Monsoon rains bring a torrent of colors to the Colorado Plateau. Yellow sunflowers emerge beside purple asters, blush-colored penstemons, and mauve lupine. Each flower is distinct in its shape, smell, and color. This isn’t a decorative accident; it’s explained by pollination ecology.
The evolutionary value of pigmentation has long fascinated botanists. Studies related to flower colors are among the oldest works in plant science. They first appeared in the literature in the early nineteenth century. Researchers have identified thousands of different pigment compounds in plants producing an endless range of colors and shades. Many of them are indiscernible to the human eye, but not to insects.
Insects evolved color vision millions of years before flowering plants appeared. That’s why scientists believe flowers evolved their colors specifically to catch the attention of these already-color-sensitive pollinators…. leading to a boom in plant diversity and an incredible show of floral varieties.
Different pollinators are drawn to these different colors. Bees tend to show a strong pull toward purple and blue blooms. Beetles favor white and yellow. Flies and wasps often gravitate toward yellow tones, while butterflies and moths lean toward pink and red. Many of these pollinators are generalists, capitalizing on many types of flowers.
In late summer, look for the classic pairing goldenrod and purple asters. With colors opposite to each other on the color wheel, they’re working in tandem to attract a larger diversity of pollinators than either could alone.
This episode of Earth Notes is funded in part by Pink Jeep Tours, written by Danika Thiele and produced by KNAU and the Sustainable Communities Program at Northern Arizona University.
