Bee Bonanza: From Hive Politics To Beekeeping
IRA FLATOW, host:
You're listing to SCIENCE FRIDAY. I'm Ira Flatow.
As you prepare for your holiday meals, perhaps honey is on your table or in your recipe, but stop and think - how are those bees spending their winter? How are they surviving, keeping warm in sub-freezing temperatures?
A lot of colonies are out there in the winter cold right now, and how they survive the winter, massed into tight clusters around their honeycombs, feeding on stores of honey they've saved up, it's really an incredible story.
For instance, did you know if you poked your finger inside a beehive in the winter, you'd find it really actually toasty and warm in there? The bees have to keep it up around 90 degrees Fahrenheit all winter. And they do this without any form of external heating.
They've got no, you know, hot-water system going in there. How do they keep the thermostats turned so far up? It's just one of the amazing stories about life of a bee colony, how it survives and how it moves from place to place, setting up new hives as they go.
And my next guest has written a whole book about how the bees do it, how they stay warm, make honey, come back to the hives to do their little dances and how they have to make decisions collectively without the advice of the royal head of the household, of course, the queen bee.
The book is called "Honeybee Democracy," and its author, Tom Seeley, is with us. He's author of "Honeybee Democracy" and professor in the Department of Neurobiology and Behavior at Cornell University in Ithaca, New York. He joined us by phone. Welcome to SCIENCE FRIDAY, Dr. Seeley.
Dr. TOM SEELEY (Cornell University): My pleasure to be here, Ira.
FLATOW: So what are the bees doing right now in the cold weather?
Dr. SEELEY: They're doing just as you said. They're forming a tight cluster, about the size of a soccer ball. And they're burning through about a pound or two of honey each week as they shiver with their muscles to keep - to generate and keep themselves warm.
FLATOW: You mean it's the shivering that drives the heat all the way up?
Dr. SEELEY: That's right, that's right. It's just like our own bodies. If we're cold, we shiver to produce heat.
FLATOW: Now, your book is called "Honeybee Democracy." Why is - I mean, it's hard to think that honeybees have a democracy. What is the intention of the title there?
Dr. SEELEY: The title was chosen because I'm looking at how a colony of bees chooses its home, and they do that in a democratic fashion. That is to say the decision is performed by the worker bees and not by her majesty, the queen. So it's a distributed decision-making process, like our own democratic elections are.
FLATOW: And if you go to our website, you can get a chance to watch the bees in action in a video that Tom narrates. It shows a colony of bees that you've actually created this or had this colony set up outside, where you can watch them in action. You can watch this bee democracy in the wild. That's on our website at sciencefriday.com.
And there are a couple of amazing - there are 10 little amazing videos on there, and people keep commenting about them. But let's talk about the democracy part of this. What goes on when the colony wants to move to a new location? And that's the story we're telling here.
Dr. SEELEY: Right, right. Well, let's start at the very beginning and talk about why - how this democratic sort of the election process gets set in motion.
It happens in the late spring or early summer, when a colony has gotten strong, and it can fission itself. It can divide itself, rather like an amoeba divides itself into two, a honeybee colony goes from one colony to two.
And the mother queen, the elderly queen, leaves with about two-thirds of the workers. On a sunny afternoon, they fly out in a few minutes, and this is about 10,000 worker bees, along with the queen, and they don't actually fly very far. They only fly about 100 feet, and then they form a cluster, which hangs from a tree branch.
It looks a lot like a beard of bees, and these bees are now homeless, and they're now in a situation where they have to choose, find and choose a new home site.
FLATOW: And so there are some bees, then, that go out and search for a new site?
Dr. SEELEY: Right, right, yeah, and the situation of these bees is that they have to now make a decision that is going to - is a very, very important decision. It's really a life or death decision because in order for a bee colony to survive the winter, it has to find just the right sort of nesting cavity.
It's usually a cavity in a hollow tree, though it can be a space in a wall of a building. But the key thing is that it has to be roomy enough to store the 50 pounds of honey they need for their winter feeding fuel, and it also has to be snug. It can't be drafty, otherwise the cold air blowing through there will make the heating problem just very, very - so costly for the bees that they would burn through their honey supply.
So they're there hanging from a tree branch. They will send out scouts for several miles around. They will find 10 or 20 possible home sites, different cavities in trees or whatever, and then they face the problem of choosing the best one.
FLATOW: And the scouts that come back actually have to sell it to the other bees, that their site is best.
Dr. SEELEY: That's right. The scouts are a small fraction of the swarm. The swarm has about 10,000 worker bees. Of those 10,000, there's about 300 to 500 scout bees. These are some of the oldest, most experienced bees in the swarm. And they constitute the search committee of the swarm.
They are charged - they have the responsibility of choosing the new home. And these are the ones that go out, they find things, several hundred fly out. As I say, only maybe 10 or 20 actually find a potential home site. And those that do then come back to the swarm, and they will add each one that has found something, after she's evaluated the site, will come back and advertise her discovery on the surface of the swarm using a little dance.
FLATOW: That's that famous bee dance.
Dr. SEELEY: That's right.
FLATOW: And on the website at sciencefriday.com, it's amazing because the beehive right there, it's not the hive, the swarm is exposed, and you can watch the dancing of these bees as they try to communicate. And I guess they're like politicians. They're trying to say, I've got a site, let's go with this one.
Dr. SEELEY: That's right. That's right. Each bee is advertising - each successful scout is advertising her find to the other scouts that didn't find something. And a key thing is that the bee, having evaluated her site, knows -is able to judge it on an absolute scale of goodness, whether it's a one, not very good, or a 10, tip-top.
And she adjusts how long she performs her dancing according to the goodness of the site. If it's really good, she'll dance for 10 minutes and spread a very strong signal announcing its location to other bees.
But if it's not good, it could be only a few seconds or just a few minutes, and that won't muster as many bees to such a site.
FLATOW: All right, so what happens, then, when they've decided, okay, you've convinced us, we're ready to leave this hive. What happens then?
Dr. SEELEY: Well, at that point - and I should stress that there's been this competition among scouts from advertising different locations. And the way they decide which one will eventually be their home is it's a race among those different parties of scout bees advertising different candidate sites. It's a race to see which group will first muster a sufficient number of bees to the site.
And that's what we call a quorum. It has to get up to about 50 or 100 bees. Those bees that are at the site that wins this competition, they sense that okay, our site has reached the critical number of bees. They then come back to the swarm, and they start making a sound called piping.
You might want to play the - I think you have a sound clip of that.
FLATOW: Let's play a sound of piping.
(Soundbite of bees)
FLATOW: That sounds more like elephants.
Dr. SEELEY: Yeah, it does. It's a very striking sound. And the message that they are sending with that piping signal is - they're sending actually two messages. One message is to the scout bees from all the other sites. They're basically telling those bees, the decision's been made, you don't need to dance anymore. No more waggle dancing is needed. So that shuts down the debate.
And the other thing that the signal, the other message of the signal is that now it's time to get ready to fly. And most of the bees, the 95 percent of the bees that have been hanging in that cluster, have just been hanging there quietly for a couple of days. Their body temperatures, they've allowed their body temperatures to drop to the ambient temperature.
They need to warm up their flight muscles to about 35 degrees centigrade, 95 degrees Fahrenheit, so that those muscles can contract fast enough to generate the lift bees need for flight.
So this piping signal is also telling most of the bees, time to warm up.
FLATOW: And then there's another signal. There's a run when they're all ready to leave the hive, correct?
Dr. SEELEY: Right. We call it the buzz run. And the bees - the same little bees, the same little scout bees, the bees that made the decision, have sensed the agreement, have signaled to the others to warm up. As they're running around with the piping, telling the other bees to warm up, once they sense that everybody in that swarm cluster is warm enough to go into - to launch into flight, they make this signal called the buzz run. And I think you might have an audio clip of that, as well.
FLATOW: And this is what it sounds like.
(Soundbite of bees)
FLATOW: Wow, and when you look at our video on sciencefriday.com, it looks like a sprint.
Dr. SEELEY: Yeah, that's right.
FLATOW: A sprint through the swarm.
Dr. SEELEY: Right. She's rushing through the - she's pushing through the other bees in the swarm with her wings spread and buzzing. And it's like she's saying time to go, time to go, and that triggers all the - all 10,000 bees to launch into flight.
They're all there ready to fly, and they just need that last signal to tell them now's the time to take off. And they all take off in about 60 seconds.
FLATOW: And that's interesting because on our video, you can watch this later on or when you'd like to, on these videos taken by Carl Flatow. They show that, literally, 10,000 bees are gone in 60 seconds.
Dr. SEELEY: That's right.
FLATOW: That's amazing. And there's a little clock that counts down. You watch the bees' population just disappear.
Dr. SEELEY: Yeah, Carl did a great job making that video, that countdown clock. It's great.
FLATOW: And so they're now off to the new site.
Dr. SEELEY: That's right.
FLATOW: And they all get there at the same time, or do they hang out, or what happens?
Dr. SEELEY: Well, what happens next is the scout bees that have visited that site, remember it's maybe a couple hundred, maybe 100 or thereabouts that have visited that site, those are the only bees of the 10,000 that know where to go. So, now the bees have the problem of, how can that small minority, that tiny minority of informed bees, guide the rest of the bees to the new site?
And this is a very difficult problem, but it's one that we've made some pretty good progress on.
FLATOW: Well, I'm going to tell you to hold that thought, this cliffhanger of getting to the new home. Talking with Thomas Seeley, author of "Honeybee Democracy."
We're going to take a break, and we'll get to the answer of how do 10,000 bees find their way with a couple of dozen scout bees leading it.
Also, we're going to bring on May Berenbaum, author of "Honey, I'm Homemade," about bees and how to make recipes with the honey on a special edition of SCIENCE FRIDAY. We'll tell you why it's a special edition when we come back after this break. Lots of answers, so stay with us. We'll be right back.
(Soundbite of music)
FLATOW: You're listening to SCIENCE FRIDAY from NPR. I'm Ira Flatow.
We're talking about honeybees this hour. "Honeybee Democracy" author Tom Seeley. Tom, quickly get to the end of that story because I want to know what happens, how they get there. You were telling us how the bees find - get their new home, how they find it.
Dr. SEELEY: Right. The scout bees point the way. So you've got this cloud of 10,000 bees swirling around. It's about the size of a school bus. Most of the bees don't know where do go. How do they find out?
The scout bees point the way by flying at a very high speed through the top of the cloud of the swarm, and the other bees look up and can see those bees, and they latch on in the direction that they are flying.
So the scouts streak forward. They reach the front of the cloud. Then they slow down, circle probably to the back and streak through again. And it's an amazing process. They can steer them on a journey that can often stretch for miles.
It goes across swamps, lakes, forests, whatever. And the amazing, the most amazing thing, Ira, is when they get within about 80 meters of their destination, somehow they know - they can put on the brakes. So the swarm cloud comes to a graceful stop right at the front door of their new home, just breathtaking.
FLATOW: It's amazing. And I mentioned this was a special edition of SCIENCE FRIDAY because we are celebrating the 200th birthday of the man who actually invented the modern beekeeping method, the modern beehive.
I want to bring in May Berenbaum, author of "Honey, I'm Homemade: Sweet Treats from the Beehive Across the Centuries and Around the World," a new book out, to talk about who this gentleman was. Hi, May, welcome to SCIENCE FRIDAY.
Professor MAY BERENBAUM (University of Illinois): Hi, a pleasure. Hi, thanks.
FLATOW: Tell us about this gentleman, what his name was, where he comes from. How did he invent modern beekeeping?
Prof. BERENBAUM: Well, Lorenzo Lorraine Langstroth was born in Philadelphia. He was basically, he had a long-standing interest in natural history, but he was sort of destined to the ministry.
He was a student at Yale College, studied - went to divinity school but had this life-long fascination with insects that basically led to this moment of epiphany around 1837 or '38, when he saw a friend's honey in a jar, in a glass globe, the way they used to raise honey back then. And he decided he absolutely had to keep bees.
And he wasn't trained formally as a beekeeper, but he was a voracious reader. Plus, with his classical education at Yale, he was familiar with the classical work on bees and beekeeping and was a very keen observer of natural history and bee behavior.
And sort of a combination of things led him to recognize the shortcomings of the beekeeping of the era, in particular the fact that to harvest the honey, which is the main reason people kept bees, many bees died.
That's because the honey had to be hacked out in the wax cells, and often the bees were killed by burning sulfur, brimstoning the bees, it was called, and this - he regarded this as a barbarous practice and unworthy of the bees and just began to make intense study of the life of bees, recognizing - also had a real gift for words - that, as he wrote: To men, time is money; to bees, time is honey. All the arrangements of the hive should be such to economize it to be very utmost.
He realized that one of the reasons people had to hack out the wax cells to get the honey is that bees will fill a large space, any empty space, they're cavity nesters, they like hollow trees naturally, people raise them in boxes, they'll fill it with wax cells to put in more honey.
But small spaces, they'll actually fill with a material called propolis, which is a resin they gather from tress, because they seal it. They view it as a flaw or a fault, and they seal it like people would caulk up cracks.
But if there's a space of about three-eighths of an inch, they leave it alone because that's what they leave for the passageways through their hive. It's basically the way they get around.
So if you put a wax foundation, those wax cells, in a wooden frame and leave three-eighths of an inch on all four sides, you can pick it up and put it back. And that was the major innovation. That was what revolutionized - it was the biggest innovation in beekeeping since the 12th century, when the straw skep was invented, you know, the straw quail thing.
And it changed not only the way that beekeepers raised bees, greatly reduced mortality, greatly increased their productivity, and it allowed bee scientists, people to study the biology of bees just like Dr. Seeley explained, to see into the hive.
It allowed beekeepers to estimate how much honey had been put up for the winter in order to help the bees survive the winter. It just was a total revolution in beekeeping. It changed everything about beekeeping and everything about how we eat honey today.
FLATOW: Interesting. And you may be wondering why May knows so much. She's not - May Berenbaum's not just the author and editor of "Honey, I'm Homemade," she's also the head of the Department of Entomology at the University of Illinois in Urbana-Champaign.
People who study bees, they get stung, so to speak, by this. They really get into this whole thing, about how magnificent the bees are.
Prof. BERENBAUM: Absolutely. Yeah, it's really, they are amazing animals. I mean, you heard how incredibly elaborate and sophisticated the process is for house-finding. Well, honey, making honey is not such a small deal, either.
You know, people know that bees are pollinators, that they collect nectar, and they collect pollen. But they don't, like most other pollinators, eat nectar and pollen. They make their own food. They make honey, and they make a substance called bee bread.
And, you know, bees have a reputation for busy, and it's being busy, it's well-deserved because they produce about two pounds of honey, a kilogram of honey, requires 100,000 loads of nectar, on average. So that's visits to about 10 million flowers because each individual flower doesn't even fill up the little transport organ, the honey stomach.
And that 10 million flowers is about 400,000 kilometers, which is 10 times the Earth's circumference. So this is very hard work.
FLATOW: Wow, 1-800-989-8255 is our number. We're talking with Tom Seeley and also with May Berenbaum. Tom is the author of "Honeybee Democracy," and May is of "Honey, I'm Homemade." 1-800-989-8255.
Tom, one of the things, looking at the video on our website at sciencefriday.com, the people have, countless numbers have asked me: You are handling the bees in your fingers, and in the last slide, it says: No humans were stung during the making of these videos. Why is it so easy for you to handle them without the bees not being angry?
Dr. SEELEY: It's because when the bees are homeless and hanging from a tree branch, they don't have a hive to defend. They don't have honey stores. They don't have brood. They are - the only resource they have is themselves, and they're in a point, they're in a situation where it's not in their own interest to be defensive.
When a bee stings, if a bee did attack and sting, that would be one less worker bee in the swarm. So they - because they don't have anything there to defend, they are not defensive.
FLATOW: May, tell us how - you said the bees are busy, very busy as a bee. How do they actually make the honey out of the...
Prof. BERENBAUM: Well, the honey comes - it starts as nectar in the organ called the honey stomach. So a foraging bee collects nectar, brings it back to the colony, and then she discharges he load to a bee that is a worker in the colony. And that worker bee then begins the processing.
So nectar is 80 to 90 percent water. What bees do, the most important thing they do with honey is concentrate it down. They basically drive the water content from 18 - 80 percent down to about 18 percent. And this makes honey essentially a super-saturated solution of sugar.
And this is very useful to the bees because it has such a low water content that microbes can't grow without that - with so little water, which means honey doesn't spoil unless water is introduced. So it keeps for - indefinitely.
So that's the - one important thing. And the way they do that is that the workers repeatedly suck up and spit out and suck up and spit out the nectar 100 to 200 times to allow it to evaporate.
Meanwhile, other workers are fanning their wings, beating them 250 or more times a minute, to create moving air to drive that evaporation process.
They also inject chemicals for processing. They pre-digest the sugars. Much of what's in nectar is called sucrose. It's a disaccharide. It's a complex sugar made of two smaller sugars.
The bees use an enzyme called invertase to chop it up into the two smaller sugars, one of which, by the way, tastes sweeter than sucrose. So to humans, honey is actually sweeter on a weight basis than sugar is. It's also easier to digest. And they inject a number of other enzymes. They make it a little more acidic, which also retards microbe growth.
And then when it's all concentrated down, they pack it up in little wax containers and seal it up, and it's good for - indefinitely. It's an amazing substance.
FLATOW: Well, let me go to the phone. Sam in San Francisco. Hi, welcome to SCIENCE FRIDAY.
SAM (Caller): Thanks, Ira. I had a question about how you say that bees really use that honey for survival during the cold winters. And I'm wondering if it's almost like if you really wanted to be super-nice for the bees, maybe it wouldn't be best to steal their resources, or maybe they're fine with it. They have plenty of extra. And they just wanted to find out...
SAM: ...if it sort of hurts their long, busy efforts.
FLATOW: Tom Seeley, is it - does it hurt the bees when you take their honey?
Dr. SEELEY: Not if you don't take too much. And that's one of the key things the beekeeper has to be careful about, is making sure he or she leaves them enough honey to get through the winter. One of the parts of the craft of beekeeping is to encourage bees to store up much more honey than they need. Often a healthy hive in a good area can store up 100 to 200 pounds of honey. So there's quite a bit of surplus for the beekeeper to take.
FLATOW: Mm-hmm. And you keep bees yourself...
Dr. SEELEY: I keep about 50 hives of bees.
Dr. SEELEY: Yup. Makes about - a lot of our hives, the - we don't run them for - completely for honey production. But we still produce over a ton of honey each summer.
FLATOW: Did you see the colony collapse, we heard so much about, in your bee system?
Dr. SEELEY: No. Actually, I haven't. It seem - the colony collapse problem seems to be spotty and maybe largely associated with very large scale beekeeping operations, where one can't take quite as good care of the bees.
FLATOW: Hmm. And so it's a multiple cause. May, you think also it's a multiple cause that's going on here?
Prof. BERENBAUM: Well, there's been sort of an intensive, nationwide effort to try to figure what is causing this problem. And it is ongoing. There are still surveys that have been instituted annually since 2006, when the first reports filtered in about colony collapse. It sort of demonstrated about a third of America's bees essentially go missing each year. And there's - these multiple studies all seem to be converging on one - not one precise mechanism but a common class of mechanisms, just basically multiple pathogens. So pathogen overload.
Among the revelations that resulted from the honeybee genome project is that honeybees actually are a little short on immunity genes relative to other insect genomes. A lot of how they deal with disease is by behavior. But - so there is a - they have a limited capacity to cope with pathogens. And lately, due to all kinds of factors, including the presence of a parasitic mite - it's a vector for many of these, globalization of trade and intermingling of pathogens from all over the world - that the pathogen load seems to be increasing and it seems to have a very adverse effect on the bees.
FLATOW: On the other hand, in your book, you say that the FDA has actually approved one kind of honey as a treatment for MRSA...
Prof. BERENBAUM: That's really very interesting. It turns out, well, honey, for a long time was disparaged as being just sugar water. Because it is nectar, it has every other kind of phytochemical that plants manufacture. It is an incredibly biologically rich and diverse material and its properties depend on the nectars that go into it.
And the FDA recently approved a honey called Manuka honey, which is from New Zealand, from a particular type of shrub, for treatment of methicillin-resistant Staphylococcus aureus. It is effective in - so not only is honey inimical to microbial growth because of its low water content, its constituents also have antibacterial, antimicrobial activity.
FLATOW: Wow. 1-800-989-8255 is our number. We're talking about the bees this hour on SCIENCE FRIDAY from NPR. I'm Ira Flatow. I'm talking with Thomas Seeley, author of "Honeybee Democracy," and May Berenbaum, author of "Honey, I'm Homemade." I hope I say that right, as the title I'm sure wants me to say it.
What - so what is - I mean, there are lot of people who got - have lots of interests. Let's see if we can get some phone calls here. Let's go to the phones. Let's go to Allan(ph) in Franklin, Kentucky. Hi, Allan.
ALLAN (Caller): Hi there, Ira.
FLATOW: Hi there.
ALLAN: Great program.
FLATOW: Thank you.
ALLAN: I just wanted to share a story that I was part of. When - many years ago in Canada, I was walking through arboretum, snow-covered fresh snow. And there was a man picking up small objects off the ground. And I stopped and noticed that they were bees. And I said, well, why are you doing this? And he said, well, yesterday I came through here and saw these bees in a long line, put some in my pocket, went, had a cup of coffee and those bees emerged from my pocket in the coffee shop. So I decided I was going to come back, collect some more, perhaps start a beehive. That was - I never saw the man again. I don't know if he was successful. But it was an interesting encounter for me, to learn that bees, even on a sunny, cold day, don't always make it to their destination.
FLATOW: Tom, what do you say? Good question, Allan.
Dr. SEELEY: Yeah, that's a great - it's a great example of how the bees are alive and active all winter long. And what was happening there is it was a warm sunny day in the winter. The bees were leaving the hive. Some of the bees were leaving the hive to defecate. And if the bees make a mistake and land on the snow, their body temperature quickly drops. They lose their ability to fly and they are stuck there.
Yes, indeed. If you can pick them up, bring them home. They'll be nice and warm and they'll buzz around. But unfortunately, without - if they're not put back in the hive, they will - separated from the rest of their hive mates, they will die within a day or two.
FLATOW: And speaking of that house-cleaning, bees are very good house-cleaners. They keep their place neat and tidy, don't they?
Dr. SEELEY: The inside of a hive is almost sterile. Through the combination of the bees themselves removing debris from the hive, such as dead bees, but also they spread around tree resins, which has many antimicrobial compounds in them. And as May explained, the honey itself is antimicrobial. So, yes, the inside of the hive is extremely clean, though there are, as pointed out, we humans have brought to the bees in North America and in Europe and other parts of the world some new microbes and new mites which act as vectors of the microbes which are creating problems for the bees.
FLATOW: Mm-hmm. And May, what would you like to know about bees that you don't know yet?
Prof. BERENBAUM: Oh, gosh. It's...
FLATOW: I got about a minute left, so you have to be short on that answer.
Prof. BERENBAUM: Here's what I'd like to know. When they - it's not just honey that they prepare, they also make bee bread. It's not just pollen. It's processed. And bees are the closest things I know to humans in that they make prepared foods. They don't eat anything that's basically unprocessed. I would like to know how bee bread is made, whether they actually obtained microbes, like we do when we pickle things, and whether bee bread is basically pickled pollen. That's one thing I'd like to know.
FLATOW: And Tom, quickly, what you'd like to know?
Dr. SEELEY: I would love to know how the bees decide when they're going to swarm. That's a big problem for beekeepers and it's still an utter mystery.
FLATOW: Do we know for sure what they're saying in those dances? I mean...
Dr. SEELEY: That we do know a lot about. We know that they're saying go to this location and you'll find a good thing, be it a new home site or a nice patch of flowers.
FLATOW: All right. Some mysteries and some answers. Thank you both for joining us. May Berenbaum, author and editor of "Honey, I'm Homemade: Sweet Treats from the Beehive Across the Centuries and Around the World." She's also head of the department of entomology at the University of Illinois, Urbana-Champaign. Tom Seeley, author of "Honeybee Democracy," professor at - in the department of neurobiology and behavior at Cornell University. Thank you both for staying with us.
Dr. SEELEY: My pleasure.
Prof. BERENBAUM: Thank you.
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