A functional bio-assay framework for evaluating arthropod dietary ingredients: a case study with commercial brown...

Selecting high-quality commercial ingredients is crucial for success in arthropod mass-rearing and laboratory research, yet chemical labels often provide incomplete information for predicting in vivo performance. A gap exists for rapid, cost-effective functional assessment tools. This study proposes and validates a pragmatic bio-assay framework to address this need, using two commercial brown sugars (a common dietary supplement) with different labeled protein contents [high-protein brown sugar (HPBS), 28 g kg^-1; low-protein brown sugar (LPBS), 7 g kg^-1) as a case study.

In starvation survival assays, wolf spider (Pardosa pseudoannulata) juveniles provided with the HPBS solution showed significantly prolonged survival compared to those on the LPBS solution. In life-cycle assays with fruit flies (Drosophila melanogaster), flies reared on a HPBS-supplemented diet exhibited significantly higher cumulative fecundity and superior climbing ability compared to those on the LPBS diet. By contrast, no significant difference in total developmental time was observed among the dietary treatments.

The proposed bio-assay framework successfully distinguished the functional quality of the two commercial ingredients based on key performance metrics. The consistent superiority of the HPBS product, despite the 'black box' nature of commercial products (i.e. potential confounding factors), validates this approach as a powerful tool. It provides practitioners in applied arthropod nutrition with a rapid, accessible, and functionally relevant method for ingredient quality control, complementing or even preceding more complex chemical analyses. © 2025 Society of Chemical Industry.