中科院昆明动物研究所的王瑞武、张亚平院士等合作在互利合作行为演化及系统维持机制（协同进化）研究取得重要进展，相关成果文章Interference Competition and High Temperatures Reduce the Virulence of Fig Wasps and Stabilize a Fig-Wasp Mutualism发表在11月12的PLoS ONE上。
互利合作行为不仅存在于种内系统的各个群体内(Group)，也广泛存在于物种之间，而越来越多的发现显示几乎所有的物种都至少与一个其它物种存在互利的共栖行为（Bronstein 2001 in Ecology Letters）。
从十九世纪二十年代开始，榕树与其特有的传粉昆虫系统一直是研究物种之间是如何形成稳定的合作关系的模式系统之一。在探讨物种间互利合作行为的过程中，一个基本的理论问题一直未曾得到解决：互利共栖的物种之间存在公共资源，而任何一个物种的个体对公共资源的过度利用都会导致合作关系的解体，这就是著名的“公共地的悲剧”（该悖论由Hardin于1968年在Science提出）。
经典理论认为合作双方利用的空间资源存在分化，因而合作一方不能利用另外一方的资源。
然而，王瑞武等的实验表明：资源的空间分化理论可能是不可信的（对文献提到多个空间分化假说逐一实验验证和分析发现都是不可信的），合作关系将会随着公共资源的减少而转化为冲突关系，公共资源丰富时，双方表现为合作关系，而在公共资源紧张时表现冲突或竞争关系（Wang et al. 2008, in Journal Animal Ecology）。
王瑞武等的实验发现：传粉小蜂之间存在干扰性竞争，这种干扰性竞争将导致传粉小蜂对公共资源利用效率的降低，因而公共资源的利用由于传粉小蜂之间的干扰性竞争而不能达到最大化，合作双方的公共资源利用很少达到紧张状态，物种之间因而能够维持比较稳定的合作关系。
这是国内首次用实验证据论证了空间分化在互利合作系统中并不能维持合作关系的稳定，并首次提出了非对称性的干扰可能是维持互利合作系统稳定的关键机制。（生物谷Bioon.com）
生物谷推荐原始出处：
PLoS ONE 4(11): e7802. doi:10.1371/journal.pone.0007802
Interference Competition and High Temperatures Reduce the Virulence of Fig Wasps and Stabilize a Fig-Wasp Mutualism
Rui-Wu Wang1#, Jo Ridley2#, Bao-Fa Sun1,3, Qi Zheng1,4, Derek W. Dunn2,5, James Cook5, Lei Shi6, Ya-Ping Zhang1, Douglas W. Yu1,2*
1 Ecology, Conservation, and Environment Center (ECEC), State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China, 2 Centre for Ecology, Evolution and Conservation (CEEC) and School of Biological Sciences, University of East Anglia, Norwich, Norfolk, United Kingdom, 3 Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China, 4 School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China, 5 School of Biological Sciences, University of Reading, Reading, Berks, United Kingdom, 6 Statistics and Mathematics College, Yunnan University of Finance and Economics, Kunming, Yunnan, China
Fig trees are pollinated by fig wasps, which also oviposit in female flowers. The wasp larvae gall and eat developing seeds. Although fig trees benefit from allowing wasps to oviposit, because the wasp offspring disperse pollen, figs must prevent wasps from ovipositing in all flowers, or seed production would cease, and the mutualism would go extinct. In Ficus racemosa, we find that syconia (‘figs’) that have few foundresses (ovipositing wasps) are underexploited in the summer (few seeds, few galls, many empty ovules) and are overexploited in the winter (few seeds, many galls, few empty ovules). Conversely, syconia with many foundresses produce intermediate numbers of galls and seeds, regardless of season. We use experiments to explain these patterns, and thus, to explain how this mutualism is maintained. In the hot summer, wasps suffer short lifespans and therefore fail to oviposit in many flowers. In contrast, cooler temperatures in the winter permit longer wasp lifespans, which in turn allows most flowers to be exploited by the wasps. However, even in winter, only in syconia that happen to have few foundresses are most flowers turned into galls. In syconia with higher numbers of foundresses, interference competition reduces foundress lifespans, which reduces the proportion of flowers that are galled. We further show that syconia encourage the entry of multiple foundresses by delaying ostiole closure. Taken together, these factors allow fig trees to reduce galling in the wasp-benign winter and boost galling (and pollination) in the wasp-stressing summer. Interference competition has been shown to reduce virulence in pathogenic bacteria. Our results show that interference also maintains cooperation in a classic, cooperative symbiosis, thus linking theories of virulence and mutualism. More generally, our results reveal how frequency-dependent population regulation can occur in the fig-wasp mutualism, and how a host species can ‘set the rules of the game’ to ensure mutualistic behavior in its symbionts.
