Several weeks ago I noticed the cocoon in the upper photo attached to the eye-level branches of a small shrub. Returning to the site several days later I searched the lower limbs in the tall grass and found the second cocoon.
These are the cocoons of Callosamia promethea - one of the giant silkmoths of the eastern U.S. The caterpillar creates this structure by wrapping the petiole of a leaf with strands of silk, then wraps his/her body in the leaf itself and seals it shut with additional silk. The caterpillar remains inside this structure through the long cold Wisconsin winter.
It's a remarkably effective camoflage, looking ever so much like a curled, dead leaf that simply didn't fall from the plant. The camo is necessary because these caterpillars are fat, juicy treats that would be a delicious meal for a variety of predators - especially parasitic wasps.
I placed both cocoons inside a terrarium on our screen porch. Tomorrow I'll show you what emerged this week...
(Both pix enlarge to wallpaper with a click)
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