TERRY GROSS, HOST:
This is FRESH AIR. I'm Terry Gross. Every year, more than half the honeybee hives in the United States are taken to California to pollinate the state's almond crop. Our guest, biologist Laurence Packer, says that fact illustrates both our dependence on honeybees to pollinate many plants we rely on for food, and the devastating decline in the domestic honeybee population in recent years. As you'll hear, the loss of honeybees has been attributed to a variety of causes from nasty parasites to the stress of being transported from state to state to feed on various crops in need of pollination.
Laurence Packer has spent his career studying bees, and he believes we'll be better off if we rely less on honeybees and managed hives for pollination and more on some of the 20,000 species of wild bees. Packer's new book is an exploration of bee pollination and a celebration of bee diversity from stingless bees that feed on tears, to others that survive by invading other bees' nests. Laurence Packer is a professor of biology at York University in Toronto. He spoke to FRESH AIR contributor Dave Davies about his book "Keeping The Bees: Why All Bees Are At Risk And What We Can Do To Save Them."
DAVE DAVIES, BYLINE: Well, Laurence Packer, welcome to FRESH AIR.
LAURENCE PACKER: Thank you very much.
DAVIES: Let's start with some basics. I mean, we know that bees pollinate flowers. But remind us why bees are doing it and why it's important for so many plants.
PACKER: Well, plants reproduce - flowering plants reproduce by pollen being transferred from the male part of the plant to the female part of a plant. And bees are the most abundant animal pollinators that do this for the plants. So they visit plants for nectar and pollen. And they do this because the female bee has to collect nectar to fuel her own energies, and she eats some pollen to help her to develop eggs.
But more importantly, those two plant products are used by bees as food for the next generation of bees. And so what bees do when they pollinate a plant, is actually - they're messy shoppers. They're leaving some part of the food that they have collected from the plant behind on the next flower that they visit. That is the result - pollination by bees, but the bees actually want as much pollen and nectar as they can get to take it back home.
DAVIES: Right, so this critical function for reproducing plants and crops is essentially by bees being sloppy. They're not actually trying to deposit the pollen in the female part of the plant. It just - it just slips off.
PACKER: It just drops off. Normally the stigma is the female parts of the plant are a little sticky, and so that helps the pollen to be loosened from the surface of the bee.
DAVIES: Somebody said - I think this is a quote misattributed to Einstein - that if bees disappeared, humans would have only four years of life left. That's apparently an exaggeration, but give us a sense of what plants rely on bees for pollination.
PACKER: Well, for example, watermelon - a nice, economically valuable watermelon that's large and quite round, not malformed, requires a couple of thousand pollen grains to be deposited. And that might require seven or so different visits of a bee to the - to the flower. And in California, where these studies have been done in the most detail, there are 40 different species of bees that will perform that service. And so if not enough pollen gets onto the watermelon, then you get a malshapen one, or if you don't get any pollen, you don't get any watermelon at all.
Some crops are entirely dependent upon pollination, and others don't require pollinators at all, such as cereal grains. Others are pollinated by the wind, such as grapes. But most of the tastiest products from plants, such as most fruits and vegetables, these require pollination for the development of the fruit or the vegetable, or at least for the propagation of - of the vegetable plants through seeds.
DAVIES: So for - I don't know - blueberries and other plants that are out there, it's - it's really bees that are doing the work and that are critical to their reproduction.
PACKER: For most of the plants that require an animal pollinator, it is bees. There are some exceptions. So there are some cactus fruits that you get as the result of the pollinating activities of nocturnal bats. And chocolate - who doesn't like chocolate? Chocolate is brought to us by tiny little midges that nobody can really identify.
DAVIES: And they do the pollination.
DAVIES: But just give us a list of some things that are bee-pollinated.
DAVIES: Well, zucchini, all squashes, raspberries, blueberries, apples. Then there are things that can self-pollinate, that don't actually need an animal to mediate the pollen, such as coffee. But when it - the bees are present in the coffee fields, the yield of coffee is greater because the proportion of flowers that set seed, and you get coffee beans, is greater with there are bees carrying pollen around. So you'd get perhaps a quarter of the amount of coffee without the bees pollinating the coffee plants, but you wouldn't get none. However, in the absence of bees, not only would we be not able to get some of our favorite fruits and vegetables, we'd get less - less coffee, and so people would be even grumpier in the mornings.
DAVIES: OK. If there were no bees, of course there would be certain plants that wouldn't reproduce, presumably. But these are all parts of a food chain. What might be some of the wider and long - longer-term impacts?
PACKER: Well, plants, most reproduce sexually though pollination - flowering plants reproduce sexually through pollination. They can reproduce asexually also. But the evolutionary responses, adaptations to climate change etc., all this requires the genetic mixture that is brought about by sexual reproduction. And so immediately in the absence of bees the - the effect on the natural ecosystems would be that there'd be much fewer plants setting seed, many fewer nuts and berries, fewer nuts and berries, fewer birds, fewer bears. The whole ecosystem would be impacted at some level, and - and especially in the long-term.
DAVIES: How long have the numbers of domestic honeybees been declining and - and at what rate. Do we know?
PACKER: OK, there is - there's a table on this in a - in a publication by the National Academy of Sciences in the U.S., and the graph shows, I think a halving in number of - of the colonies are kept in the USA over the previous 50 years or so. The number of colonies being kept is - is partly a measure of the need for honey and pollination services. So it used to be that beekeepers would earn a living by selling honey. Unfortunately, the North American market was swamped by cheap Chinese honey, starting maybe a decade ago - I'm not sure of the exact time. And so most beekeepers now earn most of their income through selling the pollination services of the hives. With Colony Collapse Disorder, there's been high death rates of colonies over winter. But the number of colonies in the wild, these are feral honeybees, was also declined dramatically and that's largely a result of varroa mites, which are bloodsucking parasites which beekeepers can fend off from their hives by using management practices. But the feral colonies in the great outdoors, that aren't managed by people, these suffer from those and as a result, they're almost no feral honeybees left - at least in Canada. I'm not sure of the situation in the U.S.
DAVIES: Let's go over a couple of those things in a little more detail. You said that most beekeepers now make their money from essentially renting out the pollinating services of their hives. Does that mean they put them on trucks, carry them into a berry field and just say, go forth and pollinate?
PACKER: In a - well - yes. So, in late March I think it is, just something like 96% of honeybee colonies in the U.S. are in California for almond pollination. After that, a large proportion will go to the southeast for high bush blueberry pollination. And then they move further north, as the various tree fruit crops start developing. And so you imagine a situation where you're feeding your kids nothing but almonds for one month, nothing for - but blueberries the next month and nothing but apples the month after that. And to get from one crop to another, you've got to drive thousands of kilometers and you've 10,000 kids in the back all saying, are we there yet? It's not surprising that bees are somewhat stressed out. And also, you know, it's not just the transport and the diet, there's also the factor - they're exposed to a wide range of different environmental and chemical conditions in the environment when they're treated that way.
DAVIES: So they're really migrant farm workers.
PACKER: Yes, exactly.
DAVIES: Laurence Packer's book is, "Keep the Bees - Why All Bees Are at Risk, and What We Can Do to Save Them.". We'll continue our conversation in just a short moment. We'll be right back. This is FRESH AIR.
DAVIES: This is FRESH AIR. And if you're just joining us we're speaking with biology professor Laurence Packer. He's at York University in Toronto. His new book about bees is called "Keeping The Bees: Why All Bees Are At Risk And What We Can Do To Save Them." You write about some bee parasites that have been very troubling. Let's talk about a couple of those - tracheal mites - that's the trachea, the windpipe, right?
PACKER: Yeah. So, insects exchange gases through little holes along the side of the body called spiracles. And these let air with high oxygen in and then let air with less oxygen in it out. These spiracles lead to a series of tubular pathways inside the body of the bee that reach into every tissue of the insect. So tracheal mites - it's a bit like having cockroaches crawling around inside your lungs and sucking on the fluids inside your body, so they're not too good for bees. It's kind of gross but entertaining to anthropomorphize this I find.
DAVIES: Yeah, no - it's a vivid image that you use in the book. You also write about varroa mites - that's another parasite. Tell us about them, what they do.
PACKER: These are larger, substantially larger. And they live on the outside of the bee, primarily during the bee's development and they suck the blood from the bees. So it's, you know, it's a bit like having a rat-sized bloodsucker between your shoulder blades. You know, the bees can't reach them easily, although in a social colony they can find - they can get other individuals to brush them off. That's not so much the case when the bee is developing as a larvae or a pupa.
DAVIES: And are there treatments for these mites and how much damage are they doing?
PACKER: They were very well controlled until comparatively recently. There are various, fairly simple, methods that the beekeepers use to control these mites. But the varroa mite has become immune to some of the easier treatments and now it's getting a little bit more difficult to get rid of those. Some people have claimed that varroa mites are a major cause of the colony collapse disorder. But I think it's a part of the problem and it's certainly a large part of why we don't have feral bees around so much but I don't think they're the main culprit in this case.
DAVIES: All right. There's this phenomenon of bee colonies just declining. And it bears the name colony collapse disorder. What are some of the theories for what's causing it and what do you think?
PACKER: Well, there's been a wide range of theories about this, including cell phone towers which I gather has been ruled out. Even though I don't like cell phones - I wish it was part of the problem because then they'd all be turned off during my lectures because the towers will be inoperative. But the main issues, as far as the data I am aware of, seem to be a combination of these new systemic pesticides along with introduced diseases. It's an extremely controversial topic but there was a survey of 800 research papers that was published just a couple of weeks ago and it seemed to be fairly clear that from that that the pesticides are at least some extent a cause of the problem.
DAVIES: And how do the pesticides affect the bees? Do we know?
PACKER: Most of these chemicals are used as seed coating and they get into the plant and into the pollen and the nectar and it seems that they have an impact on the bee's both the immune system - making them more perceptible to the new diseases that have been brought around by people carrying bees around all over the place. But it also seems to make them less capable of finding their way home - so it's confusing them.
DAVIES: So we have a circumstance now where there is a declining honeybee population and beekeepers are taking their hives around or at least letting others take their hives around to pollinate crops throughout the United States. Has this reached a critical point where there just are not enough pollinating bees?
PACKER: Not in the United States yet and worldwide it hasn't become a problem. Certainly there are some parts of the world where - such as some parts of China - where people have to go with paint brushes up into the trees to hand pollinate the apples to get a crop. We're not approaching that in North America and I don't think we will. As long as we have honeybees and wild bees which actually do a much larger proportion of the pollination than they get credit for. For example, a study in Britain showed that even if you assumed every honeybee colony was in exactly the right place at the right time throughout the year honeybees were responsible for at most a third of the pollinator dependent crop yield. And so wild bees and also some flies were responsible for two-thirds of it. So we really need to start paying a lot more attention to the wild bees.
DAVIES: Well, what's the distinction? What do we mean when we say wild species?
PACKER: Well, I guess, by definition wild bees are those that we are not domesticating. So there are about nine species of true honeybees and at least two of them are actively managed. The one that's most commonly used is the western domesticated honeybee, but they've got a second species that they use in a very similar manner in Southeast Asia and in Japan. There are other bees that people manage in the tropics - stingless bees are managed in a fairly rustic manner by indigenous peoples in Africa quite a bit and especially in Mexico, Southern Mexico and south into Brazil. And then there are a few other species that we're actively domesticating, such as the alfalfa leafcutter bees, and bumblebees for greenhouse pollination, and the alkali bee and some orchard bees. But the difference between the most domesticated bees, the honeybees, and the other bees is the social life is kind of different. The way that the honeybee recruits other bees to the food resources and to a new nest - the waggle dance, other bees don't do that. Most bees do not produce honey. Only a few hundred species of bees produce more than a teaspoon of honey. Most solitary bees just to make a loaf of pollen, moistened and held together with nectar and then they lay an egg on it once they put all that food together. So most bees are in fact solitary and there are comparatively few bees out of 20,000 plus that we know exist out there will make honey at all.
DAVIES: There's a fair amount of insect warfare that you write about in here. There are wasps, bee wolves, right? Bumblebee wolves and honeybee wolves that can kill up to 1,000 bees an hour.
PACKER: Well, an aggregation of them will, not as a single individual. In fact, in Egypt some areas were for honey bee keeping were wiped out by the Honeybee Wolf because their aggregations built up to such large numbers. They would just wait outside the hive for a worker to leave and then they would paralyze it, take it back and lay an egg on it - after they collected between four and 10 of them and then their offspring would eat the paralyzed bee. When you paralyze your food it stays fresh without the need for refrigeration. So that's one of the reasons that the sting evolved, initially, to paralyze prey for offspring - it's defensive function is secondary.
DAVIES: These wolves are actually wasps right? And so they...
PACKER: Yeah. Sorry they're in the group of wasps that's most closely related to bees. So that's a little creepy.
DAVIES: Right. And so they paralyzed the bee with the sting. The bee remains alive while the wasps little larva eat the bee. Is the bee - can the bee feel it? Is it aware of it? Let's just get really gross here.
PACKER: Yeah. I don't want to put people off. This isn't a lunch hour program, huh? I'm not sure if that's known. Certainly you would hope that that's not the case. But some people would argue that pain and insects aren't two things that go together. But I think insects feel pain, yeah.
DAVIES: OK. A couple of other exotic kinds of insects that you write about - vulture bees. Tell us about them.
PACKER: OK. So the idea that all bees collect pollen is not quite true. There is a group of bees, they're called stingless bees. That sounds as if they're really nice and friendly but in fact what they do instead of stinging you, they'll use their mandibles to grab hold of a part of your eyelid, or inside your ear, or up your nose, or your lips and then they will vibrate their wing muscles and pinch - so they're not nice. The idea of stingless bee sounds really cute, they're not as cute as that seems. But what these collectors - for the protein source - is dead meat. So the workers from - they're social bees - the workers will go to a dead animal and they will chew away at it and then the glandular products that result from that, that's what is fed to actually their siblings back home in the nest. Since I wrote the book, there's been a finding of an even more unusual behavior and some other stingless bees in Southeast Asia has been shown to collect tears from vertebrates - so the story goes - that use the proteins from the antibacterial enzymes in tears as the protein source for the bee larvae, so that's pretty unusual. And the researcher who did this Hans Benzinger in Thailand actually had the bees feeding at his eyeballs and said that normally it didn't cause much pain but when he had 40 bees in his eyes at once the irritation was quite intense and lasted for quite some time.
DAVIES: (Laughing) They weren't stinging? They were just collecting his tears?
PACKER: If you got 40 little insects walking over your eyeballs and licking at your eyelids I think it would get irritating pretty quickly.
DAVIES: That's a photo that will get clicks, I imagine.
PACKER: Yeah. You can see pictures of this somewhere. I'm not quite sure where. You Google ice accretion bees or tear bees, you'll probably get there eventually.
GROSS: Laurence Packer will continue his interview with FRESH AIR contributor Dave Davies in the second half of the show. Packer is the author of "Keeping The Bees: Why All Bees Are At Risk And What We Can Do To Save Them." I'm Terry Gross and this is FRESH AIR.
GROSS: This is FRESH AIR. I'm Terry Gross. Let's get back to Dave Davies' interview with biologist Laurence Packer, author of the new book "Keeping The Bees: Why All Bees Are At Risk And What We Need To Do To Save Them." When bees are threatened, it means our food supply is threatened because we depend on bees to pollinate many plants we rely on for food. Packer's new book is an exploration of bee pollination and a celebration of bee diversity.
DAVIES: I have to say, one of the most entertaining moments in the book is when you described this Francisco oil beetle, a parasite that has a really wicked way of getting at bees. Tell us what it does.
PACKER: Yeah, the subtitle for that is sexually transmitted, child-eating female impersonators on a California sand dune - and it is a remarkable story that's been discovered by Leslie Saul and coworkers. And the Californian sand dune in question is the Kelso dunes, and oil beetles eat the resources in bee nests. But the baby beetle larvae have to get into the bee nests in the first place. And what many oil beetles, meloes, do is their first-instar larvae, they're newly hatched from the egg, they're very active and they manage to find their way onto a bee and then get taken back to the nest that way.
What the San Francisco oil beetle does is the females lay hundreds of eggs in a big mass. When these eggs hatch, they climb up anything vertical that they can find, and they sit there in a blob altogether looking to something with poor eyesight like a bee. And what they do is they release a chemical mixture that is very similar to the pheromones released by the female bees to attract a male. So what happens is the males are attracted to these hundreds of little larvae sitting on a stem. And they come into contact with it and instantly - and you can find videos of this on the in Internet - I have no idea how they do it - so instantly, you get from a situation where the bee's approaching these larvae, and then all of a sudden there's hundreds of larvae covering its body, and the weight crashes it down to the ground.
Then this bee will attempt to mate with real females. Because it's giving out these female pheromones, other male bees will think it's a female. So these little larvae attach to the females that the male mates with and also to the males that think this male bee is a female bee. And then eventually they get back into the nests where they eat the resources there. It's a remarkably weird story. And, as they say, it's a bit like going to a bar and chatting somebody attractive up and thinking that you are going to be able to enjoy their company, and then all of a sudden they turn into several hundred rat-sized parasites that you're forced to take home, and then they eat your children.
DAVIES: (Laughing) It's nasty out there, isn't it?
PACKER: (Laughing,) Yeah, but I love it.
DAVIES: So there are as many as 20,000 species of bees, and many of these wild bees play important roles in pollination. Tell us to what extent whether we know whether those populations are declining and as a result, you know, we're facing a crisis of pollination and viability of these plants or crops.
PACKER: Certainly overall number of bee species you'll find in an area where we've got long-term data, the number of species seems to have declined fairly substantially. In terms of loss of individual species, that's best documented for bumblebees because they're big and furry, they're like the charismatic minor fauna - everybody loves the bumblebee. They're so furry and brightly colored so there's lots of data available on those. And something like 24 percent of the bumblebee species in Europe are on the endangered species list or heading there. And in North America there are certainly some species which are declining or have disappeared.
DAVIES: You know, you write that there are many natural predators for bees, the biggest one of course is us, human beings. Can we imagine the extinction of bees or many species of bees? How close are we to that?
PACKER: I don't think all bees are at risk right now and I don't foresee that happening in the long future - long-term future. There are some bee populations that are increasing dramatically. So while some bumblebee species are disappearing, others are becoming more common. But what this results in is a simplified ecosystem and, you know, you don't put all your eggs in one basket type approach. The more diverse the bees are in a community, it's likely that things are going to be working out better in the long run.
DAVIES: To make the distinction here - we're talking - bumblebees are wild bees. Colony collapse disorder is affecting the domesticated honeybees, right?
PACKER: That's right, yes. And so bumblebee decline started being noticed in the 1990s, and if we'd had more people looking at this at that time we might be ahead of the game compared to where we are now in understanding the declines of all sorts of things.
DAVIES: You know, we talked earlier about the fact that domesticated honeybee populations are being transported around to pollinate crops and vegetables in different parts of the country and that that's stressful for them and it is one of the things that's contributing to this mysterious kind of collapse of many colonies. Are we at risk of not having enough honeybees to do the pollinating that farmers expect of them?
PACKER: We are at risk in the future. There was a study looking at global honeybee diversity by an Argentinean Marcelo Aizen and the Canadian Lawrence Harder. And they showed that we've not reached the point where the need for honeybees is outstripped by the resources that we need for them to pollinate, but if things don't change, it will soon reach a point where the amount of flowers we need pollinated will be greater than the bees can manage under current circumstances. So the area for growing almond trees in the U.S. Southwest, for example, is increasing dramatically. And we've already got most of the North American - most of the United States honeybee colonies there when the almonds are in bloom. So if you increase the area of almonds remarkably, it's going to be more work than the bees are going to be able to manage.
DAVIES: Lawrence Packer's book is "Keeping The Bees: Why All These Are At Risk And What We Need To Do To Save Them." We'll talk some more after a short break. This is FRESH AIR.
DAVIES: This is FRESH AIR. And if you're just joining us we're speaking with Laurence Packer. He's a professor of biology at York University in Toronto. His new book is "Keeping The Bees: Why All Bees Are At Risk And What We Can Do To Save Them." You said that there are some things that all of us can do to help preserve pollinating bees. Among them, grow bee friendly plants - like what?
PACKER: Well, I like raspberries for a bunch of reasons. One, I like eating raspberries. But the other two groups of reasons are that the flowers are open flowers and just about bee can access the pollen and so there's quite a diversity of different bee species that will visit the raspberries in my backyard. And also the raspberry canes are perfect for a large number of stem and twig nesting bees to use as a nest site. So I leave the old raspberry canes out in my garden for years and I've got three different genera of bees nesting in them. So in general if you're going to plant plants for ornamentation or for food, ones with simpler, open flowers are better. If you like growing roses - the wild roses - these are an open source of food. It's like a plate with the pollen in the middle, easily accessible. You look at most of the horticultural variety of roses and it's almost impossible for a bee to burrow into the flower to try to find anything in the middle of it because all the petals are so clustered so close together. So the simpler the flower in the general the greater diversity of bees that can use it.
DAVIES: And you provide a more abundant food source, you'll have a more robust bee population. You also say you can provide nest sites for bees. How do you do that?
PACKER: Well, I get into trouble with horticulturists by saying this - because I say you shouldn't use mulch. Most bees nest in the ground and you wouldn't like it if somebody tipped a compost - garbage truck full compost on top of your home and bees don't like it either. So most bees prefer sparsely vegetated soil. So lot's of gardens in my neighborhood, they put woodchips or gravel or some other such stuff over the surface of the garden or they grow a lawn and these are pretty barren for bees. There are a few bees that will build a resin nest on stones but they're pretty rare and they usually are only found in deserts. There are some bees that nest in gardens. And in Europe there are whole pest-control companies dedicated to removing burrowing bees from people's lawns. But in general if you want to help the bees have the kind of garden that your neighbors will be irritated at you for having because it looks kind of messy. The end of the talks I give on this, on bees, in general I show a picture of my backyard and I've had people stand up and shout at me - what do I do if I want to help bees but not of a garden that looks as ugly as yours? And I don't really know how to answer that. I like my garden.
DAVIES: You know, you are clearly fascinated with these animals and there are great descriptions of some of their exotic kind of characteristics and behavior. And you know there are naturalists who a lot of them love big mammals - I mean, it's easy to love the panda bear or a majestic lion. Do you feel affection for bees?
PACKER: Oh absolutely, yeah. Passion is a bit of an understatement. Maybe I'm obsessed. Perhaps I'm psychologically unhealthy so. But, no, I'm lucky in that my wife is also a scientist. She's an ornithologist so we got the birds and the bees between us and nothing could be better than that. But I spend as much time as I can actually looking at bees under the microscope or out in the field studying.
DAVIES: How many times do you think you've been stung?
PACKER: On an average day in the field I get stung at least once. And usually it doesn't bother me. I only get bothered if I get stung in the same place more than once. So sometimes I'll have very painfully throbbing finger or thumb for hours. But most bees the sting is just enough so that you release it. They are not trying to inflict pain to keep you away from a large colony like honeybees are. They just want you to release it. And so most bee stings don't last very long - 5, 10 minutes or so. But if you get some twice in the same place that can last a lot longer.
DAVIES: Laurence Packer, thanks so much for speaking with us.
PACKER: You're more than welcome. Thank you.
GROSS: Laurence Packer spoke with FRESH AIR contributor Dave Davies who is also senior reporter at WHYY. Packer's new book is called "Keeping The Bees" you can read an excerpt on our website freshair.npr.org.
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