榕树–榕小蜂协同进化中的非对称性相互作用及其集合种群效应  

Asymmetric interaction and its effects on the meta-population dynamics in co-evolved fig-fig wasps systems

作　　者：路程[1,2] 耿宇鹏[1] 王瑞武[2] 

机构地区：[1]云南大学生态学与地植物学研究所,昆明650091 [2]中国科学院昆明动物研究所遗传资源与进化国家重点实验室,昆明650223

出　　处：《生物多样性》2012年第3期264-269,共6页Biodiversity Science

基　　金：国家自然科学基金(31170408; 31000112);云南省自然科学基金(2009CD104);西部之光;中国科学院优秀青年科技专项(KSCX2-EW-Q-9)

摘　　要：在协同进化研究中,传统观点认为物种之间的相互作用是对称性的,在进化过程中将形成一个稳定的均衡状态或进化稳定策略。然而,近来的观测和实验数据表明,物种间的协同进化可能存在非对称性相互作用,而且这种非对称性可能造成集合种群效应(metapopulation effect)或形成非均衡状态(例如混沌,chaos)。本文利用"榕树–榕小蜂"这一经典的协同进化模式系统来介绍协同进化过程中的非对称性相互作用,以及这种非对称性如何产生集合种群效应。在榕–蜂共生系统中,栖身于榕果中的榕小蜂除了传粉小蜂之外,还有一些"投机"的非传粉小蜂。非传粉小蜂比传粉小蜂具有更强的竞争力,而榕树则可惩罚不合作的非传粉蜂,同时奖励合作的传粉小蜂,从而形成了复杂的非对称性种间相互作用。在某个斑块生境中,非传粉小蜂通过竞争作用排斥传粉小蜂,然而随着非传粉小蜂在蜂群中的比例不断升高,榕树惩罚作用(如落果等)常常会导致整个非传粉蜂群的数量急剧下降,甚至局域性灭绝。随后,其他斑块的传粉小蜂则迁移过来填补空白。然而,随着传粉小蜂种群的数量增长,该斑块又会集聚更多的投机性非传粉小蜂,进而诱发榕树再次进行惩罚。这样的非对称性相互作用导致了非传粉小蜂、传粉小蜂以及榕树种群的集合效应,其种群大小呈现周期性的"此消彼长"式的循环。Interactions among co-evolved species has been assumed to operate in a symmetrical manner, resulting in stable equilibrium or evolutionary stable strategies for the observed species. However, recent observational and experimental data highlight the existence of asymmetrical interactions, which may lead to meta-populations or non-equilibrium states （e.g. chaos） between co-evolved species. Here, we explore the asymmetrical interaction in the classic ＇fig-fig wasp＇ co-evolution model system and show how such asymmetric interactions may produce meta-populations. It is well known that there are two different kinds of fig wasps inhabiting fig fruits （i.e. pollinator wasps and non-pollinating exploiter wasps）. Exploiter wasps have a fitness advantage over pollinator wasps because they do not pay the cooperative cost. However, figs can ef- fectively restrict exploiter wasps, and reward the pollinator wasps, resulting in complex asymmetric interac- tions among species. Specifically, the discriminative restriction of paretic wasps by fig trees will cause dras- tic population decreases or even local extinction of the exploiter species in some fig trees, syconia, or associ- ated habitats. In patches where populations of exploiters are low or extinct, pollinator wasps will immigrate leading to concomitant population size increases due to the high reward of fig trees. The prosperity of pollinator wasps will then attract more exploiters, and population increases of exploiter wasps will lead to the sanction by fig trees again. Over the long term, populations of different wasps will chaotically oscillate either temporally or evolutionary through asymmetric interactions.

关 键 词：集合种群效应 传粉小蜂 非传粉小蜂 互利共生 非对称性 惩罚 

分 类 号：Q948[生物学—植物学]