GENETIC VARIATION AND COVARIATION FOR CHARACTERISTICS ASSOCIATED WITH CADMIUM TOLERANCE IN NATURAL POPULATIONS OF THE SPRINGTAIL ORCHESELLA CINCTA (L.).

Heavy metals can be strong and stable directional selective agents for metal-exposed populations. Genetic variation for the metal-tolerance characteristic "cadmium excretion efficiency" was studied in populations of the collembolan Orchesella cincta from a reference- and a metal-contaminated forest soil. Previously it has been shown that "excretion efficiency" influences tolerance through midgut-mediated immobilization and excretion of toxic metal ions, and that an increased mean excretion efficiency is present in animals inhabiting metal-contaminated litter.

Bioaccumulation of cadmium by the freshwater isopod Asellus aquaticus (L.) from aqueous and dietary sources.

Experiments were conducted to determine the kinetics and relative importance of aqueous and dietary uptake of cadmium by the freshwater isopod Asellus aquaticus (L.). Test animals were exposed during 30 days to aqueous Cd in a continuous flow system (exposure levels: 0.

The role of food in the population dynamics of Orchesella cincta (Linné) (Collembola).

The feeding activity of the collembolan species Orchesella cincta (Linné) was studied in the laboratory and in the field. In the laboratory it was shown that at any one time only about 50-60% of the animals were feeding; the remainder were occupied with molting activities. Most of the time similar values were obtained in the field but during winter and during dry summer periods high percentages of empty guts could be demonstrated, indicating an absence or inaccessability of food.