Abstract: This study aims to optimize the rearing efficiency of Harmonia axyridis eggs in the ‘Mythimna separate-Harmonia axyridis’ rearing system, addressing the issue of only mating without laying eggs in H. axyridis adults that feed on young and old M. separate larvae. Three sugar solutions, including honey, sucrose and glucose, were tested for their impact on the development and reproduction of H. axyridis. The results showed that, when fed with M. separate eggs and supplemented with sugar sources, H. axyridis developed faster and generation duration was significantly shortened, and showed higher reproductive capacity. Among the sugar sources, glucose had the best effect, with a generation development duration of 20.71 days and an average oviposition amount of 937.00 eggs per female in 30 days. When fed with young and old M. separate larvae and supplemented with sugar sources, H. axyridis deposited eggs, and honey feeding resulted in the highest reproductive capacity, with average oviposition amounts of 434.80 eggs and 645.11 eggs per female in 30 days, respectively. Overall, the current results show that the sugar source has a significant effect on the ‘Mythimna separate-Harmonia axyridis’ rearing system, not only improving the effect of feeding M. separate eggs, but also addressing the issue of low-age larvae and high-age larvae of only mating without laying eggs in H. axyridis feeding on young and old M. separate larvae. The optimized system can replace the ‘plant-aphid-Harmonia axyridis’ rearing system. This system breaks the limitations of host plants and environments, achieves a breakthrough in the artificial rearing of H. axyridis, and may shed light on future improvement of mass production of H. axyridis.

Key words: Harmonia axyridis, Mythimna separata, sugar source, developmental duration, reproductive capacity