Lethal and sublethal effects on stingless bee (Partamona helleri) larvae caused by chronic exposure to three agrochemicals

Abstract

Over the last few decades, agrochemicals have been partially associated with a global reduction in bees. Toxicological assessment is 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. The recommended field doses of CuSO4 (200 Active Ingredient, a.i., µg) and spinosad (8,16 a.i. µg) reduced survival, but not glyphosate (148 a.i. µg). No significant adverse effects on bee development were observed in any treatment with CuSO4 or glyphosate, but spinosad 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.