Collecting pollen can be as exhausting for bees as flight take-off, study shows | Bees

According to a study, bees use as much energy to collect pollen via “floral buzzing” as they do to take off.

Scientists have found that the vibrations bumblebees use to extract pollen from flowers are among the most exhausting behaviors they engage in, forcing bees to “carefully choose” which flowers are worth visiting.

The study, published by the Royal Society, is the first to directly measure the energy cost of floral sonication, or “buzz pollination” – where bees vibrate flowers to extract pollen.

Natacha Rossi, a researcher at the University of Sussex who led the study, said: “As nectar availability changes due to climate change or habitat loss, the energetic demands of pollination could influence the behavior of bees and, ultimately, where they feed and which plants they pollinate.

“These results help us better understand plant-pollinator relationships and how hard a buzzing bee works.”

By 2024, bumblebee numbers in the UK have fallen by almost a quarter compared to the 2010 to 2023 average, according to the Bumblebee Conservation Trust. The researchers said the drop was likely due to cold and wet conditions in the UK that spring. Despite a rebound in 2025, the numbers of many species remain below average.

Using lasers and respirometry equipment to monitor three colonies of buff-tailed bumblebees, researchers found that a single “buzz” required about the same amount of energy as a flight takeoff. Since the hum may last longer, the total power consumption may be even greater.

Dr Beth Nicholls, lead researcher at the University of Sussex, said: “The results suggest that floral buzzing could represent a major part of a bee’s daily energy budget, something that has been overlooked before.

“These bees must carefully choose which flowers they visit to ensure they have enough energy to pollinate.”

The research says the findings “challenge the common assumption that flight dominates bees’ energy budgets.”

According to the study, a floral buzzing bee’s metabolic rate is more than 30 times higher than its resting metabolism, making this process one of its most energy-demanding behaviors.

Researchers have warned that declining nectar supplies caused by the climate crisis and habitat destruction could intensify pressure on pollinators.

Professor Mario Vallejo-Marin, from Uppsala University, said: “We have long suspected that buzz pollination is an energy-expensive affair. We can now put a number on it and start to make quantitative predictions about how it might affect the ecology and evolution of buzz-pollinated bees and flowers.”

The study highlights that the bee’s energy loss does not stop when pollination stops. According to the paper, once the bee has vibrated the pollen, it must engage in a “pollen grooming and conditioning phase.”

This grooming requires even more energy. The bee must then force a high-power takeoff to carry its new, heavier load, making the entire process a demanding two-phase sequence.

Find more Age of Extinction coverage here and follow biodiversity journalists Phoebe Weston and Patrick Greenfield in the Guardian app for more nature coverage.