The effects of field-realistic doses of imidacloprid onMelipona quadrifasciata(Apidae:Meliponini) workers

The presence of Brazilian native bees can improve tomato production by increasing pollination effectiveness. However, the extensive use of pesticides in tomato cultures may be harmful to bees. Imidacloprid-based insecticides are used in tomato plantations because of its high efficiency against tomato pests. This study investigated the effects of oral intake of field-realistic concentrations of imidacloprid byM. quadrifasciataworkers, a stingless native bee from Brazil and effective pollinators of tomato crops. The oral intake of sucrose syrup added with 10, 35, or 70 ppb of imidacloprid did not increase the mortality rate when compared with the control group. However, we observed a reduction in the workers' motility and food consumption. We also treatedM. quadrifasciataworkers with sucrose syrup mixed with an imidacloprid-based insecticide (Evidence 700 WG (R), Bayer), with the final concentration of 250 ppb of imidacloprid. This treatment did not cause visible alterations of the intestine absorptive cells of the bees' midgut and did not increase DNA damage. Therefore, the observed reduction of food consumption and locomotion behavior ofM. quadrifasciataworkers may contribute to the global effort to understand the contribution of neonicotinoids on bees' population decline process.