Crop Pollination Exposes Honey Bees to Pesticides Which Alters Their Susceptibility to the Gut Pathogen Nosema ceranae
August 1, 2013
Honey bees, Apis mellifera, are one of the most important pollinators of agricultural crops. Recent declines in honey bee populations in many North American and European countries and increasing cultivation of crops that require insects for pollination.
We collected pollen carried by foraging honey bees returning to the hive for nine hives in seven crops: almond, apple, blueberry, cranberry, cucumber, pumpkin, and watermelon. For each crop, we selected three fields that were separated by at least 3.2 km. Hives were deployed in these fields for pollination services based on growers' needs. Within each selected field, we chose the three honey bee hives with the strongest foraging forces by observing flight in the bee yard for 5-10 min, and attached plastic pollen traps (Brushy Mountain Bee Farm, Moravian Falls, NC) to these hives. Pollen traps collect the pollen pellets bees carry on their hind tibiae in flattened regions called corbiculae. Bees use this pollen to make food for larvae inside the nest. We checked traps after three days, and removed them if they contained at least 5 g of pollen. Traps with less than 5 g remained on hives until they contained 5 g of pollen or for 10 days. We placed pollen removed from traps in 50 mL centrifuge tubes and stored the samples on ice until they could be transferred to a -29°C freezer in the lab.