We have known for a long time that bees shake behind to communicate with their fellows in the fields of flowers, a dance studied closely by scientists. A team of American biologists has decoded more than 1,500 of these dances to better understand their food preferences, with the ultimate aim of helping the protection of bees, whose populations are declining.
The most interesting thing about bees is how they communicate, says Morgan Carr-Markell, doctoral student at the University of Minnesota and lead author of the study published in the scientific journal PLOS One on Wednesday. I wanted to exploit this to help land managers who would like to plant for the benefit of bees.
The two main questions of the researchers were: what types of flowers are most taken for their pollen and nectar, the two main sources of food for bees? And when do they go out looking for food?
Dance floor
Biologists have placed bee colonies in glass viewing hives at two sites in Minnesota. Before colonization by the Europeans, Minnesota, in the central part of the north of the United States, was covered with grasslands, but these occupy only 2% of the surface of the state. This is one of the reasons for the decline of bees there, a decline that is dangerous for the entire ecosystem since insects have a crucial role in pollination.
For two years (2015-2017), the team recorded the dances of the female bees on the dance floor, a surface at the entrance of the hives (the males have only one role in the bees: procreate). The dance is explained in this video created by a co-author of the study, Margaret Couvillon.
The bees perform a dance in which they vibrate their abdomen to describe the angle, relative to the Sun, which indicates the direction of the food, for example, 270 relative to the Sun (0 is the direction of the Sun, 180 is opposite direction, 270 is left). For the distance, the bee varies the duration of the vibration of its body: a second is about 750 meters. Finally, the more abundant the food source, the more the bee will repeat the dance, and perform rapid rotations.
The result of observations from 1528 dances: Bees communicated more frequently with their sisters about sources of nectar in meadows towards the end of the foraging season, says Morgan Carr-Markell, that is, in August and September. This could be explained by the fact that the colonies prepare for winter.
Bees are useful in reproducing three quarters of the plants
The researchers also found out what types of flowers were considered very interesting by bees. They isolated certain bees (by placing them in an ice cage to knock them out) and collected, analyzed and sequenced the pollen loaded under their legs. We can safely say that bees classified seven types of grassland as very good sources of pollen, says Morgan Carr-Markell.
Bees are useful in reproducing three-quarters of the world’s plants, transferring pollen from male flowers to females. Knowing what their dishes of choice can ultimately benefit all these plants. If the colonies are well nourished, they can better resist pesticides and pathogens, and everything that puts pressure on it, concludes the researcher.
(Nxp / afp)
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