Project: Collaborative Research: The impacts of mating system variation on ecological performance and evolutionary diversification in a clade of marine snails

At present, virtually nothing is known about how mating systems vary within and among individuals, populations, and species of marine organisms. Indeed, characterizing mating system variation in the sea, and its effects on fundamental ecological and evolutionary patterns and processes, now represents a challenge perhaps equal in importance to the study of population connectivity that has occupied many marine ecologists for the last three decades. Snails in the genus Nucella are important intertidal predators and provide an exceptional model system for exploring how mating systems control critical ecological and evolutionary processes and patterns. By integrating insights from population and behavioral ecology, and life-history theory, combined with genetic, experimental, and phylogenetic approaches, this project will generate novel insights into the impacts of mating system variation on the ecological and evolutionary dynamics of marine systems. This project will significantly advance our understanding of how mating system variation in marine systems influences individuals, populations, and species, with important implications for better predicting how processes such as climate change, habitat fragmentation, and harvesting will influence population dynamics, speciation, and ecosystem function. In collaboration with a number of ongoing programs this project will train numerous under-represented students, scientists, and teachers in modern ecology, genetics, and phylogenetics. In addition, the project interfaces with multiple educational programs through partnerships with the Exploratorium, NOAA's expansion of west coast marine sanctuaries and outreach programs, and science communications programs at UC Davis and UNCW.

Worldwide, anthropogenic and natural processes are rapidly modifying patterns of environmental variation that affect the traits of individuals, populations, species, and communities, and that ultimately threaten both biodiversity and ecosystem functioning. These threats are often viewed in the context of (a) reductions in population size or density; (b) changes in demographic and genetic connectivity; and (c) Allee effects, where reduced local densities limit mating success. Though less-well studied - especially in marine systems - environmental perturbations can also rapidly alter the mating systems of populations. Numerous studies show that intra- and inter-specific variation in mating systems has major impacts on a broad spectrum of ecological and evolutionary processes (e.g., dispersal, population dynamics, life-history diversity, and speciation), that can profoundly influence the sustainability of marine ecosystems. The investigators' previous NSF-funded work established, for the first time in any marine organism, that the mating system strongly influences both offspring size variation and reproductive compatibilities in the predatory marine snail Nucella ostrina. This work raised several major questions regarding the ecology of marine organisms. Through field experiments, mating trials, genetic analyses, and phylogenetically explicit comparisons, the present project will comprehensively examine the fundamental roles that mating systems play in (1) generating ecologically relevant trait variation; (2) driving reproductive isolation; and (3) shaping macro-ecological patterns of life-history variation. This research will broaden our understanding of the critical role that mating systems play in the ecology and diversification of marine organisms, and provide the foundation for understanding how changes in population demographics and mating systems can influence both short term population dynamics and longer term responses to environmental change.