Deciphering Huhu (Prionoplus reticularis) grub development: Transcriptomic insights into metabolic and nutritional shifts in larval stages

Background The Huhu grub ( Prionoplus reticularis ), an edible beetle larva endemic to New Zealand, has been traditionally consumed by Māori, the indigenous people of New Zealand. Despite its nutritional significance as an excellent source of proteins, little is known about the molecular mechanisms governing its developmental transitions. This study delivers the first de novo transcriptome assembly of P. reticularis and investigates differential gene expression between its small and large larval stages, aiming to uncover their metabolic capabilities and potential contributions to human dietary protein. Results Comparative transcriptomic analysis revealed distinct gene expression patterns between small and large larvae, with large larvae exhibiting enhanced protein biosynthesis, metabolic activity, and mitochondrial function. A conserved isoleucine-to-phenylalanine mutation was detected in ubiquitin-processing genes, suggesting potential impacts on protein degradation pathways. Functional annotation revealed an enrichment of membrane transport proteins, secretory peptides, and metabolic regulators in large larvae, indicating improved nutrient assimilation and physiological adaptation. Conclusion This study provides novel insights into the molecular basis of P. reticularis development, demonstrating that large larvae possess superior metabolic efficiency, enhanced protein integrity and increased biosynthetic activity. These findings corroborate previous research on the nutritional composition of the Huhu grub. They also lay the groundwork for future proteomic and metabolomic studies aimed at evaluating the nutritional potential, bioactive properties and allergenic safety of proteins derived from Huhu grubs. *Ruchita Rao Kavle and Bennett Henzeler contributed equally to this work.