Spiller D A, Schoener T W
Department of Zoology, University of California, 95616, Davis, CA, USA.
Oecologia. 1990 Jun;83(2):150-61. doi: 10.1007/BF00317746.
To determine the effect of lizards on webspider populations, we conducted a long-term field experiment in the Bahamas. Numbers of spider individuals were about 3 times higher in lizard-removal enclosures than in control enclosures with natural densities of lizards. Dietary analyses showed that lizards ate spiders and that lizard and spider diets overlapped substantially. Lizards reduced biomass of prey consumed by spiders; details indicated that they reduced biomass of large (> 4 mm) prey consumed by spiders more than biomass of small (≤4 mm) prey. Similarly, lizards reduced biomass of large aerial arthropods caught in sticky traps but not biomass of small aerial arthropods. We found no evidence that the lizard effect on prey consumption by spiders was caused by a spatial shift from areas with high aerial arthropod abundance to areas with low aerial arthropod abundance. Lizards reduced adult female cephalothorax width and fecundity of spiders. In a separate experiment, food-supplemented spiders were more fecund than control spiders. This study indicates that the interaction between lizards and spiders includes both predation and competition for food.
为了确定蜥蜴对蜘蛛种群的影响，我们在巴哈马群岛进行了一项长期的野外实验。在移除蜥蜴的围栏中，蜘蛛个体数量比蜥蜴自然密度的对照围栏中高出约3倍。饮食分析表明，蜥蜴会捕食蜘蛛，且蜥蜴和蜘蛛的食物存在大量重叠。蜥蜴减少了蜘蛛所消耗猎物的生物量；具体细节表明，它们减少的蜘蛛所消耗的大型（>4毫米）猎物的生物量比小型（≤4毫米）猎物的生物量更多。同样，蜥蜴减少了粘蝇板上捕获的大型空中节肢动物的生物量，但没有减少小型空中节肢动物的生物量。我们没有发现证据表明蜥蜴对蜘蛛猎物消耗的影响是由从空中节肢动物丰富区域向空中节肢动物稀少区域的空间转移所导致的。蜥蜴降低了蜘蛛成年雌体的头胸甲宽度和繁殖力。在另一项实验中，补充食物的蜘蛛比对照蜘蛛繁殖力更强。这项研究表明，蜥蜴和蜘蛛之间的相互作用包括捕食和对食物的竞争。
