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Miami Blue Hemiargus thomasi


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Family: Lycaenidae, Gossamer-wing Butterflies view all from this family

Description The Miami blue (Cyclargus thomasi bethunebakeri) is a small butterfly that is native to coastal areas of southern Florida.

Miami blue adults are short lived in the wild; females may live five days, males about two days. Adults typically stay within thirty feet of their birthplace. Miami blues were known to lay their eggs exclusively on balloon vine (Cardiospermum corindum), but the last known wild population uses grey nicker bean (Caesalpinia bonduc).

The Miami blue was described in 1943 based on specimens found near Miami. In the mid-twentieth century the Miami blue was common throughout a range that ran from Daytona Beach south around the tip of the peninsula and up to the Tampa Bay area, and throughout the Florida Keys to the Dry Tortugas. Its habitat includes the edges of tropical hardwood hammocks, scrub, and pine rocklands. The Miami blue is the only subspecies of Cyclargus thomasi found in the United States.

Dimensions 3/4-1 1/8" (19-28 mm).

Habitat Forests & woodlands, Shorelines & salt marshes.

Range Florida.

Discussion Once very common throughout its range, it has become critically endangered, and may be the rarest insect in the United States. Its numbers have recently been increased by a captive breeding program at the Florida Museum of Natural History.

The range of the Miami blue was reduced in the second half of the twentieth century due to the loss of habitat to urban development. It had disappeared from the mainland of Florida and from the barrier islands along the peninsula by 1990. It had become confined to a few spots in the Florida Keys and was becoming rare there. Hurricane Andrew appeared to have wiped out the species in 1992. Searches were made, but no Miami blues were found.

In 1999 some Miami blues were spotted in Bahia Honda State Park. It was estimated that fewer than fifty of the butterflies were left. Acting on a request from the North American Butterfly Association, the Florida Fish and Wildlife Conservation Commission 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 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. However, the 2005 Atlantic hurricane season caused damage to all of the release sites as well as at Bahia Honda. The Bahia Honda colony has recovered, and the University continues its breeding and wild release program.

In November and December 2006, more colonies were discovered on other islands in the Florida Keys.

In August 2011, the United States Fish and Wildlife Service used an emergency measure that gives the species 240 days of temporary federal protection while they go through the formal process of placing it on the federal list of endangered species.