Contemporary Evolution of Reproductive Isolation and Phenotypic Divergence in Sympatry along a Migratory Divide

Department of Evolutionary Biology and Animal Ecology, University of Freiburg, Hauptstrasse 1, D-79104 Freiburg, Germany.
Current biology: CB (Impact Factor: 9.57). 12/2009; 19(24):2097-101. DOI: 10.1016/j.cub.2009.10.061
Source: PubMed


Understanding the influence of human-induced changes on the evolutionary trajectories of populations is a fundamental problem [1, 2]. The evolution of reproductive isolation in sympatry is rare, relying on strong selection along steep ecological gradients [3-7]. Improved wintering conditions owing to human activities promoted the recent establishment of a migratory divide in Central European blackcaps (Sylvia atricapilla) [8, 9]. Here, we show that differential migratory orientation facilitated reproductive isolation of sympatric populations within <30 generations. The genetic divergence in sympatry exceeds that of allopatric blackcaps separated by 800 km and is associated with diverse phenotypic divergence. Blackcaps migrating along the shorter northwestern route have rounder wings and narrower beaks and differ in beak and plumage color from sympatric southwest-migrating birds. We suggest that distinct wing and beak morphologies are ecomorphological adaptations resulting from divergent, multifarious selection regimes during migration. We hypothesize that restricted gene flow accelerates the evolution of adaptive phenotypic divergence toward the contrasting selection regimes. Similar adaptive processes can occur in more than 50 bird species that recently changed their migratory behavior [10, 11] or in species with low migratory connectivity. Our study thus illustrates how ecological changes can rapidly drive the contemporary evolution of ecotypes.

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    • "Are the same genes involved across different groups (species, genera, families, classes)? Information on the genetic basis of migratory orientation is relevant to many fields, including evolution (e.g., behavioral genetics, Hoekstra, 2010; microevolution,Rolshausen et al., 2009;and speciation, Irwin and Irwin, 2005) ecology and conservation (e.g., environmental contributions to variation, the establishment of conservation strategies,Faaborg et al., 2010a,b;Winkler et al., 2014;and pest management, Jones et al., 2015). In this perspective, we will: (1) describe molecular genetic techniques employed thus far to identify the causative variants and genes for migratory orientation (including potential pitfalls) and (2) highlight new and suggested techniques for future work on this topic. "
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    • "All rights reserved. differentiation (Perez-Tris &amp; Bensch 2005;Bensch et al. 2009;Rolshausen et al. 2009;Lundberg et al. 2013), and is likely promoted by assortative mating resulting from differences in arrival time (Bearhop et al. 2005). Together with evidence for a (simple) genetic basis of migratory behaviour (Helbig 1996;Pulido 2007), these findings support the notion that selection might promote rapid evolutionary change. "
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    • "Our results complement the recent evidence that blackcaps migrating to Britain in winter are diverging phenotypically , as well as genetically, from those that use the traditional migration route to southern Spain (Rolshausen et al., 2009). Notably, Rolshausen et al. (2009) demonstrated that blackcaps wintering in Britain have relatively narrower and longer beaks than those wintering in Spain, suggesting that British migrants have adapted to a more generalist diet. Our results provide empirical evidence that selection for a beak morphology facilitating the handling of seeds and fats supplied in bird Table 3 The results of modelling the effects of supplementary feeding and climate (TOTFOOD and CLIMATE) on blackcap occupancy rate, accounting for urban land cover variation (SUBURBAN). "
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