Effects of Cd accumulation on cutworm Spodoptera litura larvae via Cd treated Chinese flowering cabbage Brassica campestris and artificial diets

Abstract

By exposing herbivorous cutworm Spodoptera litura (Lepidoptera: Noctuidae) larvae to Cadmium (Cd) stress via Cd treated cabbages Brassica campestris and artificial diets, we investigated effects of Cd accumulation in larvae on their survival and food utilization. The results showed that Cd transferred from soils contaminated with different Cd concentrations through cabbages-larvae, and be mainly accumulated in larvae guts. There was a dose-response relationship between Cd accumulations in larvae cuticle, head, guts and Cd concentrations in artificial diets, and the highest one was found in the guts, regardless of generations. High Cd stress (10 mg kg−1 Cd in soil, 40.6, 81.2 mg kg−1 Cd in artificial diets) had inhibited effects on larvae growth and food utilization, whereas low Cd stress (Lvbao 701 planted in 2.5 mg kg−1 Cd soil, 4.06 mg kg−1 Cd in artificial diets) showed stimulated effect. Cd accumulations in the guts were significantly negative correlated with efficiency of conversion of ingested food (ECI) and relative growth rate (RGR) of larvae feeding on Cd treated diets or cabbages while were significantly positive correlated with relative consumption rate (RCR). Therefore, after S. litura larvae feed on Cd treated natural food or artificial diets, Cd could be transferred to different tissues, and mainly accumulated in the guts, which significantly affected growth and food utilization. Additionally, Cd stress via Cd treated artificial diets presented less detrimental effects on S. litura larvae than via Cd treated cabbages.