BRC-BIO - Expanding the ‘community’ in Community Genetics: Infracommunity genomics of duck symbionts to determine the eco-evolutionary factors underpinning holobiont evolution.

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How host-parasite interactions are maintained over ecological time and evolutionary time (i.e. many generations) is a significant biological question, with real-world applications in medicine, public health, and conservation. It is often overlooked, though, that a single host can contain a diverse community (i.e. infracommunity) of parasites.. The proposed research focuses on duck hosts and seeks to understand their parasite infracommunity structure and predictability. Ducks transmit several diseases of human importance, including Avian Influenza Virus (AIV) and Human Cercarial Dermatitis (HCD). As a group, ducks can be divided based on ecological traits (habitat selection, feeding behaviors) into two groupings, dabbling and diving ducks. Prior studies have suggested that dabbling ducks may support a higher rate of transmission of AIV and HCD. This work will characterize infracommunities of four dabbling and four diving duck species within the Eastern USA, to determine if infracommunities are specific to host species and/or ecological group. We will look deeply into the genetics of recovered parasite populations to determine if host species and/or ecological group help explain critical public health parameters, such has higher rates of transmission. Human-induced environmental change has resulted in significant changes to duck populations, such that some species are thriving in altered habitats, and others are in decline. There is thus an urgency to understand the ecology and evolution of duck parasite infracommunities to better model diseases such as AIV and HCD in a changing world. Within an individual host, a community of symbionts (infracommunity) assembles in response to both ecological and evolutionary processes. Does the shared host environment act in a concerted way to shape the structure, assembly, and microevolution of infracommunities? The proposed research takes a community genetics approach to provide robust insights into the evolutionary processes within and across species of a shared host environment. This work will investigate the helminth (parasitic worms) and viral communities of eight duck species, which can be divided into two distinct ecological groups (dabbling vs. diving species) based on host-traits. The proposed research will use long-read Oxford Nanopore Sequencing to 1) characterize infracommunity structure across hosts and ecological groups and 2) compare population genetic structure and diversity of recovered core taxa (i.e. 70% prevalence). Merging community ecology and population genetics will help uncover the ecological determinants of infracommunity assembly, microevolution and ultimately provide insights into the evolution of the hologenome. Prior work with both helminths (Trematoda: Trichobilharzia) and Avian Influenza Virus (AIV) have shown higher prevalence, genetic diversity, and larger effective sizes are associated with dabblers, suggesting host-traits shape infracommunity assembly and within-host microevolutionary patterns. Understanding the predictability and taxonomic scalability of infracommunity assembly, and identifying what ecological factors support transmission, could improve our ability to model zoonotic waterborne diseases associated with waterfowl.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.