On the 13th day after they were laid, the eggs of the Cecropia moth hatched. I placed a few freshly-cut shoots from my lilac bush into the container with the tiny caterpillars, which already appear much larger than the eggs from which they recently emerged.
The caterpillars chew their way out of the 2mm-diameter eggs and almost immediately begin feeding on the leaves of suitable host plants including maple, birch, cherry, and lilac (shown here).
1st instar Cecropia moth caterpillars on lilac leaves. Empty egg shells at bottom of container.
1st instar Cecropia moth caterpillars are black with black hair-bearing spicules on their backs and sides.
Hatched Cecropia moth eggs.
1st instar Cecropia moth caterpillars on a lilac leaf.
These so-called “1st instar” larvae (caterpillars that have not performed their first molt) are entirely black with tiny black “spicules” on their backs. The spicules are hard, shiny projections and at this stage carry long hairs that extend from tiny turrets along their crowns.
This one has already begun gnawing on the edge of the lilac leaf on whose edge it clings.
For the next 3 months or so, the caterpillars will do nothing but eat leaves and grow. Their size will increase about 20 times until they are larger than an adult finger. They will shed their skins four times and emerge from each molt with a different color scheme.
The 5th instar caterpillars will then construct a durable silken cocoon which will turn to a dark brown color. After passing the winter in the cocoon they will emerge as spectacular adult moths in late Spring. During their brief life as adults - about a week - they will mate and then die, with the females producing up to about 100 eggs to carry the species forward into its next generation.