Honey bee foraging and pesticide exposure in a desert urban agroecosystem

Abstract

The negative impacts of industrial farming on honey bee health have been widely recognized regarding pesticide use and natural foraging habitat loss. An assessment of suitability of urban farms regarding honey bee health is necessary for sustainable development of agriculture and apiculture in urban settings. Urban farms that adopt organic farming practices with restrictions on synthetic pesticide use and conservation of natural habitat can potentially create an environment to mitigate these environmental stressors on honey bees. In this experiment, bee-collected pollen was taken from honey bee colonies that were located on five organically managed urban farms located in Albuquerque, New Mexico, to evaluate pesticide exposure and forage use. We also explored the influence of hive equipment on honey bee health in a high desert climate. We found that honey bees on organic urban farms were not stressed by pesticides with limited pesticide types detected (2 out of 187), low residue levels (< 20 µg/kg) and low toxicity (either no, or low toxicity with LD50 at 1,450,300 µg/kg). Honey bees had access to diverse forage resources based on pollen barcoding data. When comparing hive equipment between 10-frame, 8-frame Langstroth and top bar hives, it was determined that 8-frame hives could significantly enhance honey bee health including colony survival and weight growth, comb construction and brood production. Our results suggest that organic urban farms are appropriate locations for securing honey bee health and food safety in a desert climate; while, the selection of hive equipment should be considered when mitigating environmental stress to colonies.