Accumulation and detoxification of cadmium by larvae of Prodenia litura (Lepidoptera: Noctuidae) feeding on Cd-enriched amaranth leaves.

Cadmium is a potentially toxic and carcinogenic nonessential heavy metal. This study investigated Cd accumulation along the soil-plant (Amaranthus hypochondriacus L.)-insect (Prodenia litura) food chain and the detoxification strategies at different trophic levels. A. hypochondriacus leaves could accumulate high levels of Cd from polluted soil. The Cd concentration in P. litura larvae increased with increasing Cd concentrations in the food plant. Transfer coefficients of Cd were high from soil to leaf and from larvae to feces. The leaves of A. hypochondriacus had the highest value of Cd accumulation in pectates and protein-integrated forms (extracted by 1M NaCl). Among all the subcellular fractions in larvae of P. litura, the heat-stable protein fraction was the dominant metal-binding compartment for Cd. The Cd subcellular level played an important role in Cd sequestration and excretion by P. liura larva feeding on Cd contaminated amaranth leaves. This is the first attempt to account for subcellular distribution associated with Cd in P. litura when interpreting Cd detoxification and transfer along insect food chain.