Pettersen Amanda K, Hall Matthew D, White Craig R, Marshall Dustin J
School of Biological Sciences/Centre for Geometric Biology Monash University Melbourne VIC 3800 Australia.
Department of Biology Lund University Lund 221 00 Sweden.
Evol Lett. 2020 Jun 12;4(4):333-344. doi: 10.1002/evl3.174. eCollection 2020 Aug.
Metabolism is linked with the pace-of-life, co-varying with survival, growth, and reproduction. Metabolic rates should therefore be under strong selection and, if heritable, become less variable over time. Yet intraspecific variation in metabolic rates is ubiquitous, even after accounting for body mass and temperature. Theory predicts variable selection maintains trait variation, but field estimates of how selection on metabolism varies are rare. We use a model marine invertebrate to estimate selection on metabolic rates in the wild under different competitive environments. Fitness landscapes varied among environments separated by a few centimeters: interspecific competition selected for higher metabolism, and a faster pace-of-life, relative to competition-free environments. Populations experience a mosaic of competitive regimes; we find metabolism mediates a competition-colonization trade-off across these regimes. Although high metabolic phenotypes possess greater competitive ability, in the absence of competitors, low metabolic phenotypes are better colonizers. Spatial heterogeneity and the variable selection on metabolic rates that it generates is likely to maintain variation in metabolic rate, despite strong selection in any single environment.
新陈代谢与生活节奏相关联，与生存、生长和繁殖共同变化。因此，代谢率应该受到强烈的选择，如果具有遗传性，随着时间的推移其变异性会降低。然而，即使考虑了体重和温度，种内代谢率的变化仍然普遍存在。理论预测可变选择会维持性状变异，但关于代谢选择如何变化的实地估计却很少见。我们使用一种典型的海洋无脊椎动物来估计在不同竞争环境下野外对代谢率的选择。在相隔几厘米的不同环境中，适应度景观有所不同：相对于无竞争环境，种间竞争选择了更高的代谢率和更快的生活节奏。种群经历了各种竞争模式的镶嵌；我们发现新陈代谢在这些模式之间介导了一种竞争 - 定殖权衡。尽管高代谢表型具有更强的竞争能力，但在没有竞争者的情况下，低代谢表型是更好的定殖者。空间异质性以及它所产生的对代谢率的可变选择，可能会维持代谢率的变异，尽管在任何单一环境中都存在强烈的选择。
