The goal of this project is to conduct a thorough study of the pattern of spread of the cicadas, deducing how it has formed new species and colonized new areas over time. This colonization will be understood using DNA data to build evolutionary-trees and assign dates to branching events (past speciation). Results will be viewed against the backdrop of past climate change. Cicadas are excellent models for this type of study because they occur worldwide, their courtship songs make them easy to collect and identify, and their sedentary life histories generally result in clear boundaries between species. This research will aid in the establishment of a better taxonomy of cicada species and help catalog and understand the earth?s rapidly disappearing biodiversity.
Because this project involves researchers in the US, China, Australia, New Zealand, Slovenia, France, the Netherlands, and South Africa, it will promote the international exchange of ideas and technology as well as specimens. This research will address a broad range of important questions, such as how climate change affects speciation and the application of information on mechanisms of molecular change over time to molecular tree-building. Species new to science will certainly be discovered. This research will contribute to the training of undergraduate, graduate, and postdoctoral researchers including under-represented groups. The results of this research will be made available through our website and will include an electronic field guide with distributions of collected cicada species and photographs and songs of many species. The website will also provide an updated list of world cicada workers, status of world cicada taxonomy research, links to other cicada sites, three large web-searchable databases (Magicicada, NZ cicadas and World Cicadas), lists of locations of types, maps, phylogenetic trees, locality guides, and more.
Intellectual merit: The major goal of this award was to reconstruct the evolutionary history/biogeography of the worldwide cicada tribe Cicadettini, a tribe comprising approximately one third of the world cicada fauna. Our specific objectives/goals were to: a) understand the evolutionary relationships among the genera of the tribe, b) determine whether the tribe had a single origin or multiple origins, c) test the "Out of Australia" hypothesis for the spread of the tribe worldwide, d) assess the validity of selected genera, e) explore relationships among species in selected genera, f) expand our Cicada Central website, and g) Continue to develop human resources. Our research resulted in the collection of more than 15,000 cicada specimen records that have been studied, databased, and stored for future research. We collected DNA sequence data from more than 300 species and created an evolutionary tree or genealogy. We found a strong pattern suggesting Australasian ancestry for the tribe. These lineages arose approximately 40 million years ago and have twice expanded out of Australasia, between 15 and 30 million years ago (after the major continents had drifted apart). Evolutionary trees were created for selected genera of importance for understanding how species originate, spread across the landscape, and survive in the face of interbreeding with other species. Broader Impacts: Scientific Products. Over the five years of this award, thirteen papers have been published that address the goals of this award. An additional eight papers that acknowledge the award but are not directly relevant to goals largely focus on the genus Magicicada. Four other papers are soon to be submitted. Science and Technology Training. Seven undergraduate students were trained in our laboratory in DNA sequencing and molecular tree building and analysis as a result of this award; six of these completed undergraduate theses. Two graduate students were directly supported by this award, one completed a PhD thesis and the other is nearing completion. One postdoctoral research associate and one technician received training. Two other graduate students and one additional postdoc benefited from interactions and mentoring by all other grant personnel. Placement of students and postdocs in Systematics jobs or PhD programs: One undergraduate entered the PhD program at UC Santa Barbara (to study the molecular systematics of ostracods); another undergraduate trained by our project was accepted into the PhD Program at U. Illinois (to study the phylogenomics of paraneoptera); One new PHD has moved on to a postdoc in molecular bioinformatics at George Washington University. A postdoc (supported by a different award but trained by personnel supported by the current award) moved to a curatorial position at the Natural History Museum, London. Websites and Databases: Our Cicada Central and Magicicada Central websites provide valuable information regarding cicada taxonomy, distributions, identifications, phylogenies, species-specific song recordings, and molecular lab protocols as well as links to other web resources, an updated list of world cicada workers, status of world cicada taxonomy research, three large web-searchable databases (Magicicada, New Zealand, and World Cicadas), and other useful features. The genus Magicicada (Cicadidae: Cicadettinae), a particularly charismatic mega-invertebrate, serves as a flagship species for educating school children and the general public on the importance of studying insect systematics (and insect biology in general). Over the course of this award, the PI’s, postdoc and technician have provided expert services to a wide variety of media outlets, children’s authors, and film-makers. The website InsectSingers.com, including online guides for the identification of eastern North American cicada songs. Contributions to other disciplines: Many disciplines in biology use phylogenetic trees to understand the evolution of traits ranging from morphological and anatomical features to physiology to biochemistry. Our work has contributed to the understanding of modelling of DNA sequence evolution that is essential to improve the way that we build evolutionary genealogies from DNA data. We have begun a collaboration with a bacterial genomics researcher. His group is studying the evolution of symbiosis and the origin of cell organelles and using cicadas as a model system. Our phylogenetic trees serve as a framework for their taxon sampling and data interpretation. In addition, we provide cicada specimens to them from our frozen collections. Cicadas have proved to be excellent model systems for the evolution of symbioses. So far, one species turns out to have a symbiont that although normally responsible for producing two essential amino acids has undergone a lineage duplication with each daughter lineage producing one of the two to make a complete set. Even farther afield, we are also collaborating with a materials scientist, who is studying the wing ultrastructure of cicadas. Wings of many cicada species have micropillars that have been used for nanolithography and microfabrication of light scattering or water repellent fabrics or optical nano-properties. These micropillars have also been shown to have antibacterial properties. We are providing wings and advice on taxon selection.
