What's a bee's favourite flower?

Using DNA analysis to unpick pollen preference in bees...
15 July 2021

Interview with 

Elie Kent, University of East Anglia


A bumblebee on a flower


Animals have been a feature of the exhibition for hundreds of years as we heard from the Royal Society's Keith Moore...

Keith - There's a famous magazine illustration, which shows a lady looking at an electric eel in a case at the Royal Society. And they were administering shocks to visitors just to demonstrate the properties of the creature. Jimmy, the dog, who was the pet of Augustus Waller helped in the exhibitions as well. He demonstrated his own heartbeat from Waller's electrocardiogram and questions were asked in parliament about that. In the 17th century at Royal Society meetings, if someone discovered at a London market, for example, an interesting fish, they might well bring it into the Royal Society. In Newton's presidency, a German gentleman was given ten and six for making his dog talk, and apparently it was a very talented dog. It spoke in English, French and high Dutch.

Talking dogs aside, important research into animal behaviour is on display this year, specifically featuring bumblebees. Bumblebees are crucial pollinators in nature’s ecosystem, and farmers will even buy commercial beehives, plonk them in their fields, and hope they will do the hard work of pollinating their plants. But do they? Elie Kent is a PhD student from the University of East Anglia who has been trying to find out, as she told Chris Smith...

Elie - Hi. So we want to know which flowers the bees have been visiting on the farm. I've been working on soft fruit farms where you have a large area of one crop. So you might expect the bees to visit the most abundant flower, which would be the crop. But bumblebees can fly one kilometre to find food, and even farms have really diverse habitats with lots of different flowers in. So we want to know which flowers the bees have been visiting. And one way to do this is by studying the pollen the bees collect. So pollen is a really important part of the bees' diet because it's high in protein and fat, and bees make foraging trips where they collect pollen from flowers and take it back to their colony. So we can take that pollen from the bee and see which flowers the bees visited.

Chris - And how do you actually do that, Elie? How do you know which pollen came from which flower?

Elie - Previously it would have been done using microscopy, which takes a really long time and a lot of the closely related species look very similar...

Chris - So you mean actually putting bits of pollen under the microscope in order to identify which plant it came from, just on the shape and size of the pollen grains.

Elie - Yeah, exactly

Chris - Oh goodness. That sounds like a bit of a nightmare.

Elie - It is. It takes a really long time. I've actually had a go at doing it and I can confirm it's pretty time-consuming. So what we've been doing is looking at the DNA in the pollen. So we can use the DNA as a code, which is unique to each plant species, and then we can use that to identify the flower the pollen has come from.

Chris - What did you do then? Collect a whole bunch of bumblebees and scrape the pollen off and then get the genetic codes of all the pollen and then marry it up to flowers or plants?

Elie - Yeah, pretty much. I've done some fieldwork where I've collected about a thousand pollen samples from bees. And you can scrape off the pollen because they collect it into these balls on their hind legs. So it's quite easy to get. And then we can extract the DNA. And with this small device called a minION, it can take just a few hours to tell us what the pollen DNA is. And then like you said, we can compare the pollen DNA to plant DNA, and the ones which are most similar, provide that match.

Chris - So you can actually work out then basically what the bees have been dining out on. You'd better put us out of our misery. What do they actually go for? Do they do what the farmers want, which is to pollinate the monoculture of the one crop that's growing or do they think, "Actually I'm a bit bored of that. I'm going to go elsewhere"?

Elie - Of course, it's never that simple. Bees don't really have a favorite flower. It really depends on the species of bee, the time of year, so what's in flower at that point in time, what the landscape looks like, so how much of it could be agricultural or woodland. But what we do know is that bees do require really diverse diets. So whatever landscape they're in, they will be going to several different flower species.

Chris - In other words, if they were to get a restaurant of all the same fast-food chain, they would actually actively seek out to dine somewhere different from time to time. What can farmers do then given that their motivation is they want their crops pollinated, this will give them the best yields and that will make them the most commercial revenues. What can they do to tempt the bees to actually get the most efficient pollination?

Elie - So the results have shown that these do prefer some types of flower, and we can use that information to build up a more pollinator-friendly landscape. So we can plant more of these flower species in, say, hedgerows and field margins, and that will help wild populations of bees. And so that's sort of a win-win situation for the farmers because then they don't have to depend on buying bees. They can use this natural resource where the wild bees are doing the same job as the ones they bought.

Chris - Jeremy Clarkson did this in his farm series, I don't know if you've caught any of it, in his farming series. He actually literally mowed down the crops down in the middle of his field and planted a big strip of wildflowers. And the motivation was to try to tempt the pollinators into the middle of the crop rather than just from the edges.

Elie - Yeah. That's a really great idea to get more of these wildflower areas where you're getting flowers at all times of the year, not just when the crop is flowering. You're going to get a much more diverse range of insects, which will do the same job.

Chris - I never thought we'd be mentioning Jeremy Clarkson on the Naked Scientists. And just in 20-30 seconds, if people go online to see your exhibit, what can they find out about it? What can they learn about if they come to your exhibit, Elie?

Elie - So, we've got a short film where we talk in more detail about pollinators on farms and how we've been studying the DNA. And there's a short game where you can have a go at collecting the DNA. And there's also a citizen science questionnaire about how bee hotels are used by the public. So it'd be really fantastic to get lots of responses from that.

The bee hotel survey is now available, for more info please see: https://saviourbees.co.uk/


Add a comment