Revision of the genus Epiphyas (Lepidoptera, Tortricidae, Tortricinae, Archipini s. Str.)

Abstract

Epiphyas is the largest genus of moths within the Australian Tortricinae and the only indigenous tortricine genus of economic importance in Australian orchards. Epiphyas postvittana (the light-brown apple moth) is a widely polyphagous horticultural pest that is listed as a serious quarantine threat in many countries. The larvae of four other Epiphyas taxa (E. liadelpha, E. pulla, Epiphyas sp. (1) and E. xylodes) are also pests of horticultural crops in Australia. The larvae of all five pest Epiphyas appear similar and even the adults can be difficult to reliably identify using morphology. To address the concerns of Australia's trading partners and therefore; protect Australia's horticultural exports from unjustified quarantine measures, this revision aims to provide the tools to reliably identify the five economically important Epiphyas, at any life stage. Results on average, the COI sequences sampled from E. postvittana in Australia were 99.7% similar to those sampled from E. dotatana in the Kosciuszko National Park, and 98.8% similar to those sampled from Epiphyas sp. (1) across southern Australia. Epiphyas postvittana, E. dotatana and E. sp. (1) are herein referred to as the "postvittana complex". The average sequence divergence sampled between E. postvittana and E. pulla was 3.4% and between E. postvittana and E. liadelpha (sampled in Western Australia), the average sequence divergence sampled was 5.8%. Between E. postvittana and E. xylodes (sampled in the eastern Australian mainland), the average sequence divergence was 6.8%. In an analysis of nucleotide sequences from the mitochondrial COI gene region, using a Bayesian statistical framework in BEAST v1.4.8 (Drummond and Rambaut, 2002-2007), the postvittana complex, E. pulla and four more species form a monophyletic group that has high statistical support (posterior probability = 1.00). This group, which is highly morphostatic, is herein referred to as the "postvittana species group". In an analysis of concatenated sequence data from four gene regions (COI+IDH+MDH+CPS-CAD) and two genomes (mDNA, nDNA), using a maximum likelihood framework in Tree-puzzle v5.2 (Schmidt et al., 2004), statistical support for the postvittana species group is lower (QP branch reliability = 63%). The horticultural pests E. liadelpha and E. xylodes are not closely related to each other, or to the postvittana species group. Conclusions At any life stage, nucleotide sequences from the nuclear gene region IDH, or MDH, or CPS-CAD, will allow Epiphyas to be distinguished from the Australian crop pest Merophyas divulsana (the lucerne leaf-roller). Adult Epiphyas can be assigned to the appropriate species group using genitalia morphology. However, at all life stages COI nucleotide sequences are required to confirm the identity of a particular Epiphyas pest lineage. For confirmation of typical E. postvittana in non-crop habitats in eastern Australia, it is essential that both the mitochondrial gene region COI and the nuclear gene region CPS-CAD be sequenced. CPS-CAD sequences differentiate typical E. postvittana from E. dotatana, a close relative with an uncertain natural distribution. Reference nucleotide sequences for each taxon are indicated in Appendix I (pages AI:13 and AI:39) and saved in (.txt) format in Appendix III (CD). Show more