Modeling nitrogen flux by larval insect herbivores from a temperate hardwood forest
Modeling nitrogen flux by larval insect herbivores from a temperate hardwood forest
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模拟温带阔叶林食草动物幼虫昆虫的氮通量
作者：
T. Meehan;R. Lindroth
草食性昆虫将大量的氮以粪便的形式从森林冠层转移到土壤中。氮通量的量取决于食草动物的特征，它们的食物资源和物理环境。我们使用的概念，从代谢生态学和生态化学计量学发展的一般模型，个人的氮通量通过粪便下降蛾和叶蜂幼虫从温带硬木林北方威斯康星州，美国。我们发现，个体氮通量（QN，mg N/天）与幼虫体重（MB，mg干重）、环境温度的短期变化（T，K）和幼虫氮浓度（NB，干重比例）相关，公式为QN = e25.75MB0.77 e−0.83/kTNB−1.56，其中k为玻尔兹曼常数（8.62 × 10−5 eV/K）。我们还发现，幼虫的氮通量不随食物的氮浓度而变化，并建议这是由于补偿性摄食幼虫生活在低质量的叶片。随着进一步的工作，个人的N通量模型可以被用来缩放个人通量的人口和社区水平，从而连接的特点，昆虫草食动物社区与氮通过森林生态系统的流动。
Herbivorous insects flux considerable amounts of nitrogen from the forest canopy to the soil in the form of frass. The amount of nitrogen fluxed varies depending on the characteristics of the herbivores, their food resources, and their physical environment. We used concepts from metabolic ecology and ecological stoichiometry to develop a general model of individual nitrogen flux via frass fall for moth and sawfly larvae from a temperate hardwood forest in northern Wisconsin, USA. We found that individual nitrogen flux (QN, mg N/day) was related to larval body mass (MB, mg dry), short-term variation in environmental temperature (T, K), and larval nitrogen concentration (NB, proportion dry mass) as QN = e25.75MB0.77 e−0.83/kTNB−1.56, where k is Boltzmann’s constant (8.62 × 10−5 eV/K). We also found that larval nitrogen flux did not vary with the nitrogen concentration of food, and suggest that this was due to compensatory feeding by larvae living on low-quality leaves. With further work, models of individual N flux could be used to scale individual fluxes to population and community levels, and thus link the characteristics of insect herbivore communities with the flow of nitrogen through forested ecosystems.