INSPIRED BY BEES. Stephen Buchmann is a pollination ecologist specializing in bees. He is an Adjunct Professor in the Departments of Entomology and Ecology & Evolutionary Biology at the University of Arizona and a Fellow of the Linnean Society of London who works towards a world where nature is understood, valued and protected. In his most recent book What a Bee Knows Buchmann explores the thoughts, memories and personalities of bees.
You can listen to the podcast of this interview here.
Stephen Buchmann, how did you get into bees?
I kept honey bees when I was in high school, and I soon became interested in native ground nesting bees, especially the genus Centris in the Mojave and Sonoran deserts of California and Arizona. Most of my research with collaborators and various colleagues around the world has been with native solitary bees.
What is the difference between native bees and honeybees?
A honeybee colony is a queen and 30,000 or more of her loyal servants – the worker bees – but only about 10% of the world’s 21,000 or more bee species are social, and even fewer of those make honey. I joke that the bees I study are single mothers with families to feed. They have no help from the males that they recently mated with. They’re off on their own, digging burrows and tunnels in the ground and then going out to forage for nectar and pollen, bringing that back, forming a little ball, laying an egg on it, sealing those cells up and having no contact with their offspring. Those solitary bees may only live for a month, while a honeybee colony is essentially immortal; as long as you keep replacing the queen bee that colony lives on and on.
“Pollination makes the world go round and allows us to eat.”
Stephen Buchmann, are bees economically important?
The most important bee of commerce around the world is the Western Honeybee, Apis mellifera, that beekeepers extract honey from to sell. But today there is a huge industry where beekeepers are not making their living by harvesting and selling honey but by entering into legal pollination contracts with growers. For example, there are 800,000 acres of almonds (requiring one million colonies of honeybees trucked in) in California and now the money to be made as a beekeeper is through pollinating various crops rather than producing honey.
What does pollination mean?
Pollination makes the world go round and allows us to eat. Approximately every third bite – about 33% – of the global diet is due to honeybees and bees and other pollinators moving pollen around and pollinating our crops. Pollen, the male gametophyte which is plant sperm, has to get from the male portion of one flower to land on the female portion of another flower. That can happen by wind and water; or by bees and other pollinating insects like flies, wasps, beetles, butterflies and moths; or by vertebrate animals like hummingbirds, sunbirds and white-eyes; or by mammals like nectar feeding bats in our Sonoran Desert here in Arizona and in northern Mexico.
In your book What a Bee Knows you say that because humans are afraid of being stung by bees that we are exterminating – probably very stupidly – a huge amount of bees. Instead of being perceived to be essential to our food chain they are perceived as our enemies. Why do bees, which are fed by the plants they pollinate, attack human beings?
In Western cultures especially there’s a pronounced fear of insects, and this is strongest amongst those with stingers: so wasps, ants and bees. Bees evolved about 140 million years ago from a small group of wasps, and the stinger first evolved from even farther back when it was an egg laying tube. This became modified during evolution into a defensive weapon like a hypodermic syringe that could inject a painful cocktail of biochemical that we call venom. But bees are not out to get us. You’re not in danger from even the infamous killer bees, the Africanized honey bees that we have here in Arizona, unless you go too close to their colony or attack them. Then the guard bees will come out and sting you.
Bees can be defensive, but attack is a last resort?
Yes, but humankind is directly poisoning bees through use of agrochemicals. In the US we still use a class of insecticides called neonicotinoids, or neonics, and they’ve been banned in many EU countries for quite a while. Only 3 of the 50 states in the United States have banned these systemic insecticides which, if they’re used as a seed treatment or applied to a crop, make the entire plant poisonous. When that plant blooms, the nectar and pollen which are the floral rewards for bees and other pollinators become poisonous as well. And, these chemicals build up year after year in soils. In our nurseries in the United States I warn customers that they should ask the supplier if the garden plants they’re buying have been treated with systemic insecticides; and many times they have.
The brain of the bee is very small but bees live together and are social animals?
Even the solitary ones sometimes nest in a group, so they’re gregarious and they do quite a lot with their tiny brains. About the size of a poppy seed, their brain is divided into structures inside it. Two of them, called mushroom bodies because of what they look like, are central processing units where higher order neurological things happen. There are also massive optical lobes coming directly out of the huge compound eyes. In my book I talk about the fact that bees can run through a maze as well as a mouse or a rat. They are problem solvers and tool users who demonstrate social learning. Professor Lars Chittka in London wrote a really nice book called The Mind of a Bee, and he goes into these neurological things even more than I do.
“The vast majority of bees are honest, hardworking, and do their own thing and don’t bother one another.”
Stephen Buchmann, why do bees tend to nest underground?
The bees of the world evolved from different kinds of wasps that were nesting in the ground, and so the bees do also, but some bees nest in cavities. This could be a hollow tree like honey bees, or the famous stingless bees of the tropics – about 400 species of those actually are honey makers. Certain solitary bees will go to a stem broken by the wind and excavate it and make a little tunnel and then make their nest in there. 90% of bees might nest in the ground, but around 10% nest in cavities or stems and plants. We can think of them like birds taking over a preformed cavity.
Is the nest as important for bees as it is for birds?
Yes. Think of a female bee that has found a good space, a little nice place of bare ground, close to her food plants, and her nest is her tunnel where she sleeps and makes the brood cells. This nursery for her offspring is like a bird’s nest. In the morning she will fly out and visit dozens or hundreds of different flowers to collect enough nectar and pollen to bring back for food for her brood. A central place forager, when she goes out from home she makes a spiral, flying up and out and away from the nest, memorizing the physical landmarks. A small bee can fly out a few hundred meters – a larger bee might go several kilometers – and she can very accurately find her way back, also because of something known as the sun compass. All bees are very aware of where the sun is in the sky and how fast the sun moves across the sky and they have a very accurate time sense. If a flower opens only at 9 in the morning the bees are there on time, or even waiting at that flower anticipating the bloom.
Do bees also go out at night?
There are a few bees around the world that fly at night. My colleague Bill Wcislo at the Smithsonian Tropical Research Institute in Panama studies sweat bees that only fly on moonlit nights. There are also some desert bees that fly at dawn, when there’s very little ambient light.
What is their relationship with other insects?
Bees are generally peaceful, but the stingless bees of the tropics can raid other bees. A genus called Lestrimelitta is a true robber bee; its female bees do not go out and visit flowers on their own and make an honest living, but they instead find a host colony of a Tetragonula – another kind of stingless bee – and the Lestrimelitta will come in and chemically overpower the colony with Citral, a very lemony chemical. Then they’re able to raid it and take the honey. My late research mentor when I was at the University of California at Davis found that honeybees on sunflowers were stealing pollen out of the leg hairs of certain native bees. But the vast majority are honest, hardworking, and do their own thing and don’t bother one another.
Do different insects compete for the same pollen?
Flower flies or beetles or wasps or butterflies may often be visiting the same flowers and competing for the same nectar and pollen. Scout honeybees can go out and find rich new patches of flowering plants, come back, do the famous waggle dance and report to their hive mates, and soon there’s a rush of hundreds or thousands of newly recruited bees. So if honeybees find a rich flower patch they can swamp it out and eat up all of the nectar and pollen before other native bees or other pollinators can even find it.
Do bees play valuable roles in addition to pollination?
Most of the world’s bees are ground nesters so they perform bioturbation. They’re mixing up the soil, and their tunnels allow air and water to penetrate the soil. You can almost think of them like earthworms, and, since their larvae are being fed nitrogen rich pollen, when the larvae eat it they will defecate it, and that stays in their old brood cells in the ground. By nesting in the ground and feeding their young bees are performing a very valuable fertilization (adding nitrogen, phosphorus and potassium) thereby enriching the soil. Beyond that bee larvae and adults serve as food for the many birds, lizards, spiders and other animals around the world that eat bees routinely.
Stargazer Lily. Floral parts labeled. Pollination. Illustration by Paul Mirocha of Tucson.
The honey bee brain, diagrammatic.
Nervous system of the honeybee, by the late/great R. E. Snodgrass.
A typical solitary female burrowing bee and her underground nest by artist Steven Buchanan of Connecticut.
A pair of mating Centris pallida bees. Photo by Bruce Taubert of Arzona.
Longhorn bee (Idiomelissodes duplocincta) males sleeping together. Photo by Bruce Taubert of Arizona.
“I’m not quite willing to go as far as to say that bees are happy or joyful.”
Stephen Buchmann, as bees have venom are they poisonous for other animals?
Not so much. Maybe they are spicy food for the other animals! Birds will sometimes catch a bee in their beak and try very carefully not to get it in their mouth until they’ve bashed it dead against a branch. Other animals may be somewhat immune to the venom, but skunks, badgers and bears routinely attack honey producing bee nests and typically try to protect the tender areas on their face, so certainly they are feeling pain from bee stings.
Can bees feel pain?
Bees do have pain receptors and things called nociceptors for the detection of noxious stimuli so then they can move away from them. My thought is that bees do in fact feel pain and that, as a scientist, when I am experimenting with bees in a laboratory I have a responsibility to treat them in a humane fashion that does not inflict undue suffering or pain.
Do they have feelings like sadness, jealousy, anxiety and fear?
Several experiments lead myself and others to believe that they may have simple emotional states. Lars Chittka and his students of insect sensory systems in England created little robot spiders with padded foam pinchers and when a bumblebee came close to one of these fake spiders, the spider would grab it and hold the bee for 2 or 3 seconds and not let it go. Later, when those bees were released, they seemed to show an anxious state. They were hesitant to go anywhere near that robotic spider again, or even anywhere that was close to it. That indicates that bees may have some kind of emotions. I’m not quite willing to go as far as to say that bees are happy or joyful. Maybe they do get “excited” when they find flowers that are overflowing with nectar, but it’s a difficult thing to know about the consciousness of any animal. Philosophers have debated this for centuries.
Where are the largest bee populations?
The richest areas for bees in the world are right here in the southern United States, in Arizona and California. Arizona has about 1300 species of native bees. Other biodiversity hotspots for the native bees that have evolved there are South Africa and Israel, which is extremely rich in bees.
What about Asia?
I studied the world’s largest honeybees Apis dorsata that are honey hunted by indigenous Malay people. They will climb the tallest trees in Asia – Koompassia excelsa which the native peoples call the Tualang trees and which can be 40 meters or more tall – and these really fierce bees create 1 to 2 meter wide wax parabolic two sided combs that they live on in these canopy emergent trees. There can be more than 100 of their nests in a tree, and it’s easy to set them off. Then you can have a lot of these nearly inch long bees coming down to try to sting you and defend their nests.
Do bees thrive more in dry, warm climates than in wet and mountainous regions?
In mountainous areas there tend to be fewer kinds of bees, but in the Rocky Mountains, the Alps, and areas in China there are many kinds of bumblebees. We have about 250 species of the genus Bombus around the world, and they’re more common in mountains. The hotspots that I mentioned – South Africa, Israel, California, Arizona – are the richest in native ground nesting bees because their larvae do very well in the dry ground. I’ve done a lot of work in the rainforests of Costa Rica and Panama, where the soils are pretty much always waterlogged and the larval bees can be attacked by pathogenic fungi that kill them. The Tucson Mountains has a flora that is so rich that there are about 600 kinds of flowering plants. Even though you don’t see that many every year the seed bank is still there in the ground, so when we have a huge rain event every ten years or so and you get these super blooms of flowers, those seeds that are lying dormant come out, and then you have specialized bees that can also wait. Some of these ground nesting bees act like seeds, because they can wait several years underground. We don’t know exactly what stimuli trigger them – it could be temperature, it could be soil moisture – but those bees have to be synchronized with their bloom or they die. I believe the world record for a bee waiting underground for a bloom is seven years, discovered by bee biologist Jerome Rozen at the American Museum of Natural History in New York City.
In your experience, which is the best honey in the world?
The world’s best tasting honey comes from the Royal Lady Bee, Melipona Beecheii, that has been tended by the native Mayan people of the Yucatan region of Mexico for 3 or 4000 years. These stingless bees form small colonies of about 5000 individuals and nest in logs. The Mayans cut the trees down and take sections of logs which they call jobón and bring them to their villages and put them under thatched shelters. Then they have wooden or ceramic plugs so that they can reach in and take the honey. When you get that honey directly from those beekeepers and you open the bottle and you smell it and you taste it, it is overwhelmingly floral. I can’t really describe it other than that, but it’s my number one honey in the world, from the sacred bee Xunán Kab in the Mayan language.
Stephen Buchmann, thank you very much for this interview, warmest wishes for What a Bee Knows. Hopefully it will be a best seller.
Images courtesy of Stephen Buchmann.
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