Diapause-disruption
Guides
Coenonympha tullia california
California Ringlet
Coenonympha tullia california is a subspecies of the Common Ringlet butterfly, historically found in low-elevation areas of central and northern California. According to long-term monitoring by UC Davis professor Art Shapiro, this subspecies was regionally extirpated from the Sacramento Valley and surrounding lowlands by 2007, becoming one of several butterfly species to disappear from Shapiro's study transect between Chico and Stockton. The decline is attributed to climate change disrupting diapause cues and pesticide exposure, particularly neonicotinoids. The subspecies exemplifies broader patterns of butterfly population collapse documented across North America.