The Cayman Islands is home to a number of plants and animals found nowhere else on Earth, and among them is a butterfly that, due to its very limited habitat, can be found only in a few pockets of Grand Cayman and was discovered in North Side.
The Cayman Islands Department of Environment states there are 57 species of butterflies recorded in the Cayman Islands: 52 from Grand Cayman, 31 from Little Cayman and 34 for Cayman Brac.
According to the DOE, the Cayman Islands hosts five endemic subspecies of butterflies:
Cayman brown leaf butterfly (Memphis verticordia danielana), found in Grand Cayman and Little Cayman
Cayman pygmy blue (Brephidium exilis thompsoni), found in Grand Cayman
Cayman Lucas’s blue (Hemiargus ammon erembis), found in Grand Cayman
Cayman Julia (Flambeau Dryas iulia zoe), found in all three islands, and
Cayman swallowtail (Heraclides andraemon taylori), found in Grand Cayman only.
According to the DOE, the Cayman pygmy blue is one of the smallest butterflies in the world.
“Its salt marsh habitat is rapidly being lost to development, making this endemic subspecies of special conservation concern,” states the DOE website.
DOE literature notes that the pygmy blue is highly dependent on salt-tolerant succulents for all stages of its life cycle. In its larval form, the caterpillars feed on Salicornia perennis, known in Cayman as glasswort, a succulent flowering plant that grows in mangroves. Today, the plants are found in Barkers and in Midland Acres, and, as the Compass reported in January, the caterpillars have recently been spotted at a rocky outcrop at Meagre Bay pond in Bodden Town. Adults depend on the nectar of Sesuvium portulacastrum (commonly known as shoreline purslane or sea pulsey) a shoreline perennial succulent with pink and purple flowers.
As previously reported in the Compass, the butterfly was named after Gerald Thompson, one of the young Oxford University students who discovered it in 1938 on the Oxford Expedition to the Cayman Islands. The little butterflies were recorded in what was once known as English Sound, a lagoon off the North Sound in the Rum Point area of North Side named after T. M. Savage English, a naturalist who resided in North Side from 1912-1914.
In 2008, Tom Watling of Cayman Kayaks, along with Jessica Coni and James Macfee, went on another foray to seek out glasswort and sea pulsey plants via kayak at the same spot, and found not only the plants, but four Pygmy Blues as well.
The DOE notes that since the butterflies depend on salt-tolerant succulents for all stages of its life cycle, and such plant habitats being highly fragmented in the Cayman Islands, the pygmy blues’ habitable areas are generally small and can even constitute only a few square meters.
In terms of providing habitat for these very rare butterflies, the DOE notes that artificially created salt-tolerant succulent habitats will likely attract the butterflies and establish them over time.
“This makes salt-tolerant succulents potentially attractive candidates for artificial creation, and restoration projects,” the literature notes.
“[However] water regime is critical to the functioning of salt-tolerant succulent habitat. Elevation or reduction in water level is likely to result in a change in vegetation, and the loss of typifying species, such as Salicornia perennis and Sesuvium portulacastrum.”