Biological invasions
Population dynamics play out in time and space.
Invasive range expansion by the cactus moth, Cactoblastis cactorum, through the Southeast. (Insect picture: a cactus moth eggstick on a native host-plant).
Understanding and predicting population trajectories in both
dimensions are core objectives in the study of biological invasions, a term that can be applied broadly to any population expansion into an unoccupied region (e.g., exotic invaders, biocontrol agents, recovering species). Ecologists have developed a large body of theory for spatial spread but empirical tests are limited, since invasions in nature are un-replicated and records of range expansion are prone to observation error. We conduct experimental invasions using bean beetles in the laboratory as a means to bridge the gap between invasion theory and range expansion in the real world. Our current experiments are evaluating theoretical predictions for the influence of sex-biased dispersal on the velocity of range expansion, and testing the efficacy of alternative management strategies for slowing down invasions. (Related papers: Miller and Tenhumberg 2010 Ecol.
Applications , Miller et al. 2011 Am Nat, Miller and Inouye (in prep))
A traveling wave of bean beetles in a laboratory invasion (lines represent generations).
