Prey selection by several orb-web spiders

A）测量了蜘蛛网的几个特征，并计算了每个物种的网的以下指数：捕获指数=螺旋强度X螺旋强度X半径强度X半径数量X螺旋之间的间隔八个蜘蛛网根据捕获指数的值分为以下三组：1）捕获指数很大，所以网可以捕获非常大和重的猎物昆虫。当然，小型和中型的猎物也可以被网捕获。2）捕获指数很小，只能捕获很小和/或很轻的猎物。3）捕食指数为中等，可捕食中小型昆虫。B）捕获指数大的网能捕获各种大小的猎物，以小型猎物最多。但是，Argiope bruennichi选择性地喂养较大的猎物。捕食指数小的蜘蛛网捕获的猎物主要是小型昆虫和蜉蝣。而孔氏圆腹蛛的网主要捕获蜉蝣类，网的捕获指数为中等，证实了网的特征与其猎物的关系密切。

A) Several characters of spider webs were measured and following index was calculated for the webs of each species :Capture Index = Intensity of adhesiveness X Strength of spirals XStrength of radii X Number of radii * Interval between spirals Eight spider webs are divided into following three groups by the value of the capture index :1) Capture index is very large, so the web can capture very large and heavy prey insects. Of course, small and intermediate sized prey can also be captured by the webs. The webs of Argiope bruennichi, A.amoena and Nephila clavata.2) Capture index is very small, so the web can capture only very small and / or light prey. The webs of Tetragnatha maxillosa, T.praedonia and Leucauge magnifica.3) The value of capture index is intermediate, so the web can small and intermaediate sized prey insects. The webs of Argiope boesenbergi and Metleucauge kompirensis.B) The webs with large capture index captured various sized prey, and very small prey were most abaundant. But, Argiope bruennichi fed larger prey selectively. The webs with small capture index captured small prey, mainly nematocerous insects and mayflies. And the webs of Metleucauge kompirensis, with intermediatecapture index, captured mainly mayflies.So, it was verified that there was the close relationship between the characteristics of the web and its prey.