Colonization and expansion into novel landscapes determine the distribution and abundance of species in our rapidly changing ecosystems worldwide. Colonization events are crucibles for rapid evolution, but it is not known whether evolutionary changes arise mainly after successful colonization has occurred, or if evolution plays an immediate role, governing the growth and expansion speed of colonizing populations. There is evidence that spatial evolutionary processes can speed range expansion within a few generations because dispersal tendencies may evolve upwards at range edges. Additionally, rapid adaptation to a novel environment can increase population growth rates, which also promotes spread. However, the role of adaptive evolution and the relative contributions of spatial evolution and adaptation to expansion are unclear. Using a model system, red flour beetles (Tribolium castaneum), we either allowed or constrained evolution of populations colonizing a novel environment and measured population growth and spread. At the end of the experiment we assessed the fitness and dispersal tendency of individuals originating either from the core or edge of evolving populations or from nonevolving populations in a common garden. Within six generations, evolving populations grew three times larger and spread 46% faster than populations in which evolution was constrained. Increased size and expansion speed were strongly driven by adaptation, whereas spatial evolutionary processes acting on edge subpopulations contributed less. This experimental evidence demonstrates that rapid evolution drives both population growth and expansion speed and is thus crucial to consider for managing biological invasions and successfully introducing or reintroducing species for management and conservation.
|Original language||English (US)|
|Number of pages||6|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - Dec 19 2017|
Bibliographical noteFunding Information:
ACKNOWLEDGMENTS. We thank Madeline Morris and Consuelo Reyes for help with data collection and Andrew Norton for useful discussions. This manuscript was improved by thoughtful comments from the editor and two anonymous reviewers. Funding was provided by US National Science Foundation Grants DEB-0949619 (to R.A.H.) and DEB-0949595 (to B.A.M.), and Graduate Research Fellowship 1144083 (to C.W.-L.), with additional support from the US Department of Agriculture National Institute of Food and Agriculture, the Colorado Agricultural Experiment Station via Hatch Projects 0231900 and 0229555, Agropolis Fondation (CfP 2015-02, Labex Agro:ANR-10-LABX-0001-01), and LabEX-CeMEB.
- Dispersal evolution
- Eco-evolutionary dynamics
- Range expansion
- Rapid evolution