Sun Syuan-Jyun, Dziuba Marcin K, Jaye Riley N, Duffy Meghan A
Department of Ecology and Evolutionary Biology University of Michigan Ann Arbor Michigan USA.
International Degree Program in Climate Change and Sustainable Development National Taiwan University Taipei Taiwan.
Ecol Evol. 2023 Feb 3;13(2):e9767. doi: 10.1002/ece3.9767. eCollection 2023 Feb.
Organisms are increasingly facing multiple stressors, which can simultaneously interact to cause unpredictable impacts compared with a single stressor alone. Recent evidence suggests that phenotypic plasticity can allow for rapid responses to altered environments, including biotic and abiotic stressors, both within a generation and across generations (transgenerational plasticity). Parents can potentially "prime" their offspring to better cope with similar stressors or, alternatively, might produce offspring that are less fit because of energetic constraints. At present, it remains unclear exactly how biotic and abiotic stressors jointly mediate the responses of transgenerational plasticity and whether this plasticity is adaptive. Here, we test the effects of biotic and abiotic environmental changes on within- and transgenerational plasticity using a - zooplankton-fungal parasite system. By exposing parents and their offspring consecutively to the single and combined effects of elevated temperature and parasite infection, we showed that transgenerational plasticity induced by temperature and parasite stress influenced host fecundity and lifespan; offsprings of mothers who were exposed to one of the stressors were better able to tolerate elevated temperature, compared with the offspring of mothers who were exposed to neither or both stressors. Yet, the negative effects caused by parasite infection were much stronger, and this greater reduction in host fitness was not mitigated by transgenerational plasticity. We also showed that elevated temperature led to a lower average immune response, and that the relationship between immune response and lifetime fecundity reversed under elevated temperature: the daughters of exposed mothers showed decreased fecundity with increased hemocyte production at ambient temperature but the opposite relationship at elevated temperature. Together, our results highlight the need to address questions at the interface of multiple stressors and transgenerational plasticity and the importance of considering multiple fitness-associated traits when evaluating the adaptive value of transgenerational plasticity under changing environments.
生物体越来越多地面临多种应激源，与单一应激源相比，这些应激源可能同时相互作用，产生不可预测的影响。最近的证据表明，表型可塑性能够使生物体对变化的环境做出快速反应，包括生物和非生物应激源，这种反应既可以在一代内发生，也可以跨代发生（跨代可塑性）。父母可能会使后代“做好准备”，以便更好地应对类似的应激源，或者，由于能量限制，也可能产生适应性较差的后代。目前，尚不清楚生物和非生物应激源如何共同介导跨代可塑性的反应，以及这种可塑性是否具有适应性。在这里，我们使用浮游动物 - 真菌寄生虫系统测试生物和非生物环境变化对代内和跨代可塑性的影响。通过将亲代及其后代连续暴露于温度升高和寄生虫感染的单一及联合影响下，我们发现温度和寄生虫应激诱导的跨代可塑性影响宿主的繁殖力和寿命；与未暴露或同时暴露于两种应激源的母亲的后代相比，暴露于其中一种应激源的母亲的后代更能耐受温度升高。然而，寄生虫感染造成的负面影响要强得多，并且跨代可塑性并不能减轻宿主适应性的这种更大程度的降低。我们还表明，温度升高导致平均免疫反应降低，并且在温度升高的情况下，免疫反应与终生繁殖力之间的关系发生了逆转：在环境温度下，暴露母亲的女儿随着血细胞生成增加而繁殖力下降，但在温度升高时则呈现相反的关系。总之，我们的研究结果强调了在多个应激源和跨代可塑性的交叉点解决问题的必要性，以及在评估不断变化的环境下跨代可塑性的适应性价值时考虑多个与适应性相关的性状的重要性。
