Today I came across five separate colonies of baltimore checkerspot butterfly larvae. When young, the larvae are colonial, living in a tent similar to that of tent caterpillars. They make their nests almost entirely on the native wildflower turtlehead. The image bottom left shows the web, bottom right shows some of the young larvae, and top, the adult butterfly. In later instars (that is, when they are bigger), the larvae set out on their own.