Diet Quality and Conspecific Larval Density Predict Functional Trait Variation and Performance in a Polyphagous Frugivorous Fly

In this study, we hypothesized that extreme macronutrient content in the larval feeding substrate of frugivorous insects is a barrier for optimal performance that can be overcome by the collective feeding behaviour of large numbers of larvae. To test this hypothesis, we experimentally examined how multiple traits of Anastrepha ludens were expressed across extreme levels of dietary macronutrient content (protein plus carbohydrate combinations) and across extreme levels of conspecific larval densities in the larval feeding substrate.