Evidence for ecology's role in speciation.
A principal challenge in testing the role of natural selection in speciation is to connect the build-up of reproductive isolation between populations to divergence of ecologically important traits. Demonstrations of 'parallel speciation', or assortative mating by selective environment, link ecology and isolation, but the phenotypic traits mediating isolation have not been confirmed. Here we show that the parallel build-up of mating incompatibilities between stickleback populations can be largely accounted for by assortative mating based on one trait, body size, which evolves predictably according to environment. In addition to documenting the influence of body size on reproductive isolation for stickleback populations spread across the Northern Hemisphere, we have confirmed its importance through a new experimental manipulation. Together, these results suggest that speciation may arise largely as a by-product of ecological differences and divergent selection on a small number of phenotypic traits.
McKinnon
Jeffrey S
JS
Biological Sciences, University of Wisconsin-Whitewater, Whitewater, Wisconsin 53190, USA. mckinnoj@uww.edu
Mori
Seiichi
S
Blackman
Benjamin K
BK
David
Lior
L
Kingsley
David M
DM
Jamieson
Leia
L
Chou
Jennifer
J
Schluter
Dolph
D
D000413:Alaska; D000818:Animals; D001824:Body Constitution; D001955:British Columbia; D004463:Ecology; D004777:Environment; D005260:Female; D005399:Fishes / Q000145:classification* / Q000235:genetics / Q000502:physiology*; D005843:Geography; D007055:Iceland; D007564:Japan; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics; D009664:Norway; D010641:Phenotype; D012098:Reproduction / Q000235:genetics / Q000502:physiology*; D012606:Scotland; D012641:Selection, Genetic; D012726:Sexual Behavior, Animal / Q000502:physiology; D013045:Species Specificity