«Bees are short-sighted, males confuse females with orchids»

«I am happy that my book has been translated and published in Italian, so that many Europeans can learn more about the bees I study, appreciate them and not fear them». Words of Stephen Buchmann, professor in the Department of Entomology and in that of Ecology and Evolutionary Biology at the University of Arizona. The book you are referring to is titled The personality of the bee. Thoughts, memories, emotions (Environment Editions).

Professor, I admit all my ignorance: I never knew that the bee had a personality, a conscience and self-awareness. Enlighten me….

«Not all scientists agree. I like to follow the research and teachings of Dr. Lars Chittka of St. Mary’s College in London who last year wrote the book “The Mind of a Bee”. I believe bees are sentient organisms. Additionally, many, but not all, scientists think that bees can feel pain. They are equipped with nociceptors and therefore nociception, the detection and avoidance of harmful stimuli. Here’s an experiment that I think shows that bees are self-aware, especially when it comes to their sense of body and size. Some were trained to fly through a narrow gap to reach a sugar feeder on the other side. Bumblebees are of various sizes, depending on the amount of food they have received from larvae. The little bees flew through the gap and got their reward. The fat bumblebees turned sideways to pass! This is why they know how great they are compared to the others.”

You explain that bees see the world in three primary colors, managing – and I quote you – “to look beyond the rainbow”. What does it mean?

«Both bees and humans have trichromatic vision. This means that each of us has three primary color vision receptors in our eyes. For humans these are red, green and blue. For bees they are blue, green and ultraviolet. Human vision is shifted towards the red, while for bees it is shifted towards the UV region, which we cannot see except with the help of a camera and special lenses such as quartz. Each bee’s compound eye has about 5,000 receptor cells called ommatidia. Humans, on the other hand, have millions of retinal cells. Therefore, bees are very short-sighted. A bee cannot see the details of a flower except from about 10 inches away. Bees have a flickering fusion frequency. In the cinema, we see still images projected at 24-30 frames per second. To make a bee see its blurry movement, you would have to speed up the movie a lot, even 200 or 250 frames per second. They can also see polarized light and have a wonderful sense of solar compass that coincides with the time of day.”

He writes that they are even capable of dreaming: what do they dream? And: do they dream in color or black and white?

«This is a highly speculative hypothesis. We don’t know if bees can dream. We know that they sleep for a long time and hang in particular positions. We believe that bees consolidate their memories during sleep, just like humans. I like to think that bees can dream of rich flower meadows full of delicious nectar. They go through three distinct phases of sleep, first with some movement and then completely quiescent. Bees appear to have simple emotions, perhaps anxiety. I tell her about an experiment conducted in Lars Chittka’s laboratory: bees entered a foraging arena in the laboratory to reach a sugar trough. Nearby was a mechanical spider. If the bumblebees got too close, the artificial spider grabbed them with its foam-padded legs and held them for 2 seconds. Afterwards, the bees that had been temporarily held by the spider were reluctant to go to that area of ​​the flight cage again. This also occurred in the following days. I don’t know if bees feel comfortable in certain conditions and not in others; however, sometimes they feel safer from predators such as ants, spiders, lizards.”

Mating occurs in a unique way: they do it while flying. They may have a personality but the concept of comfort is perhaps something they don’t know…

“Honey bee queens mate in the air in areas called drone congregation areas while flying at 15 miles per hour. They mate with multiple drones, 12 or more in a given mating flight. The poor drones lose their genitals in the queen and fall to the ground dead. Other bees I study, for example solitary bees that nest on the ground, can mate on flowers or on the ground. Some male carpenter bees, called Xylocopa sonorina, produce a mixture of three chemicals that smells like roses. They give off this scent as they hover over the top of a hill. It is a sexual pheromone produced by males to attract virgin females.”

From his test, males don’t come out so well if they confuse an orchid with their possible companion…

«Yes, there are many locations and mating strategies that male bees use to be the first and only mate of their female partner. There are solitary bees that nest on the ground in Europe and also in Australia. In Europe there are specialized orchids, those of the genus Ophrys, which imitate the appearance and smell of female Andrenid bees. The males are attracted to and grab the “dummy female” which is actually the orchid flower. Before leaving, the orchid sticks a packet of pollen grains on the male’s body. Then, at the next flower they are fooled by, they deposit pollen grains – like male sperm – and fertilize the flower, giving rise to an orchid seed pod.”

The male wants only one partner in his life (and who can blame him given the end he ends up with?) and with the flower he is on the safe side by avoiding dying. The mother is single: could it be because she is jealous of the orchids?

«It’s a funny question, but I don’t think so. There are many more real female bees for males to find, and they do. Orchids, on the other hand, are rare.”

She dedicates a part of the book to those who are terrified of bees. What do you suggest to overcome it?

«I suggest sitting on a bench or a camping chair at the edge of a garden or flower meadow. Sit and watch the bees and other pollinators, for example, flies, wasps and butterflies come and go. Even if a bee lands on you, which is rare, it will not sting you. You can also build “bee hotels”, which are boards with 7-8mm holes, and place them under the eaves of a house or garden shed. Non-stinging female bees will find and appreciate these empty nests. It’s more fun than watching a reality show: they are calm and you might see them carrying back pieces of leaves (which happens with leaf cutter bees) or lumps of mud (like mason bees, in the Osmia genus).”

Bees play a fundamental role in biodiversity and the survival of the earth: can you explain how?

“Certain. Bees are first and foremost pollinators. They pollinate around 30% of the world’s crops including wild flowers which are important sources of food for other animals: think of bears who fatten themselves on berries in autumn for the long winter hibernation. Female bees, since around 90% of them nest on the ground, also carry out bioturbation activities: this is an activity of digging tunnels which makes bees a bit like earthworms. Their tunnels allow water and air to penetrate the ground. Furthermore, all the nitrogen-rich pollen that the larval bees feed on in their brood cells remains in the soil after the chicks defecate it. Their feces, rich in nitrogen, enrich the soil and help plants. Furthermore, bees (not on purpose, of course!) also become a vital food source for other animals: spiders, ambush insects, praying mantises and so on, along with lizards, birds and small mammals that feed on them when they manage to capture them . There are also parasitic bees (called kleptoparasites, and they represent about 10% of the world’s 21,000 bee species) that prey on other bees. Then there are parasitic flies, such as bee flies, and mutillid wasps, called velvet ants, which parasitize some types of bees.”

I imagine that to study these animals you had a close relationship with them. Was there one or another with whom he managed to establish a “form of friendship”?

“Not quite like a human friendship, but yes, I appreciate and am happiest when I’m around the bees I study here in the Sonoran Desert. Good examples are the palo verde bee, Centris pallida, but also cactus-loving bees (Diadasia spp.) and large black carpenter bees that dig tunnels in dead wood. Every spring I eagerly await the emergence of the new generation of bees from the underground brood cells and observe their behaviors on flowers and in nests. Most solitary bees live for about 4 weeks: the exception is carpenter bees, which can live for several years. We see them on the flowers as adult bees, but for the other 11 months of the year they develop underground, hidden from our sight, as larvae, then as pupae before metamorphosing into the adult stage and burrowing.”

PATRIZIA PERTUSO