Nentwig Wolfgang, Wissel Christian
Institut für Zoologie der Universität, Universitätsstr. 31, D-8400, Regensburg, Federal Republic of Germany.
Fachbereich Biologie der Universität, Postfach 1929, D-3550, Marburg, Federal Republic of Germany.
Oecologia. 1986 Mar;68(4):595-600. doi: 10.1007/BF00378777.
Field observations and laboratory experiments were carried out to determine the influence of body length of preys on the acceptance rate by spiders. Feeding experiments with 13 spider species and a model prey (crickets) reveal a decreasing acceptance rate with increasing prey size. Prey sizes of 50-80% of the spiders' size yielded the highest acceptance rates, crickets of double the spiders' size were accepted by two species only. By fitting the acceptance rate Y versus prey size X by Y(x)=Y(0) (1-βx), two coefficients could be calculated: Y(0), the size-independent palatibility of the prey and β, a coefficient of size-induced refusal of the prey. These values describe the degree of specialisation towards (a) crickets and (b) large prey, respectively. Further comparison showed (a) that labidognath (= araneomorph) spiders do not necessarily subdue larger prey items than orthognath (=mygalmorph) spiders and (b) that webbuilding spiders are superior to non-webbuilding spiders in respect of catching large prey. A modified model of the generalized pattern of the length relations of predator and prey is given with special reference to spiders and compared to other polyphagous predator groups.
通过实地观察和实验室实验来确定猎物体长对蜘蛛接受率的影响。对13种蜘蛛和一种模型猎物（蟋蟀）进行的喂食实验表明，随着猎物尺寸的增加，接受率降低。猎物尺寸为蜘蛛尺寸的50 - 80%时接受率最高，只有两种蜘蛛会接受尺寸为其两倍的蟋蟀。通过用Y(x)=Y(0) (1 - βx)拟合接受率Y与猎物尺寸X，可计算出两个系数：Y(0)，即猎物与尺寸无关的适口性；β，即猎物因尺寸导致被拒的系数。这些值分别描述了对（a）蟋蟀和（b）大型猎物的专业化程度。进一步比较表明：（a）游走蛛（=新蛛亚目）不一定比原蛛亚目蜘蛛制服更大的猎物；（b）织网蜘蛛在捕捉大型猎物方面优于非织网蜘蛛。给出了一个针对蜘蛛的捕食者与猎物长度关系广义模式的修正模型，并与其他多食性捕食者群体进行了比较。
