The development of a synthetic diet for investigating the effects of macronutrients on the development of Plodia interpunctella

Abstract

The use of chemically defined artificial diets has allowed researchers to examine questions within nutritional ecology about how macronutrients affect life history traits and resource-based trade-offs. Using a chemically defined diet, it is possible to manipulate both the total nutritional content and the ratio of macronutrients (i.e., protein, carbohydrate, or lipids) within the diet. Studies using the geometric framework have made use of these diets to examine lifespan, fecundity, and immune responses. Here we develop an artificial diet suitable for rearing Lepidopteran larvae. We created diets with three different proportions of non-nutritive material (30, 50, and 70% indigestible cellulose) relative to protein and carbohydrate macronutrients, and compared these to standard wheat bran laboratory diet. We were then able to examine the effects of variable nutrient content on lifespan and development time in Plodia interpunctella Hübner (Lepidoptera: Pyralidae). The diet was able to support development that is comparable to bran-based laboratory diets. Total nutrient content affected development time: females that fed on the diet with the highest nutrient content took the longest time to reach eclosion. We also found evidence to support dietary restriction, with larvae receiving the fewest nutrients having the longest lifespan as adults. These findings are indicative of the usefulness of this diet as a tool to further investigate the effects of nutrient content and macronutrient imbalance on resource based trade-offs and life-history traits.