Longevity-enhancing Effects of Rosmarinic Acid Feeding on Honey bees (Apis mellifera L.) after Exposure to Some Pesticides Used in Strawberry Greenhouse

Abstract

Bee pollination plays important roles in increasing the yield, weight, and quality of strawberries grown in greenhouses. Use of pesticides is often included in the pest management strategy to control insects, fungi and weeds. However, these pesticides can negatively affect bees, compromising greenhouse pollination programs. In this study, we investigate the effect of rosmarinic acid (RA) feeding on the longevity of honey bees after oral and contact exposure of bees to some selected 14 different pesticides and G-3KM (commercial product) was used as a positive control. Among the 14 pesticides tested, six were found to be highly toxic to honey bee workers as indicated by their 48h-LD50 (㎍/bee) values obtained from oral and spray bioassays; thiamethoxam (0.0002/0.0011), dinotefuran (0.005/0.018), emamectin benzoate (0.002/0.0002), spinetoram (0.018/0.001), sulfoxaflor (0.04/0.01), and cyantraniliprole (0.1/0.03), respectively. It was interesting to note that RA and G-3KM-supplemented feeding reduced honey bees mortality by 20-30% after they were exposed to high concentrations of the 6 highly toxic pesticides. The results indicate that RA could be used effectively in reducing honey bee mortality caused by pesticides.