c 2007 by Daniela Maeda Takiya. All rights reserved. SYSTEMATIC STUDIES ON THE LEAFHOPPER SUBFAMILY CICADELLINAE (HEMIPTERA: CICADELLIDAE) BY DANIELA MAEDA TAKIYA B. Sc., Universidade Federal do Rio de Janeiro, 1998 M. Sc., Universidade Federal do Rio de Janeiro, 2001 DISSERTATION Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Entomology in the Graduate College of the University of Illinois at Urbana-Champaign, 2007 Urbana, Illinois Abstract The leafhopper subfamily Cicadellinae (=sharpshooters) includes approximately 340 genera and over 2,000 species distributed worldwide, but it is most diverse in the Neotropical region. In contrast to the vast majority of leafhoppers (members of the family Cicadellidae), which are specialists on phloem or parenchyma fluids, cicadellines feed on xylem sap. Because xylem sap is such a nutritionally poor diet, xylem specialists must ingest large quantities of sap while feeding. They continuously spurt droplets of liquid excrement, forming the basis for their common name. Specialization on xylem sap also occurs outside the Membracoidea, in members of the related superfamilies Cicadoidea (cicadas) and Cercopoidea (spittlebugs) of the order Hemiptera. Because larger insects with greater cibarial volume are thought to more easily overcome the negative pressure of xylem sap, previous authors suggested that there may be a threshold of 8 mm above which, the energetic cost of feeding is negligible. In chapter 1 the method of phylogenetic contrasts was used to re-investigate the evolution of body size of Hemiptera and test the hypothesis that shifts to xylem feeding were associated with an increase in body size. After correcting for phylogenetic dependence and taking into consideration possible alternative higher-level phylogenetic scenarios, statistical analyses of hemipteran body sizes did not show a significant increase in xylem feeding lineages. However, these results should be viewed cautiously, because the lack of support for an increase in body size of xylem-feeders was the strong negative contrast of supposedly xylem-feeding myerslopiids and the phloem-feeding ancestor of the remaining Membracoidea. Additionally, the calculation of ancestral body sizes does not corroborate the previous assumption of a size threshold, as all xylem-feeding ancestors, with the exception of cicadas, were smaller than 8 mm. Sharpshooters host two mutualistic bacterial endosymbionts to complement their poor diet. Chapter 2 addresses the question of whether these two dominant bacteria have undergone long-term codiversification with their hosts. Twenty-nine leafhopper species, spanning six tribes with emphasis on sharpshooters, were characterized for both Baumannia and Sulcia. Phylogenetic analysis were conducted based on the 16SrDNA from both bacteria and on COI, COII, 16SrDNA, and H3 for sharpshooter hosts. To test whether cospeciation occurred three statistical tests were conducted: a topology and maximum-likelihood-based iii Shimoidara-Hasegawa test, a parsimony and event-based test (TreeFitter), and a parsimony and dataset- based ILD test. A congruent evolutionary history of both Baumannia and Sulcia with their sharpshooter hosts is supported based on all (Baumannia) or most (Sulcia) statistical tests conducted here, suggesting a long-term association of these bacteria with their hosts. Chapter 4 presents studies on the taxonomy of Homalodisca St˚al,1869, the most economically important proconiine genus. These studies include a new designation of the type-species (Cicada triangularis Fabricius, 1803) of the genus based on an original misidentification; transfer of Cicada triquetra Fabricius, 1803 to Propetes Walker, 1851; designation of the lectotype of Tettigonia vitripennis Germar, 1821 and synonymy of Tettigonia coagulata Say, 1832, making the former the appropriate scientific name for the glassy-winged sharpshooter; a key to Brazilian species; description of the male of H. ignota Melichar; and description of a new species of Homalodisca from Northeastern Brazil. Previous authors included in Cicadellinae different combinations of the tribes Cicadellini, Proconiini, Mileewini, Errhomenini, Evacanthini, and Makilingiini. Incongruences in the classification were mainly due to the lack of robust phylogenetic hypotheses. A phylogenetic study on the Cicadellinae with emphasis on the tribe Proconiini is presented in the final three chapters. A morphological study based on 183 characters coded for 50 outgroup taxa and 121 ingroup species is presented along with a molecular study based on partial regions of COI, COII, 16S rDNA, and H3 gene sequences from 74 ingroup and 17 outgroup taxa. Results support changes in the higher-level classification of Cicadellinae including the erection of the tribe Oncometopiini based on previous members of the Proconiini; the treatment of Phereurhinini within the subfamily Cicadellinae; and the transfers of the following to genera (to appropriate Cicadellinae tribe or subfamily): Archeguina, Jilijapa, Namsangia, and Ochrostacta (Cicadellini), Ectypus (Proconiini), Pamplona and Pamplonoidea (Oncometopiini), Homalogoniella (Phereurhinini), and Vidanoana (Mileewinae). Finally, based on a combined analysis of both molecular and morphology, the origin of the egg-powdering behavior and related sexually-dimorphic morphological characteristics were studied. Results suggest a single origin of the egg-powdering behavior, possibly in the ancestor of Phereurhinini and Oncometopiini. Modifications of the female hindlegs for scraping the brochosomes off onto the egg nests were also acquired once in the ancestor of the Oncometopiini, while modifications on the female forewing setation for better anchoring of brochosome pellets, seem to have been acquired multiple times. Multiple losses of the behavior and its related associated traits occurred in various oncometopiine lineages. iv This thesis is dedicated to my mother, Christina M. Takiya, who once thought that Entomology was a dead science. v “We are glorious accidents of an unpredictable process with no drive to complexity, not the expected results of evolutionary principles that yearn to produce a creature capable of understanding the mode of its own necessary construction.” –Stephen J. Gould “-Sadie: Daddy, why are starfish shaped like stars? -Professor: That’s a very interesting question, Sadie. Functional adaptability and anatomical determina- tion in biological systems is a fascinating issue that certainly warrants further investigation. -Sadie: Does that mean you don’t know? -Professor: It’s beyond the scope of my research. ” –Jorge Cham @ phdcomics.com “She’s filled with secrets. Where we’re from, the birds sing a pretty song, and there’s always music in the air.” –The man from another place (Twin Peaks, written by Mark Frost) vi Acknowledgments After almost six years of working on this thesis I am indebted to many incredible people. In the first place to Chris Dietrich and Roman Rakitov, whose interest in leafhopper evolution and biology made possible for me to come to do my graduate studies in the University of Illinois and immensely broaden my research interests. This opportunity came accompanied by field trips to Mexico, Peru, and Taiwan and my learning of new techniques and research areas, which would not have been possible back home. Uncountable discussions on leafhopper morphology were carried in our weekly meetings, which would not have been the same without the input of my esteemed fellow lab members: Adam Wallner, Jamie Zahniser, Jesse Alberston, Natasha Novikova, Suni Krishnankutty, and especially Dima Dmitriev, who set up the system for my sharpshooter database and continuously improves the software. Secondly, I would like to acknowledge my colleagues, who directly contributed in some of the papers presented in this thesis. Gabriel Mejdalani (MNRJ) was a collaborator in CHAPTER 5, who definitely molded myself with his own ideas of proconiine evolution, besides wholly supporting my decision to come to the United States. Rodney Cavichioli’s (DZUP) enthusiasm towards sharpshooters is contagious and just keeps me going on describing new species. He and Stu McKamey (USNM) were collaborators in CHAPTER 4. Stu’s grant on the revision of Homalodisca by the University of California Pierce’s Disease Research Grant financed my flying to the Ukraine to study the type of H. vitripennis and take myself, Roman, and Jamie into field trips to Costa Rica, Panama, and Venezuela, where material was collected and used in CHAPTER 6. Finally, Nancy Moran and Phat Tran (University of Arizona) whose interests in phytophagous insects endosymbionts were instrumental in producing the bacterial data studied in CHAPTER 3. Support towards my research and career goals also came in various ways through many people. Mike Wilson (National Museums and Galleries of Wales) allowed me to be a part of his incredible effort on imaging all sharpshooter species in the world, to be published as books sometime in the near future, and supported my re-analysis of his body size constraints ideas in CHAPTER 2. Brian Wiegmann (NCSU) allowed me the use of laboratory for trials of amplification of more useful gene regions in leafhoppers. Inspiration to conduct my research comes from amazing biologists who love their study groups with all their passion: vii Adalberto Santos (Universidade Federal de Minas Gerais), Eduardo Venticinque (Wildlife Conservation Society), Gustavo Graciolli (Universidade Federal do Mato Grosso do Sul), Jorge Nacimento (MNRJ),