Leafing cabbage behind: kale’s nutritional edge for cabbage loopers

Nutrients play a crucial role in supporting growth and development throughout various life stages of organisms, and differences in the nutritional quality of food can have significant impacts on life history. For instance, cabbage looper (Trichoplusia ni) individuals fed on kale exhibited shorter larval duration, lower larval mortality, and higher pupal weight relative to those fed cabbage. However, why such life history differences were observed is unknown. Previous work in our lab suggests that higher water content in cabbage may explain the negative effect, so we will eliminate this variable by using an artificial powder diet. Our hypothesis is that the documented differences in micro- and macronutrients could explain the variation in larval growth and development. This project aims to evaluate this hypothesis by drying and grinding cabbage into a powder to make an artificial diet with a water content equal to kale. This will allow us to control water content differences and test the effect of added micronutrient and macronutrient levels. Furthermore, this approach will allow us to determine the extent of an interaction effect between the difference in water content and nutritional content in cabbage and kale. We will analyze the impact of water content and specific nutrients on larval duration, larval mortality, and pupal weight. This research aims to establish a foundational understanding that will open the door for future studies exploring the influence of different nutrients on the growth and development of T. ni.