Abrahamson Warren G, Armbruster Paulette O, Maddox G David
Department of Biology, Bucknell University, 17837, Lewisburg, Pennsylvania, USA.
Biological Sciences Building, Cornell University, 14853, Ithaca, New York, USA.
Oecologia. 1983 Jun;58(3):351-357. doi: 10.1007/BF00385235.
The field site conditions (soil pH, soil moisture, soil nutrient availability, etc.) and abundances of Solidago altissima (often included in S. canadensis sensu lato), three S. altissima specific stem gall formers, and the parasitepredator guilds for two of the three gall insects were investigated. It was found that S. altissima is tolerant of a wide range of site conditions. Herbivore (stem gall insects) occurrences were positively correlated with plant occurrence, in a linear fashion. However, there was no disproportionate increase in stem gall insect densities with plant density as might be predicted by the resource concentration hypothesis. Parasitoid guilds were exploiting stem gall insect populations over a wide range of occurrence, but were under-utilizing fields of higher herbivore occurrences. Path analysis showed a high degree of predictability in the causal models, with all but 14% of the ball gall parasitoid guild and all but 43% of the elliptical gall parasitoid guild occurrences explained by the direct influences of stem gall insect occurrence and the indirect influences of goldenrod occurrence and site conditions. The numerical relations of this three trophic level system suggest a well-integrated and well-controlled food chain.
研究了田间现场条件（土壤pH值、土壤湿度、土壤养分有效性等）以及加拿大一枝黄花（通常包含在广义的加拿大一枝黄花中）、三种加拿大一枝黄花特定的茎瘿蚊形成者的丰度，以及三种瘿蚊中的两种的寄生性天敌和捕食性天敌群落。结果发现，加拿大一枝黄花能耐受广泛的现场条件。草食动物（茎瘿蚊）的出现与植物的出现呈正相关，呈线性关系。然而，茎瘿蚊密度并没有随着植物密度的增加而出现不成比例的增加，这与资源集中假说的预测可能不同。寄生性天敌群落在广泛的出现范围内利用茎瘿蚊种群，但在草食动物出现率较高的田地中利用不足。通径分析表明，因果模型具有高度的可预测性，除14%的球形瘿蚊寄生性天敌群落和43%的椭圆形瘿蚊寄生性天敌群落外，所有出现情况都可以通过茎瘿蚊出现的直接影响以及一枝黄花出现和现场条件的间接影响来解释。这个三级营养系统的数量关系表明存在一个整合良好且控制良好的食物链。
