Under gray skies, on the snowball viburnum, I found a strange creature with branches on its back.
This, it turned out, was the larva of the Baltimore checkerspot butterfly (Euphydryas phaeton). Its host plant is turtlehead (Chelone glabra), which used to be very scarce here on the mountain until we got the white-tailed deer numbers down to a more reasonable level. Just last year, we were excited to find a big patch of turtlehead in a wet part of the field about a hundred feet away from where I snapped this picture.
The Baltimore checkerspot lays her eggs in clusters on the undersides of turtlehead leaves in mid-summer. The young caterpillars spin a communal web, like tent caterpillars or fall webworms, and over-winter as half-grown caterpillars just under the surface of the soil. The coloration of the adult preserves the orange and black from the juvenile, but white replaces the blue. These beautiful insects – the official state insect of Maryland – are yet another argument for longer hunting seasons and/or the recovery of top predators in the East – wolves and cougars.