Mutualisms, such as the ones between ants and aphids, evolve and persist when benefits outweigh the costs from the interactions between the partners. We show here that the trail pheromone of the red imported fire ant, Solenopsis invicta, can enhance these benefits by suppressing aphid dispersal and stimulating their reproduction. The ant’s mutualistic partner, the cotton aphid Aphis gossypii, was found to readily perceive and respond to two specific trail pheromone components. Two pheromone components, Z,E-α-farnesene and E,E-α-farnesene, both suppressed walking dispersal of apterous aphids, whereas only the major pheromone component, Z,E-α-farnesene, also increased aphid reproduction rate. The ants, as well as the aphids, benefit from this inter-species function of the trail pheromone. For the ants it increases and prolongs the availability of honeydew as a key food source, whereas the aphid colony benefits from faster population growth and continuous ant-provided protection. These findings reveal a hitherto unknown mechanism by which ants and aphids both increase the benefits that they provide to each other, thereby likely enhancing the stability of their mutualistic relationship.

当合作伙伴之间的互动带来的收益超过成本时，诸如蚂蚁和蚜虫之间的互惠主义就会发展并持续下去。我们在这里展示了红色进口火蚁Solenopsis invicta的踪迹信息素可以通过抑制蚜虫传播和刺激它们的繁殖来增强这些益处。蚂蚁的共生伙伴棉蚜Aphis gossypii被发现很容易感知和响应两种特定的线索信息素成分。两种信息素成分Z , E -α-farnesene 和E , E -α-farnesene 均抑制无翅蚜的行走扩散，而只有主要信息素成分Z , E-α-法呢烯，也增加了蚜虫的繁殖率。蚂蚁和蚜虫都受益于踪迹信息素的这种跨物种功能。对于蚂蚁来说，它增加并延长了作为主要食物来源的蜜露的可用性，而蚜虫群则受益于更快的种群增长和持续的蚂蚁保护。这些发现揭示了一种迄今为止未知的机制，蚂蚁和蚜虫都通过这种机制增加了它们相互提供的好处，从而可能增强了它们互惠关系的稳定性。