Strategic investment explains patterns of cooperation and cheating in a microbe
Strategic investment explains patterns of cooperation and cheating in a microbe
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DOI：
10.1073/pnas.1716087115
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发表时间：
2018-05-22
影响因子：
11.1
通讯作者：
Wolf, Jason B.
中科院分区：
文献类型：
--
作者：
Madgwick, Philip G.;Stewart, Balint;Wolf, Jason B.
为合作做出贡献通常代价高昂，而其回报往往是社会群体的所有成员都能获得的。那么，为什么个人愿意支付这些成本，特别是如果他们可以通过利用他人的投资来欺骗的话？亲属选择理论广泛地预测，如果个体与群体成员的关联度高（假设他们能够区分亲属和非亲属），那么他们应该在合作上投入更多。为了更好地理解相关性如何影响合作，我们得出了。集体投资”游戏，它提供了定量预测的模式，战略投资取决于相关性的水平。然后，我们测试这些预测的实验操纵相关性（基因型频率）在混合合作聚集的社会阿米巴Dictyosteelium discoideum，它建立了一个柄，以促进孢子传播。测量秸秆投资的天然菌株对应的预测模式的相关性依赖的战略投资，其中投资的菌株增加其与集团的相关性。此外，如果总体群体相关性相对较低（即，没有菌株在一个群体中出现的频率高）菌株面临类似于“囚徒困境”的情况，并遭受集体投资不足的困扰。我们发现，菌株采用相关性依赖隔离，以避免这些有害的条件。这些发现表明，简单的生物，如D。discoideum并不局限于“骗子”或“合作者”，而是衡量他们与他们的群体的关系，并相应地战略性地调整他们的投资以进行合作。因此，由于战略投资的动态性，所有个人有时会表现出合作，有时会表现出欺骗。
Contributing to cooperation is typically costly, while its rewards are often available to all members of a social group. So why should individuals be willing to pay these costs, especially if they could cheat by exploiting the investments of others? Kin selection theory broadly predicts that individuals should investmore into cooperation if their relatedness to group members is high (assuming they can discriminate kin from nonkin). To better understand how relatedness affects cooperation, we derived the. Collective Investment" game, which provides quantitative predictions for patterns of strategic investment depending on the level of relatedness. We then tested these predictions by experimentally manipulating relatedness (genotype frequencies) in mixed cooperative aggregations of the social amoeba Dictyostelium discoideum, which builds a stalk to facilitate spore dispersal. Measurements of stalk investment by natural strains correspond to the predicted patterns of relatedness- dependent strategic investment, wherein investment by a strain increases with its relatedness to the group. Furthermore, if overall group relatedness is relatively low (i.e., no strain is at high frequency in a group) strains face a scenario akin to the "Prisoner's Dilemma" and suffer from insufficient collective investment. We find that strains employ relatedness-dependent segregation to avoid these pernicious conditions. These findings demonstrate that simple organisms like D. discoideum are not restricted to being "cheaters" or "cooperators" but instead measure their relatedness to their group and strategically modulate their investment into cooperation accordingly. Consequently, all individuals will sometimes appear to cooperate and sometimes cheat due to the dynamics of strategic investing.