ecotoxicological responses of two planorbarius corneus s. lato (mollusca, gastropoda) allospecies to exposure of heavy metals

planorbarius corneus (linnaeus, 1758) is the most widespread and numerous gastropods in central- european waters, which range covers from the atlantic to the ural and outside the latter to the ob river basin. before the beginning of 21 century, malacologists had no doubts about its species status. this situation changed when genetic labeling showed that p. corneus is not a species, but a superspecies complex, planorbarius (superspecies) corneus s. lato, according to the centromere indices of the 12^th pair chromosome. this complex consists of two vicarious genetic allospecies, western and eastern one, which ranges are separated by a narrow (up to 100 km) zone of the introgressive hybridization lying just in ukraine. ecotoxicological features of p. corneus s. lato allospecies under the influence of any pollutants have not been studied yet. our research focused on how different concentrations (0,001–1000 mg l^-1) of some heavy metal ions (cu^2+, zn^2+, ni^2+, mn^2+) in the water environment affected the main ecotoxicological parameters of each vicarious allospecies, and on the limits of toxic effects for studied pollutants. we found the duration of the latency period, time-to-death, and mean time-to-death, as well as the coefficients of persistence and adaptation for each allospecies. according to our results, eastern allospecies are more sensitive to the heavy metals in the aquatic environment than western one. that creates a significant threat to the eastern allospecies populations, because the concentrations of these pollutants in the ukrainian waters remain rather high, despite some positive downward trends.