Hieber Craig S, Uetz George W
Department of Biology, St. Anselm College, 03102, Manchester, NH, USA.
Department of Biological Sciences, University of Cincinnati, 45221, Cincinnati, OH, USA.
Oecologia. 1990 Feb;82(2):145-150. doi: 10.1007/BF00323527.
While a number of advantages may result from group living, it may also lead to increased levels of attack by parasites because groups may be easier to find. This leads to the prediction that levels of parasitism should increase with colony size. We test this prediction by comparing colony size and parasitoid load for two species of colonial orb-weaving spiders from Mexico, Metepeira (undesc. sp., tentatively named atascadero) and Metepeira incrassata, which exhibit contrasting levels of social organization and utilize different habitats. For M. atascadero, which occurs solitarily or in small groups in desert/mesquite grassland habitat, rates of egg-sac parasitism fluctuate widely from year to year, and are closely tied to spider egg output. There is no relationship between colony size and rate of parasitism. For colonial M. incrassata, which occur in tropical rain forest/agricultural habitat, rates of parasitism are relatively constant from year to year. However, there is a positive relationship between colony size and rate of parasitism in this species. These differences are discussed with regard to the stability of the two habitats, prey availability, and the foraging behavior of the respective parasitoids.
虽然群居可能带来许多好处，但也可能导致寄生虫攻击水平的增加，因为群体可能更容易被发现。这就引出了一个预测，即寄生水平应该随着群体规模的增加而上升。我们通过比较来自墨西哥的两种群居圆网蛛——未定种的梅特佩拉蛛（暂定名为阿塔斯卡德罗蛛）和梅特佩拉厚蛛——的群体规模和寄生蜂负载来检验这一预测，这两种蜘蛛表现出不同程度的社会组织，并利用不同的栖息地。对于单独或小群体生活在沙漠/豆科草原栖息地的阿塔斯卡德罗蛛来说，卵囊被寄生的比率年际波动很大，并且与蜘蛛的产卵量密切相关。群体规模与寄生率之间没有关系。对于生活在热带雨林/农业栖息地的群居厚蛛来说，寄生率年际相对稳定。然而，在这个物种中，群体规模与寄生率之间存在正相关关系。我们从两种栖息地的稳定性、猎物可获得性以及各自寄生蜂的觅食行为等方面对这些差异进行了讨论。
