Genetic differentiation between populations of Orchesella cincta (Collembola) from heavy metal contaminated sites.
Genetic differentiation in Orchesella cincta populations from various sites contaminated by heavy metals in the Netherlands, Belgium and German Federal Republic was studied by comparing the toxic effects of cadmium and zinc on 1st-generation individuals in the laboratory. The effects were measured as growth responses for individuals exposed to different concn of cadmium or zinc. The growth response to zinc differed slightly between the sexes: males showed increased growth, but females showed reduced growth, when exposed to a zinc concn in their food (algae) of 68.8 µg/g dry wt. There was no difference in growth response to zinc between populations. However, a significant reduction in growth in response to cadmium occurred in populations descended from the reference site and from sites contaminated by industrial activities. Populations descended from highly contaminated sites with a long history of contamination showed no significant growth reduction. It is concluded that population differentiation in O. cincta to heavy metals is, at least in part, caused by genetically determined changes, resulting in different growth responses to cadmium.