Measuring foraging activity in bumblebee nests: a simple nest-entrance trip recorder

We describe a new, electronic, apparatus for measuring the activity of bumblebees as they fly from and to their nests. The bee activity recorder (BAR) works on the principle that bees leaving and returning to their nest crawl through a tube equipped with infrared emitters and detectors so that when the beam is interrupted by the passage of a bee, the event is recorded as either an exit or an entry. Tests of BARs indicate that they are highly accurate, BAR counts and visual counts highly correlated with an almost one-to-one correspondence. We suggest that BARs can be used for recording the foraging activities of bumblebees through nest exit and entry counts in many practical and research applications.