Multi-trait pedigree-based selective breeding to optimise farmed insects: Evidence from a house fly population

Abstract Selective breeding has been proposed as an effective mean to enhance the production of insects used for food and feed. Despite advantages of incorporating pedigree information in selective breeding schemes no studies have yet explored this approach for insects farmed for food and feed. Here we performed a multi-trait selective breeding experiment aimed at increasing larval size and decreasing egg-to-adult development time in a pedigreed house fly ( Musca domestica ) population. Estimated breeding values (EBVs) based on family average phenotypic records were used as the primary selection criterion, and selection responses were evaluated over the seven generations of the selective breeding experiment. Following termination of selection, larval size, egg-to-adult development time, larval heat stress tolerance, and egg-to-adult survival were compared between the selection line and a non-selected control line when reared in a mass-rearing setup on a standard and a low-quality diet. The selection line had higher larval size compared to the control line, while no differences were found for egg-to-adult development time, larval heat stress tolerance and egg-to-adult survival. The larger larval size of the selection line compared to the control line was most evident when larvae were reared on the low-quality diet, indicating that the selection line copes better with nutritionally stressful conditions. The selection line exhibited genetic improvement throughout the selective breeding experiment, but those effects were not reflected in the phenotype, possibly indicating negative and accumulative environmental influences on the traits.