Zoological Institute & Museum, University of Greifswald, Johann-Sebastian-Bach Str. 11/12, Greifswald, 17489, Germany.
Glob Chang Biol. 2013 Nov;19(11):3272-82. doi: 10.1111/gcb.12297. Epub 2013 Sep 14.
Globally increasing temperatures may strongly affect insect herbivore performance, as their growth and development is directly linked to ambient temperature as well as host-plant quality. In contrast to direct effects of temperature on herbivores, indirect effects mediated via thermal effects on host-plant quality are only poorly understood, despite having the potential to substantially impact performance and thereby to alter responses to the changing climatic conditions. We here use a full-factorial design to explore the direct (larvae were reared at 17 °C or 25 °C) and indirect effects (host plants were reared at 17 °C or 25 °C) of temperature on larval growth and life-history traits in the temperate-zone butterfly Pieris napi. Direct temperature effects reflected the common pattern of prolonged development and increased body mass at lower temperatures. At the higher temperature, efficiency of converting food into body matter was much reduced being accompanied by an increased food intake, suggesting compensatory feeding. Indirect temperature effects were apparent as reduced body mass, longer development time, an increased food intake, and a reduced efficiency of converting food into body matter in larvae feeding on plants grown at the higher temperature, thus indicating poor host-plant quality. The effects of host-plant quality were more pronounced at the higher temperature, at which compensatory feeding was much less efficient. Our results highlight that temperature-mediated changes in host-plant quality are a significant, but largely overlooked source of variation in herbivore performance. Such effects may exaggerate negative effects of global warming, which should be considered when trying to forecast species' responses to climate change.
全球气温上升可能会强烈影响昆虫食草动物的表现，因为它们的生长和发育与环境温度以及宿主植物的质量直接相关。与温度对食草动物的直接影响相比，通过温度对宿主植物质量的间接影响知之甚少，尽管这些影响有可能对表现产生重大影响，并因此改变对不断变化的气候条件的反应。在这里，我们使用完全因子设计来探索温度对温带蝴蝶 Pieris napi 幼虫生长和生活史特征的直接（幼虫在 17°C 或 25°C 下饲养）和间接（宿主植物在 17°C 或 25°C 下饲养）影响。直接的温度效应反映了在较低温度下延长发育和增加体重的常见模式。在较高温度下，将食物转化为身体物质的效率大大降低，同时伴随着食物摄入量的增加，表明存在补偿性喂养。间接的温度效应表现为幼虫在较高温度下生长的植物上进食时体重减轻、发育时间延长、食物摄入量增加以及将食物转化为身体物质的效率降低，从而表明宿主植物质量较差。在较高温度下，宿主植物质量的影响更为明显，在这种情况下，补偿性喂养的效率要低得多。我们的研究结果强调了温度介导的宿主植物质量变化是食草动物表现显著但在很大程度上被忽视的变化源。这些影响可能会夸大全球变暖的负面影响，在试图预测物种对气候变化的反应时应考虑到这些影响。
