By Wendy Langhans
I’m not the only one who likes a cozy sun-lit porch on a cool winter’s day. Bumblebees also seek out places that are warmer than the surrounding air. They function best when their internal body temperature is around 30°C (86°F). So on cold days, they seek out a place to warm up, so they can conserve their metabolic energy. And if they can grab a bite to eat at the same time, so much the better. That’s why, on cold days, bumblebees like to bask inside flowers.
But not all flowers are equally warm. Their temperature depends, in part, on their color. All else being equal, a dark purple flower absorbs more sunlight than a pink flower and, therefore, is warmer. And the bees learn though experience, which flower colors are likely to be warmer.
All else being equal, a purple flower is warmer
A few years ago, British scientists conducted an experiment; they tested bumblebees using nectar in artificial flowers of different colors. “In a ‘foraging bout’ the creatures were given a choice between four purple flowers or four slightly cooler pink ones that were placed in a random order.”
A bee grabbing a morning snack on Buckwheat
“In one test, 58% of the bees chose the warmer purple flowers. When the colours were switched and warm nectar was placed in the pink petals, 61.6% headed for the pink blooms.”
They also found that, given the same nectar reward, “bumblebees consistently chose warmer flowers over cooler flowers.” I suppose this is the bee equivalent of choosing to dine “inside” while actually dining outside.
Our back porch also allows us to dine “inside” while actually dining outside. The walls are painted beige, just like the rest of houses in our neighborhood. I suspect this neutral color was chosen as a compromise – designed to absorb a bit of sunlight on cold winter days and reflect a bit of sunlight on hot summer days. But sometimes I wish it could be more colorful. Maybe I could line the interior walls of our porch with drapes – purple in the winter and pink in the summer? Do you suppose the homeowner’s association would allow that? I guess I’d better check the CC&R’s before I do anything rash.
Upcoming Outdoor Events:
For Facebook Users: 90 Days of Santa Clarita Valley Wildflowers.
Here’s a new way to familiarize yourself with our local wildflowers. Become a fan of the page, “90 Days of Santa Clarita Valley Wildflowers” and from now through April, each day you’ll receive a photo of a local wildflower and a link to a website where you can learn more.
Saturday, February 20, 8-10 AM. Early morning bird hike. With our local deciduous trees bare, now is a great time to view nests. Beginning birders are most welcome. Heavy rains cancel. For map, click here.
You can listen to stories like this every Friday morning at 7:10 a.m. on “The Hike Report”, brought to you by your hometown radio station KHTS (AM1220) and by the Mountains Recreation and Conservation Authority.