How tri-trophic interactions and social behaviour drive early instar survival rates of caterpillars

我的目标是通过确定物候、植物物理和化学防御、群体生活和天敌如何相互作用，产生幼虫生存的紧急模式，为毛虫早期生态学建立一个基于过程的概念框架。一般来说，幼体幼虫的研究很少，但往往遭受非常可变的高死亡率，造成相互作用的物种特异性压力源。这种空间和时间上的高度变异表明，早期幼虫存活在种群动态中起着重要作用。******我的比较方法使用了三种系统，因为它们在生活史、群居性和种群动态方面存在差异：两种重要的加拿大森林暴发害虫——云杉budworm （chistoneura fumiferana，独居，以针叶树为食）、森林帐篷毛虫（Malacosoma disstria，群居，以落叶为食）和各种热带清翅蝴蝶（Ithominae，一些物种群居，另一些物种独居）。* * * 1。是什么行为机制导致了加拿大东部最重要的森林害虫早期存活率的波动？早期存活的极端差异构成了预测budworm爆发的重要知识缺口。我将通过测试将寄主植物物候、叶片化学和先前的落叶与分散、竞争和建立取食地点联系起来的行为机制来填补这一空白。* * * 2。群体生活如何调节森林帐篷毛虫的三营养相互作用？我将验证这样一个假设，即群体生活意味着随着群体规模的缩小，存活率会下降，这种反馈会加速由于捕食和植物防御而造成的损耗。* * * 3。群体生活如何调节清理毛虫的三营养相互作用？我将把在温带群居毛毛虫身上发展起来的概念和工具应用到热带地区更为多样化的毛毛虫身上；具体来说，我将测试分组如何允许在机械防御的植物上建立和定居受干扰的栖息地。******这些子目标利用每个研究生物的特定自然历史来形成关于驱动早期生态的机制的假设。它们共同构成了一个雄心勃勃、创新而广泛的研究项目，综合了相互作用的压力源的影响，以解释早期生存中复杂的涌现模式。我独特的基于个体的方法为热带森林的保护和北方森林爆发动态的机制解释提供了坚实的科学基础，包括对气候变暖的反应。对爆发害虫的研究尤其及时，因为这两种害虫目前在加拿大大部分地区都处于高涨状态

My goal is to build a process-based conceptual framework for caterpillar early-instar ecology, by determining how phenology, plant physical and chemical defenses, group-living and natural enemies interact to produce emergent patterns of larval survivorship. In general, young larvae are poorly studied, but often suffer very variable high mortality rates caused by interacting species-specific stressors. This high variability in space and time implies that early-larval survival plays an important role in population dynamics. ******My comparative approach uses three systems chosen for their differences in life history, gregariousness and population dynamics: two important Canadian outbreaking forest pests - spruce budworm (Choristoneura fumiferana, solitary, conifer-feeders), forest tent caterpillars (Malacosoma disstria, gregarious, deciduous-feeders) and the diverse tropical clearwing butterflies (Ithominae, some species gregarious, others solitary). ***1. What behavioural mechanisms drive fluctuations in early-instar survival of Eastern Canada's most important forest pest? Extreme variations in early-instar survival constitute an important knowledge gap in predicting budworm outbreaks. I will fill this gap by testing behavioural mechanisms linking host plant phenology, leaf chemistry and previous defoliation to dispersal, competition and establishment of a feeding site. ***2. How does group-living modulate tri-trophic interactions in the forest tent caterpillar? I will test the hypothesis that group living implies a decrease in survival rate as groups get smaller, and that this feedback accelerates the attrition due to predation and plant defenses. ***3. How does group-living modulate tri-trophic interactions in clearwing caterpillars? I will apply the concepts and tools developed using temperate-zone gregarious caterpillars to the far greater diversity found in the tropics; specifically, I will test how grouping permits establishment on mechanically defended plants and colonization of disturbed habitats. ******These sub-objectives draw on the particular natural history of each study organism to formulate hypotheses about mechanisms driving early-instar ecology. Together they form an ambitious, innovative, wide-ranging research programme that synthesizes the effects of interacting stressors to explain complex emergent patterns in early-instar survivorship. My unique individual-based approach provides solid scientific grounding for conservation in tropical forests and mechanistic explanations of outbreak dynamics in the boreal forest, including responses to climate warming. The research on outbreaking pests is particularly timely since both are currently on the upsurge across much of Canada.**