Variable Checkerspot (Euphydryas chalcedona) is a small-medium butterfly, with a wingspan of 1.25 to 2.25 inches. In our local area, it can usually be seen from the end of March through June. Before this year, it had been seen in July only in 2023, when all butterflies appeared late, due to quirky weather in the spring. But in 2024, it was sighted in the Garden twice in July. Numbers peak in April-May. Host plants include several plants that were formerly classified as Scrophulariaceae, including Sticky Monkeyflower (Diplacus aurantiacus, Phrymaceae), Penstemon (Plantaginaceae), Paintbrush (Castilleja, Orobanchaceae). These plants are all rich in catalpol, a chemical compound that makes the butterfly unappetizing to birds.
Adults live for about 15 days. Males are highly territorial.
It is a North American butterfly, found primarily on the west coast, from Alaska in the north to Baja California in the south, although the range extends east through the Rocky Mountains into Colorado, Montana, New Mexico and Wyoming. The appearance is variable across different parts of its range, rather than across individuals in a given area.
