DescriptionThe adaptive capacity of many organisms is seriously challenged by human-induced environmental change. Water management measures in the 1970s in the Netherlands have produced a large number of land-locked ‘resident’ populations of three-spined sticklebacks (Gasterosteus aculeatus), which are cut-off from the originally ‘migrant’ populations. Here, we made use of this unintended field-experiment, to study the impact of human-induced isolation on behavior and morphology. We detected differences between migrant and resident populations in virtually all phenotypic traits studied: compared to the migrants, residents were smaller in size and were significantly more active, aggressive, exploratory and bolder and showed lower shoaling and migratory tendencies. Furthermore, to investigate if these differences in wild-caught residents and migrants reflect genetic differentiation, rather than different developmental conditions, we performed a ‘common-garden experiment’. We raised offspring of four crosses (migrant ♂ x migrant ♀, resident ♂ x resident ♀, migrant ♂ x resident ♀, resident ♂ x migrant ♀) under similar controlled conditions and tested for differences in phenotype as adults. We found that lab-raised resident sticklebacks exhibited lower shoaling and migratory tendencies as compared to lab-raised migrants, retaining the differences in their wild-caught parents. This indicates genetic differentiation of these traits. For all other traits, the lab-raised sticklebacks of the various crosses did not differ significantly, suggesting that the earlier-found contrast between wild-caught fish reflects differences in their environment. Our study shows that barriers to migration can lead to rapid behavioral divergence over contemporary timescales (~50 generations), and that part of these differences reflects genetic differentiation.
|Event title||International Society for Behavioral Ecology Congress 2022|
|Degree of Recognition||International|