Plants and insects represent the majority of multicellular species on Earth. Most of those species are tropical; yet, most species in the tropics remain undiscovered. The proposed research has three primary goals: 1) discover and describe species of parasitic wasps that attack a very diverse group of plant-feeding flies; 2) discover patterns of host-use by the wasps; and, 3) reconstruct the history of the wasps' diversification (the evolution of many wasp species). To reach these goals, the team of investigators and their students will collect and rear insects, analyze the DNA of immature stages and adults, and analyze physical traits of adults.
This project addresses a major biological question: is diversification mediated by interactions among organisms or is diversification an ecologically neutral process? The project focuses on three groups of economically important organisms: plants related to pumpkins; fruit flies related to major agricultural pests; and wasps that attack the flies and are potentially important for pest control. Undergraduate education is a key component of the project. Undergraduates will be involved in all aspects of the research, including fieldwork in the tropics, molecular data collection and analysis in the laboratory, and communication and dissemination of the research.
Report 2013-2014 Our main award allowed us to carry out collecting trips in Costa Rica (March and August 2010), French Guiana (Feb 2011), Bolivia (December 2011), Panama (February 2012), Brazil (June 2012), and Peru (July-August 2012). Analysis of collections has been delayed due to problems associated with foreign permits to allow us to conduct genetic analyses. Specimens from Peru (2012) are still in Peru because export permits required permits for genetic analysis (still pending). We are still waiting for permits to allow us to analyze specimens from Costa Rica and Peru. Without those permits, our analyses of other specimens from other sites lack the geographic perspective we need to achieve the objectives of our proposal. Although samples from diverse localities are critically important for tests of evolutionary hypotheses, we have made progress with respect to analysis of local patterns of diversity. Analysis of specimens collected at a single site in Peru in 2008 reveals patterns of extreme host-specificity and diversity. Each species of parasitoid in the hymenopteran genus Bellopius successfully parasitizes only one species of Blepharoneura (flies in the family Tephritidae); however, many Bellopius species attack more than one species of Blepharoneura, but never emerge as adults from more than one species of fly. This pattern suggests that each species of fly can defend itself against all but one species of Bellopius. We reported these results in a manuscript submitted to the journal Science (22 August 2013). The manuscript was sent for in depth review. We are awaiting the decision from editors of Science. Analysis of non-specialist parasitoids resulted in a recent publication of a new species of figitid wasp. Analysis of specimens collected in Brazil likewise reveals extreme patterns of specificity. Collaboration with a Brazilian graduate student (Gessica Costa) suggests that flies and their parasitoids distinguish among recently diverged host-plant species. Supplementary awards (REU) supported research by two Hispanic undergraduates. Adriana Vega carried out a comparative study of genitalia of flies in the genus Strauzia ("sunflower flies"), and attended a conference of the Guild of Natural Science Illustrators. Jarod Armenta carried out a survey of populations of Strauzia associated with several species of putative hosts, and analyzed the DNA of his collections. A supplementary RET award allowed Darius Ballard (an African American who teaches high school in Cedar Rapids Iowa) to recruit several high school students to join the study of sunflower flies. Cornell College supported the work of three other undergraduates (two African Americans—Neisha Croffit and Demaceo Howard, and Maren Elnes) who collected flies from plants found diverse midwestern sites (Nebraska, Iowa, Illinois, Wisconsin). Andrew Forbes (University of Iowa) and I are analyzing specimens resulting from those collections. Collaborative work with Andrew Forbes, his undergraduate and graduate students, and a Cornell College undergraduate resulted in one publication (with graduate and undergraduate authors) in 2013. 2014-2015 We finally obtained "genetic access" permits from Peru and from Costa Rica. I travelled to Lima, Peru both to obtain our permits from MINAG and to export the specimens we had collected in August 2012. I have a talk to a group at MINAG including ecologists, pest-management biologists, wildlife biologists, and a lawyer. Permits from Peru now allow us to analyze ~1,000 specimens collected by Luz Maria Huerto Santillan (a Peruvian collaborator). Analysis involves extracting DNA from adults (flies and wasps) and from post-emergence puparia associated with parasitoids (to identify the fly-hosts of the parasitic wasps). Luz will visit during Summer 2015 to analyze the morphology of the specimens identified genetically. Additional progress (2014-15): Guianan Shield (Suriname and French Guiana) All adults and post-emergence puparia associated with wasps have been sequenced and identified. All "pre-emergence puparia" have been extracted, and flies indentified. Those puparia are currently being screened for presence of parasitoids. Major finding: Adult flies contain DNA of parasitoids. Our 2014 Science paper reported patterns of bidirectional "lethality": parasitoids lethal to flies, and flies lethal to parasitoids; however, we had no evidence that flies that are lethal to parasitoids can actually survive to adulthood. We have now screened a subset of adult flies and can confirm that we can identify the DNA of unsuccessful (dead) parasitoids in those flies. SUMMER (REU supplement): Four Cornell College undergraduates (all female) carried out research on Strauzia during Summer 2014 in collaboration with undergraduates and graduate students in Andrew Forbes's laboratory at the University of Iowa. Cornell students work in two tandem teams and collected >2400 adult flies on Helianthus and ragweed. PUBLICATION: Condon et al. 2014. Science 343: 1240-1244. PRESENTATIONS AT PROFESSIONAL MEETINGS Kristina Ottens (who began work on Blepharoneura and their parasitoids when she was an undergraduate at Cornell College) reported results from analysis of microsatellites (developed in part with ROA funding to Forbes) at the annual Evolution meetings in North Carolina and at the European Entomological meetings in York, England.
