Biodiversity Research Centre and Department of Zoology, 6270 University Blvd, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
Sci Rep. 2017 Dec 1;7(1):16766. doi: 10.1038/s41598-017-16919-9.
Colonisation can expose organisms to novel combinations of abiotic and biotic factors and drive adaptive divergence. Yet, studies investigating the interactive effects of multiple abiotic factors on the evolution of physiological traits remain rare. Here we examine the effects of low salinity, low temperature, and their interaction on the growth of three North American populations of threespine stickleback (Gasterosteus aculeatus). In north-temperate freshwater habitats, stickleback populations experience a combination of low salinity and low winter temperatures that are not experienced by the ancestral marine and anadromous populations. Here we show that both salinity and temperature, and their interaction, have stronger negative effects on marine and anadromous populations than a freshwater population. Freshwater stickleback showed only a ~20% reduction in specific growth rate when exposed to 4 °C, while marine and anadromous stickleback showed sharp declines (82% and 74% respectively) under these conditions. The modest decreases in growth in freshwater stickleback in fresh water in the cold strongly suggest that this population has the capacity for physiological compensation to offset the negative thermodynamic effects of low temperature on growth. These results are suggestive of adaptive evolution in response to the interactive effects of low salinity and low temperature during freshwater colonisation.
生物的定殖可能会使生物接触到新的非生物和生物因素组合，并促使其产生适应性进化。然而，研究多种非生物因素对生理特征进化的交互作用的研究仍然很少。在这里，我们研究了低盐度、低温及其相互作用对三种北美的刺鱼（Gasterosteus aculeatus）种群生长的影响。在北温带淡水生境中，刺鱼种群经历了低盐度和冬季低温的组合，而这种组合是其祖先的海洋和溯河洄游种群所没有经历过的。我们发现，与淡水种群相比，盐度和温度及其相互作用对海洋和溯河洄游种群有更强的负面影响。当暴露在 4°C 时，淡水刺鱼的特定生长率仅下降了约 20%，而海洋和溯河洄游刺鱼在这些条件下则急剧下降（分别为 82%和 74%）。在寒冷的淡水中，淡水刺鱼的生长适度下降强烈表明，该种群具有生理补偿的能力，可以抵消低温对生长的负热力学影响。这些结果表明，在淡水定殖过程中，对低盐度和低温的相互作用的适应进化。
