Rypstra Ann L, Tirey R Scott
Miami University, 1601 Peck Boulevard, 45011, Hamilton, OH, USA.
Oecologia. 1991 Mar;86(1):25-30. doi: 10.1007/BF00317384.
Selection might favor group foraging and social feeding when prey are distributed in patches that do not last long enough for a solitary individual to consume more than a small fraction of them (Pulliam and Millikan 1982; Pulliam and Caraco 1984). Here we considered the foraging behavior of a social spider, Anelosimus eximius, in light of this ephemeral resource hypothesis. This species builds large webs in which members cooperate to capture a wide variety of different sizes and types of prey, many of which are very large. The capture success of this species was very high across all prey sizes, presumably due to the fact that they foraged in groups. Group consumption times in natural colonies for all prey larger than five mm were less than the time that dead insects remained on the plastic sheets that we used as artificial webs. Solitary consumption estimates, calculated from the rate at which laboratory individuals extracted insect biomass while feeding, were the same as the residence times of insects on artificial webs in the field for insects between 6 and 15 mm in length and were significantly longer than the persistence of insects on plastic sheets for all larger insects. Large prey, that contribute substantially to colony energy supplies, appeared to be ephemeral resources for these spiders that could not be consumed by a single spider in the time they were available. These factors made the food intake of one spider in a group less sensitive to scavenging by others and could act to reinforce the social system of this species.
当猎物分布在斑块中，且这些斑块存在时间过短，以至于单独的个体无法消耗其中一小部分以上时，选择可能有利于群体觅食和社会进食（普利姆和米利坎，1982年；普利姆和卡拉科，1984年）。在此，我们根据这种短暂资源假说，研究了一种群居蜘蛛——卓越暗蛛（Anelosimus eximius）的觅食行为。该物种会织造大型蛛网，成员们在其中合作捕获各种不同大小和类型的猎物，其中许多猎物非常大。该物种在所有猎物大小范围内的捕获成功率都很高，大概是因为它们以群体形式觅食。自然群体中，对于所有大于5毫米的猎物，群体消耗时间都短于我们用作人工蛛网的塑料片上死昆虫停留的时间。根据实验室个体进食时提取昆虫生物量的速率计算得出的单独消耗估计值，与6至15毫米长的昆虫在野外人工蛛网上的停留时间相同，且对于所有更大的昆虫，该估计值显著长于昆虫在塑料片上的停留时间。对群体能量供应有重大贡献的大型猎物，似乎是这些蜘蛛的短暂资源，单个蜘蛛在其可利用的时间内无法将其消耗殆尽。这些因素使得群体中一只蜘蛛的食物摄入量对其他蜘蛛的 scavenging 不太敏感，并且可能有助于强化该物种的社会系统。 （注：原文中“scavenging”此处翻译可能不太准确，推测可能是“争抢食物”之类的意思，但由于原文如此，暂按此翻译）
