The Cecropia moth, Hyalophora cecropia, also called the robin moth, is one of the largest giant silkworm moths found in the U. S. and Canada. Rarely does this moth cause much damage to trees, although in l927 and in l940 it was a major defoliator of maples in Manitoba prairie shelterbelts. Occasionally it has caused similar damage to several hardwood trees and shrubs in Mid-western prairie shelterbelts.
Its six-inch wingspan, reddish-brown body with a white collar and abdominal cross bands, and dark bark brown wings with four white and crescent-shaped spots near the middle and irregular white and reddish bands near their edges, all combine into a beautiful moth seen from May to July. Eggs are laid in groups of three to thirty on the underside of leaves, and the caterpillars feed on the leaves of many different hardwood trees and shrubs from July to October.
Even the larvae are fascinating. Their sea green bodies have prominent dorsal thoracic orange knobs or tubercles, yellow abdominal knobs, and pale blue knobs along both body sides. They grow as large as 3½ inches long and 3/4 inch thick before they spin a spindle-shaped cocoon lengthwise on a twig for the winter, emerging as adult moths the next spring.
To change from the caterpillar into the very different adult body, the
Cecropia Moth, like other moths, butterflies, beetles, bees, wasps, ants
and flies, must undergo complete metamorphosis. Hormones control
this breakdown and restructuring of larval organs into pupal organs and
finally into the adult moth's beautifully colored body. During this
metamorphosis, existing organs are either completely broken down
or only partially so changed and incorporated into new organs.
A wonder of nature!