Choi, Ji-Yeong, Chon, Kyongmi, Kim, Juyeong, Vasamsetti, Bala Murali Krishna, Kim, Bo-Seon, Yoon, Chang-Young, Hwang, Sojeong, Park, Kyeong-Hun, and Lee, Ji-Hoon
Simple Summary: This study assessed the toxic effects of two pesticides, lambda-cyhalothrin (LCY) and spinetoram (SPI), on honey bee larvae. Through single (acute) and repeated (chronic) exposures, the research determined the lethal dose, 50% (LD50). The acute LD50 values for LCY and SPI were 0.058 (0.051–0.066) and 0.026 (0.01–0.045) μg a.i./larva, respectively. The chronic LD50 values were 0.040 (0.033–0.046) μg a.i./larva for LCY and 0.017 (0.014–0.019) μg a.i./larva for SPI, indicating higher toxicity with prolonged exposure. The study also found that the chronic no-observed-effect dose was 0.0125 μg a.i./larva for both pesticides. Chronic exposure to LCY and SPI in the larval stage resulted in deformed wings and antennae in newly emerged bees. The activities of enzymes related to detoxification, antioxidation, and neurotransmission were altered in bees exposed to these pesticides at sublethal and residue concentrations. Collectively, these data suggest that larval exposure to LCY and SPI disrupts normal development, thus posing a potential health risk to honey bees. Honeybees play a crucial role as agricultural pollinators and are frequently exposed to various pollutants, including pesticides. In this study, we aimed to evaluate the toxicity of lambda-cyhalothrin (LCY) and spinetoram (SPI) in honey bee larvae reared in vitro through single (acute) and repeated (chronic) exposure. The acute LD50 values for LCY and SPI were 0.058 (0.051–0.066) and 0.026 (0.01–0.045) μg a.i./larva, respectively. In chronic exposure, the LD50 values of LCY and SPI were 0.040 (0.033–0.046) and 0.017 (0.014–0.019) μg a.i./larva, respectively. The chronic no-observed-effect dose of LCY and SPI was 0.0125 μg a.i./larva. Adult deformation rates exceeded 30% in all LCY treatment groups, showing statistically significant differences compared to the solvent control group (SCG). Similarly, SPI-treated bees exhibited significantly more deformities than SCG. Furthermore, we examined the activities of several enzymes, namely, acetylcholinesterase (AChE), glutathione-S-transferase (GST), catalase (CAT), and superoxide dismutase (SOD), in larvae, pupae, and newly emerged bees after chronic exposure at the larval stage (honey bee larval chronic LD50, LD50/10 (1/10th of LD50), and LD50/20 (1/20th of LD50)). LCY and SPI induced significant changes in detoxification (GST), antioxidative (SOD and CAT), and signaling enzymes (AChE) during the developmental stages (larvae, pupae, and adults) of honey bees at sublethal and residue levels. Our results indicate that LCY and SPI may affect the development of honey bees and alter the activity of enzymes associated with oxidative stress, detoxification, and neurotransmission. These results highlight the potential risks that LCY and SPI may pose to the health and normal development of honey bees. [ABSTRACT FROM AUTHOR]