Consequences of Larval Interactions to Mayfly Survival, Fecundity and Population Growth

9306842 Peckarsky拟议研究的目的是(1)确定溪流栖息的二尾双尾小蜂幼虫的死亡率中有多少是由于石蝇和鲑鱼的捕食以及线虫的寄生所致，(2)测量在避开竞争对手、捕食性石蝇和鲑鱼的同时减少取食对雌性产卵量和与大小相关的雄性交配成功的影响，以及(3)使用各种方法估计可能苍蝇的数量增长，确定捕食者、寄生虫和竞争对手对梅弗里种群长期维持能力的相对影响。为达到这些目标而提出的方法包括：(A)在小型(25厘米)和大型(1.5米)围栏中进行实验，以测量捕食石蝇和鲑鱼对果蝇死亡率的影响；(B)进行行为实验，以确定鲑鱼捕食对进入水柱以躲避石蝇捕食的果蝇的风险；(C)解剖果蝇幼虫和成虫，以估计线虫感染、绝育和死亡的阶段和性别；以及(D)在小型和大型围栏中进行实验，以测量捕食者对果蝇生长速度、成虫大小和产卵的影响，(E)现场实验将确定较大的雄性蚂蚁是否有更大的交配成功，以及(F)在捕食者竞争对手密度不同的地点或溪流中，大小和产卵量以及完成幼虫阶段的蚂蚁。这些数据将说明，在较小的尺度(在围栏中)观察到的任何捕食者回避的影响是否可以在自然溪流中检测到较大的尺度。这些实验的数据将被用来比较面对石蝇和鲑鱼捕食者、寄生虫和竞争对手时可能会出现的种群增长。将获得对蚂蚁种群增长的文件估计，作为对实验得出的种群增长率的“现实检查”。这项研究的主要贡献是对影响幼虫道德和行为的因素与成虫繁殖成功之间的关系进行了独特的调查。以往没有研究比较捕食、寄生和竞争等一系列选择压力对自然种群一个阶段的影响，并从整个生命周期的背景下解释这些对种群增长的影响。$！8！F(Times New Roman符号&amp；Arial*“h k k 7水晶黑剪水晶黑剪

9306842 Peckarsky The objectives of the proposed research are to (1) determine how much of the death rate of the stream-dwelling larval mayfly, Baetis bicaudatus, is due to stonefly and trout predation, and to parasitism by nematode worms, (2) measure the consequences of reduced feeding by mayflies while avoiding competitors, predatory stoneflies and trout in terms of female egg production and size-related male mating success, and (3) using methods to estimate mayfly population growth, determine the relative impacts of predators, parasites and competitors on the mayflys' ability to sustain populations over the long term. Meathods proposed to meet those objectives include: (a) experiments conducted in small (25cm) and large (1.5m) enclosures to measure the effects of stonefly and trout predation on mayfly death rate, (b) behavioral experiments to determine the risk of trout predation to mayflies that have entered the water column to escape stonefly predation, (c) dissections of mayfly larvae and adults to estimate stages and sexes of infection, sterilization and death cause by nematode worms, and (d) experiments conducted in small and large enclosures to measure the effects of predator on mayfly growth rates, sizes of adults and egg production, (e) field experiments will determine whether larger male mayflies have greater mating success, and (f) sizes and egg production and mayflies that completed their larval stage in sites or streams with different densities of predators competitors. These data will illustrate whether any effects of predator avoidance observed at a smaller scale (in enclosures) can be detected a t larger scales in natural streams. Data from these experiments will be used to compare mayfly population growth in the face of stonefly and trout predators, parasites and competitors. Filed estimates of mayfly population growth will be obtained as a "reality check" on experimentally derived population growth rates. The key contribution of this research is a unique investigation of connections between factors affecting larval morality and behavior and adult reproductive success. No previous studies have compared the consequences of a suite of selection pressures such as predation, parasitism and competition on one stage of a natural population, and interpreted these impacts on population growth in context of the complete life cycle. $ ! ! !8 ! F ( Times New Roman Symbol & Arial * " h k k 7 Crystal Blackshear Crystal Blackshear