Landcare Research - Manaaki Whenua

Landcare-Research -Manaaki Whenua

Fauna of New Zealand 72: Micropterigidae (Insecta: Lepidoptera) - Abstract

Gibbs, G W 2014. Fauna of New Zealand. 72, 127 pages.
( ISSN 0111-5383 (print), ISSN 1179-7193 (online) ; no. 72. ISBN 978-0-478-34759-3 (print) , ISBN 978-0-478-34760-9 (online) ). Published 30 Jun 2014
ZooBank: http://zoobank.org/References/D6BC8C34-6D93-4EC7-BCB3-5670B2CFE744
DOI: 10.7931/J2/FNZ.72

Abstract

New Zealand’s fauna of archaic Lepidoptera, the Micropterigidae, is revised, with the addition of four new species: Sabatinca pluvialis, S. weheka, S. bimacula, S aurantissima. The synonomy of Palaeomicra Meyrick, 1886 and Micropardalis Meyrick, 1912 with Sabatinca Walker, 1863, proposed by Kristensen and Nielsen, 1979, is supported here. Three new synonomies are established: Sabatinca passalota Meyrick is synonymised as a junior synonym of S. chrysargyra Meyrick; S. barbarica Philpott is synonymised as a junior synonym of S. caustica Meyrick; and S. aurantiaca Philpott is synonymised as a junior synonym of S. aemula Philpott. The outcome of long-standing confusion between incongruella Walker and chalcophanes Meyrick, initiated by Meyrick in 1912, is discussed because it influenced a series of publications by Tillyard and Philpott between 1919 and 1927. Adults and larvae are described and illustrated; adults in colour from life as well as museum specimens, larval examples in colour from life to show the variety of pigmentation patterns. Larvae have been matched to adult species by barcoding (8 cases), rearing (4 cases), unambiguous habitat association (6 cases); but despite these efforts three species remain where the larval form is unknown. Within Sabatinca, three monophyletic species-groups are recognised, established by DNA phylogenetic analysis and supported by morphological characters; within one of which two further informal sub-groupings are adopted based on character traits of adults, larvae and DNA (although the latter without strong support).

Current understanding of life cycles, foodplants, and general ecology are reviewed. All known Sabatinca species are confirmed as hepatic feeders, those in New Zealand utilising only the foliose types of liverwort. The precise diet of Zealandopterix larvae remains undetermined. Phenology patterns are discussed—typical life cycles being annual, with larval growth throughout winter and a relatively short pupal stadium prior to the spring/summer flight season. Members of the calliarcha-group of species appear to incorporate a diapause, resulting in a two-year cycle and more erratic seasonal emergence of adults.

The broader systematic position of New Zealand Micropterigidae is described based on current molecular understanding that the world fauna is subdivided into five strongly-supported clades—two northern and three southern hemisphere, with two occurring in New Zealand and New Caledonia: Sabatinca clade and ‘Australian’ clade. The historical biogeography and phylogeny of SW Pacific Micropterigidae is compared with the tectonic interpretation for this region, within both a deeper Zealandian perspective and from the perspective of sister species divergence patterns in the genus Sabatinca, finding that in all except one case, the New Zealand speciation events occurred prior to the development of modern geological landforms. With the incorporation of DNA phylogenetics into a predominantly morphological analysis of diversity, it has been possible to evaluate the strength of phylogenetic signal in the basic morphological structures of alpha-taxonomy. Certain features of the male phallus, gonopore, bulbous ejaculatorius, and female signa and spermatheca are evaluated in relation to their phylogenetic signal with gradings from ‘phylogenetically meaningful’ to ‘of taxonomic value only’.

Species of New Zealand Micropterigidae are widely distributed from North Cape to Stewart Island with a maximum concentration in NW Nelson region. No single species occurs throughout, the most widespread (S. chalcophanes) extends from Auckland to Fox Glacier, the most restricted (S. pluvialis) at present known only from Secretary Island in Fiordland. Of the 19 New Zealand species, four are endemic to North Island, 11 to South Island, and four occur in both islands. They are not known from Three Kings Islands, Chatham Islands, Lord Howe Island, or Subantarctic Islands.

The maculation and colours of New Zealand Micropterigidae are comprehensively described. In contrast to larvae, which are cryptically coloured, the brilliant iridescent colours of adult Sabatinca appear, to our eyes, to defy crypsis, yet in the dappled light of their complex habitats, these small moths are by no means easy to see. Two species (S. calliarcha, S. doroxena) exhibit an eye-catching pattern in which the upper part of the forewing of a resting moth (tornus) features a black patch containing several brilliant white spots. It is suggested that this theme, especially since it re-occurs in seven New Caledonian Sabatinca species and a number of other similar-sized moths that rest with their wings tent-like (e.g. certain Glyphipterix species), is likely to have survival value by mimicking the facial view of a jumping spider (Salticidae), one of their key predators. Unfortunately the hypothesis remains to be tested.