Scientists discover bees prefer warm violets in cool forests
The birds foot violet (Viola pedata) has two, common, color forms when it blooms during the cool, Missouri, April. The concolor form makes flowers with five light violet-mauve petals. The flower of a bicolor plant has three mauve petals plus two top petals that are a deep, dark, funereal purple.
Co-researcher Retha Edens-Meier, Ph.D., a professor and research scientist in SLU's School of Education, using thermocouples, and a hypodermic tissue probe, learned that these dark petals are up to 3 degrees Celsius (5.4 degrees Fahrenheit) warmer than the surrounding atmosphere when they stand in a pool of Spring sunlight. Bees, especially fuzzy females of Carlin's bee (Andrena carlinii), prefer to forage upside down on these flowers so their hind legs and bee butts are warmed by the dark petals as they drink nectar and collect pollen.