The Miami blue (''Cyclargus thomasi bethunebakeri'') is a small

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 native to coastal areas of southern

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

. 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 Thomas's blue. Once common throughout its range, it has become critically endangered, and is considered to be near

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 ...

. Its numbers have recently been increased by a

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 ...

program at the

Florida Museum of Natural History The Florida Museum of Natural History (FLMNH) is Florida's official state-sponsored and chartered natural-history museum. Its main facilities are located at 3215 Hull Road on the campus of the University of Florida in Gainesville. The main pub ...

Taxonomy

The Miami blue has had several synonyms. It was first identified in 1886 as a Florida population (south from the Indian River) of the Cuban butterfly ''Lycaemon ammon''. In 1915 G. T. Bethune-Baker observed that the Florida population of the butterfly then known as ''Hemiargus ammon'' was distinct from the Cuban population. The presence of ''Plebeius ammon'' in the

Dry Tortugas Dry Tortugas National Park is a national park located about west of Key West in the Gulf of Mexico. The park preserves Fort Jefferson and the seven Dry Tortugas islands, the westernmost and most isolated of the Florida Keys. The archipelago's c ...

was reported in 1941. The Florida population was assigned a sub-specific status in 1943 as ''Hemiargus ammon bethune-bakeri'', and the species was reassigned to ''Cyclargus thomasi'' in 1945, leaving the Miami blue as ''Cyclargus thomasi bethunebakeri''.

Description

The Miami blue has a wingspan of . The upper side of the wings is bright metallic blue in males, and dark gray with some blue towards the base of the wings in females. The underside of the wings in both sexes is gray with a white band on the hind wing and four black spots. Larvae vary in color from light green to purple. The pupae may be black or green.

Biology

Females may lay 300 eggs. Females lay one egg at a time, but more than one egg may be laid on a

host plant In biology and medicine, a host is a larger organism that harbours a smaller organism; whether a parasitic, a mutualistic, or a commensalist ''guest'' ( symbiont). The guest is typically provided with nourishment and shelter. Examples include ...

. During most of the year adults emerge from a pupa about 30 days after the egg was laid. Adults have been observed year round, with overlapping multiple generations from May to November, and a winter generation from December to April, with adults and pupae 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 It ...

. Prior to the 1970s, Miami blues were reported to use grey nickerbeans (''

Caesalpinia bonduc ''Guilandina bonduc'', commonly known as grey nicker, nicker bean,Pithecellobium ''Pithecellobium'' is a genus of flowering plants in the family Fabaceae. The generic name is derived from the Greek words πίθηκος (''pithêkos''), meaning "ape" or "monkey," and ἐλλόβιον (''ellobion''), meaning "earring," which r ...

'' species) as host plants. Beginning in the 1970s balloonvines were widely reported as hosts for Miami blues, including the native ''

Cardiospermum ''Cardiospermum'' is a genus of approximately 14 species in the soapberry family, Sapindaceae, which are native to the American, Indian, and African tropics. The genus name is derived from the Greek words καρδία, meaning "heart," and σπ� ...

corindum'' and the introduced ''

Cardiospermum halicacabum ''Cardiospermum halicacabum'', known as the lesser balloon vine, balloon plant or love in a puff, is a climbing plant widely distributed across tropical and subtropical areas of Africa, Australia, and North America that is often found as a weed a ...

''. Recently discovered populations in the Key West National Wildlife Refuge use the Florida Keys blackbead (''Pithecellobium keyense'') as the preferred host plant. Other plants reported as being used by Miami blues are peacock flower (''

Caesalpinia pulcherrima ''Caesalpinia pulcherrima'' is a species of flowering plant in the pea family Fabaceae, native to the tropics and subtropics of the Americas. It could be native to the Caribbean, West Indies, but its exact origin is unknown due to widespread cult ...

''), snowberry (''

Symphoricarpos ''Symphoricarpos'', commonly known as the snowberry, waxberry, or ghostberry, is a small genus of about 15 species of deciduous shrubs in the honeysuckle family, Caprifoliaceae. With the exception of the Chinese coralberry, '' S. sinensis'', wh ...

''), and cat's-paw blackbead (''Pithecellobium unguis-cati''). Mainland populations of Miami blues laid their eggs on balloon vine (''

'' species). Populations in the lower Florida Keys laid eggs on grey nicker bean (''

'' species). Rainfall in the Florida Keys may be an important factor in explaining the decline of the Miami blue.

Range

Before the late 20th century, the range of the Miami blue ran from

Daytona Beach Daytona Beach, or simply Daytona, is a coastal resort-city in east-central Florida. Located on the eastern edge of Volusia County near the Atlantic coastline, its population was 72,647 at the 2020 census. Daytona Beach is approximately nort ...

south around the tip of the peninsula and up to the

Tampa Bay Tampa Bay is a large natural harbor and shallow estuary connected to the Gulf of Mexico on the west-central coast of Florida, comprising Hillsborough Bay, McKay Bay, Old Tampa Bay, Middle Tampa Bay, and Lower Tampa Bay. The largest freshwater in ...

area, and throughout the

Florida Keys The Florida Keys are a coral cay archipelago located off the southern coast of Florida, forming the southernmost part of the continental United States. They begin at the southeastern coast of the Florida peninsula, about south of Miami, and e ...

to the

. Its habitat includes the edges of tropical hardwood hammocks, scrub, and

pine rocklands The South Florida rocklands ecoregion, in the tropical and subtropical moist broadleaf forests biome, occurs in southern Florida and the Florida Keys in the United States, where they would naturally cover an area of . These forests form on lim ...

. The Miami blue is the only subspecies of '' Cyclargus thomasi'' found in the United States. The Miami blue butterfly has been reported from

Bimini Bimini is the westernmost district of the Bahamas and comprises a chain of islands located about due east of Miami. Bimini is the closest point in the Bahamas to the mainland United States and approximately west-northwest of Nassau. The populat ...

, and as a stray in other parts of

The Bahamas The Bahamas (), officially the Commonwealth of The Bahamas, is an island country within the Lucayan Archipelago of the West Indies in the Atlantic Ocean, North Atlantic. It takes up 97% of the Lucayan Archipelago's land area and is home to ...

. The range of the Miami blue was reduced in the second half of the twentieth century due to the

loss of habitat 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 ...

to urban development. The decades of fragmentation have created substantial forest edge areas along roadsides that may place insects like the Miami blue at risk. It had disappeared from the mainland of Florida and from the

barrier island Barrier islands are coastal landforms and a type of Dune, dune system that are exceptionally flat or lumpy areas of sand that form by wave and tidal action parallel to the mainland coast. They usually occur in chains, consisting of anything fro ...

s along the peninsula by 1990. It had become confined to a few spots in the

and was becoming rare there.

Hurricane Andrew Hurricane Andrew was a very powerful and destructive Category 5 Atlantic hurricane that struck the Bahamas, Florida, and Louisiana in August 1992. It is the most destructive hurricane to ever hit Florida in terms of structures damaged ...

appeared to have wiped out the subspecies in 1992. Miami blues have limited home ranges. Adults recaptured after having previously being trapped were seldom found more than 25 feet away from the initial trapping location.

Sightings and breeding programs

In 1999 some Miami blues were spotted in

Bahia Honda State Park Bahia Honda (meaning ''deep bay'', in Spanish, locally pronounced: BAY-ah HON-da , also pronounced : Bah-EE-ah OWN-dah ) is an island in the lower Florida Keys. U.S. 1 (the Overseas Highway) crosses the key at approximately mile markers 36-3 ...

. It was estimated that fewer than fifty of the butterflies were left. Acting on a request from the

North American Butterfly Association The North American Butterfly Association (NABA) was created in 1992 by Jeffrey Glassberg who is the association's president. The NABA was formed in order to promote awareness of butterfly conservation and the benefits of butterfly gardening, obser ...

, the

Florida Fish and Wildlife Conservation Commission The Florida Fish and Wildlife Conservation Commission (FWC) is a Florida government agency founded in 1999 and headquartered in Tallahassee. It manages and regulates the state's fish and wildlife resources, and enforces related laws. Officers ar ...

temporarily listed the Miami blue as endangered on an emergency basis in 2002. The 'endangered' listing was made permanent in 2003. In the meantime, searches had found no other colonies of the Miami blue. In 2003 the Entomology and Nematology Department at the

University of Florida The University of Florida (Florida or UF) is a public land-grant research university in Gainesville, Florida. It is a senior member of the State University System of Florida, traces its origins to 1853, and has operated continuously on its ...

began raising and breeding Miami blues, starting from about 100 eggs collected in the wild. In 2004 they released 2,500 of the insects at selected locations. In August and September 2006 hundreds of captive-bred caterpillars and adult Miami blues were released on

Elliott Key Elliott Key is the northernmost of the true Florida Keys (those 'keys' which are ancient coral reefs lifted above the present sea level), and the largest key north of Key Largo. It is located entirely within Biscayne National Park, in Miami-Dade ...

Biscayne National Park Biscayne National Park is an American national park located south of Miami, Florida in Miami-Dade County, Florida, Miami-Dade County. The park preserves Biscayne Bay and its offshore barrier reefs. Ninety-five percent of the park is water, and t ...

. Miami blues have been reintroduced to

Everglades National Park Everglades National Park is an American national park that protects the southern twenty percent of the original Everglades in Florida. The park is the largest tropical wilderness in the United States and the largest wilderness of any kind east ...

and Dagny Johnson Key Largo Hammock Botanical State Park, but all of the attempts prior to May 2009 have failed . In November and December 2006, more colonies were discovered on

Boca Grande Key Boca Grande Key is an island in the Florida Keys in Monroe County, Florida, United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in N ...

and the

Marquesas Keys The Marquesas Keys form an uninhabited island group about west of Key West, in diameter, and largely covered by mangrove forest. They are an unincorporated area of Monroe County, Florida and belong to the Lower Keys Census County Division. ...

in the Key West National Wildlife Refuge. The population on Bahia Honda died out in 2010, and conservation efforts were then focused on the colonies in the Key West National Wildlife Refuge. Another colony of breeding Miami blue butterflies was discovered in the

Great White Heron National Wildlife Refuge The Great White Heron National Wildlife Refuge is part of the United States National Wildlife Refuge System, located in a region known as the 'Backcountry', which reaches from north of Marathon, Florida, Marathon to north of Key West, Florida, Ke ...

in 2016. The Miami blue butterfly is listed as an Endangered species by the state of Florida and the federal government. It is listed as a ''Critically Imperiled'' subspecies by

NatureServe NatureServe, Inc. is a non-profit organization based in Arlington County, Virginia, US, that provides proprietary wildlife conservation-related data, tools, and services to private and government clients, partner organizations, and the public. Nat ...

Citations

References

*Daniels, Jaret C. and Stephanie J. Sanchez. 2006. Naturalists at Large: Blue's Revival. ''Natural History''. 115:6. October, 2006. pp. 26–28, 75. * *
Miami Blue Butterfly
URL retrieved October 11, 2006 * * *Cannon, P. 2007. Rarest of the very rare: local photographer finds colonies of Miami blue butterflies. Keys Sunday, January 7 issue. pp. 16–18. * Carroll, & Loye, J. (2006). Invasion, Colonization, and Disturbance; Historical Ecology of the Endangered Miami Blue Butterfly. Journal of Insect Conservation, 10(1), 13–27. https://doi.org/10.1007/s10841-005-8315-z

External links

- Includes photos of Miami blues.
NABA Chapter: Miami Dade County
{{Taxonbar, from=Q5487594 Cyclargus Butterflies described in 1943 Critically endangered fauna of the United States Fauna of the Southeastern United States ESA endangered species Endemic fauna of Florida Butterfly subspecies