图1 3个采样点(勐仑、纳板河和补蚌)的采样树数-蚂蚁物种数曲线

Fig. 1 Sample trees and ant species curve of Nabanhe, Menglun, and Bubeng in Xishuangbanna

图2 纳板河、勐仑和补蚌3个采样点蚂蚁种类的NMDS分析。1个数据点代表在1棵树上的1个采样。点线和空心三角代表纳板河; 实线和实心圆点代表勐仑; 虚线和空心正方形代表补蚌。

Fig. 2 The NMDS analysis of ant species composition in Nabanhe, Menglun, and Bubeng. Each symbol represents a sample tree. Dotted line and triangles represent Nabanhe; solid line and solid circles represent Menglun; dashed line and squares represent Bubeng.

图3 西双版纳3个采样点的蚂蚁-植物互作关系的二分网络呈现。每个网络上方为蚂蚁物种, 下方为植物物种。长方形宽度与寄主植物相互作用次数成正比, 线的宽度表示蚂蚁与寄主植物相互作用的频率。蚂蚁和树的名称以及对应的编号见附录1。

Fig. 3 Ant-plant bipartite networks in Xishuangbanna. For each network, upper bars represent ant species, and lower bars represent host plant species. Rectangle width is proportional to the number of interactions of each ant species and host plants; the line width represents the frequency of interactions between each interacting species pair. Appendix 1 shows ant and tree name list and code in the bipartite networks.

图4 西双版纳3个采样点纳板河、勐仑和补蚌的物种灭绝曲线。图中的正方形(勐仑)、圆形(纳板河)、三角形(补蚌)表示按照每种植物上蚂蚁物种丰富度的大小, 从丰富度最小的开始, 计算每去掉1种植物后(累积删除数除以植物总数, 取值从植物总数的倒数到1, 即为灭绝曲线的自变量x)蚂蚁物种数量的相对剩余数(剩余的蚂蚁物种数除以蚂蚁总数, 即为灭绝曲线拟合的因变量y)。灭绝曲线拟合一个y = 1-xa类型的函数, 不同的线代表3个样点的拟合曲线。

Fig. 4 Species extinction slopes of Nabanhe, Menglun, and Bubeng in Xishuangbanna. In this figure, the sequence of the extinction is from the least abundant ant to the most abundant ant in the trees. The extinction function calculate the relative alive ant species number (the ratio of alive ant species number relative to total ant species number is response variable) when remove tree species one by one (the ratio of removed tree species number relative to total tree species number is explanatory variable). The extinction slopes fitted a function of type y = 1-xa. Lines in the figure represent the smooth lines of the three sites.

图5 3个采样点(勐仑、纳板河、补蚌)蚂蚁-树二分网络测量指标及标准化指标的比较。A: 3个采样点网络参数观测值; B: 根据零模型1 (r2dtable法)计算得到的参数进行了Z值转换后的标准化值; C: 根据零模型2 (vaznull)计算得到的参数进行Z值转换后的标准化值。NA表示该指标无意义(因为vaznull方法下随机生成的网络连接度被限定为相同, 因此计算Z值时分母为0)。10×指对参数进行了10倍放大, 以较好地表现标准化参数的大小关系。两个零模型均基于蚂蚁-植物互作矩阵生成999个随机矩阵, 计算每个矩阵的参数而得到一个分布, 根据此分布推断分布中的值大于或小于观测值的概率。无上标的条图其P值都 < 0.001; * P < 0.05; NS表示该参数与零模型相比不显著(P > 0.05)。

Fig. 5 The observed metrics and standard metrics of ant-tree bipartite networks of Menglun, Nabanhe, and Bubeng. A, Observed network metrics; B, Standard Z-score of metrics based on the distribution of values generated by the null model 1 (r2dtable method); C, Standard Z-score of metrics based on the distribution of values generated by null model 2 (vaznull method). NA indicate that the value is not available. 10× means ten times amplification of the value to better reveal their relationships. We use two null models, each has 999 resamples, to calculate the network metrics, and then get a metrics distribution. We calculate the frequencies of the values that is bigger or smaller than the observed network metrics in the distribution. The frequency is approximation of the probability (P value). Bars without labels are all P < 0.001; * represent P < 0.05; NS represent not significant.