MacKay William P
Department of Biology, University of California, 92521, Riverside, California.
Oecologia. 1982 Jun;53(3):406-411. doi: 10.1007/BF00389022.
Spiders have been shown to be important predators on ant populations, although ant mortality may be low. Western widow spider (Latrodectus hesperus) predation on Pogonomyrmex rugosus ant nests is slight, less than 0.2% of the nest population per day. Yet, the ants respond by halting foraging temporarily and may even close the nest entrace with pebbles. If spiders are removed from such nests, the ants become active within 24 h and within five days foraging activity reaches higher levels than at any previous time of the year.Ants have at least four responses to spiders predation: 1) Moving the nest entrace; 2) posting of "guards"; 3) attacking the spiders; 4) halting foraging. Pogonomyrmex rugosus practices the fourth response, although it results in losses of food intake into the nest. This is apparently the only option available. If the ants continue to forage, the spider density may increase, resulting in heavy mortality of the ants.
蜘蛛已被证明是蚂蚁种群的重要捕食者，尽管蚂蚁的死亡率可能很低。西部黑寡妇蜘蛛（间斑寇蛛）对粗糙收获蚁巢穴的捕食很轻微，每天捕食量不到巢穴蚁群数量的0.2%。然而，蚂蚁的反应是暂时停止觅食，甚至可能用小石子封闭巢穴入口。如果从这些巢穴中移除蜘蛛，蚂蚁在24小时内就会变得活跃起来，并且在五天内觅食活动达到一年中此前任何时候都更高的水平。蚂蚁对蜘蛛捕食至少有四种反应：1）移动巢穴入口；2）布置“警卫”；3）攻击蜘蛛；4）停止觅食。粗糙收获蚁采取第四种反应，尽管这会导致巢穴食物摄入量减少。这显然是唯一可行的选择。如果蚂蚁继续觅食，蜘蛛密度可能会增加，导致蚂蚁大量死亡。
