Data from: Direct and indirect transgenerational effects alter plant-herbivore interactions

Theory suggests that environmental effects with transgenerational consequences, including rapid evolution and maternal effects, may affect the outcome of ecological interactions. However, indirect effects occur when interactions between two species are altered by the presence of a third species, and make the consequences of transgenerational effects difficult to predict. We manipulated the presence of insect herbivores and the competitor Medicago polymorpha in replicated Lotus wrangelianus populations. After one generation, we used seeds from the surviving Lotus to initiate a reciprocal transplant experiment to measure how transgenerational effects altered ecological interactions between Lotus, Medicago, and insect herbivores. Herbivore leaf damage and Lotus fecundity were dependent on both parental and offspring environmental conditions. The presence of insect herbivores or Medicago in the parental environment resulted in transgenerational changes in herbivore resistance, but these effects were non-additive, as a result of indirect effects in the parental environment. Indirect transgenerational effects interacted with more immediate ecological indirect effects on Lotus fecundity. These results suggest that explanations of ecological patterns require an understanding of transgenerational effects and that these effects may be difficult to predict in species-rich, natural communities where indirect effects are prevalent.理论研究表明，具有跨代效应（transgenerational effects）的环境影响——包括快速演化与母性效应（maternal effects）——可能会改变生态互作的结果。然而，当两种物种间的互作因第三种物种的存在而发生改变时，便会产生间接效应（indirect effects），这使得跨代效应的影响难以预测。我们在重复设置的怀氏百脉根（Lotus wrangelianus）种群中，对昆虫植食者（insect herbivores）与竞争者斑荚苜蓿（Medicago polymorpha）的存在与否进行了操控处理。经一代繁育后，我们利用存活怀氏百脉根所结的种子启动了互惠移植实验（reciprocal transplant experiment），以探究跨代效应如何改变怀氏百脉根、斑荚苜蓿与昆虫植食者之间的生态互作。昆虫植食者造成的叶片损伤与怀氏百脉根的繁殖力（fecundity）均同时受亲本与子代所处环境条件的影响。亲本环境中存在昆虫植食者或斑荚苜蓿时，会引发植食抗性的跨代变化，但由于亲本环境中的间接效应，这些效应表现为非加性效应（non-additive effects）。间接跨代效应与对怀氏百脉根繁殖力的即时生态间接效应发生了互作。上述结果表明，要解释生态格局，需对跨代效应加以考量；而在间接效应普遍存在的物种丰富型自然群落中，这类效应往往难以预测。