Gadira acerella

This species was first described by Francis Walker in 1866 using specimens collected in Nelson by T. R. Oxley.[3][2] In 1875, thinking they were describing a new species, Cajetan von Felder and Alois Friedrich Rogenhofer named this species Botys mahanga.[4][2] This name was synonymised by Edward Meyrick in 1883.[5][2] In 1928 George Hudson discussed and illustrated this species in his book The butterflies and moths of New Zealand.[6] D. E. Gaskin, in 1973, discussed this synonym but incorrectly spelt the epithet as mehanga.[2] The male holotype is held at the Natural History Museum, London.[2]

Illustration by George Hudson.

Walker described the female of the species as follows:

Female. Aeneous-brown, whitish beneath. Head whitish. Thorax with a whitish stripe. Abdomen and hind wings aeneous-cinereous. Fore wings with whitish veins and with two whitish oblique lines, which diverge from each other near the interior border ; a transversely elongated black spot including a little longitudinal white streak; two exterior outward-curved white lines, of which the inner one is broader than the other; a few black streaks and speckles; fringe white. Hind wings aeneous-cinereous, with a white aeneous-bordered subinarginal line. Length of the body 3 lines; of the wings 9 lines.[3]

This species is distinctively patterned and coloured.[6]

This species is endemic to New Zealand and is found throughout the country.[7][8] It is regarded as being fairly common.[8]

This species inhabits native forest and can be found at altitudes from sea level up to subalpine.[8] The larvae of this species are assumed to feed on lichen or mosses.[9][8] Larvae have been observed on lichen covered rocks.[10]

Observation of living Gadira acerella.

The life history of this species is currently unknown.[8] Adults are on the wing from October until March.[8][11] They are active at night and are attracted to light.[8] This species rests with its wings together over its body in a steep V shape.[8] The adults of the species have frequently been observed resting on lichen covered rocks and fences.[6] Hudson was of the opinion that the raised scales and colouring on the forewing caused an at rest adult to resemble a bird dropping.[6] It has also been suggested the raised scales and colouring on the forewing are disruptive and ensures the adult moth blends in with lichens upon which the moth prefers to rest.[8]