Comparison of protein sources for cost-effective production and post-production operations of Queensland fruit fly sterile insect technique programs

The sterile insect technique (SIT) is used to suppress outbreaks of Queensland fruit fly (Q-fly), Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), the most economically damaging horticultural pest in Australia. Successful SIT programs require cost-effective production and release of high-quality insects. Yeast hydrolysate (YH) is a standard source of protein in the adult diet used in production and post-production operations of Q-fly SIT. YH is expensive, and so my aim was to find cost-effective alternative protein sources that might fully or partly replace YH. This study includes six experiments, comparing the performance of YH with potential alternative low-cost adult diets, including (1) commercial ‘Mubarqui’ diet (MD) (used for the SIT programs of the Mexican fruit fly); (2) protein-rich flours (soy, hemp, chickpea); and (3) plant- and dairy-based protein isolates (soy, hemp, and whey) (separately or in combinations). Observations were made of diet consumption, fecundity, hatch rate and reproductive organ development as key mass production quality parameters; and flight ability, mating and remating as key pre-release quality parameters. YH outperformed MD, each protein-rich flour and all of the plant- and dairy-based protein isolates in reproductive perform