The impact of early-life exposure to three agrochemicals on survival, behavior, and gut microbiota of stingless bees (Partamona helleri)

Over the last few decades, agrochemicals have been partially associated with a global reduction in bees' population. Toxicological assessment is therefore crucial for understanding the overall agrochemical risks to stingless bees. Therefore, the lethal and sublethal effects of agrochemicals commonly used in crops (copper sulfate, glyphosate, and spinosad) on the behavior and gut microbiota of the stingless bee, Partamona helleri, were assessed using chronic exposure during the larval stage. When used at the field-recommended rates, both copper sulfate (200 mu g of active ingredient/bee; a.i mu g bee(-1)) and spinosad (8.16 a.i mu g bee(-1)) caused a decrease in bee survival, while glyphosate (148 a.i mu g bee(-1)) did not show any significant effects. No significant adverse effects on bee development were observed in any treatment with CuSO4 or glyphosate, but spinosad (0.08 or 0.03 a.i mu g bee (-1)) increased the number of deformed bees and reduced their body mass. Agrochemicals changed the behavior of bees and composition of the gut microbiota of adult bees, and metals such as copper accumulated in the bees' bodies. The response of bees to agrochemicals depends on the class or dose of the ingested compound. In vitro rearing of stingless bees' larvae is a useful tool to elucidate the sublethal effects of agrochemicals.

Automated summary

In recent decades, agrochemicals have been linked to a decline in the global population of bees. Therefore, it is important to assess the toxicological effects of agrochemicals on stingless bees to understand the overall risks. This study examined the effects of commonly used agrochemicals (copper sulfate, glyphosate, and spinosad) on the behavior and gut microbiota of Partamona helleri stingless bees during the larval stage. The results showed that copper sulfate and spinosad, when used at recommended rates, reduced bee survival, while glyphosate had no significant effects. The agrochemicals also affected bee behavior, gut microbiota composition, and led to the accumulation of metals in the bees' bodies.