Bees may struggle in winds caused by global warming, study finds

Experiment revealed increased wind speeds reduced the efficiency of their foraging

A hardworking honey bee might feel aggrieved to be tricked into a garden shed to feed from a fake flower. Worse, she is blasted by a cheap household fan. And then timed to see how many fake flowers she can visit in 90 seconds.

But the honey bees’ tormentors are trying to help them: their ordeal is a controlled experiment that reveals how high wind speeds significantly reduce the efficiency of their foraging.

The study by University of Sussex researchers raises fears that bees and other flying pollinators may struggle in the higher and more frequent winds caused by global heating.

The bees, which usually feed on wild flowers after leaving their hives in the campus gardens, were lured into the shed with sugar water feeders. Only one bee was allowed in at a time, and their visits to artificial flowers were videoed and timed under different fan speeds, which mimicked calm and windy days.

With no wind, the bees on average took nectar from 5.45 flowers during their 90-second time trial. When wind speeds were increased, this fell to an average of 3.73 flowers. Over the course of a day, a bee’s capacity to supply its colony with food would be significantly curtailed.

Researchers also examined the indirect impact of higher winds by moving the flowers.

The findings reveal that, while flower movement did not appear to have an effect on the bees, the movement of air from the fans made them much more hesitant to take off from a flower, with time taken ranging from an initial 0.05 seconds to 54 seconds.

Georgia Hennessy, lead author of the research published in the journal Animal Behaviour, said that one possible reason for the wind causing hesitancy was that small increases in wind speed reduced the bees’ body temperature, so they require longer to warm up the flight muscles required to take off.

Another reason could be that the honey bees were waiting for a pause in the wind to take off, with gusty conditions occurring frequently in nature.

“We would expect that if it was a particularly windy summer the honey bees could be affected by it,” said Hennessy.

“With wind speeds predicted to increase in the years ahead, understanding how we can help pollinators in a changing climate is becoming ever more pressing. Although we can’t do much to control or stop the wind, we can take steps to minimise its impact on pollinators, such as placing hives in sheltered locations.”

The UN’s Food and Agriculture Organization warned last year that the decline in global bee populations was a “threat to global food security and nutrition”.

Dave Goulson, professor of biology at the University of Sussex, said: “Insect pollinators already face many pressures in the modern world, such as loss of habitat and exposure to pesticides, and a great many are in decline. Coping with increasingly blustery weather under climate change may be the final straw for some.”

The Guardian