Tabashnik Bruce E
Department of Biological Sciences, Stanford University, 94305, Stanford, CA, USA.
The Rocky Mountain Biological Laboratory, 81224, Crested Butte, Colorado, USA.
Oecologia. 1982 Dec;55(3):389-394. doi: 10.1007/BF00376927.
This study examined the effects of intraspecific variation in leaf nitrogen and water content on the growth, consumption, conversion efficiency and nitrogen use of Colias butterfly larvae. Pest and non-pest Colias philodice eriphyle larvae and Colias eurytheme larvae were fed field-collected alfalfa (Medicago sativa) and vetch (Vicia americana) leaves in laboratory experiments. In all treatments, at least one indicator of larval growth performance was positively correlated with leaf nitrogen content, which supports the view that nitrogen is a limiting nutrient for larval growth. The benefits associated with eating leaves with high nitrogen content included higher growth rates, conversion efficiencies, nitrogen accumulation rates and larval nitrogen contents. Over the ranges examined in this study, variation in leaf nitrogen content (2.8-7.0% dry wt) affected larval growth more than variation in leaf water content (66-79% fresh wt). Pest and non-pest C. p. eriphyle responded alike to variation in the leaf nitrogen content of vetch, but there were differences between populations on alfalfa. Pest larvae were more sensitive to variation in leaf water content than non-pest larve. The differences between these populations may be due to specific adaptations resulting from the shift to alfala by pest Colias. It is suggested that herbivores' responses to intraspecific variation in leaf nitrogen content may have important consequences for the evolution of plant defenses and nutrient allocation patterns, and for agricultural pest management.
本研究考察了叶片氮含量和含水量的种内变异对科利亚斯蝴蝶幼虫生长、取食、转化效率及氮利用的影响。在实验室实验中，用田间采集的苜蓿（紫花苜蓿）和野豌豆（美洲野豌豆）叶片喂养害虫和非害虫的爱氏科利亚斯幼虫及苜蓿银纹夜蛾幼虫。在所有处理中，幼虫生长性能的至少一项指标与叶片氮含量呈正相关，这支持了氮是幼虫生长的限制营养元素这一观点。取食高氮含量叶片带来的益处包括更高的生长速率、转化效率、氮积累速率及幼虫氮含量。在本研究考察的范围内，叶片氮含量（干重2.8 - 7.0%）的变异对幼虫生长的影响大于叶片含水量（鲜重66 - 79%）的变异。害虫和非害虫的爱氏科利亚斯对野豌豆叶片氮含量的变异反应相似，但在苜蓿上不同种群间存在差异。害虫幼虫比非害虫幼虫对叶片含水量的变异更敏感。这些种群间的差异可能是由于害虫科利亚斯向苜蓿转移所产生的特定适应性。研究表明，食草动物对叶片氮含量种内变异的反应可能对植物防御和养分分配模式的进化以及农业害虫管理具有重要影响。
