Assessment Rationale:

This rare species is restricted to three locations at intermediate and high elevations and is primarily associated with endemic plant species. The recorded host plants are: the dead wood of unidentified endemic 'Cabbage Trees' of the family Asteracea - 9.5% of specimens; from endemic Nesohedyotis arborea (Roxb.) Bremek. - 89.5% of specimens; and from the dead wood of Ulex europaea L. - 1% of specimens. The species is known from three locations where habitat decline is ongoing; at one location in particular (Osborne's) the current decline in habitat quality is serious as the remaining old trees have all died and there will be no replacement dead wood generation for a considerable period. It has an extent of occurrence (EOO) and area of occupancy (AOO) both of 8 km² and the population is considered severely fragmented. Therefore, this species is assessed as Critically Endangered.

Geographic Range:

This species is endemic to the island of St Helena, in the South Atlantic Ocean, where it is restricted to intermediate and upper elevations

Population:

The species is known from three locations (Basilewsky 1972, Mendel, Ashmole and Ashmole 2008). At the Osbornes She Cabbage (Lachanodes arborea (Roxb.) B.Nord.) site the last wild trees have recently died and, while young trees have been planted, there are no plants that will be generating replacement dead wood for a considerable time. The habitat for this species will therefore be declining rapidly at this site. While still present at its other two locations there is ongoing habitat deterioration as a result of invasive non-native plants, such as New Zealand flax (Phormium tenax J.R. Forst. & G. Forst.) and increasing pressure from non-native predatory species (e.g. Formicidae)

Habitat and Ecology

Larvae of this species feed on dead wood and adults probably on rotting detritus and fungi present in the habitat. The majority of records are from the wood of Black Cabbage Tree (Melanodendron integrifolium (Roxb.) DC.) and Dogwood (Nesohedyotis arborea (Roxb.) Bremek.). The species has also been found in dead Gorse (Ulex europaeus L.) at High Peak, although likely to be in the same vicinity to the two endemic tree species. At Osborne's the species was present on She Cabbage (Lachanodes arborea (Roxb.) B.Nord.).

Major Threat(s):

There has been a general decline in habitat quality and an increase in the number of invasive non-native predators (e.g. Formicidae). Global warming is also a potential threat to habitat quality.

Conservation Actions

Any research and monitoring of this species would be of value. Of critical importance is the continued expansion and linking of habitat fragments as well as removal of invasive non-native species where this is possible.