The way of the flowers
Текст: Tatiana Petukhova, Dinar Khayrutdinov | 2019-11-08 | Фото: | 14913
Little creatures known as bees are actually one of the most important living beings in the world. Not only do they provide us with honey, which is both delicious and beneficial for health, but they also participate in pollinating a lot of plants whose fruits and vegetables people (and some animals) traditionally consume as food. Therefore, increasingly frequent reports in the media about mass deaths of bees in different regions of the world make a lot of people seriously concerned. Whether bees are really at risk of extinction, and what their health depends on was the subject of our conversation with one of the world's leading experts on bees, entomologist Marla Spivak.

— Let me start by asking how much scientific knowledge about bees has advanced to date: how much do we know about bees and how many unanswered questions do still remain? What scientific knowledge is relatively recent and how has this knowledge changed our understanding of bees?

There are 20 thousand species of bees on Earth. Most people are interested in honey bees — the ones that produce honey, which is why they’re so popular and so common all over the planet. Over the course of history people intentionally brought honey bees to different places of the world to breed them. I must say that the scientific knowledge about honey bees is quite advanced — we know more about them than about any other kind of bee, although unanswered questions and mysteries always remain, and some of what there is to know about them is not yet available to us. Recently, science has focused on factors related to the health of bees — we are trying to answer the question of why they are currently experiencing health problems. At the same time, it is hardly possible to say unequivocally that the population of honey bees is declining, because there are a lot of beekeepers, and they typically propagate a sufficient number of colonies so that the dying bee colonies are immediately replaced with new ones. So, I wouldn’t say that honey bees are endangered.

An important thing is that bees themselves are able to take care of their health — this is what scientists call «social immunity». Not only bees have social immunity but also ants, wasps or termites — that is, social insects that live in colonies. These colonies are very densely populated communities, and the question is how an entire bee colony can fight parasites or diseases and stop the spread of these diseases. To do this, they have certain behaviors and strategies for organizing life in the colony (which is social immunity in a nutshell), and they are aimed at preventing the spread of diseases. This behavior is very similar to the behavior of cells in the immune system of humans or animals. Our bodies are capable of detecting anything foreign or harmful, like microbes, bacteria, viruses — and if there are too many of them, the immune system attempts to destroy them. The same thing happens in bee colonies. Bees do this in various ways. For instance, one of such defensive mechanisms is called «hygienic behavior». Bees have antennae on their heads, which help them detect odors that come from nestmates affected by diseases or parasites. They also can detect these odors coming from their brood – that is, from developing bees. They then open these cells and destroy the infected brood. The most interesting thing is that bees are able to detect infection in the brood at the stage when this infection is not contagious – that is, during the latent period, and that is why this brood cannot infect the adult bees. And that is how they manage to destroy or remove the infected brood from the bee nest without infecting any other bees.

© PollyDot / pixabay

But there is also a second form of social immunity in bees, and that is collecting propolis. Propolis is comprised of plant resin known for its anti-inflammatory, antibacterial properties. Back when this subject was not yet well-researched, beekeepers tried to use propolis to fight diseases in bee colonies, but they did not use it the right way — they fed it to bees. But bees do not consume propolis naturally. It makes much more sense to use propolis the way bees do in their natural environment. They collect resin from plants and bring it to their nests and cover the inner walls of these nests with it. Propolis kills a wide variety of pathogens. At some point in my lab, we started paying attention to this and began to study the beneficial properties of propolis for bees’ health. Now we have enough information to confidently assert that propolis serves a definite purpose, and that is to help their immune system, and help them fight off infectious diseases. Some of our very recent scientific evidence also suggests that propolis helps bees to maintain a core a microbiome in their bodies — the microflora that also helps them cope with diseases.

— Do people carry out selective breeding of bees on the basis of these two properties: the ability to fight diseases and parasites? Do they select the bees with higher resistance to parasites during breeding?

Yes, we have been doing the selective breeding of bees based on the above factors for more than 15 years, and we also explain to beekeepers how to perform the selection process. Many beekeepers and beekeeping companies do this on a commercial basis, for example they buy or sell queen bees. Today, more beekeepers understand the importance of propolis for bees, and so very often they use boxes for hives with rough wood on the inside, which allows bees to apply propolis on the boxes’ walls. Bees more willingly put propolis on the walls made of rough, raw wood because that is closer to their natural conditions when, for example, wild honey bee colonies do the same inside of a tree hollow. Now in our laboratory we are starting a new program of selective breeding of bees, aimed at breeding bees with a higher level of hygienic behavior and bees that are able to collect and use propolis. In addition, now we are also trying to breed species of bees with higher resistance to very dangerous parasitic Varroa mites, which use honeybees as hosts.

© Kai Wenzel / unsplash

— And how does the surrounding landscape affect the health and nutrition of bees? Can bees migrate in search of a better place or better food?

The environment and the landscape where bees live is incredibly important for their health because it determines their nutrition, and nutrition is a fundamental thing that affects the health of any living organisms. Very recently, a remarkable study was conducted in the laboratory of Professor May Berenbaum at the University of Illinois. They examined various chemical compounds that are contained in the nectar and pollen that honey bees collect and bring to the nest. These substances are vital for bees — they strengthen their immune system. In addition, thanks to these chemical compounds inside the bees’ bodies, special enzymes are produced that help them neutralize toxins that bees get from pesticides.

Therefore, if bees have a good habitat, and, consequently, good and varied diet, then their bodies will have a lot of such vital chemical compounds that will help reinforce their immune system and health. This means that bees that have access to a variety of pollen sources, that is, there are a lot of different flowers growing around them, have much higher chances to successfully fight diseases or neutralize pesticide toxins.

— Humans can often cause harm to bees by accident or mistake, because they simply do not know certain things. What should an average person know in order not to cause any harm to bees? What can common people or organizations do to help bees?

I’ll start with the second question: I think that a simple thing that everyone can do for bees is just plant more flowers. It is a pleasant activity — many people enjoy planting flowers and taking care of them. As for things we can do to avoid causing harm to bees, it is preferable not to spray the flowers you plant with pesticides — try to grow them in natural conditions without using any chemicals. For bees, the more flowers there are around, the better. And flowers are beneficial not only for honey bees, but also for a variety of species of wild bees. Also, beekeepers should understand that the closer the conditions that bees are kept in are to their natural habitat, the better it is for bees. I don’t know what it’s like in Russia, but in the United States, even where I live (and I live in a city), there are many apiaries and beekeepers, so we have a sufficiently large amount of apiaries per unit of area.

On the one hand, the more natural are the conditions, the better, and many beekeepers agree with this. That is why many of them refuse to use any chemical substances against Varroa mites, because they believe that the chemicals can harm the bees. On the other hand, there are beekeepers who use organic chemical treatments against mites. And here is what happens. Let’s say we have a bee colony that has been treated for mites, and because of that they don’t have any. And then there is another colony that is infested with mites and dying. Bees from the healthy colony can fly into the hive of the dying one, steal honey from them and get infected with mites. So we get the situation when either all the beekeepers must use treatments to deal with the mite problem, or all of them have to give up using them. If all of them decide not to use them, then a sufficiently large number of bee colonies will die, but the surviving ones will develop a natural immunity to mites. Therefore, coordination between beekeepers that have apiaries in the same area is very important.

— In your opinion, is the influence of beekeeping on bees generally positive or generally negative?

This is a very difficult question. I think that good beekeepers have a positive effect on bees, while inexperienced beekeepers or ones that tend to overlook some important aspects of it are more likely to have a negative impact on bees.

Marla Spivak's archive

Marla Spivak with beekeepers

— How serious is the problem with pollination in the United States today, and is this problem being solved in some way?

The largest pollination event we have in the United States is almond pollination. Every year, almond tree growers worry that there won’t be enough bee colonies to pollinate these trees, and beekeepers from all over the U.S. bring bees so they can pollinate them. There are, of course, other crops, such as blueberries or various horticultural crops, but they do not always require such a large number of bee colonies to pollinate them, as do the almonds. On the whole, I don’t think pollination poses any serious problem in the States today.

— We’ve heard of a practice of using «mobile hives,» which beekeepers move from place to place so bees can pollinate plantations. Are such mobile hives popular and how does this practice affect bees?

We call it «migratory, or nomadic beekeeping». Beekeepers can transport bees from place to place: in one area they make honey, in some other area they pollinate flowers and plantations; or, for example, they may be transported to some warmer regions for the winter — this is not actually a new phenomenon, they have been doing this since at least the 1960s, or maybe even earlier than that. The largest beekeeping companies in the United States practice nomadic beekeeping on a large scale. It is known that in Ancient Egypt beekeepers moved hives with bees up or down the Nile, depending on the season or the weather.

There are certain data that allow us to say that this practice causes certain stress for bees, but in fact they adapt to this stress and get used to it pretty quickly. This can be compared to the stress that we experience when taking an airplane flight. When you take a long plane flight, you feel a little tired and jet-lagged after that, but it doesn’t take that long to overcome that and resume your normal rhythm of life. But also if you fly in a plane and you are sick, you may well infect other passengers — and the same happens with bees, so beekeepers who do nomadic beekeeping always have to select the bees to be moved elsewhere very carefully: normally these need to be the healthiest bees.

© 1Flatworld / flickr

Almond blossom

— Can you tell us about the so-called «colony collapse disorder»? What is the reason behind this phenomenon? What research is conducted in this area and is their a general consensus among scientists about CCD?

«Colony collapse disorder» is a term that scientists coined in 2006 to refer to a phenomenon that was discovered at that time and that we couldn’t understand at first. At that point, some beekeeping companies were faced with the fact that many bee colonies were suddenly dying. For a while no one could explain why this was happening, what the reason was. Today the term «colony collapse disorder» is used very rarely, because 4 different reasons have been identified for that phenomenon, so now we talk about four different things rather than combine it under one term. These four reasons are quite simple: pathogens (diseases), parasites, pesticides, and poor nutrition. Even one of these four causes is enough to make a colony of bees die, but often it’s not one but several of these four factors at work. Now we are studying various combinations of these four factors that may occur in nature, and also how these factors may affect each other.

— Does modern agriculture, whose primary focus today is monoculture plantations, cause any harm to the bee population?

Here we have to be talking about all bees, not only honey bees. For honey bees, the problem with monoculture plantations is that they only have one source of pollen in this case, whereas in natural conditions they need several different sources to get a varied diet. On the whole, this problem can be solved, because we have nomadic beekeeping, which I have already mentioned. This means that beekeepers can release their bees to pollinate pastures or plantations for a while, and then transport them to other places and give them an opportunity to collect pollen from various other plants. Therefore, this is more of a problem for wild bees, because no one will specifically transport them anywhere — they are wild, they live on their own, no one takes care of them. For them, pesticides are particularly dangerous, because if wild bees fly anywhere near agricultural fields that are sprayed with pesticides, their lives are at risk.

— So can we say that chemicals are the main threat to bees currently? Or are there more serious threats?

In the US, I think the biggest threats to bees are Varroa mites and pathogens, particularly the bee viruses that are spread by these mites. This combination of mites and the viruses they spread can literally kill a whole colony or even several colonies of bees within a year or two. Of course, if bees are exposed to high doses of insecticides and pesticides, it is also incredibly dangerous for them and can put entire colonies at risk, but in fact there are much less cases of acute pesticide poisoning in bees than cases of serious problems associated with Varroa mites and with the diseases they spread.

Indeed, on the one hand bees are now chronically exposed to pesticides, insecticides, herbicides, fungicides and so on, but the actual doses can be quite different. Just like bees, we also receive certain doses of the same chemicals, which we breathe in with air, and our bodies have already adapted to this to a certain degree, because they are capable of neutralizing some amount of toxins. In general, bodies of bees can also neutralize a certain quantity of toxins, so, even though I agree that pesticides are a problem, I still would not call them the main reason for the decline in the bee population.

However, recently we have also been actively engaged in the study of fungicides: in the US, they are often used in combination with pesticides, and recent data show that fungicides can interfere and adversely affect the microbiome of bees. In particular, fungicides kill some beneficial bacteria in bees’ organisms, that is, they destroy part of their intestinal microflora, and, in combination with insecticides and pesticides, fungicides can often be very dangerous. Therefore, we need to pay attention to what mixtures of insecticides and fungicides we use in agriculture. The properties of these chemicals are rather well-researched separately, but what harm can mixtures cause is a question that has not yet been fully studied.

© Roman Boed / flickr

Corn field

— Today various robotics labs around the world are doing research and trying to design artificial «bees» — tiny flying robots that would pollinate plants. Have you had any experience with this kind of projects and what is your opinion of them?

Yes, I have heard about such projects, and I think that in robotics such projects are rather experimental in nature. I can hardly believe that these can potentially grow into something large-scale, and that people will actually use robots to pollinate plants. I don’t think there will ever be a replacement for living bees in the form of tiny robots: bees have evolved over millions of years and their organisms are perfectly adapted to pollination. It seems doubtful to me that people will be able to invent a machine that will do this better than bees do.

To be honest, I would prefer if people involved in robotics focused their attention on projects that would allow spot-spraying of pesticides, so that they can be used only in those places where it’s necessary, in microdoses. That way people wouldn’t have to spray pesticides from an airplane over entire fields. That would be really helpful. I think technology is best used wisely, so that it benefits the environment.

© Allan Rostron / flickr

— You’ve been studying bees for years, but is there something about bees that still surprises you or fascinates you? Also, could you tell us about the research that you and your laboratory are currently doing?

Of course, bees have never ceased to amaze me over the years — their resilience and vitality are incredibly amazing. Despite all sorts of health problems that they have, bees today are generally alive and well, maybe even better than most other species of insects. Of course, the study of propolis and the beneficial properties of this substance for bees was a great discovery for science, and, as I said, we continue doing research in this area — we are studying the benefits of propolis for the microbiome of bees.

Now as for the other research we’re doing, the following studies deserve a mention. I have a student who is doing research on what we call «bee lawns» — these are turf lawns on which you can plant flowers and then take care of this lawn (trim it and mow it and so on), but the flowers will continue to bloom. This study is an attempt to figure out how these turf lawns can provide sufficient food for bees. This idea is gaining popularity in the city where I live (St. Paul, Minnesota) — people like it, because if they have these turf lawn they won’t need to plant flowers in some wild, unkempt area, with a large amount of weeds growing there together with flowers. Instead, people can grow turf lawns, plant flowers on them and that will be provide some floral food for the bees.

Another student of mine is researching the bees’ waggle dance, which is a way of communication for them. She films these waggle dances on camera and then carefully examines them. We tried to reproduced the natural conditions of a wild prairie and planted some plants that are typical of North America. And we tried to find out whether these conditions are suitable for honey bees, as they all have been brought here from other continents. This student placed several bee colonies into these artificially reproduced prairies and then filmed them. Then she also collected pollen from these bees and analyzed it. The conclusion she came to was that honey bees actually don’t collect pollen very actively in these reconstructed prairies. One of the few species of flowers growing in these prairies, which they really like, is the goldenrod (Lat.: Solidago), because goldenrod is loved by almost all bees. However, the plants that are typical of the prairies are, for the most part, of little interest to honey bees. This study shows that if we want to keep honey bees in our area, we’ll need to plant the flowers that these bees like; and, conversely, if we want to make sure that honey bees do not fly to certain areas at all, so that the local wild bees can freely live there instead, then we should only grow local vegetation. So, those are some of the interesting conclusions we’ve come to.

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