Comparative Analysis of Nutritional Components and Feeding Effects: Towards the Improvement of Artificial Diet for Cantharides Larvae

ABSTRACT Cantharides, a medicinal insect listed in the Chinese Pharmacopoeia for its anticancer efficacies, faces increasing demand, leading to depletion of wild resources. The larvae's exclusive feeding on locust eggs hindered their large‐scale rearing. This study compared the nutritional profiles and feeding effects of an artificial diet of yellow‐black small cantharides ( Hycleus cichorii Linnaeus 1758) and its natural food, locust eggs, to inform improvements in diet formulation. The analyses revealed that the artificial diet contained significantly higher total sugar but lower crude protein and fat compared to locust eggs. Larvae fed with the artificial diet exhibited reduced survival rates, consumed more food, yet achieved lower body weights at maturity. Although the digestion rate was higher in larvae fed with the artificial diets, their conversion efficiency was notably poorer than that of larvae fed with locust eggs. Mass spectrometry identified 6689 distinct compounds, with 2739 showing significantly lower abundance in the artificial diet than in locust eggs. These diminished compounds were predominantly enriched in metabolism pathways such as sugar and amino acid metabolisms, riboflavin metabolism, and insect hormone synthesis, potentially impacting larval survival, growth, and nutrient utilization. These findings not only provide scientific insights into understanding the specialized feeding mechanisms of cantharides larvae but also offer crucial theoretical guidance for optimizing artificial diet formulations for medicinal cantharides.