Title: Using black soldier fly (Hermetia illucens) larvae as a decomposer of Drosophila media waste: implication for fly lab sustainability

Laboratory research generates substantial environmental waste, including biowaste[LA1] of feed media from model organisms such as <i>Drosophila</i> flies. Considering the widespread use of Drosophila flies, identifying alternative methods for repurposing spent Drosophila media is a step toward more sustainable laboratory practices. This study investigates the potential of <i>Hermetia illucens</i> (black soldier fly; BSF) larvae as a bioconversion solution for <i>Drosophila</i> media waste. We conducted controlled experiments to assess BSF performance (e.g., larval growth and development, adult weight and lifespan) on three diet treatments: the Gainesville diet (a widely used BSF reference diet), fresh <i>Drosophila</i> media, and processed <i>Drosophila</i> media (waste). Our findings indicate that while BSF larvae developed faster on the Gainesville diet, they attained significantly larger peak weights and adult sizes when fed with <i>Drosophila</i> media (fresh or waste). Development time was shorter on the Gainesville diet, but both fresh and processed <i>Drosophila</i> media yielded comparable larval growth and survival rates, suggesting that the nutritional value of the Drosophila media was maintained post-<i>Drosophila</i> rearing. Given the extensive use of <i>Drosophila</i> in biological research, our results highlight the potential of BSF larvae for sustainable waste management in fly labs, aligning scientific research with circular economy principles and environmental sustainability.