Systematics of Scopariinae moths in Australia: taxonomy, molecular phylogeny and evolutionary history

Systematics aims to describe, classify, and understand the evolutionary history of living organisms, and provides a critical foundation for further research in areas such as ecology and conservation. However, a large proportion of the world’s biodiversity remains undescribed, hindering research into those species. Among the insects, smaller species are more likely to be poorly known, and their taxonomy and relationships are often difficult to resolve using morphological evidence alone. In recent decades, molecular methods have provided a valuable source of new evidence for systematics, helping to resolve many long-standing problems in taxonomy and phylogenetics.
Scopariinae is a globally widespread subfamily of crambid snout moths (Crambidae: Pyraloidea) which is most diverse in temperate biomes. The Australian representatives of Scopariinae have been little studied since the 1930s, and numerous problems with their taxonomy are an impediment to understanding the group in Australia. Many species are placed in incorrect genera, and some species allocated to the subfamily are not truly scopariines. Genital morphology is important in placing scopariine species to genus, but the genitalia of most Australian Scopariinae have not been examined. There are several synonyms within the group, and numerous undescribed species. Misidentification of Australian scopariines is also widespread, including in natural history collections and online databases, partly due to striking morphological similarities between many species. It has also been difficult for Australian researchers to confirm the identity of many described species, as many type specimens are lost or held in collections outside Australia, and most species were described before 1940, without illustrations.
After a brief introduction to the study in Chapter 1, Chapter 2 presents a summary of the available literature regarding the systematics of Scopariinae. In this literature review I identify major gaps in knowledge of the evolutionary history of Australian Scopariinae, and of their phylogenetic relationships to each other and to scopariines elsewhere. Phylogenetic relationships between Scopariinae and other crambid subfamilies are also not fully understood, especially with regard to the Heliothelinae, which are most diverse in Australia. Until recently the Heliothelinae were considered part of Scopariinae, and several Australian species have in the past been transferred from heliotheline to scopariine genera and vice versa. Two of the three heliotheline genera have yet to be included in any phylogenetic study, and like the Australian Scopariinae, their taxonomy is problematic. In this thesis, I aim to resolve many of the taxonomic issues surrounding the Scopariinae in Australia, providing diagnoses and genitalia descriptions for a cross section of species as well as describing new species and summarising new information on distribution and larval host plants. I also investigate molecular phylogenetic relationships within the Scopariinae and Heliothelinae, with a focus on the Australian fauna.
Chapter 3 describes methods used in the study, and Chapter 4 presents a revision of the Australian Scopariinae. I resolve questions around the identity of species by examining type specimens held in Australian collections and the Natural History Museum, London, and using other evidence (e.g. non-type specimens from the type locality and distinctive features in descriptions) to identify species for which type material cannot be located. I provide diagnoses detailing distinctive features of each species and how to distinguish similar species, examining (where possible) specimens from a range of locations, many collected for this study, in order to characterise the morphological variation within species. I also examine and provide descriptions of the male and female genitalia of many species, and use evidence from the molecular phylogenetic analyses (presented in Chapter 5) to inform taxonomic decisions. Ten species are here transferred from Scoparia to Eudonia: E. anaplecta comb. nov., E. axiolecta comb. nov., E. charopoea comb. nov., E. eumeles comb. nov., E. gethosyna comb. nov., E. niphetodes comb. nov., E. oxygona comb. nov., E. plagiotis comb. nov., E. platymera comb. nov., and E. syntaracta comb. nov. Micraglossa spelaea comb. nov. is transferred from Scoparia. The New Zealand genus Antiscopa is newly recognised to occur in Australia, and Antiscopa gomphota comb. nov. and Antiscopa eutacta comb. nov. are transferred to this genus from Scoparia. Four new Eudonia species and one new Scoparia species are described. Three species are newly synonymised: Scoparia exhibitalis syn. nov. with Eudonia australialis, Scoparia crocospila syn. nov. with Eudonia epicryma, and Scoparia tristicta syn. nov. with Scoparia emmetropis. Scoparia encausta stat. rev., comb. nov. is brought out of synonymy with S. favilliferella.
In Chapter 5, I investigate the phylogeny and evolutionary history of the Australian Scopariinae and Heliothelinae, producing maximum likelihood and Bayesian trees based on four genes (COI, CAD, EF1a, and wg). DNA from specimens of 52 species was extracted and sequenced for this study: 41 Scopariinae, 8 Heliothelinae, and 3 outgroup crambid species. I also included sequences from non-Australian Scopariinae, Heliothelinae and outgroups downloaded from online databases. In the four-gene trees, most Australian species in the two most diverse scopariine genera, Scoparia and Eudonia, form a large Australian endemic clade in each genus. The molecular phylogeny highlighted the presence of several cryptic species, in Scoparia, Eudonia and Micraglossa. In the Heliothelinae, Phanomorpha is found to be polyphyletic, with narrow-winged Phanomorpha species forming a clade with Eclipsiodes.
The phylogeny presented here contributes to understanding the place of Australian Scopariinae in the global scopariine fauna, and begins to resolve long standing questions around the systematics of Heliothelinae. The revision of taxonomy and identification of key traits for distinguishing species will assist curators and researchers in correctly identifying Australian scopariine moths, which is vital to further research in fields such as conservation and ecology. Some of the characters used to distinguish species in this study may also be usefully applied to the scopariine fauna of other continents.