Effects of Recruitment and Post-recruitment Processes on Abundance of Stream Insects: a Comparative Approach

BARBRACTDEB 0089863 PI：Barbara L.Peckarsky补充和补充后的过程对溪流昆虫丰度的影响：一种比较的方法这项研究将帮助我们理解多种因素如何相互作用来影响自然界动植物的丰度。这项建议的目的是通过在现实的野外条件下进行观察和实验来解释溪流昆虫种群的丰度模式。在自然溪流中的实验将测试两种蚂蚁幼虫的丰度是否取决于成虫产卵的数量，或者幼虫栖息地的食物或捕食者的数量。这两种蚂蚁在产卵行为、对鲑鱼捕食的脆弱性以及面临风险捕食和低水平食物(藻类)时的行为上存在差异。首先，在与Stephen Ellner博士的合作中，我们将使用模拟模型来预测招募(产卵)、捕食者的存在和食物的数量如何影响每一种蚂蚁的相对丰富度。其次，我们将测量不同食物水平(藻类)的天然鱼类和无鱼溪流中的产卵、幼虫扩散行为(漂移)和蚂蚁数量。第三，在大规模的野外实验中，我们将添加或移除其中一种蚂蚁产卵所用的岩石和原木，以直接测试幼虫的丰度是否与招募有关。第四，我们将从装有鲑鱼的容器中将水滴入无鱼溪流，以确定蚂蚁对鲑鱼化学物质的反应漂移是否可以解释鱼类和无鱼溪流中的丰度模式。最后，我们将在溪流旁的流通室进行的实验中操纵多个因素，以确定蚂蚁对食物和捕食者的反应是否可以解释幼虫的数量。具体地说，我们希望确定与捕食者和资源的相互作用是否超过了招募，以解释溪流中蚂蚁幼虫的丰富。这项研究可以推广到适用于生活在开放系统中并具有一个或多个高度流动性生命阶段的其他有机体的种群。

ABSTRACTDEB 0089863PI: Barbara L. PeckarskyEffects of recruitment and post-recruitment processes on abundance of stream insects: a comparative approachThis study will help us understand how multiple factors interact to affect the abundance of plants and animals in nature. The goal of this proposal is to explain patterns of abundance of stream insect populations by conducting observations and experiments under realistic field conditions. Experiments in natural streams will test whether the abundance of larvae of two mayfly species is determined by the number of eggs laid by adults or the amount of food or predators in the larval habitat. The two mayfly species differ in egg-laying behavior, vulnerability to trout predation and behavior when faced with the risk predation and low levels of food (algae). First, in collaboration with Dr. Stephen Ellner we will use simulation models to predict how recruitment (egg-laying), presence of predators, and amount of food should affect the relative abundance of each mayfly species. Second, we will measure egg-laying, larval dispersal behavior (drift) and mayfly abundance in natural fish and fishless streams with different levels of food (algae). Third, in large-scale field experiments we will add or remove rocks and logs used by one of the mayfly species for egg-laying to test directly whether abundance of larvae is a function of recruitment. Fourth, we will drip water from containers with trout into fishless streams to determine whether drift of mayflies in response to trout chemicals can explain patterns of abundance in fish and fishless streams. Finally, we will manipulate multiple factors in experiments carried out in stream-side, flow-through chambers to determine whether drift of mayflies in response food and predators can explain larval abundance. Specifically, we hope to determine whether interactions with predators and resources override recruitment to explain the abundance of mayfly larvae in streams. This research can be generalized to apply to populations of other organisms that live in open systems and have one or more highly mobile life stages.