Ichneutica steropastis

Ichneutica steropastis
	Female
	Male
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Lepidoptera
Superfamily:	Noctuoidea
Family:	Noctuidae
Genus:	Ichneutica
Species:	I. steropastis
Binomial name
	Ichneutica steropastis; (Meyrick, 1887)
Synonyms
	Mamestra steropastisMeyrick, 1887 ; Persectania steropastis(Meyrick, 1887) ; Tmetolophota steropastis(Meyrick, 1887) ;

Last updated November 23, 2023

Ichneutica steropastis, or the flax notcher moth, is a species of moth in the family Noctuidae.^[1] It is endemic to New Zealand and can be found throughout the country from the Three Kings Islands to Stewart Island as well as in the Chatham Islands. The larvae of this species feed on a variety of native and introduced plants however the New Zealand flax is one of the more well known host plants for the larvae of this moth. The larvae are nocturnal, hiding away in the base of the plants and coming out to feed at night. They create a distinctive notch in the leaf when they feed. The adults of this species are on the wing from October to March. Although adult specimens of I. steropastis are relatively easy to recognise they might possibly be confused with I. inscripta , I. theobroma or with darker forms of I. arotis. However I. steropastis can be distinguished as it has a long dark basal forewing streak that these three species lack.

Taxonomy

This species was first described by Edward Meyrick in 1887 as Mamestra steropastis using specimens collected in Napier, Blenheim and Christchurch by R.W. Fereday.^[3]^[2] In 1988 J. S. Dugdale placed this species within the Tmetolophota genus.^[2] In 2019 Robert Hoare undertook a major review of New Zealand Noctuidae.^[4] During this review the genus Ichneutica was greatly expanded and the genus Tmetolophota was subsumed into that genus as a synonym.^[4] As a result of this review, this species is now known as Ichneutica steropastis.^[4] The male lectotype specimen is held at the Natural History Museum, London.^[2]^[4]

Description

George Hudson described the larva of this species as follows:

About 1+1⁄2 inches in length, of almost uniform thickness, considerably flattened; the head is ochreous, the body very pale ochreous-brown; there are no distinct markings on the thoracic segments, except a few minute black dots round the middle of each; the rest of the body is covered with a number of very fine blackish lines, which become darker posteriorly, and are stronger on the dorsal and lateral regions; there is a row of minute black dots round the middle of each segment; the spiracles are black and the underside of the larva is faintly tinged with green.^[5]

The host plant is not a reliable guide to confirm the identification of this species as larvae of both I. arotis and I. blenheimensis also feed on similar hosts including flax species.^[4] The larvae of I. steropastis can be distinguished from I. arotis as there are differences in the placement of the P1 head capsule and the anal shield has a minute double mound between the D2 setae which is lacking in I. arotis.^[4]

Meyrick described the adults of this species as follows:

Male, female. — 40-43 mm. Head ochreous, mixed with whitish, and irregularly marked with dark reddish-fuscous. Palpi dark reddish-fuscous, mixed with whitish. Antennae fuscous, in male subdentate, rather shortly ciliated. Thorax with moderately large double anterior and small posterior crest ; reddish-fuscous, with a black posteriorly whitish-margined anterior line ; patagia with two black internally whitish-margined streaks on each. Abdomen grey, and tuft pale reddish-ochreous. Legs ochreous-whitish, mixed with reddish-fuscous. Forewings moderately dilated, costa hardly arched, apex obtuse, hindmargin crenulate, obliquely rounded ; reddish-fuscous ; veins dark fuscous, margined with whitish or ochreous-whitish ; a short black median streak from base ; a slender dark reddish-fuscous longitudinal streak in disc from above apex of this to 3⁄5 , posterior extremity somewhat dilated ; a minute white discal dot near beyond its extremity ; a very oblique short blackish streak from inner margin near base ; second line hardly indicated ; subterminal hardly traceable except by two very long whitish dentations touching hind-margin below middle : cilia reddish-fuscous, slenderly barred with whitish. Hindwings dark grey ; cilia white or ochreous-whitish, with a grey line.^[3]

The adult male of this species has a wingspan of between 32.5 and 45.5 mm and the female has a wingspan of between 33 and 45 mm.^[4] Although I. steropastis is relatively easily recognisable it might possibly be confused with I. inscripta, I. theobroma or with darker forms of I. arotis.^[4] However I. steropastis has long dark basal forewing streak that these other three species lack.^[4]

Distribution

I. steropastis is endemic to New Zealand.^[6] It is common and can be found throughout the country from the Three Kings Islands to Stewart Island as well as in the Chatham Islands.^[7]^[4]

Habitat and host plant

This species inhabits the edges of native bush as well as scrubland, wetlands and coastal dunes.^[7] The larvae of I. steropastis can exist on multiple host plant species. It is best known for consuming the leaves of the New Zealand flax,^[8] but other larval host plants include endemic species in the genus Austroderia as well as introduced species in the genus Cortaderia .^[4] In particular Austroderia fulvida , A. richardii and C. selloana are all recorded as larval host species of I. steropastis as is Poa foliosa .^[4] This species has also been reared from species in the genus Libertia .^[4] The host plant is not a reliable guide to confirm the identification of this species as larvae of both I. arotis and I. blenheimensis also feed on similar hosts including flax species.

Behaviour and life cycle

The larvae are nocturnal, hiding away in the base of their host plants and coming out to feed at night.^[5] The larvae possibly pupate in the soil below their host plant.^[7] The adults of this species are on the wing from September to April.^[7] The adult moth is also nocturnal but is attracted to light.^[7]

Interactions with humans

The larvae of this species is regarded as a pest as it chews distinctive notches in the sides of the flax leaves.^[8] This damage ensures the flax leaf cannot then be used for weaving.^[8]

Related Research Articles

Ichneutica lissoxyla is a moth of the family Noctuidae. It is endemic to New Zealand. It is found in the central and southern parts of the North Island and in most parts of the South Island. The species prefers snowgrass habitat in the alpine zone. I. lissoxyla is similar in appearance to I. paraxysta but can be distinguished as I. lissoxyla lack the black streaks on the forewings that can be found on the latter species and the male I. lissoxyla also has longer pectinations on antennae. The life history of this species is unknown as are the host species of its larvae. Adults are on the wing from January to April and are attracted to the light.

Ichneutica omoplaca is a moth of the family Noctuidae. It is endemic to New Zealand. It is widespread from the Bay of Plenty in the North Island down to Southland in the South Island. Specimens have also been collected from the Auckland Islands. It lives in a variety of habitats including beech forest clearings and tussock grasslands. This species has been recorded that some of the larval hosts of this species include Poa cita, Dactylis glomerata and it has been reared on Plantago lanceolata. The larva is undescribed but pupae have been found in a pine plantation in soil under weeds. Adults of this species are on the wing from October to March. The adult moths are variable in appearance but the diagnostic feature is the pale ochreous to white colouring between the basal streak and the costa which contrasts with the ground colour of the forewing.

Ichneutica pelanodes is a moth of the family Noctuidae. It is endemic to New Zealand and has been found in scattered locations in the North, South and Stewart Islands. I. pelanodes is easily confused with I. skelloni as the two species are visually extremely similar. In the North Island though the range of the two species appears not to overlap. Generally of the two species I. pelanodes tends to be darker in appearance. I. pelanodes inhabits wetlands but the life history of this species is unknown as are the host species of its larvae. Adults are on the wing from October to February and are attracted both to sugar and light traps.

Ichneutica scutata is a moth of the family Noctuidae. It is endemic to New Zealand. This species can be found in the southern parts of the North Island as well as the eastern parts of the South Island. It is similar in appearance to I. insignis and I. skelloni but can be distinguished as I. scutata is much paler in appearance. It is likely this species inhabits lowland tussock grasslands as well as coastal dunes although it is not common in inland tussock grasslands. The larvae feed on a variety of herbaceous plants such as Plantago and Convolvulus species, Plagianthus divaricatus. It pupates on soil near its host plants. The adults are on the wing from late March to July.

Ichneutica acontistis is a moth of the family Noctuidae. It is endemic to New Zealand and is found only in the South Island, mainly on the eastern side although not in the Nelson district. This species is similar in appearance to I. paraxysta,I. stulta and I. toroneura. I. acontistis is unlikely to be confused with I. paraxysta as the later is only found in the North Island. I. acontistis can be distinguished from I. stulta as the latter species has a strongly curved forewing edge where as I. acontistis' is straight. I. acontistis can be distinguished from I. toroneura as the former has a dark stroke of colour starting from the base of the forewing that I. toroneura lacks. I. acontistis inhabits tussock grasslands and the larvae of this species feed on species of grass found in the genera Poa, Elymus and Rytidosperma. It pupates under rocks and adults are on the wing from September to January. I. acontistis are attracted to light.

Ichneutica arotis is a moth of the family Noctuidae. It is endemic to New Zealand. This species is found throughout the North and South Islands but has yet to be recorded on Stewart Island. I. arotis is variable in appearance and have been described as having a "northern dark form", a "typical" form and a "swamp" form. Robert Hoare hypothesised that this species may be in the process of evolving into several distinct species. However, as these forms show no difference in antennae or genitalia so, as at 2019, they are not regarded as separate species. Larval hosts include species in the genera Cortaderia and Schoenus as well as Phormium tenax. The caterpillar feeds at night and rests in during the day amongst dead flax leaves. It pupates in a loose cocoon either hidden at the base of a stem of flax or on the ground. The adults of this species is on the wing from September to April. In the North Island there have also been records of adults being on the wing in June to August.

Ichneutica alopa is a moth of the family Noctuidae. It is endemic to New Zealand and is found in the central and southern parts of the North Island as well as in the South Island. It inhabits tussock grasslands and wetlands and can occur at ranges from the alpine zone down to almost sea-level. The life history of this species is unknown as are the host species of its larvae in the wild. Larvae of this species have been raised in captivity on Sphagnum moss as well as on species in the genus Raoulia. Adults of this species are on the wing from late January to April and are attracted to light and to sugar traps. I. alope can be confused with I. agorastis, I. micrastra or I. sapiens but the latter three species can be distinguished externally from I. alope through differences in size, forewing pattern and the antennae of the male of the species.

Ichneutica blenheimensis is a species of moth in the family Noctuidae. It is endemic to New Zealand and is found throughout the North, South and the Stewart Islands. This species appears to prefer drier eastern localities and is rarely collected in western North Island forested areas. It does not appear to be frequently collected in inland dry tussock grassland habitats. The host plant for the larvae of this species is likely to be the golden sand sedge pīngao which is now absent from the moths type locality. However Chappell has raised very young larvae on grass species and the more developed larvae consumed Phormium tenax. Adults are on the wing from November to March and are attracted to both light and sugar traps. The blackish forewing fringes are diagnostic of this species. But worn specimens of I. arotis can be confused with worn specimens of I. blenheimensis. However I. arotis can be distinguished from I. blenheimensis as it has a scale-tuft on the thorax and dark longitudinal stripes on the tegula. This species is classified as "At Risk, Naturally Uncommon" by the Department of Conservation.

Ichneutica micrastra is a moth of the family Noctuidae. It is endemic to New Zealand. This species has been found only in the North Island and has been collected in the Northland, Auckland, Whanganui and Wellington regions. The preferred habitat of this species is wetlands and heathlands including gum fields in Northland. Adults of this species are on the wing from October to December. The life history of this species is unknown as are the host species of its larvae however it has been hypothesised that the likely larval host is a grass or grass like plant. This species is very similar in appearance to I. phaula and I. sapiens but can be distinguished as a result of differences in male antennae, the shape, colour and size of forewings, the range of the species as well as differences in genital shape.

Ichneutica phaula is a moth of the family Noctuidae. It is endemic to New Zealand. It is found only in the South Island in the Nelson district, the eastern side of the South Island and Stewart Island. I. phaula inhabits tussock grasslands and coastal sand dunes. Host species include Ficinia spiralis, Ammophila arenaria, Poa cita and other "tussock grasses". The adults of this species are on the wing from October to December and are attracted to sugar traps. I. phaula is similar in appearance to both I. micastra, with whom it does not share a range, and I. sapiens which differs from I. phaula as I. sapiens is darker and has a more reddish tinge.

Pyrgotis plinthoglypta is a species of moth of the family Tortricidae. It is endemic to New Zealand and is found throughout the whole country. The preferred habitat of this species is native forest. The larvae of this species feeds on rimu leaves from under a silken web. It pupates in loose cocoons amongst rimu foliage. Adults are on the wing from October to May and are night flying. They are attracted to light and can be collected by beating their host tree. The adult insect resembles a small dried fragment of rimu foliage when at rest.

Ichneutica toroneura is a moth of the family Noctuidae. It is endemic to New Zealand. This species is similar to I. unica but can be distinguished from that species by the uniform black vein markings on the forewings of I. toroneura. It is also similar in appearance to I. acontistis but the base of the forewings of I. toroneura lack the dark stripe that can be found on the forewings of I. acontistis. The males of I. toroneura have longer pectinations on their antennae. I. toroneura is found in the centre of southern South Island in the tussock grasslands of Central Otago and the Mackenzie Basin. Larvae feed on tussock grasses Poa cita and Festuca novae-zelandiae. Adults are on the wing from November to January.

Ichneutica paraxysta is a moth of the family Noctuidae. It is endemic to New Zealand. This species is very similar in appearance to its close relative I. acontistis but as the range of the two species do not overlap this is unlikely to cause confusion. I. paraxysta is only found in the North Island at the subalpine zones in the Mount Taranaki region and at Mount Ruapehu. It prefers tussock grassland and shrubland habitat. The life history of this species is unknown as are the host species of its larvae however it has been hypothesised that the larval host plants are species in the genera of Poa and Festuca.

Ichneutica epiastra is a moth of the family Noctuidae. It is endemic to New Zealand and is found throughout the North, South and Stewart Islands. This species prefers open habitats such as wetlands, dunes and forest clearings. Eggs are laid in the summer or autumn and larvae feed during winter and spring. The larval host species are found within the genus Austroderia. The adult moths are on the wing between October and February. Adult I. epiastra can possibly be confused with the similar species I. arotis and I. haedifrontella however there are differences in appearance that enables I. epiastra to be distinguished from these two species. In particular I. epiastra has long sharp-tipped ‘horns' on its head that are diagnostic. The adults of this species appear reluctant to be attracted to light although they do come more frequently to the brighter mercury vapour traps.

Ichneutica agorastis is a moth of the family Noctuidae. This species is endemic to New Zealand. This moth is similar in appearance to two other species in the genus but can be distinguished through the colour and size of its forewings. This species is found in the South Island and Stewart Island in open habitats in the subalpine zone. However, in Southland I. agorastis can be found down to sea-level. Adult moths are on the wing between January and April. The life history and host species are unknown.

Ichneutica ceraunias is a moth of the family Noctuidae. It is endemic to New Zealand. This species is found from the central North Island to the bottom of the South Island. Hosts of the larvae are species of Chionochloa and Festuca. This colourful moth is variable in appearance and can be mistaken for Ichneutica dione. Adults are on the wing from October to February.

Ichneutica bromias is a moth of the family Noctuidae. This species is endemic to the Chatham Islands of New Zealand where is found on the Chatham, Pitt and Rangatira Islands. This species is similar in appearance to Ichneutica mutans but is darker and duller in its overall appearance. However, as I. mutans is not present in the Chathams this similarity is unlikely to cause confusion. The adults of the species are on the wing from November to March. The life history and the larval host species are unknown.

Ichneutica sollennis is a moth of the family Noctuidae. This species is endemic to New Zealand. This species is known from the eastern and central areas of the southern South Island. It inhabits alpine zones and has been collected in tussock grasslands. The life history of this species is unknown. Although the host species is currently unknown it has been hypothesised that this species have grass or grass like plants as host plants. Adults are on the wing from November to February and are attracted to light.

Ichneutica sapiens is a moth of the family Noctuidae. This species is endemic to New Zealand. I. sapiens is found in the central North Island, in the South Island in Westland and also the southern parts of the South Island, and in Stewart Island. This species inhabits wetland habitat but its life history is unknown as are the host species of its larvae. The adult moths are on the wing between December and early January and are attracted to sugar traps and to light. I. sapiens is very similar in appearance to I. micrastra but is a smaller moth with a shorter wingspan, has differently formed antennae and slightly different forewing markings.

Ichneutica paracausta is a moth of the family Noctuidae. This species is endemic to New Zealand. It is found locally in the central North Island, is widespread in the South Island and can also be found in Stewart Island. I. paracausta is variable in colour, but as it has a distinctive black streak on its forewing as well as a wing pattern that is characteristic, I. paracausta is unlikely to be confused with other species. It is present on the North Island volcanic plateau as well as Little Bush Reserve in Hawkes Bay in the North Island as well as in tussock grassland, alpine and subalpine shrubland and in alpine forest. Larvae have been recorded as feeding on grasses, a pupa has been found in a cocoon under the bark of a tree and adult moths are on the wing from October to January.

References

1 2 "Ichneutica steropastis (Meyrick, 1887)". www.nzor.org.nz. 2021. Retrieved 2021-08-08.
1 2 3 4 Dugdale, J. S. (1988). "Lepidoptera - annotated catalogue, and keys to family-group taxa" (PDF). Fauna of New Zealand. 14: 210. Archived from the original (PDF) on 2019-01-27. Retrieved 2018-01-16– via Landcare Research New Zealand Ltd.
1 2 Meyrick, Edward (1887). "Monograph of New Zealand Noctuina". Transactions and Proceedings of the New Zealand Institute. 19: 3–40 – via Biodiversity Heritage Library.
1 2 3 4 5 6 7 8 9 10 11 12 13 Hoare, Robert J. B. (2019-12-09). "Noctuinae (Insecta: Lepidoptera: Noctuidae) part 2: Nivetica, Ichneutica". Fauna of New Zealand. 80: 1–455. doi:10.7931/J2/FNZ.80.
1 2 Hudson, G. V. (1928). The Butterflies and Moths of New Zealand. Wellington: Ferguson & Osborn Ltd. p. 60. OCLC 25449322.
↑ "Ichneutica steropastis (Meyrick, 1887)". nztcs.org.nz. 2021. Retrieved 2021-08-08.
1 2 3 4 5 Robert J. B. Hoare (2014). A Photographic Guide to Moths & Butterflies of New Zealand. Illustrator: Olivier Jean-Philippe Ball. p. 13. ISBN 978-1-86966-399-5. Wikidata Q59396160.
1 2 3 "Insect pests and diseases". www.landcareresearch.co.nz. Manaaki Whenua Landcare Research. Retrieved 25 August 2018.

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[NZOR-1] 1 2 "Ichneutica steropastis (Meyrick, 1887)". www.nzor.org.nz. 2021. Retrieved 2021-08-08.

[:3-2] 1 2 3 4 Dugdale, J. S. (1988). "Lepidoptera - annotated catalogue, and keys to family-group taxa" (PDF). Fauna of New Zealand. 14: 210. Archived from the original (PDF) on 2019-01-27. Retrieved 2018-01-16– via Landcare Research New Zealand Ltd.

[:0-3] 1 2 Meyrick, Edward (1887). "Monograph of New Zealand Noctuina". Transactions and Proceedings of the New Zealand Institute. 19: 3–40 – via Biodiversity Heritage Library.

[:4-4] 1 2 3 4 5 6 7 8 9 10 11 12 13 Hoare, Robert J. B. (2019-12-09). "Noctuinae (Insecta: Lepidoptera: Noctuidae) part 2: Nivetica, Ichneutica". Fauna of New Zealand. 80: 1–455. doi:10.7931/J2/FNZ.80.

[Hudson1928-5] 1 2 Hudson, G. V. (1928). The Butterflies and Moths of New Zealand. Wellington: Ferguson & Osborn Ltd. p. 60. OCLC 25449322.

[6] "Ichneutica steropastis (Meyrick, 1887)". nztcs.org.nz. 2021. Retrieved 2021-08-08.

[Hoare2014-7] 1 2 3 4 5 Robert J. B. Hoare (2014). A Photographic Guide to Moths & Butterflies of New Zealand. Illustrator: Olivier Jean-Philippe Ball. p. 13. ISBN 978-1-86966-399-5. Wikidata Q59396160.

[:2-8] 1 2 3 "Insect pests and diseases". www.landcareresearch.co.nz. Manaaki Whenua Landcare Research. Retrieved 25 August 2018.

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