Daugherty M P, Alto B W, Juliano S A
Division of Behavior, Ecology, Evolution, and Systematics, Department of Biological Sciences, Illinois State University, Normal, IL 61790-4120, USA.
J Med Entomol. 2000 May;37(3):364-72. doi: 10.1093/jmedent/37.3.364.
Terrestrial invertebrate carcasses are an important resource for insects developing in pitcher plants. However, little is known of the role of these carcasses in other containers, which also receive leaf fall and stemflow inputs. This experiment investigated effects of accumulated invertebrate carcasses as a resource for two competing mosquitoes, Aedes albopictus (Skuse) and Aedes aegypti (L.), whether either species differentially benefited from accumulated carcasses, and if such a benefit affected interspecific competition. First, we measured accumulation of invertebrate carcasses in standard containers at a field site. We then used a replacement series with five different species ratios at the same total density, and varied the input of invertebrate carcasses [dead Drosophila melanogaster (Meigen) ] in three levels: none, the average input from our field site, or the maximum input recorded at our field site. Survivorship, development time, and mass were measured for each mosquito species as correlates of population growth, and were used to calculate a population performance index, lambda'. There were strong positive effects of invertebrate carcass additions on all growth correlates and lambda'. Differences in performance between species were pronounced in small or no carcass additions and absent in large inputs of invertebrate carcasses, but there was little evidence that inputs of invertebrate carcasses altered the competitive advantage in this system. These results suggest that terrestrial invertebrate carcasses may be an important resource for many types of container communities, and large accumulations of dead invertebrates may reduce resource competition between these mosquitoes, thus favoring coexistence. We propose that the total amount of resource, including accumulated invertebrate carcasses, may explain observed patterns of replacement involving these mosquitoes.
陆生无脊椎动物尸体是猪笼草中发育的昆虫的重要资源。然而，对于这些尸体在其他也接收落叶和茎流输入的容器中的作用，我们知之甚少。本实验研究了积累的无脊椎动物尸体作为两种竞争蚊子——白纹伊蚊（Skuse）和埃及伊蚊（L.）的资源的影响，是否有任何一种蚊子从积累的尸体中获得不同的益处，以及这种益处是否影响种间竞争。首先，我们在一个野外地点测量了标准容器中无脊椎动物尸体的积累情况。然后，我们使用了一个替代系列，在相同的总密度下设置了五个不同的物种比例，并将无脊椎动物尸体（黑腹果蝇（Meigen）的尸体）的输入量分为三个水平：无、我们野外地点的平均输入量或我们野外地点记录的最大输入量。测量了每种蚊子的存活率、发育时间和体重，作为种群增长的相关指标，并用于计算种群表现指数λ'。添加无脊椎动物尸体对所有生长相关指标和λ'都有很强的积极影响。在添加少量或不添加尸体时，物种间的表现差异明显，而在大量添加无脊椎动物尸体时则不存在这种差异，但几乎没有证据表明无脊椎动物尸体的输入改变了这个系统中的竞争优势。这些结果表明，陆生无脊椎动物尸体可能是许多类型容器群落的重要资源，大量死亡无脊椎动物的积累可能会减少这些蚊子之间的资源竞争，从而有利于共存。我们认为，包括积累的无脊椎动物尸体在内的资源总量可能解释了观察到的涉及这些蚊子的替代模式。
