Abstract: Type-Ⅱfunctional responses are frequently observed in mammalian herbivores feeding in patches where plants are concentrated in space. In the patches of fresh alfalfa ( Medicago satival) leaves , we devised leaf biomass density by changing leaf size to measured and the patterns and to tested the mechanism of the set of alfalfa leaf variables influencing on instantaneous intake rates of root voles(Microtus oeconomus) . Alfalfa leaf size could control the intake rates of root voles through regulating bite size. There was an asymptotic functional relationship between bite size of root voles and their intake rates , which belonged to a type-Ⅱfunctional response with a non-linear regression equation I = 0.094 S/ (0.001 + S) . With the increase and the decrease in the cropping rate , there was a relationship of non-linear decreasing with a non-linear regression equation B = 0.095/ (0.001 + S) . The observed and predicted maximum handling rates of root voles consuming alfalfa leaves were quite similar , and the regression of the observed and predicted intake rates was significantly different ( P < 0.01) . These results fully indicated that (a) the hypothesis of the competition between mammalian herbivores cropping and chewing can regulate cropping rates and intake rates , and (b) the model of type-Ⅱfunctional responses can effectively predict the intake rates of small mammalian herbivores.

Key words: Small mammalian herbivore, Root vole (Microtus oeconomus), Foraging functional response, Leaf size, Bite size, Instantaneous intake rate, Cropping rate

摘要： 采用新鲜苜蓿叶片密集的食物斑块, 测定和检验根田鼠觅食苜蓿叶片功能反应模型及其机制。苜蓿叶片大小可调节根田鼠口量, 进而控制其瞬时摄入率; 根田鼠觅食苜蓿叶片的口量( S) 与其瞬时摄入率( I) 为渐进函数关系, 属Ⅱ型功能反应, 回归方程为I =01094S/ (01001 + S) ; 根田鼠收获率( B) 随其口量( S) 的增加呈非线性递减, 回归方程为B = 01095/ (01001 + S) ; 最大处理速率的测定值与模型预测值极为近似; 瞬时摄入率测定值与预测值之间存在极显著( P < 0101) 的线性回归关系。结果验证了植食性哺乳动物Ⅱ型功能反应模型能有效地预测其瞬时摄入率动态, 收获与咀嚼间的竞争可调节其收获率及瞬时摄入率的假设。

关键词: 植食性小型哺乳动物, 根田鼠, 觅食功能反应, 叶片大小, 口量, 瞬时摄入率