Abstract:
Increased temperature can induce plastic changes in many plant traits. However, little is known about how these changes affect plant interactions with insect pollinators and herbivores, and what the consequences for plant fitness and selection are. We grew fast-cycling Brassica rapa plants at two temperatures (ambient and increased temperature) and phenotyped them (floral traits, scent, colour and glucosinolates). We then exposed plants to both pollinators (Bombus terrestris) and pollinating herbivores (Pieris rapae). We measured flower visitation, oviposition of P. rapae, herbivore development and seed output. Plants in the hot environment produced more but smaller flowers, with lower UV reflectance and emitted a different volatile blend with overall lower volatile emission. Moreover, these plants received fewer first-choice visits by bumblebees and butterflies, and fewer flower visits by butterflies. Seed production was lower in hot environment plants, both because of a reduction in flower fertility due to temperature and because of the reduced visitation of pollinators. The selection on plant traits changed in strength and direction between temperatures. Our study highlights an important mechanism by which global warming can change plant-pollinator interactions and negatively impact plant fitness, as well as potentially alter plant evolution through changes in phenotypic selection.
摘要:
温度升高可以诱导许多植物性状的塑性变化。然而,人们对这些变化如何影响植物与昆虫传粉者和食草动物的相互作用知之甚少,以及对植物适应性和选择的影响。我们在两个温度(环境温度和升高的温度)下种植了快速循环的芸苔属植物,并对它们进行了表型分析(花卉性状,气味,颜色和芥子油苷)。然后,我们将植物暴露于传粉者(Bombusterrestris)和传粉草食动物(Pierisrapae)。我们测量了鲜花参观,油菜的产卵,草食动物发育和种子产量。炎热环境中的植物产生更多但更小的花,具有较低的紫外线反射率和发射不同的挥发性混合物与整体较低的挥发性排放。此外,这些植物受到大黄蜂和蝴蝶的首选访问较少,蝴蝶很少去花。在炎热的环境中,种子产量较低,这既是因为温度降低了花朵的繁殖力,也是因为传粉者的访问量减少。在温度之间,植物性状的选择在强度和方向上发生变化。我们的研究强调了全球变暖可以改变植物-传粉媒介相互作用并对植物适应性产生负面影响的重要机制。以及通过改变表型选择可能改变植物进化。