Honeybees (Apis mellifera) offer ecosystem services such as pollination, conservation of biodiversity, and provision of food. However, in recent years, the number of honeybee colonies is diminishing rapidly, which is probably linked to the wide use of neonicotinoid insecticides. Middle-aged honeybees were fed with 50% (w/v) sucrose solution containing 0, 0.2, 0.6, and 2.0 mg/L thiacloprid (a neonicotinoid insecticide) for up to 13 days, and on each day of exposure experiment, percentage survival, sucrose consumption, and bodyweight of honeybees were measured. Further, changes in honeybee gut microbial community were examined using next-generation 16S rDNA amplicon sequencing on day 1, 7, and 13 of the exposure. When compared to control-treatment, continuous exposure to high (0.6 mg/L) and very high (2.0 mg/L) concentrations of thiacloprid significantly reduced percentage survival of honeybees (p < 0.001) and led to dysbiosis of their gut microbial community on day 7 of the exposure. However, during subsequent developmental stages of middle-aged honeybees (i.e. on day 13), their gut microbiome recovered from dysbiosis that occurred previously due to thiacloprid exposure. Taken together, improper application of thiacloprid can cause loss of honeybee colonies, while the microbial gut community of honeybee is an independent variable in this process.
Keywords: Gut microbial community; Middle-aged honeybee; Percentage survival; Recovery from dysbiosis; Thiacloprid.
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