Revisiting Long-Standing Hypotheses of Codiversification
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!!! University of Nevada, Reno Butterflies, inchworms, and plants: revisiting long-standing hypotheses of codiversification A dissertation submitted in partial fulfillment of the Requirements for the degree of Doctor of Philosophy in Ecology, Evolution, and Conservation Biology by Joshua P. Jahner Dr. Matthew L. Forister/Dissertation Advisor August, 2015 !!! Copyright by Joshua P. Jahner 2015 All Rights Reserved THE GRADUATE SCHOOL We recommend that the dissertation prepared under our supervision by JOSHUA P. JAHNER Entitled Butterflies, inchworms, and plants: revisiting long-standing hypotheses of codiversification. be accepted in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Matthew L. Forister, Advisor Lee A. Dyer, Committee Member Christopher R. Feldman, Committee Member Stephen B. Vander Wall, Committee Member Elizabeth A. Leger, Graduate School Representative David W. Zeh, Ph. D., Dean, Graduate School August, 2015 "! ! Abstract The purpose of this dissertation was to understand how changes in short-term ecological factors have lead to long-term evolutionary consequences, with a particular focus on the diversification of herbivorous insects and the plants they feed on. I begin with a general discussion of current theory on how changes to a species’ niche, or general way of life, can shape evolutionary processes across a broad diversity of organisms, including adaptation, selection, diversification, and hybridization. Additionally, I discuss two important and unresolved questions specifically regarding the diversification of herbivorous insects and discuss how the subsequent three dissertation chapters attempt to address these areas of investigation. In Chapter 1, I investigate the evolutionary history of Neotropical moths in the hyperdiverse genus Eois (Geometridae), with an emphasis on documenting the roles of host conservatism, geography, and elevation in promoting diversification. In Chapter 2, I examine the evolution of secondary defense chemistry in one clade of Piper plants (Radula), the predominant genus that Eois caterpillars feed on. Finally in chapter 3, I elucidate patterns of novel host using Californian butterflies and exotic plants as a model system in an effort to determine the characteristics of herbivores that promote host shifting, which is typically the predominant mechanism by which diversification is thought to occur in herbivorous insect lineages. ""! ! Table of Contents Abstract ......................................................................................................................... i Table of contents ............................................................................................................ ii List of Tables ................................................................................................................. v List of Figures ................................................................................................................ vi Introduction ~ Shifting ecological niches and their evolutionary consequences ......... 1 Evolutionary consequences of shifting ecological niches ....................................... 2 What are the relative roles of biotic and abiotic changes in shaping long-term evoloutionary processes? ......................................................................................... 5 What factors explain the variation in changeability found across species and lineages? ................................................................................................................... 6 References ................................................................................................................ 8 Chapter 1 ~ Host conservatism, geography, and elevation in the evolution of a Neotropical moth radiation ............................................................................................ 13 Abstract .................................................................................................................... 14 Introduction .............................................................................................................. 15 Methods.................................................................................................................... 18 Specimen collection ........................................................................................... 18 Sanger sequencing ............................................................................................. 19 Genotyping by sequencing ................................................................................. 21 """! ! Analyses of trait evolution ................................................................................. 22 Results ...................................................................................................................... 24 Sanger sequencing ............................................................................................. 24 Genotyping by sequencing ................................................................................. 25 Discussion ................................................................................................................ 26 Acknowledgements .................................................................................................. 31 References ................................................................................................................ 31 Tables ....................................................................................................................... 40 Figure legends .......................................................................................................... 42 Figures...................................................................................................................... 44 Supplementary material ........................................................................................... 50 Chapter 2 ~ Phylogenetic signal and the evolution of secondary chemistry in Radula (Piperaceae): persistant trait correlations despite rampant trait lability ......................... 60 Abstract .................................................................................................................... 61 Introduction .............................................................................................................. 62 Methods.................................................................................................................... 64 Study system and sample collection ................................................................... 64 Chemical profiling ............................................................................................. 65 Phylogenetic analyses ........................................................................................ 66 Results ...................................................................................................................... 69 Discussion ................................................................................................................ 71 Acknowledgements .................................................................................................. 76 "#! ! References ................................................................................................................ 76 Tables ....................................................................................................................... 85 Figure legends .......................................................................................................... 86 Figures...................................................................................................................... 88 Supplementary material ........................................................................................... 91 Chapter 3 ~ Use of exotic hosts by Lepidoptera: widespread species colonize more novel hosts ............................................................................................................................... 98 Abstract .................................................................................................................... 99 Introduction .............................................................................................................. 100 Materials and methods ............................................................................................. 101 Study organisms ................................................................................................. 101 Data collection ................................................................................................... 102 Phylogenetic data and independent contrasts ................................................... 104 Analyses ............................................................................................................. 104 Results ...................................................................................................................... 106 Discussion ................................................................................................................ 107 Acknowledgements .................................................................................................. 110 Literature cited ......................................................................................................... 110 Figure legend ........................................................................................................... 116