Department of Crop Production Ecology, Swedish University of Agricultural Sciences, P.O. Box 7043, SE-75007, Uppsala, Sweden.
Department of Ecology, Swedish University of Agricultural Sciences, P.O. Box 7044, SE-75007, Uppsala, Sweden.
Ecol Appl. 2018 Dec;28(8):2187-2196. doi: 10.1002/eap.1807. Epub 2018 Oct 15.
Increased plant genotypic diversity in crop fields can promote ecosystem services including pest control, but understanding of mechanisms behind herbivore population responses to cultivar mixtures is limited. We studied aphid settling on barley plants exposed to volatiles from different cultivars, aphid population development in monocultures and two-cultivar mixtures, and differences in volatile composition between studied cultivars. Aphid responses to one cultivar in a mixture were neighbor-specific and this was more important for pest suppression than the overall mixture effect, aphid colonization patterns, or natural enemy abundance. Aphid populations decreased most in a mixture where both cultivars showed a reduced aphid-plant acceptance after reciprocal volatile exposure in the laboratory, and reduced population growth compared to monocultures in the field. Our findings suggest that herbivore population responses to crop genotypic diversity can depend on plant-plant volatile interactions, which can lead to changes in herbivore response to individual cultivars in a mixture, resulting in slower population growth. The impact of plant-plant interaction through volatiles on associated herbivore species is rarely considered, but improved understanding of these mechanisms would advance our understanding of the ecological consequences of biodiversity and guide development of sustainable agricultural practices. Combining cultivars in mixtures based on how they interact with each other is a promising strategy for sustainable pest management.
农田中增加植物基因型多样性可以促进包括害虫防治在内的生态系统服务，但对害虫种群对品种混合体的反应背后的机制的理解是有限的。我们研究了暴露在不同品种挥发物下的大麦植株上蚜虫的定殖、单一种植和两种品种混合物中蚜虫种群的发展，以及研究品种之间挥发物组成的差异。蚜虫对混合物中一个品种的反应是特定于邻居的，这对害虫抑制比总体混合物效应、蚜虫定殖模式或天敌丰度更为重要。在混合物中，当两种品种在实验室中相互暴露挥发物后表现出降低的蚜虫-植物接受性时，蚜虫种群减少最多，并且与单一种植相比，田间种群增长减少。我们的研究结果表明，食草动物种群对作物基因型多样性的反应可能取决于植物-植物挥发性相互作用，这可能导致混合物中单个品种对食草动物反应的变化，导致种群增长放缓。通过挥发物对相关食草动物物种的植物-植物相互作用的影响很少被考虑，但对这些机制的更好理解将有助于我们理解生物多样性的生态后果，并指导可持续农业实践的发展。根据品种之间的相互作用将它们混合在一起是可持续害虫管理的一种有前途的策略。
