Life history traits of a key agricultural pest, Helicoverpa armigera (Lepidoptera: Noctuidae): are laboratory settings appropriate?

Abstract Helicoverpa armigera is intensively researched in laboratory settings, yet developmental rates can vary considerably even under controlled conditions. Here, dietary choice and light spectra were tested as possible factors influencing this variability, a range of fitness indicators were collected and dietary choice behaviour in early instars was observed. We show that early instars of H. armigera exhibited self‐selection of nutrient intake, a novel finding. Larvae given a choice between two artificial diets varying in macronutrient ratios were heavier, exhibited a higher relative growth rate, shorter developmental time and longer eclosion time compared with larvae reared on a single diet. Wing size relative to body mass was higher for larvae on extreme no choice treatments and smallest for those on the choice diets, indicating a potential adaptation to escape poor nutrient landscapes. Light spectra had an effect on the size of pupae, with H. armigera reared under white LED light having larger pupae than those reared under fluorescent white light. Larvae reared under LED light took longer to emerge from pupation. Giving larvae a choice of diets with a range of nutrients may reduce developmental variability rather than assuming that one diets suits all.