垂叶榕种子的二次散布：蚂蚁和非蚁传植物互惠关系的新证据

Secondary seed dispersal of Ficus benjamina:New evidence for ant-nonmyrmecochorous mutualism

蚂蚁对热带森林中小种子的二次散布会影响种子最终到达地点和种子命运。本文以一种由鸟散布的榕树垂叶榕(Ficus benjamina)为研究对象,观察蚂蚁对不同处理种子二次散布的影响。共记录到菱结大头蚁(Pheidole rhombinoda)、法老小家蚁(Monomorium pharaonis)、横纹齿猛蚁(Odontoponera transversa)和布立毛蚁(Paratrechina bourbonica)等4种蚂蚁参与了种子的搬运,其出现频率分别为71.7%、23.3%、2.5%、2.5%。蚂蚁对种子的搬运距离为179cm±13cm(n=159)。其中,最主要的散布者菱结大头蚁把种子搬进蚁巢后,取食了内果皮,并把58.6%的净种子抛弃在巢外垃圾堆中。蚂蚁取食内果皮显著提高了种子萌发特性(萌发率由49.3%提高到93.3%)。去除内果皮后种子被蚂蚁搬走的比率显著下降(由75.0%降为29.5%)。垂叶榕种子外着生的内果皮,明显提高了对蚂蚁的吸引力,而蚂蚁取食内果皮显著提高了种子萌发能力,垂叶榕和二次散布的蚂蚁之间存在着明显的互惠关系。

The secondary dispersal of small seeds in tropical forest mediated by ants often determines the final arrival site of the seeds and their fate. With Ficus benjamina, a bird-dispersed nonmyrmecochorous fig species, as test object, this paper investigated how ants respond to its seeds with different treatments （seeds from fruit with pericarp, seeds from fruit with periearp removed, seeds from bird＇ s feces with pericarp, and seeds from bird＇ s feces with pericarp removed）. Four ant species, i. e. , Pheidole rhombinoda , Monomorium pharaonis , Odontoponera transversa and Paratrechina bourbonica, were recorded in the seed dispersal. The visiting frequency of the four ants was 71.7% , 23.3% 2. 5 % and 2.5 %, respectively, and the mean dispersal distance was 179 cm ± 13 cm （n = 159）. The major dispersal ant Ph. rhombinoda discarded 58.6% of the carried seeds in the refuse piles after consuming the periearp. The seeds collected from ant＇ s refuse piles had a significantly enhanced seed germination rate （from 49.3% to 93.3 % ）. Seed removal rate decreased significantly after the periearp was removed （from 75.0% to 29.5 % ）. Seed pericarp enhanced the attraction to ants, and the seeds treated by ants gained significant higher germination rate. Therefore, a significant mutualism relationship existed between F. benjamina and its dispersal ants.