BODY SIZES OF ANIMAL PREDATORS AND ANIMAL PREY IN FOOD WEBS
BODY SIZES OF ANIMAL PREDATORS AND ANIMAL PREY IN FOOD WEBS
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DOI：
10.2307/5483
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发表时间：
1993-01-01
影响因子：
4.8
通讯作者：
SALDANA, J
中科院分区：
文献类型：
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作者：
COHEN, JE;PIMM, SL;SALDANA, J
1.我们测量了在自然群落的食物网中发现的动物物种的身体大小(重量或长度)。在大约90%的已知体型的动物物种之间的取食环节中，体型较大的捕食者会吃掉体型较小的猎物。体型较大的捕食者比体型较小的捕食者吃的猎物的体型范围更广。捕食者的几何平均大小随着猎物大小的增大而增大。捕食者几何平均大小的增加与猎物大小的增加不成正比(即在对数-对数坐标上的斜率小于1)。捕食者和捕食者的几何平均大小随着网的栖息地从水生到陆地再到沿海到海洋的变化而增加。在每种类型的栖息地中，猎物的平均大小总是小于捕食者的平均大小，并且猎物和捕食者的大小总是正相关。摄食关系将生物体的代谢类型从无脊椎动物到脊椎动物外温体再到脊椎动物内温体排序。生物通常吃代谢类型相同或较低的其他生物，但(非常罕见的例外情况)生物不吃代谢类型较高的其他生物。猎物的平均大小随着猎物的代谢类型从无脊椎动物到脊椎动物的转变而增加，但对于捕食者来说并非如此。在从无脊椎动物猎物到无脊椎动物捕食者的链接中，猎物和捕食者的大小呈正相关。在与猎物和捕食者代谢类型的其他组合相联系时，猎物和捕食者的身体大小之间的相关性很少是正的，在某些情况下甚至是负的。物种大小大致呈对数正态分布。身体大小提供了一个很好的(尽管不是完美的)解释在级联模型中假定的动物物种的有序性，级联模型是食物网络结构的随机模型。当将体型作为对级联模型中假设的排序的物理解释时，当不同动物物种的体型为对数正态分布时，许多经验结果都可以用级联模型来解释。
1. We measured the body sizes (weights or lengths) of animal species found in the food webs of natural communities. In c. 90% of the feeding links among the animal species with known sizes, a larger predator consumes a smaller prey.2. Larger predators eat prey with a wider range of body sizes than do smaller predators. The geometric mean predator size increases with the size of prey. The increase in geometric mean predator size is less than proportional to the increase in prey size (i.e. has a slope less than 1 on log-log coordinates).3. The geometric mean sizes of prey and predators increase as the habitat of webs changes from aquatic to terrestrial to coastal to marine. Within each type of habitat, mean prey sizes are always less than mean predator sizes, and prey and predator sizes are always positively correlated.4. Feeding relations order the metabolic types of organisms from invertebrate to vertebrate ectotherm to vertebrate endotherm. Organisms commonly eat other organisms with the same or lower metabolic type, but (with very rare exceptions) organisms do not eat other organisms with a higher metabolic type. Mean sizes of prey increase as the metabolic type of prey changes from invertebrate to vertebrate ectotherm to vertebrate endotherm, but the same does not hold true for predators.5. Prey and predator sizes are positively correlated in links from invertebrate prey to invertebrate predators. In links with other combinations of prey and predator metabolic types, the correlation between prey and predator body sizes is rarely large when it is positive, and in some cases is even negative.6. Species sizes are roughly log-normally distributed.7. Body size offers a good (though not perfect) interpretation of the ordering of animal species assumed in the cascade model, a stochastic model of food web structure. When body size is taken as the physical interpretation of the ordering assumed in the cascade model, and when the body sizes of different animal species are taken as log-normally distributed, many of the empirical findings can be explained in terms of the cascade model.