The biology and molecular ecology of Oreixenica and related southeast Australian Satyrinae

In the Australian region, the family Nymphalidae contributes one fifth of the butterfly fauna, with the endemic species and genera all belonging to the subfamily Satyrinae, which is most diverse in the south eastern part of the continent. Here, extensive geographical variation has developed in the phenotype of many satyrines. This is best illustrated in the genus Oreixenica, which is endemic to the cooler parts of southeast Australia. This thesis comprehensively examines the relationships of a cross section of five genera and fourteen species from this group. New morphological data from the eggs and genitalia of these taxa are provided and used to test existing hypotheses of relationships. On this basis, it can be shown that the southeast Australian Satyrinae conform to a monophyletic group. Further evidence was sought from molecular data. Sequence data from three genes: the mitochondrial Cytochrome Oxidase Subunit 1 gene (C01), the nuclear Elongation Factor 1a (EF-1a) protein-coding gene, and the nuclear Wingless gene, were utilised to construct a phylogeny of twelve satyrine species plus two nymphalid outgroup genera. Phylogenetic trees derived from all data sets recovered very similar, well-supported relationships. The major findings from these analyses are: the temperate zone southeast Australian Satyrinae are indeed a monophyletic group based upon molecular evidence; the Heteronympha clade is sister to the Oreixenica clade; 0. latialis from the Australian Alps is the sister species to the Tasmanian endemic 0. ptunarra; H cordace is derived from the ancestor of H penelope and H merope; and, G. klugii is placed basally within the group. Estimated ages of divergence for the taxa are presented and these are related to the broad evolutionary history of the expansion of native grasslands in southern Australia. Whilst these results have implications for the conservation management of Australian Satyrinae, particular attention is focussed on the threatened Tasmanian 0. ptunarra, which has a fragmented and restricted distribution. Since European settlement a considerable reduction and modification of O. ptunarra habitat has occurred, particularly throughout the Midlands, a major agricultural region. The genetic relationships between sampled populations suggest that O. ptunarra does broadly interact within the traditional subspecies ranges, and some populations are becoming increasingly genetically isolated particularly in the Midlands and eastern regions of Tasmania. This detail is presently overlooked in current management plans and conservation efforts which are opportunistic in their approach to butterfly protection.