Submitted by PAM VARGA, Sahli Park Manager
On a recent walk through the Sahli Nature Park meadow, I discovered some tiny, flat, brownish eggs on the leaf of a Buttonbush. Curious to find out what insect critter laid these eggs, I clipped off the leaf and took the eggs into the greenhouse where I placed them in a small, lidded plastic container.
In a few days, tiny black spiky caterpillars hatched from the eggs. Many species of newly hatched butterfly and moth caterpillars are black and covered with spikes, so I was unable to identify them. I continued to feed the larva Buttonbush leaves, and after a week or so, the caterpillars shed their skins. Now, they were a golden orange color with black spikes. Looking through several field guides, I was still unable to identify the caterpillars. Many species of caterpillars completely change color and appearance as they mature, so I waited patiently as the mystery caterpillars ate and grew. Another week passed by, and the caterpillars molted again. Now they were light green with red, yellow, and blue knobs (tubercles) and black hairs arrayed along their bodies. Aha! Now I knew what they were—Cecropia moths!
Having a wingspan of five to seven inches, the Cecropia Moth (Hyalophora cecropia) is the largest moth in North America. With their fuzzy, dark red and white bodies and their brownish-gray wings with dark red false eye spots, red and white stripes, and delicate scalloped edging, Cecropias are as colorful and beautiful as any butterfly. Like all members of the Saturnid or Silk Moth family, Cecropia adults have no mouth parts. During their adult two-week life spans, they do not eat. Their only purpose is to find a mate and lay eggs. To attract a mate, the female moth gives off a scent (pheromones). The male’s large feathery antenna can detect the scent from 1-3 miles away, and he will fly as far as seven miles searching for a female. After mating, the female lays up to 100 eggs in groups of 2-6 on the leaves of oak, cherry, beech, apple, and buttonbush trees. After mating, the adults die.
The Cecropia caterpillars in our greenhouse continued to eat and grow over the summer and now they are about seven inches long. Next each caterpillar will begin to spin a silken strand from a tube below its mouth. Using its legs, the caterpillar will shape the silk into a cocoon. The caterpillar often weaves nearby leaves into this fuzzy, tan, bag-like structure. Perfect camouflage! Snug inside the cocoon, the caterpillar will shed its skin for the last time and become a pupa with a hard brown shell around its body. During the long winter months, the pupa will slowly transform into an adult moth that will emerge from its cocoon in early spring and fly off on its nocturnal journey to find a mate.
There are always interesting things to discover at Sahli Nature Park, an unknown insect, a never-before-seen flower, an unfamiliar bird song, or a new view of the light shining on the snow-covered branches of a majestic Spruce Tree. We welcome you to visit us and make your own discoveries.