The rates of spatial expansion of range following the introduction of animals to new areas are extremely variable between species. Data on a selection of species from a range of taxa show that these rates vary over about five orders of magnitude. The range expansion of a limited number of pest species of aphids have been mapped following colonisation. Studies on rates of colonisation are important as they are central to pest risk analysis. In addition, the observed variation in rates have significant implications for the development of realistic models of metapopulations.