Discovering the Impacts of the Food Environment on Mexican Fruit Fly Larvae: Nutrient Accumulation, Gene Expression and Response to Oxidative Stress

ABSTRACT Proper diet formulation is crucial for the successful mass‐rearing of tephritid fly larvae to ensure that they receive adequate nutrition. Nutrient acquisition can vary significantly across different developmental stages due to adaptations to specific environments where access to nutrients is limited by diet composition. It is imperative to determine the metabolic relationship between the fat body and the hemolymph in order to understand how insects respond to changes in their food environments. The main objective of this study was to investigate how the food environment affects the metabolism of Mexican fruit fly larvae, focusing on nutrient accumulation, gene expression, and response to oxidative stress in the hemolymph and fat body. The study employed a two‐way experimental design with three environments for larval development: corncob powder and coconut fibre as artificial diets and Mexican apple fruit ( Casimiroa edulis ) (Sapindales: Rutaceae) as a wild host, and two tissues (hemolymph and fat body). The results showed that hemolymph provides valuable information on oxidative stress levels, while the fat body serves as an indicator of protein and glycogen accumulation. Additionally, Lsp‐2 expression was identified as a means to determine the developmental stage of fruit fly larvae. A particularly significant contribution of this study is that dietary factors and the food environment can influence the size and shape of lipid droplets, thereby affecting the structure and functionality of the fat body. This information holds practical importance as these processes can impact the overall quality and sexual competitiveness of mass‐reared insects used for the SIT.