhrmann, 1913) (Cyclophyllidea, Hymenolepididae) were found in 1.0 ± 0.6% of S. balanoides in the Barents Sea with an invasion intensity (I I) of 2-5 specimens, and in one of two B. crenatus from the Pechora Sea (I I = 15). For the first time in both B. crenatus from the Pechora Sea, taken from the valves of the mussel Mytilus edulis, metacestodes Microsomacanthus sp. I (I I = 13 and 20) with proboscis hooks 38-41 (39.4 ± 0.1) µm long, blades of 9.5-11 (10.7 ± 0.1) µm were obtained. One of four B. crenatus from the Kandalaksha Bay was infected with another Microsomacanthus sp. II (I I = 19) with proboscis hooks 44.0-49.5 (45.7 ± 0.5) µm long and blades - 14.0-16.0 (14.8 ± 0.07) µm. 362 S. balanoides were collected and dissected in Gizhiginskaya Bay of the northern part of the Sea of Okhotsk in 2021, of which 8.0 ± 1.4% were infected with F. intermedia metacestodes (I I = 1-19). Study results of the infestation of S. balanoides on the Koni-Pyagin coast of the Sea of Okhotsk (according to the collections of 2006-2007) were supplemented and clarified. Description of metacestodes and the taxonomic affiliation of cysticercoids Microsomacanthus spp. are given.

In this paper, we provide a catalogue of mite species (Gamasina) recorded in Saratov Province in 1929-2022. As a result of the analysis of the currently available information, an electronic dataset has been created on mites, which includes information about 38 districts of Saratov Province. The database contains materials (81 species, 41 genera and 20 families) on the habitats and locations where mites occurred and provides a comprehensive list of literature related to the fauna of Saratov Province.

A female of I. ricinus was found above the generally accepted northern boundary of the range (the White Sea biological station of RAS “Cape Kartesh” (66°20.230ʹ N, 33°38.972ʹ E). The possibility of the existence of independent populations of the sheep tick in the conditions of the northern taiga is discussed.