Home – Home – Jornals – Contemporary Problems of Ecology 2022 number 6

Trematodes of Plagiorchis genus are widespread endoparasites with a life cycle involving several hosts. The present work on the study of the second intermediate hosts of the genus Plagiorchris was carried out in the basin of Chany Lake, located in the forest-steppe of Western Siberia, where pass the migration routes of many species of aquatic and near-water birds - the final hosts of these trematodes. The work was carried out in 2014-2015 in the reed zone of the Fadikha Lake, which is the habitat of the first intermediate hosts of plagiorchids - snails. Representatives of the classes Insecta, Malacostraca, Gastropoda were studied to identify the potential second intermediate hosts of the genus Plagiorchis. In the Chany Lake basin, metacercariae of Plagiorchis genus (P. elegans и P. multiglandularis) were found only in insects from the order Odonata: the largest part of infected were larvae of Sympetrum vulgatum (68 %), followed by species S. flaveolum (18 %), S. sanguineum (9 %) and Aeshna serrata (5 %). The prevalence of metacercariae of the detected trematode species for 4 Odonata species during the study years varied in the range from 3.3 to 45.5 %, the intensity of invasion - from 2 to 4 trematodes per 1 odonate larva. Infection with metacercariae increased with the age of odonate larvae. The tendency of a positive relationship between the infection (prevalence) of the first (snails) and the second (odonate larvae) intermediate hosts was revealed. A reliable relationship has been established between the prevalence of the invasion of odonate larvae and the abundance of their populations, which varies throughout the season. Seasonal changes in the infection of odonates with metacercariae of Plagiorchris genus are associated with the phenology of these insects: periods of increased infection were recorded on the eve of the mass emergence of odonates, when the number of odonate larvae in the reservoir is extremely high, and vice versa, periods of decline in infection were noted after the mass metamorphosis of odonates.