After the games are over: life‐history trade‐offs drive dispersal attenuation following range expansion. Issue 18 (18th August 2016)

• Record Type: Journal Article
• Authors: Perkins, T. Alex; Boettiger, Carl; Phillips, Benjamin L.
• Is Part Of: Ecology and evolution. Volume 6:Issue 18(2016:Oct.)
• Page Start: 6425
• Page End: 6434
• Publication Date: 2016-08-18
• Subjects: Fitness -- life‐history evolution -- natural selection -- theory -- traveling wave; Ecology -- Periodicals; Evolution -- Periodicals; 577.05
• DOI: 10.1002/ece3.2314
• Languages: English
• ISSNs: 2045-7758

Abstract

Abstract : Cane toad ( Rhinella marina ) with a tracking device on its waist sitting on a road in northern Australia. Cane toads are an example of a species that has evolved increased dispersal propensity over the course of their range expansion but then later evolved lower dispersal propensity after range expansion concluded. This study performed theoretical analyses that shed light on why dispersal attenuates in cane toads and other species following range expansion. Abstract: Increased dispersal propensity often evolves on expanding range edges due to the Olympic Village effect, which involves the fastest and fittest finding themselves together in the same place at the same time, mating, and giving rise to like individuals. But what happens after the range's leading edge has passed and the games are over? Although empirical studies indicate that dispersal propensity attenuates following range expansion, hypotheses about the mechanisms driving this attenuation have not been clearly articulated or tested. Here, we used a simple model of the spatiotemporal dynamics of two phenotypes, one fast and the other slow, to propose that dispersal attenuation beyond preexpansion levels is only possible in the presence of trade‐offs between dispersal and life‐history traits. The Olympic Village effect ensures that fast dispersers preempt locations far from the range's previous limits. When trade‐offs are absent, this preemptive spatial advantage has a lasting impact, with highly dispersive individuals attaining equilibrium frequencies that are strictly higher than their introduction frequencies. When trade‐offs are present, dispersal propensity decays rapidly at all locations. Our model's results about the postcolonization trajectory of dispersal evolution are clear and, in principle, should be observable in field studies. We conclude that empirical observations of postcolonization dispersal attenuation offer a novel way to detect the existence of otherwise elusive trade‐offs between dispersal and life‐history traits.