When out in nature, most human visitors quietly move about hoping to see or hear an animal, bird or insect that is elusive unless one can successfully blend into their surroundings.
However, the last month at Durango Nature Studies Learning Center has brought an entirely different experience. The cicadas that have come out of their shells have begged to be heard or noticed. The constant hum and click is the background of every activity. Almost every shrub, tree or stump has a cicada or its old skin clinging to it, reminding one of the breath of new life or the remains of an old encasing left behind.
As I was working in our new welcome building two weeks ago, I listened, unnoticed, as a kindergarten group from Park Elementary School climbed the interpretive trail at the end of their field trip. The talk was all about cicadas. Many kids had never seen so many shells and were amazed to actually see some emerging during their visit. During the week, several parents who I ran into around town said that they had taken advantage of our Saturday openings at the Learning Center, and that they, too, had observed with their children cicadas emerging from their skins.
As a child, my main memory of cicadas was of scaring my sister by pulling the old skins from trees and putting them on her when she least expected it. Of course, this may or may not have been the beginning of my lifelong obsession with the feelings of awe and fear that nature inspires in all of us. But what I didnt know during my days as an annoying sister was that these encasings were actually the old skins of the cicada nymphs, split down the back and discarded when the adult cicada emerged from the old skin. After emerging, the cicada spends several hours darkening and letting its new exoskeleton harden and dry before flying away.
Cicadas have long life cycles. The eggs are buried into plants and twigs, and as they hatch, they fall to the ground and burrow into the soil to feed on plant roots.
They spend the next three to five years as a nymph, growing underground until they burrow through the soil with their stout forelegs and crawl up the stems of their host plants, emerging from the backs of their skin as an adult cicada.
Adults are present for about four to six weeks, during which they mate and the whole cycle begins again. They actually do relatively little harm to the plants they depend upon, except for splitting some outer twigs when the egg-laying process begins.
Male cicadas attract a female with their characteristic song. They have two drum-like organs, called tymbols, on the sides of their abdomen. They contract and release their muscles to make the tymbols resonate. A large air sac in their abdomen with a thin exterior eardrum acts as an echo chamber to greatly amplify the sound.
Putnams cicada is the most common cicada found in Colorado, and likely the one in most abundance at the Learning Center, because of its dependence on the piñon/juniper habitat.
Cicadas emerge in massive numbers at one time. They used to be confused with locusts a term used for migratory grasshoppers because European settlers encountered them in large numbers and likened them to the locusts described in the Bible. The cicada is actually the largest Colorado insect in the order Homoptera, which includes aphids and spittlebugs.
Cicadas are usually heard, rather than seen, so the students and families who got a first-hand view of these emerging adult cicadas over the last month have truly seen one of natures wonders.
email@example.com or 382-9244. Sally Shuffield is executive director of Durango Nature Studies.