Chisholm Rebecca H, Connelly Brian D, Kerr Benjamin, Tanaka Mark M
Am Nat. 2018 Jul;192(1):35-48. doi: 10.1086/697471. Epub 2018 Apr 25.
Organisms often modify their environments to their advantage through a process of niche construction. Environments that are improved through positive niche construction can be viewed as a public good. If free riders appear that do not contribute to the shared resource and therefore do not incur any associated costs, the constructed niche may become degraded, resulting in a tragedy of the commons and the extinction of niche constructors. Niche construction can persist if free riders are excluded, for example, if niche constructors monopolize the resource they produce to a sufficient degree. We suggest, however, that the problem of free riders remains because it is possible that nonniche constructors with an enhanced ability to access the resource appear and invade a population of constructors. Using mathematical models we show that positive niche construction can be maintained if it is inextricably linked to a mechanism that makes free riding costly, such as a trait that confers a benefit to only niche constructors. We discuss this finding in terms of genetic interactions and illustrate the principle with a two-locus model. We conclude that positive niche construction can both evolve and be maintained when it has other beneficial effects via pleiotropy. This situation may apply generally to the evolutionary maintenance of cooperation.
生物体常常通过生态位构建过程来改变其环境以使其自身受益。通过积极的生态位构建而得到改善的环境可被视为一种公共物品。如果出现不贡献共享资源从而不承担任何相关成本的搭便车者，那么构建的生态位可能会退化，导致公地悲剧以及生态位构建者的灭绝。如果搭便车者被排除，生态位构建就能持续存在，例如，如果生态位构建者将他们所生产的资源充分垄断。然而，我们认为搭便车者的问题依然存在，因为有可能出现获取资源能力增强的非生态位构建者并侵入构建者群体。我们通过数学模型表明，如果积极的生态位构建与一种使搭便车变得代价高昂的机制紧密相连，比如一种仅赋予生态位构建者益处的性状，那么它就能得以维持。我们从基因相互作用的角度讨论这一发现，并用一个双基因座模型阐释这一原理。我们得出结论，当积极的生态位构建通过基因多效性具有其他有益效应时，它既能进化又能维持。这种情况可能普遍适用于合作行为的进化维持。
