Tanaka Koichi
Laboratory of Applied Entomology and Nematology, Faculty of Agriculture, Nagoya University, Chikusa, 464, Nagoya, Japan.
Oecologia. 1991 Mar;86(1):8-15. doi: 10.1007/BF00317382.
Prey capture rate, food consumption, and diet composition of all developmental stages of the funnelweb spider Agelena limbata were estimated in woody and open habitats by a sight-count method. Prey availability was evaluated on the basis of two indices, i.e. the ratios of daily food consumption to dry weight of predator and to daily standard metabolic rate. These indices varied seasonally and between instars in this spider. Comparison of these indices between arthropod predators suggests that A. limbata live under conditions of relatively limited food supply. In the open habitat, the spiders reduced foraging activities to avoid heat stress at midday in summer because the sheet web was exposed to the direct rays of the sun and its temperature exceeded 40°C. The daily food consumption of adult spiders in the open habitat was about half of that in the woody habitat. The lower rate of energy intake of spiders in the open habitat may cause the observed smaller size of adults and lower fecundity. A. limbata captured a great range of prey comprising ten orders of arthropods and ate chemically defended insects, e.g. stink bugs, lady beetles, and ants which were rejected by many spiders. This generalistic foraging may be associated with limited and heterogeneous food supply in this spider.
通过定点计数法，对漏斗网蜘蛛（Agelena limbata）所有发育阶段在木质栖息地和开阔栖息地的猎物捕获率、食物消耗量及食物组成进行了估算。基于两个指标对猎物可利用性进行了评估，即每日食物消耗量与捕食者干重之比以及与每日标准代谢率之比。在这种蜘蛛中，这些指标随季节和龄期而变化。节肢动物捕食者之间这些指标的比较表明，A. limbata生活在食物供应相对有限的条件下。在开阔栖息地，由于片状蛛网暴露在直射阳光下且温度超过40°C，蜘蛛在夏季中午会减少觅食活动以避免热应激。开阔栖息地成年蜘蛛的每日食物消耗量约为木质栖息地的一半。开阔栖息地蜘蛛较低的能量摄入率可能导致观察到的成年蜘蛛体型较小且繁殖力较低。A. limbata捕获了种类繁多的猎物，包括十个目节肢动物，并且会捕食化学防御的昆虫，如臭虫、瓢虫和蚂蚁，而许多蜘蛛会拒绝捕食这些昆虫。这种广食性觅食可能与该蜘蛛有限且异质的食物供应有关。
