Meeting Abstract

64.2  Saturday, Jan. 5  On the flight of foraging bumblebees in the near-wake of objects RAVI, S*; CRALL, J; COMBES, S; Harvard University; Harvard University; Harvard University

The high energy demands of a growing hive require bees to forage relentlessly, even under unfavorable weather conditions such as cool temperatures, precipitation or high winds. Bees forage in the complex environments surrounding flowering plants, bushes and trees, and the flow structures that they encounter on days with mild or strong winds can be vastly different from those encountered on calm days. Vortices shed from structures in the surrounding environment (trees, flowers, branches, etc.) can vary dramatically in size, strength and orientation, and these flow structures may influence the flight trajectories of foraging bees. Efficient flight trajectories, effective control strategies, and precise landings on nectar sources are vital to maximizing foraging success. To shed light on the interaction between bees and the wakes generated by objects in their environment, freely flying bumblebees (Bombus impatiens) were filmed with high speed cameras as they flew upstream in a wind tunnel at a range of freestream velocities, towards artificial flowers mounted on cylinders of varying size and orientation. Measurements of bumblebee approach trajectories were augmented with smoke flow visualization and high speed anemometry to obtain qualitative and quantitative insight into the flow structure in the vicinity of the cylinders. We found that bumblebees do employ approach patterns that depend on the geometric properties of the upstream object and its associated flow structures. This suggests that certain types of plants or particular habitats may be more challenging and/or costly for bees to forage in under adverse weather conditions.