Effect of endosulfan and parathion on energy reserves and physiological parameters of the terrestrial isopod Porcellio dilatatus

The in vivo effects of parathion and endosulfan on the isopod Porcellio dil atatus were investigated. Feeding parameters (food consumption and assimila tion rates), growth, and energy reserves (glycogen, lipid, and protein cont ents) of pesticide-exposed isopods were compared with those of control anim als. Isopods were exposed to a wide range of concentrations of parathion or endosulfan (0.1, 1, 10, 25, 50, 100, 250, and 500 mug/g of food) for 21 da ys. The route of uptake of the pesticides was through the diet (alder leave s). Results revealed that parathion induces a significant depression of gly cogen, lipid, and protein contents. However, no significant effect was obse rved on either feeding parameters or growth. Animals fed endosulfan-contami nated food had smaller amounts of glycogen and lipid than control animals, while protein levels were similar in all treatments. Endosulfan also induce d a significant decrease in food consumption and assimilation rates at the highest concentrations tested. Growth rate was also significantly affected by endosulfan. These results suggest that the isopod P. dilatatus is a suit able species for use in toxicity tests and that energy reserves could be us ed as effect criteria in both laboratory and field studies. (C) 2001 Academ ic Press.