Tuesday, August 16, 2011

A Monarch Caterpillar Look-Alike

Grapeleaf Skeletonizer ~ Harrisina americana


As I was walking by my grape vine that's woven into our picket fence, I caught out of the corner of my eye what looked liked a Monarch caterpillar eating the growth tips and tendrils of the grape. But wait, monarchs don't eat anything but milkweed.

On closer inspection, I realized it was probably a moth caterpillar with both spiny hairs on top and long wispy hairs beneath. As it turns out, the Grapeleaf Skeletonizer's common food plants include grape and virginia creeper (Parthenocisssus).

According to Caterpillars of Eastern North America, the young instars feed in groups on the underside of leaves, then as they mature they become more solitary. This moth's lifecycle is spent 40 out of the 65 days as a caterpillar. The pupa overwinters in a spun cocoon among the fallen grape leaves.

Minnesota is at the northern edge of its range, which includes the northeast to New Hampshire.