As the sun sets, bumblebees revisit “profitable” flowers they encountered during the day, new research suggests.
Many pollinating insects stop foraging well before sunset, but bumblebees can continue when daylight wanes.
However, this comes with risks, such as getting lost or being eaten by a predator.
The new study, conducted by the University of Exeter, examined the behavior of buffalo-tailed bumblebees in the South Devon Area of Outstanding Natural Beauty (AONB).
The results show that in the hour before sunset, bees return to the colony with smaller amounts of pollen, compared to foraging during the day.
“By analyzing the pollen, we found that bees in our study visited the same flower species at night as they did during the day,” said lead author Katy Chapman of Exeter’s Center for Research in Animal Behavior.
“More research is needed, but we think bees make a quick journey at night, to a place they know very well, to a food source they know is good, but they also choose to return. to the colony before they are full. their pollen baskets.”
The study was conducted in a mixed agricultural landscape, tracking the bees at the entrance to their colony and collecting pollen sacs from returning foragers.
In general, there were fewer departures and returns per hour in the evening than in the afternoon.
The findings, which suggest that bees forage “opportunistically” at nightfall, may help researchers understand how daily light levels — and increasing light pollution — affect bees.
Chapman added that “bumblebees are usually active during the day, when light levels are high, so low beam was a key factor for our bees in the evening period, affecting how they found food.”
“This opens up interesting questions about how diurnal insects make decisions during these diurnal changes in their visual environment.”
“We are also looking at whether light pollution can have an effect during sunrise and sunset, when bees are still active but artificial light is turned on.”
The newspaper is published in animal behavior.
Big bumblebees get to work earlier
Katherine E. Chapman et al, Bumblebees exploit known sources but return with partial pollen loads when foraging in low evening light, animal behavior (2022). DOI: 10.116/j.anbehav.2022.09.010
Quote: Bumblebees revisit favorite flowers as sun sets (2022, October 19) retrieved October 19, 2022 from https://phys.org/news/2022-10-bumblebees-revisit-favorite-sun.html
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