Port Markus, Schülke Oliver, Ostner Julia
Am Nat. 2017 Mar;189(3):E46-E57. doi: 10.1086/690218. Epub 2017 Jan 11.
In many animal species individuals compete for the sole possession of a breeding territory, whereas in other species communal territories are shared among same-sex conspecifics. Under what conditions does natural selection favor the evolution of individual territoriality, and under what conditions does it favor the evolution of sociality? We develop a self-consistent game-theoretic model that allows for feedbacks between evolutionary and population dynamics. In this model, nonresident floaters can chose between three strategies: they can wait for a territory vacancy to arise, they can try to forcefully take over an already-occupied territory, or they can share a territory with an established resident. We show that competitive environments initially favor the evolution of an aggressive (territorial) strategy. Yet as competition increases further, a shift occurs from aggressive to social strategies. Moreover, territory owners (residents) respond to the behavior of floaters, such that a feedback occurs in which residents adjust their degree of tolerance to the level of floater aggression and vice versa. This feedback resembles the dynamics of a biological market and eventually leads to the coexistence of aggressive and social floater strategies in the population. Such mixed equilibria commonly occur in nature.
在许多动物物种中，个体为独占繁殖领地而竞争，而在其他物种中，同性同种个体共享公共领地。在何种条件下自然选择有利于个体领地行为的进化，又在何种条件下有利于社会性的进化呢？我们构建了一个自洽的博弈论模型，该模型考虑了进化动力学与种群动力学之间的反馈。在这个模型中，非领地居住者（漂泊者）可以在三种策略中做出选择：他们可以等待领地出现空缺，他们可以试图强行夺取已被占据的领地，或者他们可以与已定居的领地所有者共享领地。我们表明，竞争环境最初有利于激进（领地性）策略的进化。然而，随着竞争进一步加剧，会出现从激进策略到社会策略的转变。此外，领地所有者（定居者）会对漂泊者的行为做出反应，从而产生一种反馈，即定居者将他们的容忍程度调整到漂泊者激进程度的水平，反之亦然。这种反馈类似于生物市场的动态，最终导致种群中激进和社会漂泊者策略的共存。这种混合均衡在自然界中普遍存在。
