蚂蚁在舞草种子传播及避免其被啮齿类取食中的作用

Effectiveness of ants in dispersal of seed of Codariocalyx motorius and preventing the seed from rodents' predation

选择云南思茅地区景谷县和西双版纳勐仑镇,研究蚂蚁传播舞草种子及避免啮齿类取食种子的影响,以探讨蚂蚁在舞草种群发生发展中的作用。结果显示:蚂蚁传播舞草种子的距离一般较近,但均超过种子自身的扩散距离。几种主要蚂蚁的传播曲线显示:传播的距离各自都有一高峰,平均传播距离为0.93～2.53m。阻止蚂蚁搬运,景谷和勐仑实验点啮齿类对舞草种子的取食率分别为28.3%和16.5%;而阻止啮齿类取食,蚂蚁搬运的舞草种子率白天可达77%,晚上为35.7%。成熟的舞草种子日释放时间与蚂蚁活动的时间吻合,蚂蚁可先于啮齿类将种子搬走。这表明舞草与蚂蚁互惠共生,使其种子既得以扩散,又减少了啮齿类的取食,从而促进种群的繁衍。

A mutualism of ants with Codariocalyx motorius has been formed through a long interrelationship and co-evolution. The effectiveness of ants in removing seed of Codariocalyx motorius has been studied together with its effects on seed predation by rodents in Simao and Xishuangbanna of Yunnan Province, China. The results show that dispersing distances of seed removed from their mother plants by ants are not very great, with averages of 0.93 - 2.53 m, but exceed the shooting distance attained by seeds themselves. Each of ants, which are leading remover of C. motorius seed, has its own peak in the removing distance curve. When ants can not access the seeds, the predating ratios of C. motorius seed by rodents are 28.3% and 16.5% respectively in Jinggu and Menglun, in contrast with the high rates （77%, daily and 35.7%, night） of dispersal by ants when rodents can not predate the seeds. The shooting time of mature seed falls into the ants＇ periods of activity, and therefore ants can effectively remove the seed before rodents reach it. The experiments show that coexistence of C. motorius with ants is beneficial to protection and dispersal of the seed, as well as reduction of seed loss by rodents,and so promotes the development of the plant population.