They go foraging at the slightest ray of sunshine and are surprised by the cold. Xavier Dumont, a beekeeper in Latrape, south of Toulouse, is convinced that global warming has its share of responsibility in the mortality of bees in our latitudes. For him, the mild winters deceive the vigilance of the foragers, who become too adventurous. Not to mention the queens who lay eggs instead of sleeping, attracting parasites into the hive that are fond of larvae, such as the gluttonous varroa for example. Hence his idea of recreating an “artificial winter”.
During the winter of 2020-2021, the retired bio-informatician tried the experiment alone in his corner, or rather in his cellar. Kept cool, his four hives not only survived but produced an “exceptional” amount of honey. On the strength of these initial results, the beekeeper convinced around thirty colleagues, from 23 different departments, to try the experiment the following winter. In all, 523 hives took part in the test. Among them, 280 remained “control” hives passing a classic winter. The other 243 were placed for seventy days in “artificial wintering”, in the cellar for about thirty of them, facing north for the majority, or even completely moved on a northern slope.
“30% to 50% more honey”
After collecting the feedback from his colleagues, refining his tables, doing and redoing his calculations, to the point of annoying his wife by the time spent immersed in his files, Xavier Dumont assures him, the result has “greatly exceeded [ses] hopes”. “There were about ten times more dead hives among the controls than among the hives in artificial wintering,” he says. Same satisfaction on “the vitality of the colonies”: “there was 30 to 50% more honey harvest on 28 test hives compared to their controls”. Scientific rigor obliges, the beekeeper retains only these 28 hives, because experimenters, carried away by their enthusiasm or having too few colonies, put all their bees in the same basket and did not leave a test hive.
Overall, 24 of the 31 experimenters say they are “very convinced or convinced by the method”, even if the results on protection against varroa mites are more difficult to interpret because of the very restrictive protocol they required.
Xavier Dumont, he no longer needs to be convinced. He will turn his hives to the north “within a week” before taking them down to the cellar for the third winter in a row. He probably won’t replicate his time-consuming experiment on a large scale. But he hopes that scientists, “with more resources”, will resume his research and make it their honey.