Meeting Abstract
Bumblebees, some of world’s most important pollinators, do not store large amounts of food within their hives, so they must respond rapidly to changing conditions in order to survive adverse weather events. Heavy rainstorms pose a particular challenge, as they can prevent foragers from collecting food, and may prove fatal for foragers caught outdoors. Heavy rain is typically preceded by a drop in barometric pressure, and a handful of studies have shown that other types of insects can detect and respond to these changes; however, no previous studies have explored whether changes in barometric pressure affect the behavior of bees. Here, we manipulated barometric pressure in a laboratory setting to investigate how pressure changes affect the foraging and nest activities of bumblebees (Bombus impatiens). We placed a hive of bumblebees inside an airtight chamber where they needed to exit the nest box to forage for nectar within the chamber. We pumped air through the chamber continuously, and controlled inflow and outflow rates using proportional valves to produce three different types of 6-hour barometric pressure regimes: constant pressure, rising pressure, or falling pressure. We subjected the hive and foraging chamber to a different pressure regime each day, and recorded foraging activity using motion-triggered image acquisition in the tunnel through which bees exited and entered the nest. Nest activity was recorded by capturing a 10-second video of the entire hive every 10 minutes. Each bee was outfitted with a BEEtag (QR code) on their thorax before trials began so that individual identity and orientation could be extracted from images. Our data show that changes in barometric pressure affect bumblebee activity in several ways, suggesting that bumblebees can not only detect pressure changes but respond behaviorally to prepare for imminent changes in the weather.
