Mystery moth moves in to Bermuda
A new moth has set up home in Bermuda – although how the species arrived is a mystery.
The “exceptionally large” fig sphinx moth was first recorded in Bermuda in October 2017 and their numbers have risen since then.
Claire Jessey, an entomologist with the Department of Environment and Natural Resources, said in the winter Envirotalk Newsletter that the moths had now established themselves on the island.
Ms Jessey added: “The natural range of fig sphinx moths is throughout Central and South America, the West Indies, Florida and Texas.
“These large moths are considered to be long distance migrants and strong flyers.
“It is possible that storm winds may have blown several of these moths – or possibly just one pregnant female – off course and they managed to survive the long journey, as unusual as that seems.”
She said when the first fig sphinx moth was brought to the Department in 2017 it was believed to be a one-off.
Ms Jessey added: “This moth was not previously recorded in Bermuda and so its unexpected presence was duly noted as a random and unexplained occurrence – possibly as a sole migrant blown off course – and documented for the natural history records with no expectation of seeing another.
“However, over the next several months, specimens of the same moth were reported periodically from several locations island wide.
“About every four or five months another adult moth would be submitted for identification.”
She said the DENR was sent pictures of the moth’s caterpillar form months later.
Ms Jessey added the caterpillars were discovered to be feeding on Indian laurel plants, which are common in Bermuda.
She said: “This final piece of evidence confirmed that fig sphinx moth was a new resident of the island, capable of surviving on Indian laurel host plants, of which Bermuda has plenty, and presumably breeding and producing the multiple generations seen over the preceding months.”
She added the fig sphinx moths – pachylia ficus – was a member of the sphingidae family which includes some of the largest moths in the world.
Ms Jessey said: “The caterpillars are large and have several different colour forms- called morphs – and are often well camouflaged in the foliage in which they feed.
“They often pose as motionless stems or twigs during the day, becoming active at night and feeding voraciously on the leaves of their host plants.
“The young caterpillar is often uniformly bright green, turning mottled brown, beige and white as it develops, and changing to a striking teal and orange colour combination just prior to pupation into the adult moth.”
She added the caterpillars form cocoons in the leaf litter close to their host plant and emerge after 22 days as a moth with a wingspan of up to 5½ inches and a mottled olive green and drab brown colour.
The moths fly at dusk and consume nectar from flowers and are often attracted to artificial lights.
Ms Jessey said large moths and butterflies had reached the island before, but they rarely established a lasting population.
She added: “Just as migratory birds can make their way to our small island, so too can these larger moths. Occasional visitors have included the black witch moth and the death’s-head hawk moth.
“Mimic butterflies, painted ladies and red admirals, although smaller, are just some of the butterflies that have survived the long flight to Bermuda to grace us with their presence.
“Unlike many of the visiting moths and butterflies, the fig sphinx moth has decided to take up residence with us.”