Prey selection by several orb-web spiders

A)测定了蜘蛛网的几个特征，并计算了每种蜘蛛网的下列指数：捕获指数=粘性强度X螺旋强度X半径强度X半径数*螺旋间距8个蜘蛛网根据捕获指数的大小分为三组：1)捕获指数很大，因此蜘蛛网可以捕获非常大的捕食性昆虫。当然，中小型猎物也可以被网络捕获。Argiope Bruennichi、A.amoena和NePhila clavata2)的网络捕获指数很小，因此网络只能捕获非常小和/或很轻的猎物。3)捕获量指数为中等大小的捕食性昆虫，其捕获量较小，可捕食中等大小的捕食性昆虫。(2)捕获量指数大的捕食网捕获各种大小的猎物，以极小的猎物最多。但是，Argiope Bruennichi有选择地喂食较大的猎物。捕获量指数较小的网捕获小猎物，主要是食线虫和蚂蚁。而以中等捕获量为指标的圆尾小蜂网主要捕捉的是小蜂，从而验证了小蜂网的特征与其猎物之间有密切的关系。

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.