As beekeepers, we manage those forces that influence our honey bees to provide the optimal environment for the insects to survive and thrive in. But what of those forces that are all around us and we cannot manage? Science writer Dave Black explores one of them, electromagnetics, and explains an emerging field of study which, almost certainly, has a profound influence on how bees behave.
I’d like to begin with a disclaimer. I bailed out of physics as soon as I was 18. It wasn’t that it didn’t interest me, although it was a bit… theoretical. Trouble was, physicists spoke a language I don’t - maths.
So here goes.
At the moment the world and everything we know about is thought of in terms of four fundamental interactions, or ‘forces’ between matter. Two are a matter of everyday experience, gravity and electromagnetic force, and two, the weak force and the strong force, operate at a subatomic scale and only really bother physicists.
If we think about things as I do, at a chemical or biological scale, it’s the electromagnetic force that we understand, the movements of charged electrons (particles with mass) and mass-less photons that convey energy. We think about photosynthesis, or the chemical processes that use nectar to power flight, the friction that keeps your woodware whole, and so on, all phenomena that represent electromagnetic interactions, but these things only hint at just how central electromagnetic forces are.
The Emerging Field of ‘Electric Ecology’
In a huge paper (32 pages) published as Open Access by the Cambridge Philosophical Society just last year Sam England and Daniel Robert review the emerging field of study known as ‘electric ecology’. There have been clues about how important this perspective could be. Sarah Corbet, known for her work with bumble bees, suggested in 1982 that electric charge could be significantly important for pollination; there have even been attempts to ‘charge’ pollen to make artificial pollination more effective, but here too we are still thinking about a sub-set of entries in an enormous encyclopedia.
The entire planet behaves like a large capacitor (an object that stores electrical energy) with a gradient of electric potential difference increasing by around 100Volts for each metre we climb up from the earth’s surface (up to about 50km when the air becomes too good a conductor to sustain a voltage difference, the beginning of the ionosphere). Any current that travels across the potential in one direction is balanced by a process (like lightning) somewhere else, creating a giant electric circuit. It’s known as the Atmospheric (or Vertical) Potential Gradient. It’s not uniform, and it’s constantly changing. Experts look at cloud electrification, lightning, rain, aerosol charging, radioactivity, the sun and space, pollution, volcanoes, trees, and crops and buildings and power companies and even earthquakes, all sorts of things, to understand what drives change in the electric field. We live in it without so much as a second thought.
Do Bees Give it a ‘Thought’ Though?
For many animals and plants, and certainly bees, this potential gradient has a profound influence on how they live. There are plausible proposals for organs and structures that are capable of detecting electromagnetic phenomena of the magnitude being measured, and behavioural changes observed as a result. Honey bees have been trained using electric charge as cue.
We know, and can measure, the generally negative charge on plants, and we know their shape produces the largest electric field strength around structures like flowers - complex ‘pointy’ shapes accentuate electrical potential differences. We know that plants, especially the big ones we call trees, interact to disrupt and even invert other electric fields around them. We know, and have measured, the electric charge on animals like bees moving though their environment, and this is generally a positive charge. For these small animals it not just air resistance, gravity and friction that affect motion, but electromagnetism too.
Pesticide Application, Pollination, and Seed Dispersal
People are studying the role of electrostatic charge in pesticide application, pollination, and seed dispersal. There is evidence that a change in the charge could provide a cue to reduce wasted repeat visits to ‘empty’ flowers by bees. There has been a study that suggests honey bees performing or attending to waggle dances are sensitive to the electric fields that surround them, and that this charged accompaniment forms part of the ‘language’ communicating the direction and distance of the destination. It has been proposed that electric charge improves honey bees ability to detect odours, and it is hypothesised that the charge around landmarks may be significant for how bumble bee and honey bees navigate their surroundings.
Recently (2022) it has even been suggested that, in aggregate (like honey bee or locust swarms), insects can be a, so far unrecognised, cause of electrical variability in the earth’s atmosphere. Not only does the Atmospheric Potential Gradient matter to them, they matter to the Atmospheric Potential Gradient.
And I haven’t even mentioned all the electromagnetic processes going on inside a bee yet. Or any maths.
Dave Black is a commercial-beekeeper-turned-hobbyist, now working in the kiwifruit industry. He is a regular science writer providing commentary on “what the books don't tell you”, via his Substack Beyond Bee Books, to which you can subscribe here.