Congeneric Phylogeography of Australian Ogyris Butterflies (Lepidoptera: Lycaenidae) Author Schmidt, Daniel J Published 2007 Thesis Type Thesis (PhD Doctorate) School School of Environmental Science DOI https://doi.org/10.25904/1912/2207 Copyright Statement The author owns the copyright in this thesis, unless stated otherwise. Downloaded from http://hdl.handle.net/10072/366723 Griffith Research Online https://research-repository.griffith.edu.au Congeneric phylogeography of Australian Ogyris butterflies (Lepidoptera: Lycaenidae) Daniel J. Schmidt B.Sc. (Hons) Australian Rivers Institute Faculty of Environmental Sciences, Griffith University Submitted in fulfilment of the requirements of the degree of Doctor of Philosophy, October 2006 ii iii Summary This study investigated spatial genetic structuring of two groups of Australian Ogyris butterflies (Lycaenidae). Ogyris represents one of several Australian endemic butterfly radiations that is well characterised in terms of basic biology but lacking in data useful for discriminating among the potential factors promoting divergence and speciation. A phylogeographic approach was used to document structuring in mitochondrial DNA markers (mtDNA) across the geographic range of two groups of closely related taxa. These include a pair of sister species: Ogyris zosine and O. genoveva, and the polytypic species O. amaryllis which is comprised of four subspecies. Topological relationships among recognised taxonomic units were tested and polyphyletic patterns investigated as a potential source of information relating to divergence and speciation. Sister species Ogyris zosine and O. genoveva were found to exhibit a polyphyletic relationship based on mtDNA. The deepest divergence within the group separated allopatric populations of O. zosine in northern Australia which do not correspond to a recognised taxonomic entity. The distribution of O. zosine and O. genoveva is parapatric along the east coast and additional sampling in this area along with evidence from allozyme markers revealed that the polyphyletic pattern can be explained by past mtDNA introgression at the current contact zone. The two species engage in an obligate mutualistic association with different suites of Camponotus ant species. It is hypothesised that this association may be involved in maintaining differentiation between the taxa through ant- mediated selection against hybrids. The distribution of a blue/purple wing colour polymorphism in female O. zosine is consistent with the role of wing colour as a prezygotic isolating mechanism in the contact zone although other explanations cannot be excluded. Genetic relationships were examined among four nominal taxa of the polytypic species Ogyris amaryllis which have a combined distribution spanning most of mainland Australia. Mitochondrial sequence data recovered a putatively ancestral and polyphyletic inland subspecies with several peripheral subspecies showing reduced variation within this topology. Analysis of spatiotemporal patterns of variation for the inland subspecies indicated a recurrent history of restricted gene flow and range expansion through the Pleistocene, while peripheral subspecies are characterised by higher levels of population iv structure and a history of population fragmentation. High levels of variation and population differentiation observed for allozyme markers were not consistent with subspecies boundaries. Partitioning of allozyme variation was explained better by arranging populations according to their larval host plant. Genetic data, combined with information on distribution and ecology, are consistent with a pattern of peripheral isolation associated with host plant specialisation of coastal populations in the O. amaryllis complex. v Acknowledgements I’ve been fortunate to have had Jane Hughes as my supervisor. I thank her for lots of wise advice and for introducing me to the world of population genetics, and also Roger Kitching for co-supervising my project. Rod Eastwood was enormously helpful throughout this project. He provided instruction in lab procedures as well as an extensive knowledge of butterflies and good humour. Accumulating adequate samples for this study would have been very difficult without the efforts of Roger Grund who provided samples from South Australia and other far-flung localities and also images from his excellent web site on South Australian butterflies. I owe a great deal of thanks to Michael Braby for providing samples, cheerfully answering all my butterfly questions and for generous hospitality while I was in Canberra. Steve Smith kept my sanity in check and showed me lots of nifty things you can do with DNA. All lab geeks (past and present) made working in the lab an enjoyable learning experience. I thank: Mark, Alicia, Tim, Ben, Jimmy, Joel, Ryan, Jemma, Mia, Cameron, Kate M., Kate D., Simon, Nomes, Arlene, Stacey, Jill, Jezza, Andrew, Jim He, Gio, Rachel, Issa, Suman, Tayner, Alison, Sharon, Naema, Courtenay, Ana, James H., Risto, Abe and also Petney for admin support. For technical help I thank Dave Hurwood for teaching me allozyme electrophoresis; Jing Ma for teaching me PCR and many other lab techniques; Nicole and Fraxa from GUDSF for doing lots of sequencing; Sylvain Arene for writing a computer program to help with data analysis; Keith Crandall for suggestions regarding parametric bootstrapping and Thomas Buckley for advice on Bayesian topology testing. For samples and/or advice on butterflies I thank Richard Weir (Darwin); Steve Brown (Bowral); Matthew Williams (Perth); Tony Tomlinson (Exmouth); Andrew Atkins (Newcastle); Peter Valentine (Townsville); Ray Manskie (Maryborough); Peter Wilson (Bundaberg); Peter Samson (Mackay); Cliff Meyer (Canberra); Naomi Pierce (Harvard University); Ross Kendall (Brisbane), John Olive (Cairns). Ted Edwards from the Australian National Insect Collection and Dave Britton from Australian Museum Sydney provided data on butterflies from their collections. Archie McArthur from the South Australian Museum identified my Camponotus samples. Nick Casey, Steve Rice and Rod Eastwood helped look for butterflies in the field. Allison Schmidt for hospitality on several field trips to Newcastle, and my parents for support and accommodation on several field excursions through southwest Qld. I was fortunate to receive financial support in the form of an Australian Postgraduate Award to complete this study; Griffith University provided funding for lab and field expenses; Australian Rivers Institute provided funding to attend conferences; Australian Geographic Society and Ecological Society of Australia provided funding for field work. Most of all, Adele Schmidt for her knowledge, support and love. vi This work has not previously been submitted for a degree or diploma in any university. To the best of my knowledge and belief, the thesis contains no material previously published or written by another person except where due reference is made in the thesis itself Daniel J. Schmidt vii Table of Contents Summary ........................................................................................................................................... iii Acknowledgements........................................................................................................................... v Declaration........................................................................................................................................ vi Chapter 1 Introduction.................................................................................................................... 13 1.2 Genetic divergence and speciation in butterflies......................................................................... 14 1.2.1 Allopatric divergence................................................................................................................ 15 1.2.2 Ecological specialisation .......................................................................................................... 16 1.2.3 Wing colour and mating behaviour........................................................................................... 17 1.3 Gene trees, species trees and congeneric phylogeography....................................................... 18 1.3.1 Causes of polyphyly: Imperfect taxonomy ............................................................................... 20 1.3.2 Causes of polyphyly: inadequate phylogenetic information..................................................... 21 1.3.3 Causes of polyphyly: incomplete lineage sorting ..................................................................... 22 1.3.4 Causes of polyphyly: introgression .......................................................................................... 23 1.4 Biogeography and climatic history of the Australian continent.................................................... 24 1.5 Taxonomy and conservation status of Ogyris species................................................................ 27 1.6 Biology of the genus Ogyris ........................................................................................................ 29 1.6.1 Larval host plants ..................................................................................................................... 29 1.6.2 Association with ants................................................................................................................ 29 1.6.3 Oviposition cues ......................................................................................................................