Murphy:KSNH Student Research Grant

Freshwater mussels (order Unionoida) are one of the most threatened groups of taxa both within the United States and worldwide. Kentucky is a global hotspot for mussel diversity, yet almost half of Kentucky's species are at risk of extinction. Although the causes for freshwater mussel declines are numerous, the requirement of a host for larval development has many implications for mussel conservation. First, host abundance can influence mussel population size, and this is expected to have an influence on the maintenance of genetic diversity in populations, with smaller populations having a greater risk of genetic bottlenecks. Second, because mussel dispersal occurs primarily while larvae are encysted on hosts, differences among species in host use and host mobility can influence gene flow among mussel populations. However, few investigations have examined population structure and gene flow among mussel populations and its relationship to population structure and gene flow in host populations. I propose an integrative set of objectives employing powerful population genomic data aimed to understand the relationship between a mussel and its host, as well as aid in the conservation of freshwater mussel populations in Kentucky and elsewhere in North America. First, I will assess population structure and gene flow in a host (Necturus maculosus) and an imperiled mussel species (Simpsonaias ambigua) at multiple spatial scales in lotic networks. Second, I will assess congruency in genetic structure of mussel and host at multiple spatial scales in lotic networks. By examining population structure, gene flow and congruency in these measures between host and mussel, I will determine both the spatial extent and relative importance of host dispersal for gene flow and population structure within a particular mussel species. Understanding the role of host dispersal on gene flow and genetic parameters will shed light on fundamental co-evolutionary processes between two functionally linked organisms. Furthermore, the applications of my work will be vital in constructing management plans to optimize conservation of threatened mussel species and their hosts.