has found that when foraging they maximise the amount of nectar sugar they take back to the colony each minute.
"As they forage, bumblebees are making decisions about which nectar sources will give the greatest immediate energetic return, rather than optimising the energy efficiency of their foraging," said Dr Jonathan Pattrick, joint first author of the report, who started the research while in the University of Cambridge's Department of Plant Sciences.
"It's amazing that even with a brain smaller than a sesame seed, bumblebees can make such complex decisions," said Dr Hamish Symington in the University of Cambridge's Department of Plant Sciences and joint first author of the report. In the third test, the vertical flowers offered nectar which was only slightly more sugary than the horizontal flowers. This created a situation in which the bumblebees had to make a trade-off between the time and energy they spent foraging and the energy in the nectar they were drinking -- and they switched to feeding from the horizontal flowers.