Faculty Development Grant Report
Ecology and Evolutionary Biology
Characterizing the factors that determine the geographic range limits of species is a major goal of ecology. Historically, abiotic factors (e.g., light environment) have been the focus of research of species geographical distributions. While recent work has shown that pairwise species interactions (e.g, predation) are also important for determining these distributions, the combined action of interactions spanning multiple trophic levels and the environmental mediation of such interactions are poorly understood. In this study, we explored the mechanisms by which light environments influence aphid population growth, focusing on (1) direct or plant mediated effects of light, (2) variation in predation pressure across a light gradient, in the absence of ants, and (3) variation in ant tending across a light gradient. Our results show that aphid populations perform better in high light environments because of increased tending of ants, which reduces predation pressure. This work demonstrates that understanding the consequences of abiotic factors on population performance (and, hence, species range limits) requires considering how they mediate ecological interactions in a community context.
Tillberg, Chad, "Faculty Development Grant Report" (2014). Post-Grant Reports. Report. Submission 15.