Feeding ecology of outbreak insect species

暴发昆虫的摄食生态学

• 批准号: RGPIN-2021-02392
• 负责人: Bauce, Éric
• 金额: $ 2.04万
• 依托单位: Université Laval
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=741951
• 关键词: Feeding; ecology; outbreak; insect; species

Understanding the nature and relative importance of endogenous (density-dependent) and exogenous (density-independent) effects on population dynamics remains a central problem in ecology. The relative contributions of bottom-up and top-down effects (resources and natural enemies, respectively), particularly in herbivore populations, have been difficult to compare because data on population density variation have rarely been combined with resource measurements. Testing the hypothesis of whether or not variation in food quality plays a role in spruce budworm population dynamics represents the long-term objective of my research program. In the short-term, I intend to study trans-generational effects of food quality on outbreak insect defoliator population fitness and population dynamics using the spruce budworm-host tree system of interactions. If food quality changes contribute to population dynamics, I predict that the trans-generational mechanism is the driving force of that contribution. In contrast, if food quality does not contribute to population dynamics, I predict that trans-generational effects generate a locally adaptative phenomenon that is strong enough to render population dynamics independent of food quality variation. Climate change is expected to cause increases in temperature and in the frequency of extreme climatic events, including extreme variation during winter, such as frequent thaw episodes. I predict that these anticipated winter thaw episodes, which I intend to reproduce in the laboratory, would favor local adaptation to food quality deterioration, as would occur during the course of an outbreak, by exerting additional selective pressure on insect populations in favor of stronger, more adaptable insects to poor quality nutrition. Whether food quality has or has not driven population dynamics of spruce budworm in the past, I predict that these expected new winter conditions would affect the dynamics of spruce budworm populations or at least, their fitness. The hypotheses of this research project will be tested by rearing, over multiple generations, larvae installed on host branches that were covered with sleeve cages. Results from caged and uncaged populations will be compared. Local adaptation to food quality and effects of winter thaw will be investigated using field and laboratory reciprocal transfer experiments. This research program will contribute not only to a better understanding of the role of food in the population dynamics of outbreak insect defoliator species, but also to a better understanding of how climate change and food interact on insect population dynamics and fitness. Results of the current research program will provide information useful to develop forest management practices aimed at reducing insect economic impact. Also, the current research will allow the development of models that can predict the course of insect defoliator outbreaks in a changing environment due to climate alterations.

了解种群动态的内源（密度依赖）和外源（密度无关）效应的性质和相对重要性仍然是生态学的一个中心问题。自下而上和自上而下效应（分别为资源和天敌）的相对贡献，特别是在食草动物种群中，一直难以比较，因为关于种群密度变化的数据很少与资源测量相结合。检验食品质量的变化是否在云杉芽虫种群动态中起作用的假设代表了我的研究计划的长期目标。在短期内，我打算研究跨世代的影响，粮食质量的爆发昆虫食叶虫种群健身和人口动态使用云杉芽虫宿主树系统的相互作用。如果食物质量的变化有助于人口动态，我预测，跨代机制是这种贡献的驱动力。相比之下，如果食物质量不有助于人口动态，我预测，跨代效应产生的本地适应现象，是强大到足以使人口动态独立的食物质量变化。预计气候变化将导致气温升高，极端气候事件的频率增加，包括冬季的极端变化，如频繁的解冻事件。我预测，这些预期的冬季解冻事件，我打算在实验室中重现，将有利于当地适应食物质量恶化，就像在爆发过程中发生的那样，通过对昆虫种群施加额外的选择压力，有利于更强壮，更适应低质量营养的昆虫。无论食物质量是否驱动云杉芽虫种群动态在过去，我预测，这些预期的新的冬季条件将影响云杉芽虫种群的动态，或至少，他们的健身。本研究项目的假设将通过饲养，在多个世代，幼虫安装在主机分支覆盖套筒笼。将比较笼内和非笼内群体的结果。当地适应食品质量和冬季解冻的影响将进行调查，使用现场和实验室相互转移实验。这项研究计划不仅有助于更好地了解食物在爆发性食叶昆虫种群动态中的作用，而且有助于更好地了解气候变化和食物如何对昆虫种群动态和适应性产生影响。目前的研究计划的结果将提供有用的信息，以制定森林管理措施，旨在减少昆虫的经济影响。此外，目前的研究将允许模型的发展，可以预测在不断变化的环境中，由于气候变化的昆虫食叶害虫爆发的过程。