toBees are a hive of clichés, as beguiling as they seem familiar to us. Let’s draw at random: They live in large colonies, congregate around a queen, produce honey and wear gorgeous yellow-and-black-striped wool. This is all trueApis melliferaOur good European bee. But as soon as we move away from this semi-local heroine and her twenty-eight lineages, all our certainties collapse. Of the approximately 20,000 species of wild bees, very few combine even two of the four characteristics mentioned above.
The little carpenter bee has nothing. There are no queens, no lines, and almost no hair. No honey, no hive. Solitary, it burrows its nest in dead mulberry stems and rose bushes, clover and sumac, and is not shy of human presence. In her garden, biologist Sandra Rayhan, a lecturer at York University in Toronto, studied Serratina calcarata For the first time in twenty years. “I started by raising the young and observing sexual distribution and maternal investment. I ended up deciphering its genome and combining my interests in animal behavior and molecular genetics.Says.
In an article published on September 14 in the magazine Communication biologyThe researcher and her team detail for the first time how the maternal care provided by the small insect (8 mm, half a honey bee, one-tenth of a large bumble bee) affects the future of its offspring, both in terms of the expression of its genes, the production of microorganisms in it, and its general health. Such links have already been examined in many species, from birds to mice and humans. But Sandra Rehan and her colleagues followed the processes at all stages of their development for two months: nineteen stages in all, grouped into four main periods, early larvae, advanced larvae, pupa, and juvenile.
There is no collective defense mechanism
By comparing newborns cared for by their mothers with newborns left to their own devices, the researchers were able to see the effects of care at all stages. “We expected that, The researcher said. But we were struck by the scale of the consequences in the early larval stage. » The researchers thus highlighted significant changes in the expression of specific genes, which they then linked to the explosion of pathogens in the larval microbiota. They found bacteria there, but above all, 85% of them, fungi. most coincidentally, aspergillus, It is also feared among domestic bees. “If the mothers are not around to clean them, the infected larvae are mummified.”Sandra Rayhan says. Other pathogens cause abnormalities in eye or brain development.
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