Anna Hargreaves

Assistant Professor, McGill University Department of Biology

Biotic interactions can structure ecological communities and drive evolution, but their relative importance compared to abiotic factors is hotly debated. Darwin and Dobzhansky famously proposed that biotic interactions become increasingly ecologically and evolutionarily important toward the tropics. Here I summarize three systematic tests of this conjecture: 1) an hemisphere-wide experiment measuring the ecological strength of interactions; 2) a global meta-analysis on local adaptation to interactions, and 3) a review testing whether interactions are more important at species tropical (vs polar) range limits. All three suggest that interactions are indeed more important in the tropics, but also reveal systematic research gaps and biases that currently limit our ability to evaluate the global importance of interactions.