Euproserpinus euterpe

The species is listed as Threatened under the US Endangered Species Act, although it is apparently rarer than some Endangered species and has threats to its habitats and from pesticide drift in some of its few habitats. At the time of listing one population was known, since then two other population clusters have been found, of which the one on Carizzo Plain has six known colonies, although whether these function as fewer metapopulations or are separate occurrences (viable or otherwise) has not been documented. With about 3-9 occurrences and threats, this species probably still merits critically imperiled, although as USFWS points out recovery potential is good. The Rank Calculator 3.0 rank comes out as "G2?", but no information suggests this species might rank as high as G3--implying the choices are G1 or G2, a G1G2 rank is selected.

A population in the northwest portion of Walker Basin, Kern County, California has been known for several decades. A second metapopulation, or perhaps several, was/were discovered in 2002 in Carrizo Plain, National Monument in adjacent San Luis Obispo County (Jump et al., 2006). No others were known to Tuttle (2007). These two are about 125 miles apart. USFWS (2007) also reports a population in the Cuyama Valley (county not stated). Intervening terrain is generally not suitable for the species so a polygon connecting these three small ranges would not be a realistic range extent. The basis of the last is unclear, but the others are verified by specimens. With only three populations known no meaningful current range extent can be given.

Three occurrences are known and it is unlikely there could be many more, although there could be a few more near one of these sites.

Threats are described in detail by USFWS (2007) and Jump et al. (2006), and significant ones include damage from sheep, off road vehicles, agricultural practices such as disking, pesticides and herbicides, and in some places potential development. Threat from exotic Erodium upon which females oviposit and larvae would starve is much less serious than originally thought because first instars do disperse to some extent and suitable foodplants are often nearby. Furthermore, females normally lay eggs on foodplants and non-foodplant (Jump et al. 2006). Overcollecting might have impacted the Walker Valley population temporarily in the last few years before listing, especially since females are easier to collect than males, but documentation is minimal and the population, although apparently small, persists. Given the very small habitats, and apparently very small population, collecting probably could seriously impact this population, especially if in more than one year, but USFWS (2007) provides no information on actual numbers collected and the population size then and now is not known. While there is a market for rare sphinx moths, potential penalties are severe and could include prison time. At the larger, more spread out Carrizo Plain locality, collecting pressure would probably have to be chronic, intense (and thus easily noticed), and over more than one season to have much long-term impact.