Effects of lead stress on Vg expression in the beet armyworm over five successive generations

Heavy metals have been found to be endocrine disruptors in invertebrates. Lead is one of the most widespread elements of contamination, but there has been no research about the effects of lead stress on vitellogenin (Vg) gene expression in insects exposed to lead over multiple generations. In this paper, the effects of different concentrations of lead (0, 0.3, 4.8 and 76.8 mg kg^–1) on the expression of Vg in the beet armyworm over five successive generations were studied. The results showed that lead stress had significant effects on Vg expression in a dose-dependent manner. For females at the larval and adult stages, as lead concentration increased, Vg expression was significantly inhibited; for males at these two developmental stages, Vg expression was induced and increased as lead concentration increased. In addition, with the increase over stressed generations, inhibited effects for females and induced effects for males at the larval and adult stages became increasingly more obvious. However, at the pupal stage, Vg expression in the two genders was different from that at the larval and adult stages. The results indicate that lead stress can upregulate Vg expression in males which should be a useful indicator for environmental risk assessment.