Abstract: Impacts of dietary nickel （1-40 mg/kg） on the development and the energy reserves in the hemolymph of the 5th and 6th instar larvae of Spodoptera litura Fabricius were investigated by feeding S. litura larvae with the artificial diets amended with different doses of nickel （1, 5, 10, 20 and 40 mg/kg） for 3 generations. The results indicated that the contents of total sugars in the hemolymph of larvae of 48 h and 96 h in the 1st and 2nd generation were all lower than that in the control. However, the contents of total sugars in the hemolymph of larvae at other treatments in the successive 3 generations increased at low-level nickel exposure （1-5 mg/kg）, while decreased at high-level nickel exposure （20-40 mg/kg）. Exposure to nickel for three successive generations significantly lowered the content of proteins in comparison with that in the control. The contents of proteins in the hemolymph of 72-120 h larvae in the successive 3 generations were higher than that in the control after low-level nickel exposure. However, high-level nickel exposure only decreased the content of proteins in the larvae of 72-120 h in the 1st generation and 72 h in the 2nd generation. Higher contents of lipids were observed in the hemolymph of larvae of 0, 48-72 h and 120 h in the 1st generation after 20-40 mg/kg nickel exposure in comparison with that in the control. The contents of lipids in the larvae of 24 and 96 h were lower than that in the control. Caloric values in the hemolymph of larvae of 0-48 h decreased with the increasing nickel levels in the successive 3 generations. However, caloric values in the hemolymph of larvae of 72-120 h in the 2nd and 3rd generation increased after low-level nickel exposure （1-5 mg/kg）, while decreased after high-level nickel exposure （20-40 mg/kg）. Moreover, the weights of the 5th and 6th instar larvae increased at low-level nickel exposure, but decreased at high-level nickel exposure. Therefore, it is inferred that the effects of nickel on the energy reserves of S. litura larvae are related with the type of energy substances in their bodies, their developmental stage and the number of successive generations exposed to nickel.

Key words: Spodoptera litura, nickel, hemolymph, total sugars, proteins, lipids, caloric value