Geographic variation in the tallow leaf-roller (Caloptilia triadicae): Insight into the evolution and emergence of antagonistic interactions

Stochastic (i.e., genetic drift) and deterministic (i.e., extrinsic environmental, and intrinsic genetic) mechanisms can shape the evolution of antagonistic relationships among species. However, the relative importance of microevolutionary processes shaping antagonistic relationships is poorly understood. The Chinese tallow tree (Triadica) and the tallow leaf-roller (Caloptilia triadicae) comprise a system that affords exceptional opportunities to investigate the emergence and evolution of antagonistic species interactions. This study aims to determine the relative importance of 1) stochastic, 2) extrinsic deterministic and 3) intrinsic deterministic factors in shaping this plant-antagonist interaction. Latitudinal and longitudinal comparisons of herbivore density suggest that extrinsic factors may be the most important factor shaping Triadica-herbivore relationships. However, comparisons between genetically distinct populations suggest that the observed patterns may also reflect intrinsic genetic variation in Triadica. This presentation will examine ecological and molecular data from an observational study across the invasive North American range of Triadica. In so doing, this work may transform the state of our knowledge regarding how stochastic and deterministic factors structure antagonistic species interactions that often drive community assembly and evolutionary diversification.