In April while Leonard and I were hiking the Wapama Falls Trail at Yosemite National Park (California), I noticed an interesting caterpillar.
The caterpillar had black and white longitudinal markings and rows of short, black spines on an orange base. The head was black.
This caterpillar is the larval stage of a checkerspot butterfly (Euphydryas sp). Both the butterflies and caterpillars of the genus Euphydryas are variable in color and pattern.
Checkerspots are found in open forests, riparian habitats and mountain meadows in the Pacific States and Northern Rocky Mountains.
Checkerspot larvae feed on a wide variety of plants including penstemons, figworts, snowberries, Indian paintbrushes, louseworts, owl’s clovers, Chinese houses and others. The caterpillars, often in groups surrounded by silken nets, feed on leaves and flowers. The 3rd and 4th instars of Euphydras hibernate under rocks, in plant litter or in bark crevices. In high elevations the larvae can hibernate for several years.
Euphydryas taxonomy is difficult for a novice. One reference separates the species into subspecies and varieties while another gives those same subspecies or varieties a species designation of their own. I think this caterpillar may be the larval stages of chalcedon checkerspot butterflies, also called variable checkerspots, (Euphydryas chalcedona) but would welcome more expert opinions.
A previous post gives more information about the chalcedon checkerspot butterfly (06-20-12 “Chalcedon Checkerspot Butterfly”).