Colias behrii (Sierra Sulphur Butterfly)
Credit: Zachary MacDonald
about the species
The Sierra Sulphur (Colias behrii) is a small, green butterfly that is endemic to wet, high-elevation meadows of the Sierra Nevada mountain range. This species is easily identified, as it is the only green sulphur that occurs in the region. Compared to the two other butterflies endemic to the Sierra Nevada (Parnassius behrii and Oeneis chryxus ivallda), C. behrii is relatively widespread and abundant. However, the long-term persistence of many populations is still threatened by warming and drying climatic conditions. Larvae feed on host plants that are associated with permanently-soaked, open meadows, including Blueberries (Vaccinium spp.), gentian (Gentiana newberryi), and a number of plants of the heath family (Ericaceae). Observers fortunate to frequent these meadows during the flight season (mid-summer) can likely get a close look at this wonderful species— C. behrii is notably less skittish than most other butterfly species in the region.
why species was selected
Colias behrii is likely to become a species of conservation concern as habitat and climatic conditions continue to change in the Sierra Nevada. Whole-genome sequence data will allow us to infer connectivity among isolated populations, as well as identify fine-scale population structure and genomic signatures of local adaptation. These data, coupled with forward-in-time landscape and environmental modelling, will be used to identify populations that are particularly threatened by changing habitat and climatic conditions. Two other butterflies, Parnassius behrii and Oeneis chryxus ivallda, are also endemic to the Sierra Nevada, and are similarly being addressed by the CCGP. Comparative analyses across these species will help conservation biologists understand how high-elevation ecosystems are changing.
