Toxicity of λ-cyhalothrin and fenpyroximate on Nannotrigona testaceicornis

The use of pesticides in agriculture is linked to pollinators' decline, which also impacts crop productivity. Determining pesticide effects on pollinating bees is of utmost importance for defining crop management strategies and public policies. This study assessed the toxicity of λ-cyhalothrin and fenpyroximate in Nannotrigona testaceicornis bees through three exposure routes (ingestion, topical and contact). The concentrations were selected based on field application doses and median lethal concentration for social bee species. Survival and behavioural changes were assessed up to 96 h of exposure. Data showed that λ-cyhalothrin caused a significant decrease in bee survival in all exposure routes, while fenpyroximate did not cause any lethal effect. The Bees' Behavioural Stress Index (BSI) was created as a simple tool to assess behavioural changes, allowing for the identification of stress levels and significant differences from control groups. The data presented here can be used for protecting stingless bees and as a standard testing method.