Dissertation Research: The Influence of Concurrent Costs andRisks on the Foraging Behavior of Grazing Mayflies

觅食的生物体在决定如何以及何时在食物块内和之间移动时，通常必须考虑许多因素。这项研究的目的是(1)比较两种在形态和行为上不同的溪流昆虫对觅食时所经历的成本和风险组合的反应，(2)详细研究一种潜在成本，竞争对手的存在如何影响觅食行为，以及(3)确定觅食密度和资源水平对生长和繁殖的影响。对不同环境条件下与竞争者和捕食者强迫接触的反应的行为观察将被用来比较不同因素的相对重要性。对不同密度和资源水平的喂食个体之间相互作用的行为观察将被用来确定潜在竞争对手之间相互作用的性质。衡量生长速度和繁殖力的实验将确定资源水平和竞争对手的存在是否会影响健康。这项研究的主要贡献将是评估在觅食过程中面临的多种并发成本和风险之间的相互作用，并确定竞争的作用。这些发现的潜在应用包括：管理被放养的溪流中的鲑鱼，以及预测溪流栖息地变化的影响。这项研究的基本信息还将有助于理解维持物种多样性的机制，并增加保护做法的稳健性。

Foraging organisms typically must consider many factors when making decisions about how and when to move within and between patches of food. The objectives of this research are to (1) contrast the responses of two streams insects which are morphologically and behaviorally distinct to combinations of costs and risks experienced while foraging, (2) examine in detail how one potential cost, the presence of competitors, influences foraging behavior, and (3) determine the influence of forager density and resource levels on growth and reproduction. Behavioral observations of responses to forced contacts with competitors and predators under different environmental conditions will be used to compare the relative importance of the different factors. Behavioral observations of interactions between feeding individuals at different densities and resource levels will be used to determine the nature of interactions between potential competitors. Experiments which measure growth rate and fecundity will determine if resource levels and the presence of competitors influence fitness. The principle contribution of this research will be an assessment of interactions between multiple concurrent costs and risks faced while foraging, and a determination of the role of competition. Potential applications of the findings include: management of trout in stocked streams, and prediction of effects of alterations of stream habitats. Basic information from the study will also contribute to the understanding of mechanisms that maintain species diversity and increase the robustness of conservation practices.