Plantwatch: how flowers keep themselves and their insect visitors cosy
It is tough being a flower in the chill air of springtime when pollinating insects are reluctant to fly, but some flowers turn into solar heaters to warm up visiting insects and increase the chances of pollination.
The cup-shaped white flowers of mountain avens raise their temperature by 3C to attract insects and keep them cosy, and that warmth also makes the flower produce sweeter nectar for the insects, encouraging them to visit and stick around basking and feeding in the flower to increase the chances of cross-pollination. The warmth helps accelerate the flower’s pollination process, resulting in heaver seeds and improved germination. So it’s a win-win situation for plants and insects.
Arctic poppy flowers track the sun to maximise sun exposure, but they also close up in dim light and reopen as brightness increases, helping keep the flowers warm.
Some flowers make themselves into miniature greenhouses, trapping heat in a chamber in the flower. For example, the yellow rattle uses bubble-shaped structures made from translucent bracts that surround its flowers. These filter out ultraviolet light but allow longer wavelengths to pass through, which heats the air inside the floral chamber like a greenhouse.
