Zhu Chaodong丨We dug deep into the ground to find traces of wild bees

We need to make life better for wild bees.

And then live in harmony with humans.

The bee may seem weak,

In fact, it plays an irreplaceable role in nature.

Zhu Chaodong, Researcher, Institute of Zoology, Chinese Academy of Sciences

Gezhi Lundao Issue 72 | October 17, 2021 Beijing

Today, I am very honored to be here at Gezhi Lundao to share with you the journey and story of my team and I in searching for bees across China.

Are you familiar with bees?

Completed: 10%

When it comes to bees, the first thing that comes to mind is "buzz". If you go out of the city and into the countryside, you may have seen beehives. In remote areas of the mountains and forests, some beekeepers even use wooden barrels and stakes as beehives.

Bees have two other important characteristics: The first is their honeycombs. If we open them, we will see that each honeycomb is hexagonal, so bees are known as natural "architects of nature." Another characteristic is that bees can provide sweet honey.

▲ Western honey bee (left), Chinese honey bee (right)

There are two main types of domesticated bees that provide us with honey. The Western honey bee on the left in the above picture is actually an alien species that has been introduced to China for hundreds of years. It provides a large amount of high-quality honey to the world, especially Southeast Asia. The Chinese honey bee on the right in the above picture is unique to China.

▲ The pollination service of bees ensures the normal operation of agriculture and ecology

In addition to providing honey, bees also have a function of great value, which is pollination, which is both familiar and unfamiliar to us. Simply put, pollination is when female pollinating insects, especially wild bees, fly from one flower to another, transferring pollen from the male buds to the pistil of the female flower, so that the plant can bear fruit. You can see a lot of fruits in the picture above, such as almonds, watermelons, apples, pears, etc. If there are no bees, especially wild bees, then these beautiful fruits will disappear from our dining table. About 30% of the world's food production depends on pollinating insects, including bees, for pollination.

▲ Wild bees - around us, but few people pay attention

How many species of bees are there in the world? Through the efforts of scientists around the world, more than 20,000 species of bees have been discovered. This means that the Chinese honey bees and western honey bees we are familiar with only account for one ten-thousandth of the known bees. What are the characteristics of the remaining bees? As can be seen from the picture above, they all live alone. They need to visit flowers, absorb nectar from flowers and perform pollination functions while providing enough bee food and food for their offspring.

The Pollinator Mystery

Completed: 30%

How important is the pollination function of bees? Let me give you an example: the pollination problem of oil-bearing peonies. Peonies generally have very beautiful flowers, and they must be pollinated by bees to produce seeds. As the name of the oil-bearing peony suggests, it is not only ornamental, but the peony seeds can also provide oil products.

▲ Bee pollination: significantly improve the seed setting rate of oil-bearing peony

We used domesticated bees as experimental materials to study how various types of bees can increase the yield of oil-bearing peonies. This work was mainly done by my postdoctoral professor He Chunling and his team in Luoyang, Henan.

As can be seen from the picture below, the oil-bearing peony seeds pollinated by bees are relatively round, large and numerous; the one in the middle is wind pollination, and the one on the right is self-pollination. As can be seen from the picture, self-pollination basically results in no peony seeds.

▲ Bee pollination (left), wind pollination (middle), self-pollination (right)

The second story is a little longer. I first started studying wild bees because I was encouraged by my predecessors to go to Yichun, Jiangxi to study the pollination of oil tea. The middle and lower reaches of the Yangtze River have a history of 1,000 years of oil tea cultivation, and China is now very short of oil. Many people know peanut oil and soybean oil. But in fact, there is another type of very high-quality oil, which is oil tea. The price of tea oil in supermarkets is relatively expensive, mainly because it is made from woody oil crops. There are only four woody oil crops in the world, and tea oil is known as the "olive oil of the East", which is also a very healthy food.

China has been planting oil tea for so many years, not mainly for the purpose of providing oil products, but for maintaining water and soil in the middle and lower reaches of the Yangtze River. Because these places have a lot of rainfall, it is easy to wash some soil into the river. In these barren places, oil tea can maintain water and soil without fertilizer or pesticide. In recent years, many local governments want to develop oil tea into an industry, but there is a problem. Oil tea has a characteristic: it blooms and bears fruit in winter. It is very beautiful all over the mountains and plains, but oil tea lacks enough pollinators. The reason is very simple: the activity of many bees decreases in winter, so few bees come out to pollinate oil tea at this time.

There is another more important reason. The local government once encouraged beekeepers to move their hives to the edge of the oil-tea forest to pollinate them, but the beekeepers soon left. The reason is also very simple: after these bees collect pollen, they make bee food in the hives to feed their offspring, which results in "baths" and larvae dying. This will affect the benefits of beekeepers, and beekeepers are unwilling to pollinate oil-tea trees.

Therefore, the local government invited our Academy of Sciences to lead a team to attend a seminar in Yichun, Jiangxi Province, to provide them with a consultation. We found that the local tea oil plantations were very large-scale and large-scale, just like planting apples and pears, and the land was kept very clean. In some places, herbicides and pesticides were even spread to ensure that there were no weeds, hoping to increase the yield by protecting the growth of tea oil. But in fact, this caused a very big problem: it prevented some local native bees from building nests in this place, and thus could not pollinate the tea oil here.

▲ Large-glossed bee (left), Camellia oleifera (middle), Hunan bee (right)

So, are there any wild bees that can pollinate camellia oil trees? Which camellia oil pollinating bees can provide pollination services more effectively? One of my students has been stationed there since 2007. His research found that there are actually many types of pollinators for camellia oil trees, not just domesticated bees. The picture above lists three of the 14 types of pollinating bees there, including the large split-tongue bee, the camellia oil bee, and the Hunan bee, all of which have the potential to pollinate camellia oil trees in the future. In particular, the largest and most beautiful golden large split-tongue bee on the left has a significantly higher pollination efficiency than other bees.

Where to find wild bees?

Completed: 40%

Because bees play a very important role in nature and farmland ecosystems, and can ensure food security, we need to spend a lot of effort to study and protect wild bees. But the question is: where can we find these wild bees if we want to study them? Do we have to climb up a tree to pick up a beehive and then dig out the honey from the beehive like a bear?

Let's start with science. We conducted a big data analysis on more than 20,000 species of bees around the world. The following figure is a deformed map showing the distribution of bees around the world, the number of species, and the number of individuals of each species. We analyzed about a million pieces of data and found that the darkest and largest areas are in Europe and the United States. This tells everyone: Europe and the United States have a lot of experts and rich research data, so they stand out on this map; on the contrary, China and its neighboring countries actually have a very rich variety of bees, but there is basically no trace of China on this map, and it has even become a narrow line. The reason is also very simple: in China, there are very few people studying bees, and even fewer studying wild bees, which can only be counted in the single digit. It can be said bluntly that there are no more than three people studying wild bees in China.

▲ There are 20,139 species in 7 families of bees in the world, and 1,372 species in 6 families are known in China.

There may be at least 1,000 species yet to be discovered in China.

There are still many places in China where we can find bees, discover their functions, and conduct research and protection. People generally think that there may be more types of bees in the forest, but after big data analysis and a lot of field investigations, I have gained an experience: there are actually more mosquitoes in the forest. Fortunately, mosquitoes don't bite me, so I have a natural advantage to do this work. In fact, bees are rarely seen in the forest, so where are there bees?

▲ In fact, bee abundance is lower in the forest

You can see from the photo above that this road divides the distribution of bees into two: one side is forest and the other side is grassland. If there is no forest in a place, but there are grass and flowers, then there are likely to be many species of bees. So when I go to the wild, I like to go to Tibet, Xinjiang and Inner Mongolia. It's not for the famous mountains and rivers, but because those places are very dry. You may not see a single person after running hundreds of kilometers, but as long as you see a piece of grass with a flower on it, I will stop and stay there for a morning or even a day. Why? Because where there are flowers, there must be bees, so I just need to wait for the flowers. From an academic perspective, as long as there are no trees or forests, in arid places, there will definitely be a high abundance of bees as long as there is a certain amount of plant diversity.

The picture above shows a dead tree we found in the forest of Medog, Tibet during our second expedition to the Qinghai-Tibet Plateau.

In the video above, there is a round hole in the dead wood, and a white head is vaguely visible inside. What is it doing? It turns out that it is looking at us. It is a beautiful carpenter bee.

In addition to arid areas such as the Qinghai-Tibet Plateau and Xinjiang, we also look for bees in village courtyards, especially in ancient villages and particularly dilapidated earthen walls. In the left picture above, there is a person hiding, holding a long insect collecting pole. What is he doing? He is looking for some holes in the beams and earthen walls. There are some bees in these holes. Many carpenter bees on the beams have already pupated, and there are some wall bees in the earthen walls. They can all pollinate plants.

▲ Red-footed carpenter bee X. rufipes

This season is the time to pick apples, and there are also some firewood piles next to the farmhouse courtyard. These firewood piles are also where we are going to hunt for treasures. In these firewood piles, many pieces of wood have small holes on them. These small holes may be abandoned beehives, or they may be beehives occupied by mother bees. In the spring, carpenter bees will make holes in the wood and build nests in them.

▲ A few species of carpenter bees choose to build nests in dead bamboo.

Such as golden-winged bees, long carpenter bees, bamboo carpenter bees...

So, are these bees having to work very hard to make holes in wood or walls? Can't they just be smart and find some plants with holes? We found that some very smart carpenter bees will find bamboo and reed stalks to build their nests.

▲ The Xinjiang carpenter bee X. xinjiangensis, a species of the subgenus of the proboscis carpenter bee, builds a nest in the soil

In addition to wood, walls and bamboo, bees have a very eclectic nesting environment. The picture above is a place found by Professor He Chunling in southern Xinjiang, which is particularly suitable for the nesting of a special group of carpenter bees, the subgenus of the genus Protopterus.

There are many beehives on this land. It is very difficult for this kind of bee to build a nest because the sand is very soft. What to do? The mother bee will dig tunnels in the sand, and use her secretions to build one room after another in each tunnel, and then lay eggs in it.

We dug deep to bring back the bees

Completed: 60%

If we find the bee and take a sample, how do we get it back to the lab? That requires a lot of field work.

▲ How to bring bees back to the laboratory?

The picture above shows Guo Pengfei, a doctoral student I have supervised for eight years. He has to stay in Wuyuan, Jiangxi from early April to late November every year. He needs to make some reed tubes and then put them in PVC tubes to make beehives to attract local wild bees to build nests. Therefore, he has to regularly check which beehives already have bees, bring them back to the laboratory, and find and record various data of these bees.

▲ Discovering the Camellia oleifera in the soil

Another task is a bit like excavating cultural relics. It is not easy to find oil tea bees. You can't just see them with your eyes. Why? Because after seeing the adults, we still need to find the larvae. To find the larvae, we have to dig the ground, and even dig three feet deep. Our research found that the mother bee is really great: in order to protect her children, she will dig 1.6 meters deep in the red soil. This is the deepest beehive we have ever seen. After digging the tunnel, it will build beehives around the main pipeline, and then lay eggs on the spherical bee food made by itself.

▲ Collecting adult bees

Our main method of sampling in the wild is still to use net sweeping: collect a lot of bees in the net, and then use special tools to catch them one by one into the tube. You may ask: Will the guy in the picture be stung by bees when doing this? Yes, he is often stung by bees, and he is very happy after being stung. Why? Because a sting means that he has caught another bee. So he has been to Tibet 20 times.

Explore the life history of honey bees

Completed: 80%

What other problems need to be solved after bringing these bees back?

▲ Bee classification: List of species of the three families of the Chinese superfamily Apoidea,

Includes 768 known species.

There are more than a thousand species of bees that have been discovered, and there are more than a thousand more to be studied. What should we do? We need to compare these species, learn which species they belong to, their life history, and how to use them.

▲ Obtaining morphological characteristics and molecular data

How to study it? We need to study its wings, body, internal organs and even brain to extract all the characteristics of different species. At the same time, we need to remove the front and middle legs for molecular sequencing. Why not extract DNA from the hind legs? Because the hind legs have very important structures for collecting pollen, so we keep them for future generations to study.

▲ Obtaining life history data: raising bees in the lab

After we have these species, we need to study their life history to obtain data. Why? By studying the life history, we can raise bees in the laboratory from the egg stage to the larvae, pupae, and finally adults, so that we can achieve artificial propagation.

Of course, bees are not without natural enemies in nature. The mighty leafcutter bee in the picture above is a very important pollinator, with strong mandibles. But even so, the leafcutter bee has natural enemies. The right side of the picture shows its natural enemies in the egg, larval and pupal stages, such as flies, beetles and other bees, which will eat the larvae or pupae of the leafcutter bee.

Humans and bees help each other

Completed: 90%

After the systematic basic research, we are thinking about the application of wild bees. We have cooperated with Professor Zhang Rong's team of Ningxia Academy of Agricultural Sciences. Alfalfa is a very important forage. It has been introduced to China for many years. Its biggest production bottleneck is that its seeds need pollination.

▲ Lack of leafcutter bee pollination has become a bottleneck limiting the increase in alfalfa seed yield in my country

As you can see from the picture above, its flower structure is a bit like that of legumes. Only when leafcutter bees use specific behaviors and structures to open it can they collect and spread the pollen.

▲ Give bees a special "home"

Professor Zhang Rong has introduced some leafcutter bees into the alfalfa field and provided them with special honeycombs. With the honeycombs, some bees will come back and build nests in them. The right side of the picture above is a honeycomb made of wood.

▲ Pollination of orchards in early spring

There is another most important example. You may have been to some pear orchards, such as Anhui, which produces Dangshan pears, and Shanxi, which is also a pear producing area. Pear trees are pollinated in early spring. Once early spring arrives, many farmers will use special devices to artificially pollinate pear trees. This is actually a bit dangerous, and it cannot fully guarantee the taste of the pears. According to our research, there are many wild bees in pear orchards and some early spring orchards that can complete the pollination of pear trees.

Therefore, wild bees cannot live without flowers, and flowers cannot live without bees. We need to allow wild bees to live better in places where they can build nests and collect nectar, so that they can reproduce and coexist harmoniously with humans. Bees may seem weak, but they actually play an irreplaceable role in nature.

We need to form a good team to study, protect, and then make good use of these bees in China!

This concludes my speech, thank you everyone!

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The articles and speeches only represent the author’s views and do not represent the position of the Gezhi Lundao Forum.