endemic to a single state or province
Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: (<100-1000 square km (less than about 40-400 square miles)) 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.
Comments: The moth is found in open weedy areas in desert scrub on sandy soils. One occurrence is in fairly natural desert scrub, the other in a primarily agricultural area. Some of the habitat has been disked, and some roads and development are within the population areas. The most important habitat factor is presence of the larval foodplant at rather high density, sufficient that larvae can locate new ones as needed, and some sort of nectar flowers for the adults. The larval foodplant does well in disturbed sites. Original habitat was somewhat disturbed areas in the Walker Basin, Kern County, California.
Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
Comments: Larvae feed on foliage of Camissonia strigulosa (formerly Oenothera contorta var. epilobioides), a small yellow-flowered spring annual herb endemic to California. They probably would use other Onagraceae if present. Adults apparently do not feed often, but sometimes take nectar as available from naitve or exotic flowers. Females oviposit on other plants, but larvae move to nearby Camissonia to feed.
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 1 - 20
Comments: 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.
50 - 2500 individuals
Comments: The maximum sighted during any one day of flight period at Walker Basin had been only six in recent years, so this population could be only a few dozen adults annually. Up to 40 have been seen in a day at Carizzo Plain (Jump et al. 2006). Without mark-release-recapture in several seasons, population sizes probably cannot be known, although it seems very likely there are at least hundreds some years since 40 was almost certainly not the entire population that day, not all individuals in a brood would likely be present on any single day, and males are somewhat difficult to find. A further complication is that pupae may remain in diapause for several years, so adults do not represent the entire population.
This is a localized diurnal sphingid, well-adapted to flying in cool weather. Larval foodplants are small so larvae must locate and feed on several to mature. Pupae are in the sand, probably more than five cm deep. there probably are always some pupae present
Life History and Behavior
Comments: There is one brood with adults in late winter to early spring and larvae later the same spring. Pupae are present in the soil year-round. Adults fly late February to early April at Walker Valley and about a month earlier at Carizzo Plain. Pupae remain dormant through unfavorable (e.g. drought) years, and some probably do in all years.
NatureServe Conservation Status
Rounded Global Status Rank: G1 - Critically Imperiled
Reasons: 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.
Intrinsic Vulnerability: Moderately vulnerable
Environmental Specificity: Narrow. Specialist or community with key requirements common.
Other Considerations: This species cannot be legally collected since it was Federally listed, which may, or may not, be significant protection at the Walker Basin sites. However, this has probably been a disincentive to subsequent efforts to locate new populations, except by a few researchers, because moth occurrences are generally discovered by collectors, typically hobbyists.
National NatureServe Conservation Status
Rounded National Status Rank: N1 - Critically Imperiled
Date Listed: 04/08/1980
Lead Region: California/Nevada Region (Region 8)
Where Listed: Entire
Population location: Entire
Listing status: T
For most current information and documents related to the conservation status and management of Euproserpinus euterpe , see its USFWS Species Profile
Global Short Term Trend: Relatively stable to decline of 30%
Global Long Term Trend: Unknown
Comments: Probably a very large decline over recent centuries but there are too few historic records to verify this.
Degree of Threat: High
Comments: 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.
Biological Research Needs: Some estimate of population size over several years would be useful but would require MRR, therefore permits etc. Available observations may be adequate to assess phenology and perhaps annual fluctuations, but population size is apparently not known to order of magnitude. Despite the recommendation of Jump et al. (2006) there is very little, if any basis, for not conducting such studies at least at Carizzo Plain. The moths are orders magnitude larger than the "small" butterflies in the Gall article they cite and MRR has been conducted extensively and successfully with much smaller butterflies such as Karner Blue. The Murphy article that they and others cite produced no convincing evidence against MRR, although the population was already declining and imperiled, and MRR was unusually intensive, so an impact is plausible but not documented. At least at Carizzo Plain the population is spread out sufficiently, and appears to be large enough (40 adults actually seen some days at one site), that it is very unlikely MRR could have a significant impact. Additional specimens (suitably preserved for DNA analyses) from that population and Cuyama Valley would obviously be useful to assess the possibility that these and the Kern county population are distinctive evolutionary units--or alternatively remnants of a single much larger contiguous range.
Global Protection: Few (1-3) occurrences appropriately protected and managed
Comments: Walker Basin populations are on private land which cannot be fully protected, but for now land use is more or less compatible. Other populations are partly on public land with some degree of protection, but incompatible uses such as sheep and ORVs are threats or have destroyed some habitats.
Euproserpinus euterpe (common name Kern Primrose sphinx moth or euterpe sphinx moth) is a small day-flying moth in the Sphingidae (sphinx) family. The 0.04-inch, light green eggs are laid haphazardly on various plants in the vicinity of the evening primrose host plants (Camissonia contorta epilobiodes or Camissonia campestris). Larvae emerge from the eggs about a week after oviposition and begin to feed on the flowers and young leaves of the evening primrose. Larvae hatching from eggs laid on other plants are able to wander significant distances to find the host plant.
First instar larvae (caterpillar phases) are green with dark brown to black heads, legs, lateral spiracles, thoracic shields, and blunt anal horns. Second and third instar larvae are green and red, with red heads, thoracic shields, and prolegs (leg-like appendages that are not true legs). Fourth and fifth instar larvae (i.e. caterpillars that have shed their skin 3 or 4 times) have red to dark red heads, with green and rust red bodies accented with black areas around spiracles, anal shield and anal horn. The legs are green and the prolegs are red in these mature larvae. Adult moths have a gray ground color with patterned black and brown markings on the forewings. Hindwings are off-white with black marginal banding. Males are slightly smaller than the females and are difficult to distinguish, except by close examination of the antennae. These are small sphinx moths with a wing span of a bit more than an inch from tip to tip.
Adults nectar on a variety of flowering species that occur in the region, including, filaree (Erodium sp.), goldfields (Lasthenia gracilis), and baby blue eyes (Nemophila menziesii). The adult's flight season occurs from mid-January to the first week of April, with a peak period in mid-February through mid-March. The timing may vary according to the climatic conditions in the region.
Distribution is apparently restricted to a privately owned ranch in the Walker Basin, Kern County, and the Carrizo Plain National Monument, San Luis Obispo County, California. The Walker Basin is an agricultural region, with cereals and cattle the primary crops. The moth is found in disturbed areas in association with its larval and adult food plants. More specifically, the moth favors the banks of sandy washes, in which the sand has the proper compaction and moisture content for burrowing larvae. It can apparently also use other disturbed areas including road shoulders and abandoned agricultural fields. The population in the Carrizo Plain National Monument was discovered in 2002 and is being managed by the Bureau of Land Management.
It once was believed that Erodium was a serious threat to the sphinx moth because of larval mortality after eggs were mistakenly deposited on this plant. However, emerging research shows that female moths deposit eggs on plants indiscriminately, and the larvae wander to find a suitable host. Erodium is never fed upon. Until 1974 the species was considered to be extinct, at which time a surviving population was found in the eponymous Kern County. Sphinx moths are valuable to insect collectors, who may pose a threat to these small populations. Pesticide or herbicide application could also endanger the moth. But the greatest threat is likely habitat loss and alteration. This species is extremely rare and in most years field surveys of the Walker Basin population have found few or no individuals. However, desert Lepidoptera often show great natural variations in population size in response to climatic conditions, and surveys may more accurately reflect population status in years with above-normal rainfall.
- P.M. Jump, T. Longcore, and C. Rich. 2006. Ecology and Distribution of a Newly Discovered Population of the Federally Threatened Euproserpinus euterpe. Journal of the Lepidopterists' Society 60(1): 41-50.
- C. Thelander, Life on the edge: a guide to California's endangered natural resources. Edition 1994. BioSystem Books. Santa Cruz, California. p 442-443.
- P.M. Tuskes and J.F. Emmel. 1981. The life history and behavior of Euproserpinus euterpe (Sphingidae). Journal of the Lepidopterists' Society 35:27-33.
- U.C. Berkeley, Essig Museum of Entomology. California's Endangered Insects'
- U.S. Fish and Wildlife Service. Kern Primrose Sphinx Moth Recovery Plan. 1984. Portland, Oregon.
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