Why Do Bees Plummet Out Of The Air As Soon As Lights Are Turned Off?

The most recent video was shared by Hamish Symington, a PhD student at Cambridge University, UK, studying pollination, flowers, and food security, and depicts a group of bees in a container doing the exact same behavior seen in his previous posts. So, why is this bizarre bee-haviour happening, and how could it possibly benefit the bees? 

Quite frankly, scientists aren’t exactly sure. Several ideas have been put forward, but there is very little research in the area and only a few examples of it happening. A commenter on Reddit suggests it could be a "navigational locking mechanism", which enables the hive swarm to immediately lock its position in case of sudden turns of weather. Once the weather has passed, they could then return to their hive without the risk of being blown to an unknown location by stormy conditions. This could also link to how bees use the Sun’s position to navigate back to the hive, so once the Sun dips below the horizon, they immediately stop moving. 

Another theory suggests it is a prey response, with a shadow from a large predator above them resulting in the bees dropping out of the air and falling to the ground, where they would have less chance of being spotted.  

Either way, the phenomenon is fascinating to look at, and a welcome comic relief for the PhD student. As he states in an earlier tweet: “One of the funniest noises I know: the sound of a hundred bees falling out of the sky when I turn out the lights in the bee room.” 

Some bees have adapted to fly at night, possibly as there is less competition from other pollinators, though they are mainly tropical species. However, whether bees can see in the dark depends on how we are defining "night" and "dark" as some animals can see at night because they have eyes adapted to low lighting, while dark can mean a total absence of light. 

And if you're surprised by the discovery of night-flying bees, you should also know that some bees eat meat. You're welcome.