Bee swarms create massive electrical charge

Bees are well known to create a buzz when they fly, but scientists were shocked to register an electrical charge build-up on swarming bees on par with a thunder cloud, as Will Tingle heard from Bristol University’s Sam England…

Sam - In our lab, we're really interested in the ways that, you know, animals and plants use this naturally occurring electricity that kind of exists all around us in their lives. So we are often both doing experiments or taking measurements with animals such as honeybees, but we also want to get a nice background measurement of the kind of naturally occurring electricity that's just in the atmosphere all the time. And one day we were doing some of these background recordings and it just so happened that one of our honeybee hives decided to swarm, which is when the queen of the hive, she flies away and makes a new nest somewhere else. And it just so happened that we captured this on our electric field sensor. We saw this massive spike. Obviously it wasn't the most controlled experiment ever, so that kind of told us that we should keep an eye out for next time. If there's going to be another honeybee swarm, we should be a bit more prepared with all of the recording equipment ready, all of the cameras to film the whole thing. So it was a bit of a happy accident really. But sometimes the funnest science works out that way. The main finding of our study is actually that it's pretty remarkably high. When these bees are on their own, we already know that they do carry a small amount of electric charge and this actually helps them do things like pollination. For example, It allows pollen to jump from a flower onto a bee without any contact even being made. So we already knew that there was some small amount of charge on individual bees, but we've never measured an entire swarm. And it turns out when you measure a swarm, unsurprisingly, there's a lot more charge going on. And so at ground level where we made our measurements, the strength of this electric field is really comparable to the kinds of changes in electric field you see during thunderstorms.

Will - And as we search for renewable sources of energy, though, I'm assuming it wasn't enough to hook these bees up to a dynamo and maybe power our kettle.

Sam - I mean, you could definitely get something out of it. I don't know about a kettle but you could maybe power like a very low power LED or something like that, perhaps.

Will - That's fair enough. What do you think causes these bees to generate this charge?

Sam - This is something that we're kind of trying to figure out and have been trying to figure out for quite a while. There's two main mechanisms that we think are probably behind it. The first one is something called triboelectricity, which is basically a really fancy word for friction, right? In the same way when you rub a balloon against your hair, the balloon becomes charged, your hair becomes charged, and you can move your hair around with it. We're thinking that maybe that's something that's going on. So as they fly through the air and their wings and body make friction with the air, but also with the body of the bee itself, that this charges them up. But we also think that possibly as they're flying around, they're also scavenging ions, so charged particles that are floating around in the air all the time, that they're kind of being focused onto the bee in that way. But the honest answer is that we really don't know.

Will - To postulate for a second, as you say, this is in the early stages of its development, but do you think that this electrical charge generation is only unique to bees? For instance, we have these large swarms of locusts. Would they be, do you think, generating the same sort of thing?

Sam - Yeah, I think definitely. So we've actually measured quite a lot of different insects including some, some locusts actually. And it's generally true that most insects tend to build up at least some amount of positive electric charge. So it's possible that it's quite a widespread phenomenon. What makes it really interesting with bees and locusts is that they do form these very big swarms and so their kind of collective charge can become very large.

Will - Obviously we want to look after our insects. It's important to know where they are in what numbers they're in. So if we know that they are generating electrical charge, do we have sensors that could potentially map or track our insects to better find out their distribution, maybe help preserve them a bit better?

Sam - With the honeybee swarms, it's likely that their effect on the electric field around them is going to be relatively local. So we're kind of talking within a few meters of where the swarm is. But locus swarms, for example, are much bigger and tracking them is also important because they cause huge agricultural damage. And I think there is definitely a possibility that the kinds of sensors that we've already used in our study and that other people are using to record thunderstorm activity could be repurposed for tracking locust swarms. We've really neglected the influence of naturally occurring electricity in our understanding of the lives of animals and plants and I think this provides a really nice example of that, but I think there's so much more to be discovered, because electricity really is everywhere. It's not a man made thing. You know, it's been around since before life was on earth. And so it kind of makes sense that a lot of animals and plants and other organisms would be exploiting it in some way.