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.

杂草的竞争对农业生态系统的生产力构成持续威胁。了解为什么杂草会在有或没有杂草的地方出现，对改善杂草管理措施至关重要。要做到这一点，我们必须对控制杂草种群动态和杂草物种分布的生态和进化过程有更深入的了解。种子是植物补充的一个脆弱阶段，在杂草斑块规模上的种子捕食可能会限制杂草斑块的持续和传播。在某些情况下，已观察到种子捕食导致植物种群灭绝，而在另一些情况下，即使种子阶段的大量死亡也可能对特定种群没有影响。种子的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形成杂草种群和群落中的作用。然而，无脊椎动物觅食和探测种子的机制目前尚不清楚；解决这一知识缺口是进一步理解种子捕食对杂草群落重要性的关键一步。该项目的具体目标是：1)确定并进一步解释种子大小与捕食者大小之间与种子选择的关系；2)评估种子的物理性状及其对种子选择的影响；3)确定感觉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性上有所不同的杂草物种来确定这些特性中哪些驱动种子选择。将通过识别顶空挥发物来研究化学种子防御，其结果用于设计基于嗅觉的研究，以阐明挥发物对种子选择的影响。最终，通过帮助定义决定种子选择的潜在机制，本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。这不仅对维持农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栖息地的影响也很重要。