''Speyeria zerene hippolyta'', the Oregon silverspot, is a threatened

butterfly Butterflies are insects in the macrolepidopteran clade Rhopalocera from the Order (biology), order Lepidoptera, which also includes moths. Adult butterflies have large, often brightly coloured wings, and conspicuous, fluttering flight. The ...

that is found in the U.S. states of

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

and

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

. It is a

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

of ''

Speyeria zerene ''Speyeria zerene'', the zerene fritillary, is a butterfly found in the western portions of the United States and Canada. The species was first described by William John Swainson in 1827. Description ''Speyeria zerene'' is a medium-sized butte ...

''.

Taxonomy

''Speyeria zerene hippolyta'' was described by American

lepidopterist Lepidopterology ()) is a branch of entomology concerning the scientific study of moths and the three superfamilies of butterflies. Someone who studies in this field is a lepidopterist or, archaically, an aurelian. Origins Post-Renaissance, t ...

William Henry Edwards William Henry Edwards (March 15, 1822 – April 2, 1909) was an American businessman and entomologist. He was an industrial pioneer in the coalfields of West Virginia, opening some of the earliest mines in the southern part of the state. He was a ...

in 1879 as a subspecies of ''Speyeria zerene'', Zerene Fritillary, which was described by French lepidopterist

Jean Baptiste Boisduval Jean Baptiste Alphonse Déchauffour de Boisduval (24 June 1799 – 30 December 1879) was a French lepidopterist, botanist, and physician. He was one of the most celebrated lepidopterists of France, and was the co-founder of the Société entomol ...

in 1852.

Phylogeny

''Speyeria zerene hippolyta'' is in a

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

of three closely related subspecies. In suitable habitat along the U.S. Pacific coast, it is the northernmost one found. Further south, Myrtle's silverspot ('' Speyeria zerene myrtleae'') had a range along the coast from

San Mateo County San Mateo County ( ), officially the County of San Mateo, is a county located in the U.S. state of California. As of the 2020 census, the population was 764,442. Redwood City is the county seat, and the third most populated city following Daly ...

Sonoma County Sonoma County () is a county (United States), county located in the U.S. state of California. As of the 2020 United States Census, its population was 488,863. Its county seat and largest city is Santa Rosa, California, Santa Rosa. It is to the n ...

, California, and Behren's silverspot ('' Speyeria zerene behrensii'') had a range along the northern California coast. McHugh et al. (2013) conducted a genetic analysis of ''S. z. hippolyta'' and other ''S. zerene'' subspecies using

mitochondrial DNA Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial D ...

(mtDNA) and nuclear markers with a goal of identifying evolutionarily significant units (ESUs). There wasn't consensus among mitochondrial and nuclear markers so researchers were not able to resolve

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

relationships or identify the

taxa In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ...

monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...

through

genetic analysis Genetic analysis is the overall process of studying and researching in fields of science that involve genetics and molecular biology. There are a number of applications that are developed from this research, and these are also considered parts of ...

. However, it was discovered that the populations located at Rock Creek and Mt. Hebo have mtDNA

haplotypes A haplotype (haploid genotype) is a group of alleles in an organism that are inherited together from a single parent. Many organisms contain genetic material ( DNA) which is inherited from two parents. Normally these organisms have their DNA org ...

that are distinctive.

Distribution and habitat

The Oregon silverspot used to inhabit suitable coastal habitat from northern California, through Oregon, into southern Washington. There are 20 historical sites known. It can now only be found in the wild at five remaining sites in California and Oregon. Conservation sites include

Cascade Head Cascade Head is a headland and UNESCO biosphere reserve and United States Forest Service Experimental Forest. It is situated southwest of Portland, Oregon on the Oregon Coast between Lincoln City and Neskowin. Cascade Head Preserve is a Natur ...

and the

Rock Creek Wilderness The Rock Creek Wilderness is a wilderness area comprising within the Siuslaw National Forest on the Oregon Coast. It was created in 1984, along with the Drift Creek Wilderness and Cummins Creek Wilderness.

Rock Creek Wilderness
- Wilderness.net in Oregon. The butterfly can also be found at

Mount Hebo Mount Hebo is a mountain located on the border of Tillamook County and Yamhill County Yamhill County is one of the 36 counties in the U.S. state of Oregon. As of the 2020 census, the population was 107,722. The county seat is McMinnville. ...

and Bray Point in Oregon, and at

Lake Earl Lake Earl is a lagoon on the extreme northern California coast, just south of the Oregon border. A navigable body of water, it lies partly within Tolowa Dunes State Park and partly within Lake Earl Wildlife Area in Del Norte County, California a ...

in California. The butterfly has been determined to be extirpated from

Clatsop Plains The Clatsop Plains are an area of wetlands and sand dunes between the Northern Oregon Coast Range and Pacific Ocean in northwestern Oregon in the United States. They stretch from near the mouth of the Columbia River south to the vicinity of Tillam ...

in Oregon since 2001. Nestucca Bay Landscape

The coastal habitats used by the butterfly were kept in an early successional state by high wind, salt-spray and occasional wildfires, providing the open conditions required by the hooked spur violet (''

Viola adunca ''Viola adunca'' is a species of violet known by the common names hookedspur violet, early blue violet, sand violet, and western dog violet. It is native to meadows and forests of western North America, Canada, and the northern contiguous United ...

'') which is the butterfly's larval host plant. In recent years, although the winds and ocean salt spray continue to limit other vegetation growth, the wildfires have been suppressed due to modern development in this habitat. The original habitat of open meadows has, over time, been replaced by forest habitat.

Conservation status

The butterfly was listed as threatened by the

U.S. Fish and Wildlife Service The United States Fish and Wildlife Service (USFWS or FWS) is an agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats. The mission of the agency is "working with oth ...

(USFWS) under the

Endangered Species Act The Endangered Species Act of 1973 (ESA or "The Act"; 16 U.S.C. § 1531 et seq.) is the primary law in the United States for protecting imperiled species. Designed to protect critically imperiled species from extinction as a "consequence of ec ...

(ESA) in 1980. In Washington, the butterfly is listed as endangered under that state's legislation, though it is now reported

extirpated Local extinction, also known as extirpation, refers to a species (or other taxon) of plant or animal that ceases to exist in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinct ...

from this state. California and Oregon do not have endangered species statutes that allow the listing of insect species, but they still have protection in these states under the federal ESA. It is on the Special Animals list created by the

California Department of Fish and Game The California Department of Fish and Wildlife (CDFW), formerly known as the California Department of Fish and Game (CDFG), is a state agency under the California Natural Resources Agency. The Department of Fish and Wildlife manages and protect ...

. In Oregon the Oregon Biodiversity Information Center (ORBIC), under the Oregon Natural Heritage Act (Oregon Natural Areas Act), maintains a list of threatened and endangered invertebrates. The ORBIC is located at

Portland State University Portland State University (PSU) is a public research university in Portland, Oregon. It was founded in 1946 as a post-secondary educational institution for World War II veterans. It evolved into a four-year college over the following two decades ...

(PSU) within the Institute for Natural Resources (INR). The ORBIC assists the USFWS and the

Oregon Department of Fish and Wildlife The Oregon Department of Fish and Wildlife (ODFW) is a government agency of the U.S. state of Oregon responsible for programs protecting Oregon fish and wildlife resources and their habitats. The agency operates hatcheries, issues hunting and ...

(ODFW) to carry out conservation programs for invertebrates within the state. The USFWS maintains a timeline of conservation and recovery for the butterfly on their website.

Conservation efforts

Researchers have been testing methods of maintaining and restoring the grassland habitat in coastal preserves, these include

prescribed fire A controlled or prescribed burn, also known as hazard reduction burning, backfire, swailing, or a burn-off, is a fire set intentionally for purposes of forest management, farming, prairie restoration or greenhouse gas abatement. A control ...

. As it does take several years for the hooked spur violet to reach maturity a "stop-gap measure" is underway. A team consisting of the Oregon

Nature Conservancy The Nature Conservancy (TNC) is a global environmental organization headquartered in Arlington, Virginia. it works via affiliates or branches in 79 countries and territories, as well as across every state in the US. Founded in 1951, The Natu ...

, the

Lewis and Clark College Lewis & Clark College is a private liberal arts college in Portland, Oregon. Originally chartered in 1867 as the Albany Collegiate Institute in Albany, Oregon, the college was relocated to Portland in 1938 and in 1942 adopted the name Lewis & Cl ...

and the

Oregon Zoo The Oregon Zoo, originally the Portland Zoo and later the Washington Park Zoo, is a zoo located in Washington Park, Portland, Oregon, approximately southwest of downtown Portland. Founded in 1888, it is the oldest zoo west of the Mississippi Ri ...

gather female butterflies for captive rearing. The captive-rearing projects are underway at the college and the Oregon Zoo in Portland and the

Woodland Park Zoo Woodland Park Zoo is a wildlife conservation organization and zoological garden located in the Phinney Ridge neighborhood of Seattle, Washington, United States. It is the recipient of over 65 awards across multiple categories, and had served appro ...

Seattle Seattle ( ) is a seaport city on the West Coast of the United States. It is the seat of King County, Washington. With a 2020 population of 737,015, it is the largest city in both the state of Washington and the Pacific Northwest regio ...

. After being hatched and raised at the college and the zoos, the young are reintroduced as

pupae A pupa ( la, pupa, "doll"; plural: ''pupae'') is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in their ...

to the wild to augment the existing populations. After the release of nearly 450 silverspots at Mount Hebo in 2016, Karen Lewis, a zoo conservation research associate, said in a statement, "The goal of the recovery program is to help each population grow large enough to be self-sustaining, if it weren't for this program, three of the five remaining silverspot populations would likely be extinct." The Oregon Zoo released about 2000 silverspots at the Nestucca Bay National Wildlife Refuge in 2017. In 2018, the Oregon Zoo, Woodland Park Zoo, USFWS, and

Oregon Parks and Recreation Department The Oregon Parks and Recreation Department (OPRD), officially known (in state law) as the State Parks and Recreation Department, is the government agency of the U.S. state of Oregon which operates its system of state parks. In addition, it has pro ...

(OPRD) collaborated to release 500 silverspots at Saddle Mountain in Oregon in an effort to restore a historical population. The butterflies had not been seen at Saddle Mountain since the 1970s. The establishment of new colonies may have lasting effects on the genetics of the subspecies. The founding events of isolated small populations may cause a loss of

heterozygosity Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Mo ...

over generations and an accumulation of deleterious

recessive In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and t ...

alleles An allele (, ; ; modern formation from Greek ἄλλος ''állos'', "other") is a variation of the same sequence of nucleotides at the same place on a long DNA molecule, as described in leading textbooks on genetics and evolution. ::"The chro ...

without

gene flow In population genetics, gene flow (also known as gene migration or geneflow and allele flow) is the transfer of genetic material from one population to another. If the rate of gene flow is high enough, then two populations will have equivalent a ...

from other populations. The butterflies may be at increased risk of

extinction Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

due to the increased

genetic load Genetic load is the difference between the fitness of an average genotype in a population and the fitness of some reference genotype, which may be either the best present in a population, or may be the theoretically optimal genotype. The average i ...

and reduction in

genetic diversity Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species, it ranges widely from the number of species to differences within species and can be attributed to the span of survival for a species. It is dis ...

following the

population bottleneck A population bottleneck or genetic bottleneck is a sharp reduction in the size of a population due to environmental events such as famines, earthquakes, floods, fires, disease, and droughts; or human activities such as specicide, widespread violen ...

before the

captive breeding Captive breeding, also known as captive propagation, is the process of plants or animals in controlled environments, such as wildlife reserves, zoos, botanic gardens, and other conservation facilities. It is sometimes employed to help species that ...

programs.

Adaptability to climate change

Oregon silverspots are considered to be moderately vulnerable to

climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...

due to their sensitivity to environmental conditions. However, increased fire in a warming climate may open up additional coastal prairie habitat and may help the growth of their only host plant, the early blue violet (''Viola adunca)'', which is partially dependent on fire for germination.

References

External links

Arcata Fish and Wildlife Office

Butterflies of the Northwest

Oregon silverspot recovery project at the Oregon Zoo

Oregon silverspot recovery project at the Woodland Park Zoo
{{Authority control Speyeria Butterflies of North America Fauna of the Northwestern United States Endangered fauna of California Species endangered by habitat loss Butterfly subspecies