Mutualistic species can show great variation in their demographic rates and natural abundances. Central to advancing the study of mutualistic interactions is a mechanistic theory for and empirical tests of their density dependence and population dynamics. This project extends consumer-resource theory of predator-prey and competitive interactions to the density dependence of mutualistic interactions using the pollinating seed-eating mutualism between senita cacti and senita moths in the Sonoran Desert of Mexico and Arizona. Using both experimental and modeling methods, the project will examine how variation in the densities of each mutualist affects variation in the other's demographic rates and abundance, and in turn, how such density-dependent consumer-resource interactions may prevent unbounded population growth and overexploitation from arising. Addressing such a shortcoming may more generally aid in understanding how mutualism contributes to patterns and processes of biological systems worldwide, ranging from the reproduction, survival, and dispersal of many plants and animals to ever growing conservation efforts arising from their ecosystem services (e.g., pollination, seed dispersal, nitrogen fixation). The project also provides research, education, and cross-cultural training for undergraduate students by directly involving them in international research and public outreach associated with National Parks in Mexico and the United States.
