The glasswinged butterfly (Greta oto), is rare and little-known in Cuba. However, a local species, the Greta cubana, can be found in the country's central and eastern mountains, particularly the Guamuhaya —also known as the Sierra del Escambray— in Sancti Spíritus province.
According to researcher Luis Olmo, the Greta cubana, which is also referred to as the Cuban Clearwing, is distinguished by its beautiful translucent wings, which make it the only diurnal butterfly of its kind on the island.
In recent field studies, the Cuban Clearwing was spotted in the Pico Potrerillo hills, about 900 meters above sea level, said Olmo, who is part of the Cuban Speleological Association's Grupo Samá.
The Samá group first encountered the Clearwing in 1995 in the Sierra del Escambray, which spans Sancti Spíritus, Cienfuegos and Villa Clara provinces. Specifically, it was detected in a karstic pit known as Caja de Agua in Alturas de Banao, south of the city of Sancti Spíritus and about 365 kilometres east of Havana.
According to previous research, the butterfly had been known to inhabit forests in areas such as Hoyo de las Mariposas, Hoyo de los Pitos, and Caballete de Casas, in shady, humid forests that were 500 to 700 meters above sea level.
Olmo says the Greta Cubana's beautiful translucent wings, which act as a natural defence mechanism against predators, also make it hard to spot. It has a wingspan of 5.5 to 6 centimetres and the opaque borders of its wings are dark brown, sometimes tinted with red or orange, and it has a dark-coloured body.
Some researchers believe that glasswinged butterflies from the central Cuban mountains are smaller than those from the country's east.
Cuba has some 177 species of diurnal butterflies, 28 of which are endemic and largely found in forests. Its nocturnal butterflies are much more diverse, but it is a little-studied group of species that is estimated to number in the hundreds.