Adaptation of artificial diets for Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) at laboratory rearing

Helicoverpa armigera is an important pest of crops worldwide, and several studies have focused on the development of artificial diets for this species. However, studies evaluating the insect{acute}s performance at nutritionally different diets are scarce. Larval development is dependent on the ratio of protein and carbohydrates. The aim of this study was to evaluate the biology and to compare the consumption and use of food of H. armigera larvae on diets with different protein levels. The nutritional index, the relative consumption rate, the relative metabolic rate, the relative growth rate, and the apparent digestibility were higher in the diet with added protein. On the other hand, the conversion efficiency of digested food was lower, resulting in a higher metabolic cost. In terms of biological aspects, larval survival was higher for the diet with average protein content and lower for the diet with a high protein level. The pupal period was longer for the diet with a higher protein content, while pupal survival was lower. Among the evaluated diets, the diet with an average protein content resulted in a higher net reproductive rate, a shorter time for the population to double in number, and the highest rates of population growth. The results suggest that lower or higher protein contents in the diets of H. armigera negatively affect the biological aspects of this species.