Scientific publications

The morphological variability of metacercariae of the digenean, from the vitreous eye body of the roach was studied from three water bodies in Karelia, northwestern European Russia: Lake Kamennoye (a protected natural lake), Lake Kostomukshskoye and Lake Okunyovoye (both latter contaminated by mineral wastes). Qualitative variations were revealed in the major morphological traits (shape of the body, suckers, pharynx, and holdfast organ). A high phenotypic diversity of populations was observed, these being expressed in numerous variations in traits and a wide range of their combinations. The intra-population variation range of these traits was much wider than inter-population differences. The population-level structure of the variability in was similar in the protected lake and in the contaminated ones. The dominant trait variations were consistent across the populations: oval and elongate body shape, rounded and oval oral sucker shape, rounded pharynx shape, broad and rounded ventral sucker shape, broad holdfast organ. However, samples from contaminated water bodies showed novel, rare variations, as well as an altered and more uniform distribution of their variation frequencies. The plasticity of the traits and the dynamic phenotypic diversity in lakes with different levels of contamination indicate the wide adaptive capacity of intraspecific diversity, this ensuring the resilience of this species under anthropogenic pollution.