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INVESTIGATING AN ADAPTIVE RADIATION IN TEMPERATE NEOCONOCEPHALUS _______________________________________ A Dissertation presented to the Faculty of the Graduate School University of Missouri-Columbia _______________________________________________________ In Partial Fulfillment Of the Requirements for the Degree Doctor of Philosophy _____________________________________________________ by Katherine H. Frederick Dr. Johannes Schul, Dissertation Supervisor JULY 2013 The undersigned, appointed by the dean of the Graduate School, have examined the dissertation entitled INVESTIGATING AN ADAPTIVE RADIATION IN TEMPERATE NEOCONOCEPHALUS Presented by Katherine H. Frederick, A candidate for the degree of Doctor of Philosophy And hereby certify that, in their opinion, it is worthy of acceptance. Professor Johannes Schul Professor Sarah L. Bush Professor Lori Eggert Professor Richard Houseman Professor J. Chris Pires ACKNOWLEDGEMENTS I would like to acknowledge all past and present Schul lab members, as well as all of the scientists that have contributed to the field of knowledge of Necoconocephalus acoustic communication; the time and effort of each of them contributed a data point or many points for use in comparative methods. I would like to thank Katie Kilmer, Oli Beckers, Gideon Ney, Nathan Thompson, and Megan Murphy for their help collecting specimens. I would like to thank Rob Snyder for his guidance in sequencing and tree building. Finally, I would like to thank Kate Hertweck, Roxi Kellar and Corey Hudson for their help with data analysis and discussions of evolutionary theory. Most importantly I would like to thank Johannes Schul and Sarah Bush. The Schul lab environment allowed me to bring knowledge and ideas from my previous studies and build on it in ways I never could have predicted. Thank you Johannes, for allowing me both space and time to think about what we didn’t know and build my research interests in directions beyond previous lab studies and for studying easy to capture insects living in beautiful habitats. Thank you to the University of Missouri Biological Sciences faculty and staff for this excellent opportunity of education. Since kindergarten it has been my dream to go to college and I have been working hard to do so ever since. I don’t take for granted all of the educators I have had that helped me along the way. ii TABLE OF CONTENTS ACKNOWLEDGEMENTS ................................................................................................ ii LIST OF ILLUSTRATIONS ...............................................................................................v LIST OF TABLES ............................................................................................................. vi ABSTRACT ...................................................................................................................... vii Chapters 1. COMPARINGPHENOTYPIC AND GENETIC DIVERSITY IN THREE SYMPATRIC SPECIES WITH ACOUSTIC COMMUNICATION ..................1 Abstract……….……………………………………………………………………1 Introduction..……………………………………………………………………….2 Materials and Methods …………………………………………………………….4 Results..………………………………………………………………………..….11 Discussion……...…………………………………………………………………14 Literature Cited………………………………………………………………...…30 2. UBER-RAPID DIVERGENCE DURING POST-GLACIAL EXPANSION……35 Rapid speciation of temperate Neoconocephalus ……………..…………………35 Rapid phenotypic diversification of temperate Neoconocephalus..………………39 Methods …………….…………………………………………………………….43 Literature Cited………………………………………………………………...…61 3. EVOLUTION OF A NOVEL FEMALE PREFERENCE………………..………66 Abstract………………………………………….……………..…………………66 Introduction…………………………………………………….....………………67 Methods.…………….…………………………………………………………….70 iii Results……….....……………………………...……………………………...…76 Discussion….…...……………………………...……………………………...…79 Literature Cited..……………………………...…………………………….....…92 4. THE INTERACTION BETWEEN GENETIC DRIFT AND GENETIC ARCHITECTURE OF THE NEOCONOCEPHALUS ACOUSTIC COMMUNICATION RESULTED IN RAPID PHENOTYPIC DIVERSIFICATION………………………………...………………..………96 Overview……………………………………….……………..…………..………96 Diversification at differing timescales……………………………………………98 Neoconocephalus diversification………………..………………………………101 Future Directions.....……………………………....…………………………….103 Literature Cited..……………………………...……………………………........111 APPENDIX 1. TAXA LIST FOR COI AND MITOGENOMIC DATASETS ............................113 VITA ................................................................................................................................117 iv LIST OF ILLUSTRATIONS Chapter 1 Page 1. Description of study species .....................................................................................23 2. Call trait analysis ......................................................................................................24 3. Mitochondrial haplotype network built from COI mtDNA using TCS ...................26 4. Minimum spanning network built from AFLPs .......................................................28 Chapter 2 1. Neoconocephalus time calibrated phylogeny based on mtDNA ..............................54 2. Call trait evolution in Neoconocephalus ..................................................................55 3. Cytochrome oxidase I Orthopteran phylogeny ........................................................58 4. Mitogenome Orthopteran tree ..................................................................................60 Chapter 3 1. Neoconocephalus character state reconstruction of discontinuous calls ..................88 2. Linear relationship of amplitude differences ...........................................................89 3. N. ensiger female responses to leader/follower duets .............................................90 4. Female responses to leader/follower duets ...............................................................91 Chapter 4 1. Acoustic communication phenotypes mapped onto phylogeny for two call traits (pulse pattern and pulse rate) .............................................................................107 2. Male chirp pattern and female chirp preference mapped onto Neoconocephalus phylogeny ..........................................................................................................109 v LIST OF TABLES Chapter 1 Page 1. Individual Information .............................................................................................22 Chapter 2 1. Mutation rates and clade age estimates ....................................................................53 2. Fossil calibrations for Orthopteran COI and mitogenome trees ..............................57 Chapter 3 1. Species specific stimuli generated from known female preferences ........................86 2. Angular deviation response to amplitude differences (dB SPL) ..............................87 vi Abstract Evolution of communication system is seemingly complex requiring coevolution between sender and receiver mechanisms. My dissertation uses phylogenetic methods to investigate phenotypic diversification of Neoconocephalus acoustic communication, specifically how novel traits arise, and the evolutionary history of these traits. Character state reconstructions found three lines of qualitative trait divergence in male calls, pulse rate, pulse pattern and call pattern. The combination of these call traits make up a species male call phenotype, each trait has an independent evolutionary history. The derived characters (slow pulse rate, double pulse pattern, and discontinuous call pattern) all have multiple independent origins. Double pulse pattern and slow pulse rate are only derived at the tips of the tree but discontinuous call pattern has two independent origins with subsequent reversals to the ancestral state. The receiving side of the communication system appears to have even more diversity. Species that share a derived call trait do not necessarily have similar female recognition mechanisms or even females preferences for that trait. I found that female’s preference for leaders was not due to a pre-existing sensory bias but instead has two independent origins one in each of the discontinuous calling clades. The multiple independent origins of and subsequent state reversals found in the qualitative traits of acoustic communication make Neoconocephalus a great systems to study speciation. Specifically, seven species of temperate Neoconocephalus are found in a single clade. This clade has all the phenotypic diversity, or repertoire, of call traits found in the genus. I propose that the diversification of these temperate Neoconocephalus vii is the result of an adaptive radiation triggered by post-glacial expansion of temperate grasslands and the adaptation of eggs diapause in order to overwinter. Molecular-clock analysis reveled that the diversification in this clade occurred in a single glacial cycle. In fact, this adaptive radiation occurred 11 thousand years ago. The combination of pliable secondary sexual characters and frequent occurrences of drift along the colonization front across North America allowed this adaptive radiation to occur more in the timescale of African Laucustrine cichlids. Previously the most rapid arthropod diversification event known occurred in Hawaiian Laupala crickets five million years ago. I found that temperate Neoconocephalus species were radiating into North America out of tropical grasslands at the same time that humans were entering North American by crossing the Bering Straight. viii Chapter 1 Comparing phenotypic and