EXPERIMENTAL STUDIES ON THE REACTIONS OF COLLEMBOLA TO COPPER CONTAMINATION

Laboratory experiments were carried out to explore possible causes for the absence or reduced abundance of certain Collembola species in cop per contaminated soils. The experiments were conducted in plastic boxe s filled with undisturbed arable soil. Direct toxicity was tested by s praying the soil surface with a solution containing CuCl2 . 3Cu(OH)(2) to achieve a total concentration of 150 mu g Cu/g topsoil. After 1 mo nth the mesofauna was extracted from two sets of 12 200 cm(3) soil cor es per box. No differences were found in the abundances of the dominan t species in treated and untreated soils. Willemia anophthalma was fou nd exclusively in treated soils, and the abundance of Sminthurinus aur eus was significantly higher in untreated cells. The recolonisation of Cu contaminated soils was investigated by inserting cores of defaunat ed soils from polluted and unpolluted sites into the boxes. They were allowed to recolonise from the surrounding soil for three months. The abundances of Mesaphorura macrochaeta and Folsomia manolachei were sig nificantly higher in the Cu contaminated soils. To test the perception of inorganic Cu, the distribution of Folsomia candida in Petri dishes was determined. They were kept in the dark and contained cellulose fi lter or potato pieces that had been soaked in Cu solution or water, re spectively. For both types a clear preference for uncontaminated baits was shown.