Behavior and gut bacteria of Partamona helleri under sublethal exposure to a bioinsecticide and a leaf fertilizer

The exposure of bees to agrochemicals during foraging and feeding has been associated with their population decline. Sublethal exposure to agrochemicals can affect behavior and the microbiota. Gut microbiota is associated with insect nutritional health, immunocompetence, and is essential for neutralizing the damage caused by pathogens and xenobiotics. Research on the effect of the bioinsecticides and fertilizers on the microbiota of bees remains neglected. In this study, we assessed the sublethal effect of both bioinsecticide spinosad and the fertilizer copper sulfate (CuSO₄) on the behavior and gut microbiota in forager adults of the stingless bee Partamona helleri (Friese), which is an important pollinator in the Neotropical region. Behavioral assays and gut microbiota profiles were assessed on bees orally exposed to estimated LC₅ values for spinosad and CuSO₄. The microbiota were characterized through 16S rRNA gene target sequencing. Acute and oral sublethal exposure to spinosad and CuSO₄ did not affect the overall activity, flight take-off, and food consumption. However, CuSO₄ decreased bee respiration rate and copper accumulated in exposed bees. Exposure to spinosad increased the proportional abundance of the genus Gilliamella, but CuSO₄ did not alter the composition of the gut microbiota. In conclusion, sublethal exposure to CuSO₄ induces changes in respiration, and spinosad changes the abundance of gut microorganisms of P. helleri.