Recipient Organization
IOWA STATE UNIVERSITY
2229 Lincoln Way
AMES,IA 50011
Performing Department
Entomology
Non Technical Summary
The field of insect systematics endeavors to discover and describe the diversity of life and to place this diversity in an evolutionary framework and hierarchical classification. Ultimately, these activities provide a logical and stable system of taxonomic information, one that is useful (and critical) to all fields of biological science. More than a million species of insects are known to science. Of these, more than 102,000 are aquatic insects (i.e., at least one life stage is aquatic), with approximately half of these being true flies (Diptera). When the latter is combined with semi-aquatic and terrestrial taxa, the Diptera contains nearly 160,000 species, making them one of the megadiverse orders of insects. Although these numbers may seem impressive, they represent a small fraction of the diversity thought to exist. Because the vast majority of insect species remain undiscovered and unnamed, there is an acute need for basic descriptive and revisionary work. These insects are not only taxonomically diverse, but provide myriad ecological services, including important roles as pollinators, vectors of economically disruptive diseases, trophic resources in aquatic and terrestrial food webs, and indicators of ecosystem health. Diptera (and other aquatic insects) are major drivers of ecosystem processes in aquatic environments, which makes knowledge of their diversity, biology and relationships of critical importance. To address the need for information on biology and evolutionary relationships, this project will investigate the biodiversity, taxonomy, and/or phylogenetics of selected groups of Diptera and associated aquatic insects. This will include regional studies of biodiversity, concentrating on areas or habitats that are biologically diverse and susceptible to environmental impacts. Concern about deforestation, pollution, watershed degradation, and concomitant loss of biodiversity is of particular interest to scientists, resource managers, politicians, and society; however, the documentation and evaluation of this loss requires baseline data on the composition, distribution, and abundance of the resident fauna. This project will provide these data for selected taxa. Student trainees will gain extensive skill sets and expertise not only in their group of interest, but in all groups studied by colleagues from collaborating institutions. Phylogenetic analyses will be conducted using morphological and molecular data to form the basis for natural and stable classifications of target groups. Results of phylogenetic analyses will provide a framework for testing hypotheses about aspects of morphological and behavioral character evolution, ecological transitions, and biogeographical patterns.
Animal Health Component
20%
Research Effort Categories
Basic
70%
Applied
20%
Developmental
10%
Goals / Objectives
The overall goal is to conduct research on the biodiversity and systematics of aquatic insects, particularly aquatic Diptera (true flies).Specific objectives include:Studies of the regional biodiversity of aquatic insects.Systematic revision and phylogeny of selected groups of aquatic flies.Database compilation and digitization of aquatic insects and other arthropods.
Project Methods
Regional biodiversity of aquatic insects. Past research has permitted the project director to amass important collections of various insect groups (e.g., Blephariceridae), including species from North America, Thailand, Nepal, Australasia, New Zealand, and Patagonia. Other material on long-term loan includes collections from Central- and South America. Despite these important collections, this project requires more field work, which is essential for locating additional undiscovered taxa, associating different life stages, and obtaining fresh material for molecular phylogenetic studies. Focal areas for inventory include aquatic habitats in various parts of North America and other biogeographical regions.Studies of wetlands in the upper Midwest will emphasize prairie marshes and shifting-sand rivers. Aquatic-insect sampling will use quantitative and qualitative methods, including kick samples, sediment cores, vegetation sweeps, and/or observation of substrata (e.g., rocks, macrophytes). Adult stages of aquatic insects will be gathered by sweep-netting, light traps, and/or Malaise traps. Many samples will be live-sorted and images of live examplars may be captured for placement in BugGuide.net or for other purposes. Most insect specimens will be preserved in ethanol, pinned or slide-mounted, and retained for further study or for deposition in the Iowa State Insect Collection. Association of aquatic immature stages with terrestrial adults will be accomplished via (1) co-occurrence at the time of collection; (2) the ontogenetic method; e.g., when an identifiable adult can be dissected from a mature nymph or pupa; (3) use of genetic markers / barcodes; and/or (4) rearing of immature stages in the laboratory. The latter may include mature nymphs of hemimetabolous taxa (e.g., Ephemeroptera) or mature larvae and pupae of holometabolous taxa (e.g., Diptera). Sampling protocols will also provide important life history data and accompanying environmental data for many taxa.Collecting in North America is expected to emphasize flowing-water habitats in western North America, the southern Appalachian Mountains, and Ozark Plateau, areas where the Courtney lab has already acquired data on several aquatic Diptera (e.g., Axymyiidae and Ptychopteridae). Despite this, it is apparent that some taxa (e.g., Blephariceridae and Tanyderidae) require additional investigation. The project director has also amassed significant collections of other aquatic insects from these areas, as well as other countries (e.g., Australia, New Zealand, and Chile). These collections contain valuable material of poorly known and undescribed species that are of interest to the project director and other researchers. Despite these important collections, more collecting effort is essential.Systematics and phylogeny of aquatic Diptera. Revisionary studies of selected Diptera (e.g., Blephariceridae, Deuterophlebiidae) will include detailed comparative morphology of all life stages, descriptions of new species, redescriptions of taxa, construction of keys, and phylogenetic analyses. Morphological structures will be documented using illustrations that range from drawings and digital photos to scanning electron micrographs. Comparative investigations of morphological structures will include homology assessments that can be tracked easily across target taxa. Previous studies of Diptera (e.g., Wood & Borkent 1989; Oosterbroek & Courtney 1995; Courtney et al. 2000; Yeates et al. 2007; Wiegman et al. 2011; Lambkin et al. 2013) and subgroups (e.g., Courtney 1990, 1991, 1994a, 1994b, 2000, 2015; Gibson & Courtney 2007; Curler & Courtney 2009) indicate that characters of immature stages can provide important insights into evolutionary relationships, so all life stages will be included in phylogenetic analyses. These studies will provide a foundation for comparing different morphological data sets (e.g., egg, larval, pupal, adult) as well as combined morphological and molecular data sets for testing phylogenetic hypotheses.Molecular studies of Blephariceridae (and related groups) will be accomplished through collaboration with scientists from the University of Tennessee (UT). Investigations will examine phylogeny across a broad taxonomic spectrum, from intergeneric relationships within a family to intrageneric- and intraspecific relationships of select taxa (latter a priority of the Moulton lab at UT). Single copy nuclear genes (e.g. septin-/tuftelin-interacting, aka STIP) have provided compelling signal in certain parts of the blepharicerid phylogeny (Moulton & Courtney, unpublished), but not others, indicating the need for more data. As part of a proposed NSF study, we plan to bolster genomic sampling by evaluating markers recovered from NextGen Illumina® sequencing of two taxonomically disparate genera within the family. Dozens, if not hundreds of potential markers will be screened for alignability, suitable divergence levels, and presence of suitable conserved priming sites employing the same criteria used to generate other high-performing markers (Moulton & Wiegmann 2004, 2007; Senatore et al. 2014; Winkler et al. 2015). Once potential genes have been identified, primers will be designed and tested against multiple genera within Blephariceridae. Up to 20 successfully amplifiable genes/exons will be screened for phylogenetic utility by constructing and analyzing a preliminary matrix containing a handful of taxa with known relationships (from morphology or STIP tree) and examining topology and node support in resulting trees. The 10 best performing genes will be slated for full taxon sampling and join STIP as our collective molecular sequence data applied towards this objective. Results will provide an objective framework for testing hypotheses about aspects of morphological and behavioral character evolution, ecological transitions, and current biogeographical patterns.Database compilation and digitization of aquatic insects. The wealth of data collected during this project will include inventory lists, image libraries, phenological data, habitat characteristics and distributional records. A specimen-level database of museum holdings of the target taxa will be augmented through curation by project participants and by significant additions of new material generated through project-related fieldwork.The project director will also contribute to activities that directly involve citizen scientists and stakeholders interested in aquatic-insect communities. Proposed activities will include taxonomic workshops, training in macro photography, and "bioblitzes". All will provide opportunities to convey information to stakeholders, and generate data (e.g., distributional records, images of collected taxa) for online resources. One of the best examples of a user-based website is BugGuide, a volunteer-based taxonomic guide to arthropods of North America that is hosted by Iowa State University and currently includes over 1.6 million user-contributed images, nearly 60,000 taxon pages, and contributions from more than 44,000 individuals. The proposed project will contribute images and taxon pages to BugGuide, and assist in developing a subdirectory focused on aquatic insects. In addition, live-collected arthropod specimens will be available for use in teaching and outreach programming through the Iowa State University Insect Zoo.