Bacteria typically reside in heterogeneous environments with various chemogradients where motile cells can gain an advantage over nonmotile cells. Since motility is energetically costly, cells must optimize their swimming speed and behaviour to maximize their fitness. Here, we investigate how cheating strategies might evolve where slow or nonmotile microbes exploit faster ones by sticking together and hitching a ride. Starting with physical and biological first principles, we computationally study the effects of sticking on the evolution of motility in a controlled chemostat environment. We find that stickiness allows for slow cheaters to dominate when chemoattractants are dispersed at intermediate distances. In this case, slow microbes exploit faster ones until they consume the population, leading to a tragedy of commons. For long races, slow microbes do gain an initial advantage from sticking, but eventually fall behind. Here, fast microbes are more likely to stick to other fast microbes and co‐operate to increase their own population. We therefore conclude that whether the nature of the hitchhiking interaction is parasitic or mutualistic, depends on the chemoattractant distribution.

中文翻译：

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趋化搭便车的演变

细菌通常存在于具有各种化学梯度的异质环境中，在这些环境中，运动细胞可以比非运动细胞获得优势。由于运动在能量上是昂贵的，细胞必须优化它们的游泳速度和行为以最大限度地提高它们的健康。在这里，我们研究了在缓慢或非运动的微生物通过粘在一起搭便车来利用速度较快的微生物的情况下，作弊策略如何演变。从物理和生物第一原理开始，我们通过计算研究了在受控恒化器环境中坚持对运动进化的影响。我们发现，当化学引诱物分散在中间距离时，粘性允许缓慢的欺骗者占主导地位。在这种情况下，缓慢的微生物会利用速度较快的微生物，直到它们消耗人口为止，从而导致公地悲剧。对于长距离比赛，缓慢的微生物确实从坚持中获得了最初的优势，但最终落后了。在这里，快速微生物更有可能附着在其他快速微生物上并合作增加它们自己的种群。因此，我们得出结论，搭便车相互作用的性质是寄生的还是共生的，取决于化学引诱物的分布。