Artificial light source combined with functional microorganism improves reproductive performance of black soldier fly

Black soldier fly (BSF, Hermetia illucens) has been recognized as a promising insect species for sustainable conversion of organic waste into valuable biomass. Many studies have focused on the use of BSF larvae to improve the recycling of organic waste. However, few studies have been conducted on the reproductive efficiency of BSF adults. In particular, the major problems with artificial systems are directed oviposition and the poor oviposition rate due to inadequate sunlight. This study aimed to address the bottleneck by developing an effective artificial source and finding effective attractants. Results showed that our homemade artificial light significantly enhanced the number of BSF eggs and elevated the egg hatching rate compared to commercial artificial light. Simultaneously, the isolated strain of Trichosporon asahii BSFL-2 can induce gravid BSF females to oviposit and the combination of homemade artificial light with BSFL-2 resulted in a notable increase in the number of eggs collected in the BSF adults rearing system. Analysis of the gas chromatography-mass spectrometry results and experimental validation showed that 2,5-dimethylpyrazine produced by BSFL-2 strain was able to attract gravid females to aggregate and oviposit. This study demonstrates that the use of effective artificial light source and attractant is a crucial element in addressing the bottleneck of efficient indoor reproduction of BSF.