Seed Predation in weed communities: seed detection and discrimination and their impact on invertebrate seed foraging

杂草群落中的种子捕食：种子检测和辨别及其对无脊椎动物种子觅食的影响

• 批准号: RGPIN-2018-03811
• 负责人: Willenborg, Christian
• 金额: $ 2.04万
• 依托单位: University of Saskatchewan
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=668592
• 关键词: Seed; Predation; weed; communities; seed

Competition from weeds remains a constant threat to agro-ecosystem productivity. Understanding why weeds occur where they do, or do not, is critical to improving weed management practices. To do this, we must develop a greater understanding of the ecological and evolutionary processes that govern weed population dynamics and thus, weed species distributions. Seeds are a vulnerable stage in plant recruitment and seed predation at the scale of weed patches may have the potential to limit the persistence and spread of weed patches. In some cases, seed predation has been observed to drive plant populations to extinction while in others, even massive mortality at the seed stage may have no impact on a given population. Seed foraging patterns and processes could be at least partially responsible for these discrepancies. Over the long-term, my research program will attempt to develop a comprehensive understanding of the role seed predation plays in shaping weed populations and communities. However, the mechanisms governing seed foraging and detection by invertebrates are currently not well-known; addressing this gap in our knowledge is a crucial step in further comprehending the importance of seed predation to weed communities. The specific objectives of this program are to: 1) determine and further explain the relationship between seed size and predator size in relation to seed choice, 2) assess physical seed traits and their influence on seed choice, and 3) determine the contribution of sensory modalities to seed detection and selection. I will use weed species known to differ in physical traits such as seed coat hardness and seed size to determine which of these traits drive seed choice. Chemical seed defense will be studied by identifying headspace volatiles, with the results used to design olfactometer-based studies that eludicate the impact of volatile compounds on seed choice. Ultimately, by helping to define the underlying mechanisms that determine seed selection, this research will aid our understanding of how seed predation impacts weed population dynamics and species distributions. This is important not just for maintaining crop yields and profits in agriculture, but also for reducing the impact of invasive weeds on the conservation and restoration of natural and semi-natural habitats.

杂草的竞争仍然是对农业生态系统生产力的持续威胁。了解杂草为什么会在杂草发生或不发生的地方发生，对于改进杂草管理做法至关重要。要做到这一点，我们必须更好地了解支配杂草种群动态的生态和进化过程，从而了解杂草物种的分布。种子是植物招募的脆弱阶段，杂草斑块规模的种子捕食可能会限制杂草斑块的持久性和扩散。在一些情况下，观察到种子捕食导致植物种群灭绝，而在另一些情况下，即使是种子阶段的大规模死亡也可能对特定种群没有影响。种子觅食模式和过程可能至少是造成这些差异的部分原因。从长远来看，我的研究计划将试图全面了解种子捕食在塑造杂草种群和群落中所起的作用。然而，控制无脊椎动物觅食和检测种子的机制目前还不是很清楚；解决我们知识中的这一差距是进一步了解种子捕食对杂草群落的重要性的关键一步。该计划的具体目标是：1)确定并进一步解释种子大小和捕食者大小与种子选择的关系；2)评估种子的物理性状及其对种子选择的影响；3)确定感官模式对种子检测和选择的贡献。我将使用已知在种皮硬度和种子大小等物理特征上不同的杂草物种来确定这些特征中的哪些特征决定了种子的选择。化学种子防御将通过识别顶空挥发物进行研究，结果将用于设计基于嗅觉仪的研究，以避免挥发性化合物对种子选择的影响。最终，通过帮助确定决定种子选择的潜在机制，这项研究将有助于我们理解种子捕食如何影响杂草种群动态和物种分布。这不仅对维持作物产量和农业利润很重要，而且对减少入侵杂草对保护和恢复自然和半自然生境的影响也很重要。