Find the podcast at the origin of this transcription in Bêtes de Science. © Futura.
B.terrestris, the Bourdon that announces spring
L’airair is soft, the birds sing cheerfully and the trees have found their colorscolors. It is the return of spring and with it, the waltz of founders of all kinds resumes. Among the first to point the end of their neznezthere is one, a hair noisier than the others: the Bourdon. Its dodue and hairy silhouette alternatealternate The black and yellow streaks, to its all white butt that wads up in the air to the rhythm of its buzzing. Bombus Terrestris, it is its Latin name, is the most common bumblebee in Europe, but it is found everywhere on the globe. Like its cousins, wasps and ants, this small flying insect that can reach 2 centimeters long, is a hymenoptère. It belongs to the vast family of bees which have several thousand species. Like them, the earthly bumblebee is an essential pollinator for the proper functioning of nature. At the heart of the spring effervescence, he therefore has a lot to do: let’s follow him.
Difficult to make more spring: here we are at the heart of a flower. All around us, all of its petals, gathered in the shape of a vase, form what is called the corollacorolla. In the middle of this corolla stand the reproductive organs of the flower. All in the center we see a kind of long thick tube, surmounted by a cap: it is the pistilpistilthe female reproductive organ of the flower or in other words, its ovaryovary. This organ is surrounded by several very fine stems, ended with fluffy pompoms which are in fact, reservations of pollenpollen : the whole forms the stamensstamenswhich constitute the male reproductive organ of the flower. Yes, at the heart of this flower, as in most of them, cohabite a male reproductive organ and a female reproductive organ, they are said to be hermaphroditehermaphrodite.
For a flower to be able to reproduce and give birth to other flowers or other plants, its female reproductive organ, its pistil, must come into contact with the pollen of another flower of the same species. But it is far from easy: flowers cannot move, and under these conditions, difficult to meet! This is where our champion of the day comes in. [un bourdonnement se fait de plus en plus présent]. Here it is which arises very close to us in an intense roar. The sweet scent and the shimmering colors of this flower attracted it to us. Without waiting, he deploys his proboscisproboscisthat is -to say his tongue, and plunges him into the heart of the flower to suck the nectar, a liquidliquid Deliciously sweet which he loves. All at his feast, our dear companion drops a yellow powder that hung on to his hair and legs during his previous storage: they are pollen grains. This pollen, falling, is deposited on the pistil of the flower, the fertile and will therefore allow it to transform into fruit; A fruit whose seeds will give birth … to new plants!
It is this process called pollination. It can take place thanks to the water or ventvent Who cart pollen to the heart of flowers. But in the vast majority of cases, pollinators, such as the Bourdon – but also butterflies, ants, wasps, flies and even certain birds and mammalsmammals Like the bat – are those who take care of this mission of the utmost importance. By stealing from flower in bloom to feast on itself, the Bourdon sows in its path the pollen it harvests, and thanks to it, the life cycle of plants can continue. He is a real gardener! Besides, unlike bees, which are a chilly bit, the Bourdon is not afraid of bad weather. Under its clumsy air, it’s a little hard to cook! An extraordinary capacity allows him to brave the cold: he is endotherm. By vibrating the muscles that allow it to fly, the bumblebee produces its own heatheat ! So there is no need to wait until the soleilsoleil Deign to point the nose to start to boost, the Bourdon works from morning to evening, from spring toautumnautumn.
An essential pollinator threatened by human activities
Here, this is our champion, which resumes its flight, direction the nest where the nectar and the pollen that he harvested will serve to feed his colony. Because if many pollinators, such as bones, live lonely lives, the Bourdon is for its part, a social insect. Within his colony, several hundred individuals live following a precise organization, under the direction of a queen. She was the one who made under terreterrein the former burrow of a mouse, the round nest where the Bourdons live. The nest is made up of plant debris and cocoonscocoons of wax that house larvaelarvaeBourdons babies. And among the Bourdons each has its role to play: the queen founds the colony and makes the first provisions, the males are used for reproduction, and the females, called workers, are distributed the tasks between the larvae care and the harvest of nectar and pollen. Our champion of the day is therefore a champion! Like domestic bees, bumblebees produce honey they feed, but in much lower quantity than their cousins. The end of summer marks the end of the Queen’s reign and the end of the colony. It was then that new queens, younger, left the colony in search of a cozy little corner where to start a family.
Like all pollinators, earthly buzzing is threatened by human activities, pollution and intensive use of pesticidespesticides. It is however essential to protect this little craftsman from nature, because its role, complementary to that of all other bees, butterflies and flies is essential: without pollination, neither fruits, nor vegetables, nor plants would be born, without pollination the whole of life on earth the whole is threatened. Like what a very small insect can play a big role on the planet’s scale.
The Truck Truck and the charmcharm Bourdon played a few tricks on him: considered, let’s say, less exciting than his cousins bees, he has long been abandoned by scientific research. But today theintelligenceintelligence of this animal – including the brainbrain is the size of a sesame seed – fascinates. And for good reason, his many talents are surprising.
Players and good students, do Bourdons have a culture?
Many experiences have been carried out on the laboratory bundle. Some to test his ability to orient himself, which is excellent: he searches and learns the shortest paths that lead to his favorite flowers; others to understand its vision of colors, the bumblebee sees green, blue and even ultravioletultravioletbut not the red color; and still others to test its preferences in mattermatter of art: And there it would seem that Bombus Terretris has a weakness for the famous painting of the Dutch painter Vincent Van Gogh, the sunflowersunflower.
Other equally imaginative experiences have revealed unsuspected aspects of his personality. For example, when scientists have burst beads, it slides them, grips it and rolls it spontaneously, without waiting for the slightest reward. In fact, they play the ball! Besides, young young bumblebees play more and longer than older Bourdons.
Even when faced with situations that he could never meet in nature, the Bourdon surprises scientists by its ability to adapt. For example, a bumblebee which is presented with a treat attached to a piece of string is capable of learning to shoot on the string to recover your little snack. And that, just by observing one of his comrades doing it. Sometimes he does even without example, himself the gourmet bumblebee shoots on the string to reach his reward. To be able to use a string in this way is to be able to innovate, to learn, to memorize a technique, but also to then transmit it to other bumblebees, by apprenticeship. And that is capable of it is capable even when the exercise is terribly complicated.
This is demonstrated by another fascinating study. During an experience, scientists have set up a real headache, a kind of puzzle that is so complicated that a only bumblebee is absolutely unable to resolve it. To test the transmission of techniques between bumblebees, scientists learned the solution of the puzzle to one of them. Then they allowed other Bourdons to observe him while he confronted the exercise. After looking at the bourdon trained, the naive bumblebees, which had never seen the puzzle, were able to solve the puzzle. They had learned a complex technique, observing their comrade.
This is a huge discovery, because it means that bumblebees are able to learn and transmit complex behaviors that go beyond the intelligence of each bumblebee, of each individual – these are behaviors that they learn with several, collectively. This capacity is the basis of what is called culture, that is to say all knowledge, behaviors and techniques that a group of animals shares, is transmitted from generation to generation and improves over time. It is still too early to talk about culture in the Bourdon, but its ability to learn from others is very promising and damn impressive for a small dilettante fog!
