Honeybees’ dancing reveals hive’s health

Associate Professor Guy Warman heads up a chronobiology research group in the University's Department of Anaesthesiology.

He talks to 95BfM Breakfast host Jonny Vahry, for the University-sponsored show ‘Ready, Steady, Learn’, about his group’s research on honeybees’ daily behavioural rhythms.

Originally, they used honeybees as a model to explore the effects of anaesthesia, with the goal of transferring their discoveries to human research.

Now they have turned their attention to the bees themselves, which are important pollinators and therefore vital to global food security yet are under threat in many countries.

Find out more in the transcript below or click through to the audio.

Transcript

Jonny Vahry
A big shout out to the University of Auckland and a warm welcome to Dr Guy Warman from the Faculty of Medical and Health Sciences. “Kia ora and good morning, mate.”

Now we have something which is very, very fascinating. You've been researching the life of bees and circadian rhythms. Where do we start with this?

Guy Warman
Well, probably we should start with circadian rhythms. So, there are two kinds of sides to the story. One is the circadian side, and the other is the bee side. So circadian rhythms are daily rhythms, and they're really key to us being healthy.

So, whether you're a bee or a person or a fly, having a robust daily rhythm is really key to being healthy.

And when that, when that rhythm starts to fall apart, it's a very good indicator of becoming unwell.

In fruit flies, for example, we can look at their daily behavioural rhythms falling apart, and even the genes that control those daily rhythms falling apart, and we know there's an early indicator of them becoming unwell, and we can even use that as a predictor of upcoming death.

Circadian rhythms are really key. Those of you who've travelled overseas will know about jet lag.

Recently, we went through to summertime, and people found a little bit hard to get up in the morning, that daily rhythm is really key.

And so, we are chronobiologists. We run the Chronobiology Research Group at the University of Auckland, together with some of my colleagues, Dr James Cheeseman and [Dr] David Cumin and somebody at AUT, [Dr] Matthew Pauley, and what we focus on is the importance of circadian rhythms for health and behaviour of a whole range of different species, but bees as well.

But just going back on that the daylight savings time shift. It's incredible how hard that is for a couple of weeks, and it's just getting up an hour earlier, isn't it? It is always harder to get up earlier than later.

That isn't just because you get an extra hour sleep or an extra or less an hour's sleep. It's actually fundamentally part of how your biological clock works.

We all have these little cells in our brain, again, whether we're bees or people, and they have biological clocks in them, and they tick away and they drive our daily behaviour, and shifting them to an earlier time zone is just fundamentally more difficult than shifting to a later one, so that's why it's harder to get up to get up to summertime.

Jonny
Now your research begins, a while ago. You've looked at bees in the past. Give us some background on your previous research?

Guy
The bee work really started 15 years ago, and what we were interested in was this feeling that a lot of people get when they wake up from a general anaesthetic that no time has passed.

Most people wake up and they'll say, “Well, when is my operation going to begin?”

And they're quite surprised when you say, “Well, it's all done and dusted. It was four hours ago.”

We thought we'd look at the biology behind how that happens.

And we chose honeybees to study that in because they have a very good perception of time.

Honeybees do a whole range of different things, but one of them is they fly out and they find a food source, and then they fly back into the hive, and they tell the other bees in the hive where to go to find that good food source by dancing.

In the hive, there's a dance floor, and they and they wiggle, and they do this very well characterised waggle dance, and that waggle dance is a true form of insect communication.

They're telling the other bees where to go in an abstract way in the darkness of the hive.

We took advantage of that behaviour, and we anaesthetised them.
And by doing that, what we were able to do is we were able to send them in the wrong direction flying in the field.

With a key collaborator of ours in Germany, we used harmonic radar to track where bees were flying, and we showed that after a period of six hours of anaesthesia, they were they were traveling in the wrong direction.

And, they thought it was still the morning. They thought the sun had not moved in the sky.

That was kind of a fun and exciting kind of project that we did, and now we've kind of turned it on its head.

That same collaborator of ours in Germany, Randolf Menzel, at the Freie University of Berlin, has developed this remarkable technology to see what bees are doing inside the hive without opening the hive up.

So, the key thing about the waggle dance that I was just talking about is that they're dancing around in the hive and the other bees are watching them, but they can't watch them because it's dark, it's dark and it's cramped.

There was no way that they were ever really watching the other bees in the hive.

People have been studying this behaviour for hundreds of years, but they haven't known how the bees are communicating.

And Randolf Menzel and his team have worked out that the way that they're doing this is by producing electric fields.

Jonny
This is awesome - so good.

Guy
Just like when you rub your feet on a carpet and you get an electric charge, and then you touch somebody, and you get a bit of a zap.

Bees do this because they're a little plastic box and they're flying around, and they charge themselves up.

They hold on to that charge inside the hive and they can tell each other stuff by generating different patterns in that in that field.

What we do is we go in there with a modified microphone, just like these ones we're speaking into now, that have had the little membrane ripped off them, so they detect electricity, electrostatic charges, as opposed to sound.

We can detect what the bees are doing inside the hive without opening the hive up.

And they've got these little, little charges that they produce, and they do different patterns of the charges.

And so just like an EEG, just like an electroencephalogram, we can record these different patterns of behaviour by recording their different electric field charges.

Jonny
Crazy. How does the study of circadian rhythms and bees help researchers understand human health? And how has this knowledge shaped the decision to shift focus to bee health?

Guy
Bees are a good model for humans. One of the reasons is the genes that drive our daily rhythms work in a more similar way to us than to other insects.

And the other thing is that they're day-active creatures. They're diurnal.

The irony of a lot of the mammalian models that people use is that they're nocturnal animals, so you're looking at something that's fundamentally active at a different time of the day and using as a model for us when we're active during the day.

Bees are really very good models for these types of studies to look at how circadian rhythms are important for our health and for their health.

Jonny
What disruptions in bee circadian rhythms affect their overall health and behaviour, and what parallels can be drawn to human circadian rhythms?

Guy
That's a really good question. What we're doing is we're recording the rhythms and those electric fields.

So, the bees are communicating. They've got this, these special electric fields that they produce. They've got organs that allow them to detect those electric fields, and they produce these, these electric fields with a robust daily rhythm, we think.

And so, by measuring these, these, these robust daily rhythms, and looking at when those rhythms fall apart, we can produce early indicators of different changes in the hive: maybe predictors of when they're going to swarm, when they've got a disease state like Varroa or American foulbrood, or when, they might have run out of food and their whole community is falling apart.

The real key here is that this is a social clock type thing. This is a really exciting thing about it is that it's a social clock.

All those bees have to get on, not just individually, but as a whole community.
And when the community falls apart, then the whole thing just collapses. And so, the exciting kind of paradigm here is that we're looking at clocks in a social context, not just in isolation, and that, of course, is also very important in in humans.

Jonny
What are the potential implications of studying bee circadian rhythms for improving the health and longevity of bees, I suppose, globally?In  the context of global pollination decline and overall bee health populations.

Guy
Again, a great question. So how will this allow us to try and improve their health?

Well, the real reason is that, up until now, beekeepers - to work out whether their bees are unhealthy or not - either have to open up the hive, which fundamentally changes the behaviour of the whole colony.

Jonny

Exactly. "Don't smoke me out."

Guy
Or they just turn up and there are no bees coming out of the hive. It's like, “Oh god, they're all dead.”

The idea here is that by looking at early predictors of changes in health, we can identify them nice and early, and we can intervene to try and prevent that collapse of the hive by doing standard beekeeping interventions.

By knowing we need to do the interventions early.

It's just like going to the doctor having your blood pressure measured. You've got high blood pressure. Let's try and do something about this now, as opposed to somebody having the negative effects of having high blood pressure for a long time without intervening. It's that early intervention.

Jonny

One of the things at the forefront of people's minds when they're talking about the health of bee colonies and the global bee population is some of our current agricultural practices.

How might changes in agricultural practices, such as pesticides, the use of them, or habitat loss, affect the circadian rhythms and overall health of bee populations?

Guy
That's a brilliant question. This is important. So, insecticides obviously kill insects. So, by farmers spraying their crops with insecticides, they kill the pests that they want to kill, but the important thing here is that that even sub-lethal levels of insecticides can have an effect on insect behaviour.

What we particularly concerned about with honeybees is the effects of sub-lethal levels of insecticides on their behaviour.

And there has been some pretty good evidence that that some of the colony collapse issues that are experienced by bees around the world is because of sub-lethal exposures to insecticides. It's making them get lost.

And one of the reasons they probably are getting lost is because if you muck up your biological clock, and you need your biological clock to work out where to navigate with respect to the sun, then you get lost, yeah, and you don't find your way back home.

Jonny
I've got a question about colony structure. What does the role of colony structure, e.g., like the queen, workers, drones, play in the circadian rhythms and the health of bees, and how do these roles influence the overall health of the hive?

Guy
That's brilliant. That is precisely what we're about to try and find out.

We've just received a grant from the Marsden Fund, from the Royal Society Te Apārangi to do exactly that – to look at the roles of the different types of bees within the hive in generating that consolidated, healthy daily rhythm.

What is the role of the queen? What is the role of the worker bees that are going out foraging? What is the role of the nurse bees that stay inside the hive and look after the larvae? And the drones, who have generally been assumed to do very little?

Male bees are generally considered to be very lazy and do nothing apart from one thing.

However, emerging evidence is that might not be the case, they might be important for the colony more generally.

Jonny
One last question. Can findings from your research on bee circadian rhythms be applied to other pollinators or even different species, and how might that advance our understanding of chronobiology and conservation biology?

Guy
The brief thing is, yes, chronobiology is incredibly important.

Chronobiology is important if you're a bacteria, cyanobacteria or a human.

Understanding how consolidated clocks are ticking and what's causing them to fall apart is key to understanding health and the progression of disease in humans and other species.

If we know how to record early changes in biological rhythms and bees, that allows us to intervene, to increase the health.

It also allows us to make them more effective pollinators in things like urban agriculture settings or indoor farming, which are which are really big.

These effects are not just restricted to bees, as you said, other pollinators, yes, and even ourselves.

And some of the other work that we've been doing up the road in the Faculty of Medical and Health Sciences has been about clinical trials, about kidney donor patients and a range of different things. But we don't have time for that today, I assume.

Jonny
Hey, Dr Guy Warman from the Faculty of Medical and Health Sciences. Thank you so much for coming in this morning and chatting to us about chronobiology and bees. It's been great.