Impressive learning abilities, unique pollination methods and fur that is nice to pet (but not worth it): studies from recent years reveal the amazing world of bumblebees, and warn against the severe damage to them due to the climate crisis. Special for International Bee Day
By Reot Alon, Zivata - Science and Environment News Agency
Also this year, the world celebrated the International Bee Day on May 20. And it's not just that the bee won its own day: it is one of the most important pollinators in nature, the existence of many of the fruits and vegetables we rely on imposed About her shoulders And entire ecosystems rely on its functioning.
The honey bee is the most familiar bee, but many other species of the bee family also play the critical role of pollinating the plants whose fruits we eat. in Israel alone Existing No less מ-1,100 Species של vernacular bar - one of which is the ground bumblebee (Bombus terrestris), the most common and adaptable species among Bumble bees (Bumblebees). Findings that emerged in the research of an Israeli scientist, as well as a series of findings from recent years, reveal that these bees are characterized by a fast and unusual learning ability.
The ground bumble bee has long hairs on its body that give it a furry appearance, its shape is round and it has a white spot on its back, and it is considered less aggressive than the honey bee. The number of individuals in the bumble bee hive can reach up to 400 - a tiny number compared to the thousands of individuals that live in honey bee hives, and each worker is important to the functioning of the hive. Therefore, during a threat, they do not sacrifice themselves, but deter the threatening factor by biting (which does not lead to their death).
The wisdom of the ground bumblebee was recently expressed in unpublished findings from the research of Assaf Tsadaka, agronomist and ecological beekeeper, founder Community EcoBzee and master's degree in the department of entomology (insect sciences) at the Volcani Institute under the guidance of Dr. Hagai Spiegler. As part of a study he conducted on the effect of a queenless environment on the formation of viruses in bumble bees, Tsadaka happened to observe a number of interesting phenomena. During one of the experiments, he removed from the wooden beehive where the bees live a flat container containing sugar water (which is used as a substitute for nectar in laboratory conditions). To his surprise, the bumblebees found the source from which the water taken from them was filled - a test tube with holes that was hanging in the hive, and started drinking directly from it. "I was amazed to find out that they stand on their hind legs to reach the sugar water that comes out of the holes in the test tube," he says.
Another fascinating observation concerned the creative abilities of the bees. "We placed Bristol at the bottom of the beehive, to absorb the bees' secretions," he says. "Later, we found out that they shredded it into small pieces - and wrapped the hive with it, with the aim of warming it and balancing the humidity index in it."
Bees with a strategy
As mentioned, the evidence from Tsadaka's research joins a collection of findings from recent years that testify to the extraordinary wisdom of the ground bumblebee. "The sophisticated learning ability of the bumblebees allows them to find food efficiently and quickly, thus dealing with a multitude of different situations and surviving well," says Tsadaka.
For example, bstudy Published in 2016, researchers from the UK, China and Norway found that some ground bumble bees are able to learn to independently pull on a rope to reach a reward that is out of their reach. The other bumble bees in the hive that the researchers examined also learned the action - by observing other bees (which also indicates the bees' impressive social learning abilities), or with the help of the researchers' guidance.
בstudy Another, published in 2021 by British researchers, looked at how ground bumble bees select a particular flower from a mat of flowers. The researchers found that the bees are significantly more attracted to flowers whose visibility is impressive and prominent and whose nectar quality is higher, and ignore flowers that look less attractive or have little nectar. In this study, the bees were able to learn to prefer flowers with a less attractive appearance - but with more nectar. In other words, the bees demonstrated a high learning ability - and the ability to adapt to changing conditions.
בstudy Another, conducted in 2020 by a Swiss team, found that the ground bumblebee has developed a strategy to increase the supply of food at times when flowering is irregular: the researchers discovered that the bees bite the leaves of the plant - which brings its flowering thirty days ahead. "The hypothesis is that there is a substance in the bee's saliva that encourages the bloom, or that the bite is made in a certain place and in a certain way that causes it - or a combination of both," Tsadaka explains.
make the fruit optimal
It is the bumble bees' impressive learning abilities that make them particularly important pollinators. "The bumblebees pollinate a wider variety of flowers than the honey bees," says Tsadaka. According to him, the bumblebees use a unique method called "buzz pollination", in which they flap their wings at a very high speed, which violently shakes the flower - and causes it to release its pollen. "Plants from the Solani family, such as peppers, tomatoes, and eggplants, depend on this type of pollination," he says.
Beyond that, the pollination of bumble bees is essential: according to study Published last January, man-made pollination is less effective than bumble bee pollination. According to these findings, greenhouse tomatoes that are pollinated by bees produce larger and more symmetrical fruits, which contain a higher concentration of vitamin C and have a longer shelf life. "The pollination of the bumble bee activates a biological process in the plant that causes the fruit to be of optimal quality - a process that does not occur when it comes to pollination by humans," says Tsadaka.
too hot to study
Bumble bees, like honey bees, Are found currently at risk, with one of the main reasons for this being the increase in global temperature due to the climate crisis. According to research published last month, bumble bees exposed to heatwave temperatures – 32 degrees Celsius – have a harder time learning how to identify food more successfully, compared to those working in a standard spring temperature of 25 degrees Celsius. In other words, the high heat damages the cognitive performance of the bees and their learning and memory abilities. "Since the bees' bodies were not adapted during evolution to deal with these temperatures, the increase in temperature due to human activity does not allow the bees time to adapt," says Tsadaka. "This affects their survival, because it causes them to pollinate less efficiently - they are less able to feed themselves, so they disappear."
Another reason for the disappearance of bees is spraying against pests. "There is a difficulty in matching the active ingredients in the pesticides to a certain type of pest - therefore, the spraying also harms other species, such as bees," Tsadaka explains. "In addition, agriculture in which only one crop is grown (monoculture) leads to desertification, which reduces the richness of plant species that serve as food for pollinators." According to him, urbanization also damages the open areas with wild vegetation, which are replaced by houses and urban plants that are planted and are not suitable for bees. "It is very important that we take care of the preservation of the bees, because if they disappear - part of our food will disappear with them", he concludes.
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