Berg Thomas B
Department of Arctic Environment, National Environmental Research Institute, Frederiksborgvej 399, 4000 Roskilde, Denmark.
Oecologia. 2003 Apr;135(2):242-9. doi: 10.1007/s00442-002-1176-1. Epub 2003 Feb 8.
Chemical- plant defences as mechanisms affecting herbivore populations have been debated during the past decade. Several authors have questioned the hypothesis, but the present study shows that collared lemmings ( Dicrostonyx groenlandicus) in northeast Greenland prefer food plants with a lower catechin content. Dicrostonyx species are known to have specialised on shrubs, especially Dryas spp. and Salix spp., rather than graminoids like other related microtines. Bioassays were conducted using food material from Dryas spp., Salix arctica, Vaccinium uliginosum, Kobresia myosuroides and Poa glauca. Enclosures with the first three species mentioned were further treated by clipping to simulate herbivory in order to induce the production of the plant defence compound catechin. Treatment increased the catechin content in Dryas spp., S. arctica (females only) and V. uliginosum significantly compared with the catechin concentration in untreated plants. These elevated catechin concentrations had a significantly negative effect on the consumption rate of Dryas spp. and female S. arctica by collared lemmings.
在过去十年里，作为影响食草动物种群数量机制的化工厂防御一直存在争议。几位作者对这一假设提出了质疑，但本研究表明，格陵兰东北部的环颈旅鼠（Dicrostonyx groenlandicus）更喜欢儿茶素含量较低的食用植物。已知环颈旅鼠属物种专门以灌木为食，尤其是仙女木属植物和柳属植物，而不是像其他相关田鼠那样以禾本科植物为食。使用来自仙女木属植物、北极柳、湿地越橘、嵩草和早熟禾的食物材料进行了生物测定。对提到的前三个物种的围栏进行了修剪处理，以模拟食草行为，从而诱导植物防御化合物儿茶素的产生。与未处理植物中的儿茶素浓度相比，处理显著提高了仙女木属植物、北极柳（仅雌性）和湿地越橘中的儿茶素含量。这些升高的儿茶素浓度对环颈旅鼠食用仙女木属植物和雌性北极柳的速率产生了显著的负面影响。
