Palos Verdes blue
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The Palos Verdes blue (''Glaucopsyche lygdamus palosverdesensis'') is a small endangered
butterfly Butterflies are insects in the macrolepidopteran clade Rhopalocera from the order Lepidoptera, which also includes moths. Adult butterflies have large, often brightly coloured wings, and conspicuous, fluttering flight. The group compris ...
native to the
Palos Verdes Peninsula The Palos Verdes Peninsula (''Palos Verdes'', Spanish for "Green Sticks") is a landform and a geographic sub-region of the Los Angeles metropolitan area, within southwestern Los Angeles County in the U.S. state of California. Located in the S ...
in southwest
Los Angeles County Los Angeles County, officially the County of Los Angeles, and sometimes abbreviated as L.A. County, is the List of the most populous counties in the United States, most populous county in the United States and in the U.S. state of California, ...
,
California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...
, United States. As its distribution has been proven to be limited to one single site it has one of the best claims to being the world's rarest butterfly.


Overview

The Palos Verdes blue (''G. l. palosverdesensis'') is a localized
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 specie ...
of the silvery blue ('' G. lygdamus''), which ranges over much of North America. It was described in 1977, shortly before it became one of the second groups of butterflies to be listed under the US
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 ...
in 1980.Mattoni, R. 1995. Rediscovery of the Palos Verdes endangered blue butterfly, ''Glaucopsyche lygdamus palosverdesensis'' Perkins and Emmel (Lycaenidae). Journal of Research on the Lepidoptera. 31 (3-4): 180-194. It is distinguished from other subspecies of ''G. lygdamus'' by its slightly different patterning on the underside of the wing and an earlier flight period. The subspecies was described from the southern slope of the Palos Verdes Peninsula in coastal Los Angeles County. The Palos Verdes blue butterfly was thought to be driven to extinction in 1983, primarily by
development Development or developing may refer to: Arts *Development hell, when a project is stuck in development *Filmmaking, development phase, including finance and budgeting *Development (music), the process thematic material is reshaped * Photograph ...
of its habitat. The last three to six known individuals were seen and photographed in March, 1983, but the site they occupied was scraped shortly after for fire control. Then, in 1994, the butterfly was rediscovered by Rick Rogers, Rudi Mattoni, and Timothy Dahlum at the Defense Fuel Support Point in San Pedro, which is located on the northern (inland) side of the Palos Verdes Peninsula. This new population lays eggs on an additional food plant (common deerweed, ''
Lotus scoparius ''Acmispon glaber'' (previously ''Lotus scoparius'') (common deerweed, deer weed, deervetch, California broom or western bird's-foot trefoil) is a perennial subshrub in the family Fabaceae (pea family). The plant is a pioneer species found in ...
'') but shares physical and behavioral characteristics with the other now-extinct populations.


Biology


Taxonomy and systematics

''Glaucopsyche lygdamus palosverdesensis'' is a subspecies of ''
Glaucopsyche lygdamus ''Glaucopsyche lygdamus'', the silvery blue, is a small butterfly native to North America. Its upperside is a light blue in males and a dull grayish blue in females. The underside is gray with a single row of round spots of differing sizes depen ...
'' (the "silvery blue"), a species of butterfly found throughout North America. There are currently 11 subspecies of silvery blue. ''G. lygdamus palosverdesensis'' was first described in the 1970s and was distinguished from other ''G. lygdamus'' by its faster and early flight, wing color and wing spot patterns. 1999. Habitat Evaluation and Reintroduction Planning for the Endangered Palos Verdes Blue Butterfly. Final Technical Report to California Department of Fish and Game. 1-47.


Morphology

The Palos Verdes blue butterfly has a wingspan of only . The male has a bright silvery-blue dorsal wing outlined in a narrow line of black, while the female's dorsal wing is a more brownish-gray colour. Both males and females have gray ventral wings with dark spots surrounded by white rings.


Habitat

''G. lygdamus palosverdesensis'' persists particularly on the Palos Verdes Peninsula, 15 miles south of Los Angeles, in a
coastal sage scrub Coastal sage scrub, also known as coastal scrub, CSS, or soft chaparral, is a low scrubland plant community of the California coastal sage and chaparral subecoregion, found in coastal California and northwestern coastal Baja California. It is ...
habitat. This subspecies is locally monophagous, or particular to one species of food plant. The entire subspecies was originally thought to be particular only to the locoweed or rattlepod ('' Astragalus trichopodus lonchus''), but the population rediscovered in 1994 used common deerweed (''
Lotus scoparius ''Acmispon glaber'' (previously ''Lotus scoparius'') (common deerweed, deer weed, deervetch, California broom or western bird's-foot trefoil) is a perennial subshrub in the family Fabaceae (pea family). The plant is a pioneer species found in ...
'') as its larval food plant. These two types of plants are fast becoming scarce on the Palos Verdes Peninsula because of housing development. Retention of these larval food plants is essential for conservation of the Palos Verdes blue.


Life stages

Oviposition, laying of eggs on the larval food plant, occurs only once a breeding season for the Palos Verdes blue. There are at least four larval
instar An instar (, from the Latin '' īnstar'', "form", "likeness") is a developmental stage of arthropods, such as insects, between each moult (''ecdysis''), until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or ...
s, or stages of development. After 7 to 10 days the larvae emerge and crawl to the base of the food plant where they pupate. Pupae remain in
diapause In animal dormancy, diapause is the delay in development in response to regular and recurring periods of adverse environmental conditions.Tauber, M.J., Tauber, C.A., Masaki, S. (1986) ''Seasonal Adaptations of Insects''. Oxford University Press I ...
until emerging as adults. The flight period and reproductive period occur together, beginning in late January and ending in early May. It is rare to see the Palos Verdes blue far from its home food patch, but research shows that males cover more distance and have longer periods of flight. Palos Verdes blues are a diurnal and
panmictic Panmixia (or panmixis) means random mating. A panmictic population is one where all individuals are potential partners. This assumes that there are no mating restrictions, neither genetic nor behavioural, upon the population and that therefore all ...
subspecies. They are also non-migratory and very particular in their use of larval food plants. Their adult lifespan is only five days.


Relationships with other species

Interspecific competition Interspecific competition, in ecology, is a form of competition in which individuals of ''different'' species compete for the same resources in an ecosystem (e.g. food or living space). This can be contrasted with mutualism, a type of symbiosis. ...
may occur with other lycaenid butterflies for the larval food plant. A mutualism between ants and larvae has been observed during the instars of butterfly development. ''G. l. palosverdesensis'' has a host-parasite relationship with its larval food plants, ''Astragalus lonchus'' and ''Lotus scoparius''. There has also been observed predation on Palos Verdes blue by
western yellowjacket ''Vespula pensylvanica'', the western yellowjacket, is a Nearctic species of wasp in the genus ''Vespula''.Akre, Roger D., Albert Greene, John F. MacDonald, Peter J. Landolt, and Harry G. Davis. Agricultural Handbook Number 552. United States Dep ...
s (''Vespula pensylvanica'') at the Defense Fuel Point location.


Conservation


Laws

''G. lygdamus palosverdesensis'' was listed as an "
endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...
" by the
United States 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 othe ...
on July 2, 1980. This listing also included city-owned critical habitat, plus comments and recommendations for species conservation. Insects are not currently protected by California laws.


Threats

The main threat to the Palos Verdes blue has been
habitat destruction Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...
due to weeds and rototilling, which has negative effects on the essential larval food plants. Recreational, commercial, or residential development of the Palos Verdes Peninsula is also a major concern in preservation of the food plants.


Court case

In 1982, the city of
Rancho Palos Verdes Rancho Palos Verdes (Spanish for "Green Sticks Ranch") is a coastal city located in Los Angeles County, California atop the bluffs of the Palos Verdes Peninsula, neighboring other cities in the Palos Verdes Hills, including Palos Verdes Esta ...
bulldozed the then most extensive known habitat of the butterfly to build a baseball field, an act believed to have been a principal cause of the die-off of the subspecies before its rediscovery in 1994. The US Fish and Wildlife Service maintained that the city was "well aware" of the butterfly and the site status. According to the ''Los Angeles Times'', the mayor of the city "said no one complained about butterfly destruction until grading had been completed." In 1987, the city was charged by the federal government with violating 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). The case was dismissed later that year by a federal court, which said a municipality was not a person for purposes of the ESA, and thus could not be held criminally responsible. The following year, the US Congress responded by amending the act to include any "individual, corporation, partnership, trust, association, or any other private entity; or any officer, employee, agent, department, or instrumentality of the Federal Government, of any State, municipality, or political subdivision of a State, or of any federal government; any State, municipality, or political subdivision of a State; or any other entity subject to the jurisdiction of the United States."


Reintroduction

The Palos Verdes Peninsula is split into the north and south slopes. On the north slope, reintroduction is suggested based on presence of deerweed (''Lotus scoparius'') and a native plant index number. The only habitat known so far on the north slope is the Defense Fuel Support Point location. The south slope has many more historic sites of Palos Verdes blue, which are all suggested for reintroduction, including any more sites containing locoweed (''Astragalus''). Particular sites of reintroduction and rehabilitation of the Palos Verdes blue include Defense Fuel Support Point in San Pedro and the Linden H. Chandler Preserve. In conjunction with other organizations, the Palos Verdes Peninsula Land Conservancy is installing and maintaining coastal sage scrub habitat on the slopes around the fuel tanks to benefit the blue butterfly. The Urban Wildlands Group, a nonprofit organization "dedicated to the conservation of species, habitats, and ecological processes in urban and urbanizing areas", conducts the captive breeding program. This program is a collaboration with
Moorpark College Moorpark College is a public community college in Moorpark, California. It was established in 1967 with enrollment of 2,500 students and enrolled 14,254 students in 2014. An Exotic Animal Training and Management center houses over 200 animals o ...
and is directed by Moorpark College professor Dr. Jana Johnson. Since that time, the
Defense Logistics Agency The Defense Logistics Agency (DLA) is a combat support agency in the United States Department of Defense (DoD), with more than 26,000 civilian and military personnel throughout the world. Located in 48 states and 28 countries, DLA provides su ...
, which operates the facility, has funded habitat restoration and a breeding program for the blue butterfly. Honey, produced on the premises, is provided to the captive rearing program so the butterflies are able to feed on the same food source as its wild companions. Major Jason Pike, an entomologist for the Defense Logistics Agency who has been monitoring the project, commented, "The military takes its responsibilities for endangered species on its properties very seriously, and DLA is pleased to provide support for the blue butterfly project."


Mass rearing

Mass rearing of the Palos Verdes blue has been taking place since rediscovery in 1994. The mass rearing is conducted for conservation purposes, reintroduction and prevention of extinction. The mass rearing takes place in "tent" cages containing both known larval food plants. It has been variably successful. In 2008, 2,400 butterflies were raised in a laboratory at
Moorpark College Moorpark College is a public community college in Moorpark, California. It was established in 1967 with enrollment of 2,500 students and enrolled 14,254 students in 2014. An Exotic Animal Training and Management center houses over 200 animals o ...
. In addition to accepting the conditions of the butterflies' protected status, landowners seeking to house the butterflies needed to prove they could provide sufficient numbers of " yellow-flowering deer weed plants."


Modeling

Although population viability analysis models are often very important for predicting the outcome of conservation efforts, there have been many problems with using population viability analysis models to predict Palos Verdes blue populations. This type of modeling has proved inconclusive mainly because the Palos Verdes blue utilizes habitat so variably, depending on climatic and successional changes. So far, the appropriate habitat has been hard to find, and expert intuition has often been wrong. Long-term population studies are not available to provide this information because of the many local extinctions and declining numbers of this subspecies. For this reason, the subspecies long-term viability is very difficult to predict.


Key conservationists

Current conservation efforts are supported by the
Defense Logistics Agency The Defense Logistics Agency (DLA) is a combat support agency in the United States Department of Defense (DoD), with more than 26,000 civilian and military personnel throughout the world. Located in 48 states and 28 countries, DLA provides su ...
and the
U.S. Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage o ...
and implemented by the Palos Verdes Peninsula Land Conservancy, The Urban Wildlands Group, and The Butterfly Project led by biologist Jana J. Johnson at Moorpark College. The Youth Environmental Service program of the Palos Verdes / South Bay
Audubon Society The National Audubon Society (Audubon; ) is an American non-profit environmental organization dedicated to conservation of birds and their habitats. Located in the United States and incorporated in 1905, Audubon is one of the oldest of such orga ...
and other volunteer groups have provided help weeding and establishing habitat for the butterfly. The Youth Environmental Service (YES) program started in 2012 and focuses on conserving the Linden H. Chandler Preserve, where they work on restoring native plants for the Palos Verdes blue butterfly.


See also

* El Segundo blue


References


External links


Technical Reports
Urban Wildlands Group
NatureServe
{{Taxonbar, from=Q3305730 Glaucopsyche Endemic fauna of California Fauna of the California chaparral and woodlands Natural history of Los Angeles County, California Butterflies of North America ESA endangered species Butterfly subspecies