Abstract:

The aim of this study was to explore the sensitivity of black soldier fly larvae (Hermetia illucens) to imidacloprid, to understand the impact of pesticide residue on their growth, providing a theoretical basis for the large-scale rearing of black soldier flies. Using bioassay methods, we conducted imidacloprid toxicity tests on 5-day-old and 7-day-old black soldier fly larvae with four treatments of 0.1, 0.5, 1, and 2 mg/kg, and measured mortality rate and larval weight with DMSO and blank controls serving as references. The results showed that for 7-day-old larvae, the mortality rate after 7 days of exposure to concentrations ranging from 0.1 mg/kg to 2 mg/kg was between 3.3% and 17.3%. When the concentration was ≤0.5 mg/kg, imidacloprid significantly promoted the increase in the weight of black soldier flies. Under continuous exposure to feed containing imidacloprid, the treatment at 0.1 mg/kg resulted in a 16.4% increase in individual larval weight compared to the control group. After being switched to regular feed following 3 days of exposure to imidacloprid-containing feed, the individual larval weights in the 0.1 mg/kg and 0.5 mg/kg treatments were 26.2% and 21.4% higher than those in the control group, respectively. Low concentrations of imidacloprid have no obvious adverse effects on the growth of black soldier fly larvae and are able to promote an increase in their body weight, which provides a basis for further research into the stimulatory effects of black soldier flies.

Key words: Hermetia illucens, imidacloprid, growth promotion, precocious development, sensitivity test, mortality rate, pesticide residue