Flirtatious flowers give bees a warm welcome
Last Updated: Wednesday, August 2, 2006 | 2:19 PM ET
CBC News
Bees prefer to visit warmer flowers, and plants may increase their temperature to encourage pollination, scientists say.
Bumblebees are drawn to flowers for nectar or pollen, but the heat from the bloom may offer another reward for pollinators that need to keep warm when flying far on cold days.
British researchers found bees were attracted to the warmer of two artificial flowers containing the same sugary reward.
Higher temperatures appear brighter in this infrared image of a bumblebee sitting on a flower.
(BEEgroup, University of Wurzburg)
When flowers of the same colour were at different temperatures, the bees couldn't tell them apart, which shows that colour is the warmth cue.
Prof. Lars Chittka, a behavioural ecologist at Queen Mary University of London, likened the bees' activity to drinking a hot drink on a cold day.
"If you need to warm up, you can produce your own heat, at the expense of some of your energy reserves," Chittka said.
"Or you can consume a warm drink, and save on investing your own energy."
Warm colours
"The interesting thing is that bees don't just prefer the warmer drinks — they also learn to predict the flower temperature from the flower colour."
They findings "may also have implications for the evolution of specific floral structures and for the connection between floral sensory cues, floral temperature and pollinator behaviour," the team concluded in Thursday's issue of the journal Nature.
The researchers plan to re-evaluate the role of sun-tracking by flowers, as well as light-absorbing pigments and other features that "may be part of a plant's bag of tricks for attracting pollinators," said study co-author said Beverley Glover of the department of plant sciences at the University of Cambridge.
