Data from: The emergence of performance trade-offs during local adaptation: insights from experimental evolution

Environmental heterogeneity is considered a general explanation for
phenotypic diversification, particularly when heterogeneity causes
populations to diverge via local adaptation. Performance trade-offs, such
as those stemming from antagonistic pleiotropy, are thought to contribute
to the maintenance of diversity in this scenario. Specifically, alleles
that promote adaptation in one environment are expected to promote
maladaptation in alternative environments. Contrary to this expectation,
however, alleles that underlie locally adaptive traits often fail to
exhibit fitness costs in alternative environments. Here, we attempt to
explain this paradox by reviewing the results of experimental evolution
studies, including a new one of our own, that examined the evolution of
trade-offs during adaptation to homogeneous versus heterogeneous
environments. We propose that when pleiotropic effects vary, whether or
not trade-offs emerge among diverging populations will depend critically
on ecology. For example, adaptation to a locally homogeneous environment
is more likely to occur by alleles that are antagonistically pleiotropic
than adaptation to a locally heterogeneous environment, simply because
selection is blind to costs associated with environments that are not
experienced locally. Our literature review confirmed the resulting
prediction that performance trade-offs were more likely to evolve during
selection in homogeneous than heterogeneous environments. The nature of
the environmental heterogeneity (spatial versus temporal) and the length
of the experiment also contributed in predictable ways to the likelihood
that performance trade-offs evolved.

环境异质性被认为是表型分化（phenotypic diversification）的通用解释，尤其当异质性通过本地适应（local adaptation）导致种群发生分化时。性能权衡（performance trade-offs）——例如源自拮抗多效性（antagonistic pleiotropy）的权衡——被认为在这一情境下有助于维持种群多样性。具体而言，能够促进某一环境下适应的等位基因（alleles），被预期会在其他替代环境中引发适应不良（maladaptation）。然而，与这一预期相悖的是，构成本地适应性性状基础的等位基因，往往并未在替代环境中表现出适合度成本（fitness costs）。在此，我们通过综述实验进化研究（experimental evolution studies）的结果——包括我们团队开展的一项全新研究——来尝试阐释这一悖论，这些研究考察了生物在适应同质与异质环境过程中权衡的演化历程。我们提出，当多效性效应存在变异时，分化种群间是否会出现性能权衡，将关键取决于生态背景。例如，相较于适应局部异质环境，适应局部同质环境更可能通过携带拮抗多效性的等位基因实现，究其原因在于：选择无法识别种群未在本地经历的环境所关联的成本。我们的文献综述证实了这一衍生预测：相较于异质环境下的选择作用，同质环境中的选择更易催生性能权衡。环境异质性的本质（空间异质性与时间异质性）以及实验时长，也以可预测的方式影响了性能权衡演化的发生概率。