Ichneutica ustistriga

This species was described by Francis Walker in 1857 using a specimen obtained from William Colenso.[4] The female lectotype is held at the Natural History Museum, London.[2] In 1988 J. S. Dugdale placed this species within the Graphania genus.[2] In 2019 Robert Hoare undertook a major review of New Zealand Noctuidae.[3] During this review the genus Ichneutica was greatly expanded and the genus Graphania was subsumed into that genus as a synonym.[3] As a result of this review, this species is now known as Ichneutica ustistriga.[3]

Observation of Ichneutica ustistriga.

George Hudson describes the egg of this species as follows:

The egg is semi-globose, pale green, with numerous branching ribs radiating from the micropyle and faint transverse ribs between them.[5]

Hudson described the larva of this species as follows:

The larva is dull greyish-brown with blackish subdorsal and lateral lines; there is a series of pale spots below the subdorsal line, and an obscure whitish streak below the lateral line.[5]

Walker originally described the adults of this species as follows:

Cinereous, tinged with brown. Abdomen pale cinereous, reddish ferruginous at the tip. Fore wings with three very irregular black discal ringlets, with a very incomplete ferruginous-brown band near the exterior border, with a distinct ferruginous brown streak near the interior angle, and with ferruginous marks along the costa ; ciliae ferruginous. Hind wings brownish. Length of the body 7 — 8 lines ; of the wings 16 — 18 lines.[4]

The adult male of this species has a wingspan of between 36 and 46 mm where as the female has a wingspan of between 38 and 53 mm.[3] This moth has a mauvish grey wing colour and is unlikely to be confused with other species as the patterns on its forewing are distinctive.[3]

It is endemic to New Zealand and can be found from the Three Kings Islands to Stewart Island.[6][3]

This species lives in a wide variety of habitats including domestic gardens, horticultural areas, orchards, native and exotic grasslands, as well as native forest.[3]

This species is on the wing throughout the year and is attracted to both sugar and light traps.[3][5] Adult moths can be found at rest on fences and tree trunks during the day.[5]

Muehlenbeckia complexa, a larval host species of I. ustistriga

The larvae eat a variety of herbaceous plants.[3] Recorded food plants include Muehlenbeckia australis, Muehlenbeckia complexa, Olearia hectorii, and Plantago lanceolata.[7]

A recent study suggests this moth may be assisting with the pollination of avocado trees.[8]