TOXICITY OF COPPER TO PORCELLIO SCABER LATR (ISOPODA) UNDER DIFFERENTNUTRITIONAL-STATUS

Isopods are members of the soil fauna important in decomposition. Thei r role in the decomposition of leaf litter in forest soils has been re ported for many years (Gere 1956; Griffiths et al. 1989). Isopods are reported to contain high concentrations of copper in their haemolymph (70 mg/ml) and in hepatopancreas (216 mg/g d.w.) (Gunnarson and Hedlun d 1987). The role that copper plays in the physiology and ecology of t errestrial isopods was first examined in detail by Wieser (1966, 1968) , Dallinger (1977) and Dallinger and Wieser (1977). Furthermore, Wiese r (1966, 1968) and Wieser et al. (1976) showed that copper concentrati ons of terrestrial isopods reflect the degree of environmental soil an d litter contamination. In the last decade, pollution of the environme nt with heavy metals has led many environmental scientists to search f or suitable methods to monitor distribution and effects of such pollut ion. Laboratory tests using terrestrial isopods are recommended for as sessing the ecotoxicological effects of chemicals (Drobne and Hopkin 1 994). Isopods are able to accumulate large amounts of several metals i n their hepatopancreas (Hopkin 1989, 1990) therefore they are useful b iological indicators of metal pollution (Dallinger et al. 1992). Becau se of its worldwide distribution and the high metal accumulation capac ity, Hopkin et al. (1993) proposed that Porcellio scaber could be a su itable ''bioindicator'' of metal contaminated soils. In spite of the f act that copper is an essential metal in isopods, it may become toxic if it Is highly concentrated in the environment (Dallinger 1977; Dalli nger and Wieser 1977), or released from the degraded haemocyanin (Gunn arson and Hedlund 1987) during a long period of starvation. The accumu lation, metabolism, storage, detoxication and excretion of copper in i sopods have been examined previously (Hopkin 1989). However, detailed information on the sublethal effects of copper in isopods and the infl uence of the nutritional status on the copper toxicity are sparse. In this paper we describe the effects of high concentrations of copper on consumption, growth rates and on reproduction correlates (gravids/fem ales, offsping/females) applied in different foods to Porcellio scaber using a standard laboratory method.