Preus Laura E, Morrow Patrice A
Department of Ecology, Evolution and Behavior, University of Minnesota, 1987 Upper Buford Circle, St. Paul, MN 55108, USA e-mail:
Oecologia. 1999 May;119(2):219-226. doi: 10.1007/s004420050779.
We examined the effects of the rhizome galling fly, Eurosta comma (Wiedemann), on rhizome mass and nitrogen allocation in a clone of its goldenrod host plant, Solidago missouriensis Nutt. In comparison to ungalled ramets, galled ramets initiated significantly fewer new rhizomes, and allocated less mass to leaves and stems and more to roots. Galled ramets had lower concentrations of nitrogen in roots and rhizomes but leaf and stem nitrogen concentrations were not affected. In the second year of our study, outbreaks of the leaf-eating beetle, Trirhabda canadensis (Kirby), occurred in three of our four study clones, removing ∼20%, ∼50%, and 100% of leaf area from clones 2-4, respectively. In the most heavily grazed clones, the influence of rhizome galls on plant resource allocation was least pronounced. Despite the overwhelming immediate impact of grazing, the presence of a gall population may be important because they decrease the ability of S. missouriensis clones to initiate new rhizomes and hence to recover from defoliation.
我们研究了根状茎瘿蚊（Eurosta comma (Wiedemann)）对其寄主植物密苏里一枝黄花（Solidago missouriensis Nutt.）克隆体的根状茎质量和氮分配的影响。与未受瘿害的分株相比，受瘿害的分株产生的新根状茎明显较少，分配到叶和茎的质量较少，而分配到根的质量较多。受瘿害的分株根和根状茎中的氮浓度较低，但叶和茎中的氮浓度不受影响。在我们研究的第二年，四个研究克隆体中有三个出现了食叶甲虫（Trirhabda canadensis (Kirby)）的爆发，分别从克隆体2 - 4中去除了约20%、约50%和100%的叶面积。在受啃食最严重的克隆体中，根状茎瘿对植物资源分配的影响最不明显。尽管放牧产生了压倒性的直接影响，但瘿虫种群的存在可能很重要，因为它们降低了密苏里一枝黄花克隆体产生新根状茎的能力，从而降低了从落叶中恢复的能力。
