Silvery Checkerspot

Walking our lane I came across a plant so riddled with holes that I almost couldn't identify it as our very common Verbesina virginica.  This is the frostweed that we have written about many times.  The cause of the damage was only obvious when I turned the leaf over and saw this dense collection of caterpillars.

I started my search with Illinois Wildflowers and found that it is a host plant for only one butterfly, the silvery checkerspot, Chlosyne nycteis.  The caterpillar was a perfect match.  In addition to the yellow stripes, it has the branched spines typical of the Nymphalidae family. 

Wikipedia

SC adult - Patrick Murray

BAMONA says females lay eggs in clusters of about 100 on the underside of host plant leaves and the young caterpillars move in groups as they skeletonize leaves.  Here our friend Evaly, already an experienced naturalist at 10, is studying a mass of young SC caterpillars.

I decided to try raising them to photograph the chrysalis.  After a period of time they just curled up and stopped eating.  Reading further I discovered that they spend the winter as caterpillars, waiting until spring to form a chrysalis.  I had to settle for using this photograph from Prairie Haven which has a extensive photo gallery demonstrating the silvery checkerspot life cycle.