Lead impact on nutrition, energy reserves, respiration and stress protein (hsp 70) level in Porcellio scaber (Isopoda) populations differently preconditioned in their habitats

The impact of lead on food consumption, energy metabolism and the stress pr otein (hsp 70) level was investigated in the woodlouse Porcellio scaber (Is opoda), a common representative of the saprophagous soil macrofauna. To exa mine possible acclimation or tolerance to lead in woodlice from a contamina ted habitat, animals of two populations, one deriving from a lead-contamina ted artillery range and one from an uncontaminated control stand, were expo sed to a series of lead concentrations under otherwise constant laboratory conditions for a maximum of 80 days. The applied lead concentrations (at a maximum 7945 mg/kg food dry wt) did not have any significant quantitative e ffect on the food consumption of the isopods, although the population pre-e xposed in the artillery range showed a tendency toward a higher food uptake than the control population. After 80 days of exposure, both populations s howed an equal trend toward increasing their respiration as lead concentrat ions, that they had been fed on, were increased. Accordingly, the glycogen content of the body, in both populations, was elevated with increasing lead concentrations in the food. This effect was more pronounced in the pre-exp osed isopod population than in the one from the control stand. The non-pre- exposed isopods showed a general tendency toward a lower protein content of their bodies than the pre-exposed ones, although no effect of the lead on this parameter could be statistically proven. The ability of the artillary range isopods to synthesise stress proteins (hsp 70) in response to lead co ntamination decreased at much lower lead concentrations in their food than in the non-preexposed control population, even though the artillery range i sopods seemed to be equally or even slightly better equipped with energy st orage products. Even though the better nutrient status of these animals mig ht refer to some lead tolerance of the preexposed population, the stress pr otein data suggest that a metal-resistent Porcellio population did not evol ve in this lead-contaminated site. (C) 2000 Elsevier Science Ltd. All right s reserved.