title: Sensory trait variation contributes to biased dispersal of threespine stickleback in flowing water.
abstract: Gene flow is widely thought to homogenize spatially separate populations, eroding effects of divergent selection. The resulting theory of 'migration-selection balance' is predicated on a common assumption that all genotypes are equally prone to dispersal. If instead certain genotypes are disproportionately likely to disperse, then migration can actually promote population divergence. For example, previous work has shown that threespine stickleback (Gasterosteus aculeatus) differ in their propensity to move up- or downstream ('rheotactic response'), which may facilitate genetic divergence between adjoining lake and stream populations of stickleback. Here, we demonstrate that intraspecific variation in a sensory system (superficial neuromast lines) contributes to this variation in swimming behaviour in stickleback. First, we show that intact neuromasts are necessary for a typical rheotactic response. Next, we showed that there is heritable variation in the number of neuromasts and that stickleback with more neuromasts are more likely to move downstream. Variation in pectoral fin shape contributes to additional variation in rheotactic response. These results illustrate how within-population quantitative variation in sensory and locomotor traits can influence dispersal behaviour, thereby biasing dispersal between habitats and favouring population divergence.
authors.affiliation: Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Divisions of Basic Sciences and Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
authors.forename: C L
authors.initials: CL
authors.lastname: Peichel
authors.affiliation: Texas A&M University, Corpus Christi, TX, USA.
authors.forename: L
authors.initials: L
authors.lastname: Torrance
authors.affiliation: Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Rizvi
authors.affiliation: Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA.
authors.forename: S
authors.initials: S
authors.lastname: Thompson
authors.affiliation: Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA.
authors.forename: V V
authors.initials: VV
authors.lastname: Palivela
authors.affiliation: University of Texas Health Science Center, Houston, TX, USA.
authors.forename: H
authors.initials: H
authors.lastname: Pham
authors.affiliation: Department of Fisheries Science, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China.
authors.forename: F
authors.initials: F
authors.lastname: Ling
authors.affiliation: Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA.
authors.forename: D I
authors.initials: DI
authors.lastname: Bolnick
mesh_terms: D063147:Animal Distribution; D000818:Animals; D017753:Ecosystem; D051456:Gene Flow; D060106:Lakes; D008124:Locomotion; D010641:Phenotype; D023701:Smegmamorpha
keywords: Gasterosteus aculeatus; adaptive divergence; lateral line; neuromasts; nonrandom gene flow; rheotaxis