Factors affecting the optimal consumption and digestion of Alternanthera philoxeroides by Protaetia brevitarsis larvae

Author of the article:LI Long1** TONG Chao1 ZENG Yao-Yao1 CHEN Shen-Zhi2 CAO Cheng-Quan1*** YE Bao-Hua3

Author's Workplace：1. College of Life Sciences, Leshan Normal University, Leshan 614004, China; 2. College of Extended Education, Leshan Normal University, Leshan 614004, China; 3. College of Plant Protection, Shandong Agriculture University, Tai'an 271018, China

Key Words：Protaetia brevitarsis; Alternanthera philoxeroides; transformation treatment; environmental insects; invasive species

Abstract：[Aim] To identify conditions that optimize the conversion of the invasive plant Alternanthera philoxeroides into protein and high-quality fertilizer (frass) by Protaetia brevitarsis larvae. [Methods] Larvae were randomly assigned to different treatment groups with different feed gradients, fermentation durations (0-40 days) and water content (35%-85%). The amount of plant matter consumed, larval weight gain, the yield and transformation rate of frass and the nutritional components of the larvae reared were measured and compared and the effect of frass on coriander growth was assessed through controlled experiments. [Results] Larvae achieved the most effective conversion of A. philoxeroides after 20 days of fermentation with a moisture content of 55%. Larvae kept under these conditions contained 48.1% crude protein with an essential amino acid index (EAAI) of 77.77, indicating high protein quality. Their frass comprised 29.81% organic matter and 4.48% K2O, and significantly (P < 0.05) enhanced coriander seedling emergence rate, plant height, root length, and biomass accumulation. [Conclusion] P. brevitarsis larvae can efficiently convert A. philoxeroides into high-quality protein, while producing frass that is a valuable bio-organic fertilizer. This study presents an innovative biotechnological approach for the utilization of an invasive plant.