Simple SummaryWe successfully reared the frugivorous fruit fly pest,Anastrepha ludens, in cost-free fruit waste (orange bagasse), which produced individuals with lower body nutritional content and reduced body weight, and adult males with a highly chemically diverse bouquet of odors, containing eight additional compounds when compared to adults from an artificial diet. Adults from the orange bagasse diet were sexually competitive, but their copulations were significantly shorter than the copulations of males from the artificial diet and males from the wild host plant White Sapote. From a theoretical perspective, our results are relevant because they represent a system that will allow us to study insect evolution from saprophagy to frugivory, as here we grew larvae in a proxy of an ancestral medium. From an applied perspective, our findings are relevant because understanding the role of odors in sexual behavior is key to improving biorational pest control strategies. In addition, mass-rearing pestiferous fruit flies cheaply is an essential component for control programs based on the Sterile Insect Technique.AbstractAnastrepha ludensis a polyphagous frugivorous tephritid that infests citrus and mango. Here, we report the establishment of a laboratory colony ofA. ludensreared on a larval medium that is a waste for the citrus industry, specifically, orange (Citrus×sinensis) fruit bagasse. After 24 generations of rearing on a nutritionally poor orange bagasse diet, pupae weighed 41.1% less than pupae from a colony reared on a nutritionally rich artificial diet. Larvae from the orange bagasse diet had 6.94% less protein content than larvae from the artificial diet, although their pupation rate was similar. Males from the orange bagasse diet produced a scent bouquet with 21 chemical compounds and were sexually competitive, but they had significantly shorter copulations when compared to males from the artificial diet and from the wild host,Casimiroa edulis, which had relatively simple scent bouquets. The chemical complexity in the odors of males from the orange bagasse diet might initially have attracted females to novel scent combinations, but, once in the copula, they may have been able to sense negative characteristics in males, leading them to terminate copulations soon after they began. We conclude thatA. ludenscan adjust morphological, life history, nutritional, and chemical traits when adapted to a larval environment consisting of fruit bagasse.