Beyond honey bees: Stingless bees exhibit greater sensitivity to pesticides with implications for risk assessment

Abstract

Pollinator decline is driven by multiple factors, with pesticides being among the most significant. Current regulatory risk assessments rely almost exclusively on Apis mellifera , which may not adequately represent stingless bees (tribe Meliponini), key pollinators in tropical and subtropical ecosystems. This study systematically reviews evidence on pesticide toxicity in stingless bees, comparing their sensitivity with that of A. mellifera and evaluating implications for environmental risk assessment. Following PRISMA guidelines, major academic databases were searched for studies published between 2014 and 2025. Data extraction included bee species, pesticide compounds, exposure routes, and Species Sensitivity Ratios (SSR), calculated to quantify relative sensitivity. A total of 27 studies were identified, encompassing 115 experiments and 24 stingless bee species. Stingless bees showed higher sensitivity in 72 % of trials, with adverse effects occurring at lower concentrations than those affecting A. mellifera . Oral exposure was the most common route (61 %), and insecticides dominated the dataset (98 %). Based on evidence from the past decade, stingless bees are consistently more sensitive to pesticides than A. mellifera . Thus, the continued reliance on A. mellifera as the sole surrogate species may underestimate risks to tropical pollinators. Expanding ecotoxicological testing frameworks to include stingless bees and their specific exposure routes would enhance the ecological relevance of pesticide risk assessments, strengthen pollinator conservation strategies, and contribute to the protection of biodiversity and agricultural sustainability in regions where these bees are key pollinators.