By Jean Thomas
As I stood in my kitchen garden this morning, I watched another aerial combat. This little fenced garden has flowering vines climbing the “walls” and vivid annual flowers in an array of raised beds. The combat is one common to any yard with a hummingbird feeder. This is the migratory season. Our summer residents have already moved south, and the ones we're seeing now are the transients from more northern summer homes. These little guys are more anxious, and don't nag for refills, but travel from color to color looking for fuel to enable them to travel, possibly, thousands of miles. I love watching their flights, always looking for a flash of the red (ruby) throat plumage of the males. I also just learned it's called a “gorget”, after a throat protector worn in the middle ages. AND I will see a smaller proportion of birds with the red flash because so many of the birds are juvenile males who won't develop the “red” feathers until after their first winter. The adult males always leave earlier, so there are even fewer chances to see the flashiness.
I recovered from the disappointment and enjoyed the glossy olive green color of their backs. Then some butterflies drifted past. More color, and more wonderful patterns on their wings. While the male hummingbird's bright bling serves a dual purpose of attracting females and warning competition to back off, the butterfly markings are often either a warning or a defense. Some of the butterflies have a little sparkle, but most rely on color.
Other insects, however, go all out with the glitter. There's a little guy that lives on vines, called the golden tortoise beetle. It is about the size of a ladybug and positively gleams with a metallic golden coat. I'm always rustling through my morning glory vines to try to catch one. When I researched to learn how they managed to look metallic, I found out they use a method similar to the method used by the male hummingbirds. Both have a chemical and structural thing going on that interferes with the passage of light to choose and reflect their particular color. Both also control the “flash”: the hummingbird tones the color down when he chooses, and the gold bug can drop the metallic look for defense.
There are many more insects that resort to the metallic look. The garden is full of “long-legged fly” species that dress themselves in glamorous coats of green, blue, red and copper. They also use a system of light control, having specialized ridges and other structures that bounce light around. Good news: they are mostly beneficial, don't sting, and remove lots of pest insects for us.
Another star in the bling parade is the dragonfly/damselfly family. They use several different methods to express their colors, from pigmentation to light manupulation in their cells. Males and females often have different colors, and some change their colors responding to different factors like temperature or age. Some also have a thing called “nuptial coloration,” kind of like puberty in boys. Apparently this is so the mature males don't waste time competing with immature ones. It's wonderful when clouds of dragonflies hatch at once. It's like a tangible rainbow. These, too are beneficial insects. None of them sting.
This is a very short list of the jewels that are all around us if we slow down and look. I hadn't thought about it before, but these choices are not just beautiful but beneficial. Lucky us!
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