Meeting Abstract
Foraging bumblebees regularly fly through environments filled with varying wind and clutter. In lab settings we can impose challenging flight conditions, but whether wild bees choose to avoid some conditions by altering their routes through natural habitats remains unknown. We performed a series of automated, high-throughput choice experiments, in which colonies of Bombus impatiens could forage for nectar at the end of a dual-channel tunnel. The tunnel had small fans to induce flow in each channel independently, as well as removable obstacle fields containing arrays of either small (1/4-inch diameter) or large (1-inch diameter) vertical posts staggered to induce maneuvering, with equal minimum gap distances between obstacles. We altered conditions in the two channels and collected 120 short video segments each day. We tested whether bees display a preference for flying through large vs. small obstacles, and whether the presence or direction of wind alters this preference. We used an automated program to identify and track bees in videos, yielding more than 15,000 tracked flights. Bees exhibited a consistent preference for flying between small obstacles as opposed to large ones, despite this requiring them to pass through more obstacles. This preference could be overturned, however, based on the direction of wind: bees displayed a strong preference for flying upwind or through still air as opposed to flying downwind, regardless of the type of clutter present. Taken together, these results suggest that a variety of factors, including the direction of air flow and the size scale of clutter may affect microhabitat use and determine the flight conditions actually experienced by wild bees.
