Cronin James T, Abrahamson Warren G
Department of Biology, University of North Dakota, P.O. Box 9019, 58202-9019, Grand Forks, ND, USA.
Department of Biology, Bucknell University, 17837, Lewisburg, PA, USA.
Oecologia. 2001 Mar;127(1):87-96. doi: 10.1007/s004420000561. Epub 2001 Mar 1.
Few studies have examined how the preference-performance relationship of an herbivore for different genotypes of its host plant is affected by the presence and/or feeding activity of other members of the herbivore assemblage. In an outdoor garden, we manipulated the abundance of three common herbivores, the meadow spittlebug, a leaf beetle, and an aphid, on replicate 1-m plots of 16 different genotypes of tall goldenrod, Solidago altissima. Adults of the goldenrod stem galler, Eurosta solidaginis, were subsequently released into the garden to oviposit among the host plants. Oviposition preference was strongly influenced by plant genotype and the presence of two of the herbivores, spittlebugs and leaf beetles. The effects of the herbivores were additive: the presence of leaf beetles reduced preference by 6%, spittlebugs by 18%, and both herbivores combined by 25%. Plant genotype-herbivore species interaction effects on stem-galler preference, which would indicate the presence of genetic variation among goldenrod genotypes in their norms of reaction for their acceptability as a host to the stem galler, were absent in this study. The performance of the stem galler was also significantly affected by goldenrod genotype, but in general was not affected by the presence of herbivores early in the season (the exception was a positive correlation between the proportion of ramets infested by all herbivores and gall size). Overall, we could find no correlation between preference and performance. This is in accord with results from previous studies on this system that were performed in the absence of herbivores, suggesting that the presence of herbivores in this study did not qualitatively alter the preference-performance relationship. We suggest that the lack of a positive correlation between host-plant preference and larval performance may reflect a constraint on the discriminatory ability of female stem gallers preventing them from selecting the best hosts among plants that differ in genotype and level of environmental stress (e.g., presence of interspecific herbivores).
很少有研究探讨食草动物对其寄主植物不同基因型的偏好-表现关系如何受到食草动物组合中其他成员的存在和/或取食活动的影响。在一个户外花园中，我们在16种不同基因型的高一枝黄花（Solidago altissima）的1米重复样地中，对三种常见食草动物——草地沫蝉、叶甲和蚜虫的数量进行了控制。随后，将一枝黄花茎瘿蚊（Eurosta solidaginis）的成虫放入花园，让它们在寄主植物中产卵。产卵偏好受到植物基因型以及两种食草动物（沫蝉和叶甲）的存在的强烈影响。食草动物的影响是累加的：叶甲的存在使偏好降低了6%，沫蝉使偏好降低了18%，两种食草动物共同存在使偏好降低了25%。本研究中不存在植物基因型-食草动物物种对茎瘿蚊偏好的交互作用效应，而这种效应本可表明一枝黄花基因型之间在作为茎瘿蚊寄主的可接受性反应规范方面存在遗传变异。茎瘿蚊的表现也受到一枝黄花基因型的显著影响，但总体上不受季节早期食草动物存在的影响（唯一的例外是所有食草动物侵染的分株比例与瘿大小之间存在正相关）。总体而言，我们没有发现偏好与表现之间存在相关性。这与之前在没有食草动物的情况下对该系统进行的研究结果一致，表明本研究中食草动物的存在并没有定性地改变偏好-表现关系。我们认为寄主植物偏好与幼虫表现之间缺乏正相关可能反映了雌性茎瘿蚊辨别能力的限制，使它们无法在基因型和环境胁迫水平（例如种间食草动物的存在）不同的植物中选择最佳寄主。
