Heterocrossa gonosemana

Heterocrossa gonosemana is a species of moth in the family Carposinidae. It is endemic to New Zealand and is found throughout the country. It inhabits native forest. Larvae feed on seeds and fruit of Griselinia lucida and possibly Griselinia littoralis. They can be extremely active when disturbed. This species overwinters as a pupa, enclosed in a cocoon, underneath its host plant. Adults are on the wing from November until February and can be found during the day resting on lichen covered tree trunks where they are well camouflaged. The adult is nocturnal and is attracted to light.

Taxonomy

H. gonosemana was first described by Edward Meyrick in 1882 using material he collected in Dunedin in February. In 1922 Meyrick classified Heterocrossa as a synonym of the genus Carposina. George Hudson, following Meyrick, discussed and illustrated this species under the name Carposina gonosemana in his 1928 publication The Butterflies and Moths of New Zealand. However John S. Dugdale doubted whether the illustration by Hudson of H. gonosemana was based on a specimen of that species. Also in 1928 Alfred Philpott examined the genitalia of male specimens of what were then known as C. gonoseana and C. epomiana and, as a result of that examination and after a discussion with Meyrick, resurrected C. epomiana as a distinct species. In 1978 Elwood Zimmerman argued that the genus Heterocrassa should not be a synonym of Carposina as the genitalia of the species within the genus Heterocrassa are distinctive. In 1988 Dugdale assigned this species back to the genus Heterocrossa. The male lectotype specimen is held at the Natural History Museum, London.

Description

Hudson described the larva of H. gonosemana as follows:
Hudson described the pupa as follows:
The pupa is 8mm in length and is greenish-white in colour. Its abdominal segments are short while the leg and wing cases are unusually large. The cocoon in which the pupa is enclosed is oval in shape and approximately 12mm in length.

Meyrick described the adult of this species as follows:
Adults are visually very similar to H. epomiana and to H. philpotti. Adults moths of H. ''gonosemana'' are variable in appearance and tend to be of a darker shade in the more southern parts of New Zealand in comparison to the northern localities.

Distribution

H. gonosemana is endemic to New Zealand. It is found throughout the country and has been collected at locations such as Wellington, Nelson, Ōtira River, Dunedin, Lake Wakatipu, Invercargill, Stewart Island, and Auckland Island.

Biology and behaviour

The larva is very active when it is disturbed. This species spends the winter as a pupa. The pupa is enclosed in a cocoon that can be found in the soil beneath the larvae host. The adult moth emerges in December when bred in captivity. In the wild, adults of H. gonosemana are on the wing from November until February. They can be found during the day resting on tree trucks where they blend well with lichen patches. The adult moth is nocturnal and attracted to light.

Habitat and host species

This species inhabits native forest. The larvae have been recorded feeding on seeds and fruit of Griselinia lucida. It is possible the larvae also feed on the fruit of Griselinia littoralis.