Environmental conditions change constantly either by anthropogenic perturbation or naturally across space and time. Often, a change in behaviour is the first response to changing conditions. Behavioural flexibility can potentially improve an organism’s chances to survive and reproduce. Currently, we lack an understanding on the time-scale such behavioural adjustments need, how they actually affect reproduction and survival and whether behavioural adjustments are sufficient in keeping up with changing conditions. We used house mice (Mus musculus) to test whether personality and life-history traits can adjust to an experimentally induced food-switch flexibly in adulthood or by intergenerational plasticity, i.e., adjustments only becoming visible in the offspring generation. Mice lived in six experimental populations of semi-natural environments either on high or standard quality food for four generations. We showed previously that high-quality food induced better condition and a less risk-prone personality. Here, we tested whether the speed and/ or magnitude of adjustment shows condition-dependency and whether adjustments incur fitness effects. Life-history but not personality traits reacted flexibly to a food-switch, primarily by a direct reduction of reproduction and slowed-down growth. Offspring whose parents received a food-switch developed a more active stress-coping personality and gained weight at a slower rate compared to their respective controls. Furthermore, the modulation of most traits was condition-dependent, with animals previously fed with high-quality food showing stronger responses. Our study highlights that life-history and personality traits adjust at different speed towards environmental change, thus, highlighting the importance of the environment and the mode of response for evolutionary models.

中文翻译：

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适应环境变化的速度取决于条件吗？家鼠（Mus musculus）实验

环境条件会因人为扰动或自然的空间和时间而不断变化。通常，行为的改变是对不断变化的条件的第一反应。行为灵活性可以潜在地提高有机体生存和繁殖的机会。目前，我们对这种行为调整所需的时间尺度、它们实际上如何影响繁殖和生存以及行为调整是否足以跟上不断变化的条件缺乏了解。我们使用家鼠（Mus musculus）来测试性格和生活史特征是否可以在成年期或通过代际可塑性灵活地适应实验诱导的食物转换，即调整仅在后代中变得可见。小鼠在六个半自然环境的实验群体中生活了四代，要么吃高质量的食物，要么吃标准质量的食物。我们之前表明，高质量的食物会带来更好的状况和更少的风险倾向。在这里，我们测试了调整的速度和/或幅度是否表现出条件依赖性以及调整是否会产生适应效果。生活史而非人格特质对食物转换做出了灵活的反应，主要是直接减少繁殖和减慢生长。与各自的对照组相比，父母接受食物转换的后代发展出更积极的压力应对个性，并且体重增加的速度更慢。此外，大多数性状的调节都取决于条件，以前喂食优质食物的动物表现出更强的反应。我们的研究强调，生活史和人格特征对环境变化的调整速度不同，从而强调了环境和进化模型反应模式的重要性。