Although mutualistic symbioses per definition are beneficial for interacting species, conflict may arise if partners reproduce independently. We address how this reproductive conflict is regulated in the obligate mutualistic symbiosis between fungus-growing termites and Termitomyces fungi. Even though the termites and their fungal symbiont disperse independently to establish new colonies, dispersal is correlated in time. The fungal symbiont typically forms mushrooms a few weeks after the colony has produced dispersing alates. It is thought that this timing is due to a trade-off between alate and worker production; alate production reduces resources available for worker production. As workers consume the fungus, reduced numbers of workers will allow mushrooms to ‘escape’ from the host colony. Here, we test a specific version of this hypothesis: the typical asexual structures found in all species of Termitomyces—nodules—are immature stages of mushrooms that are normally harvested by the termites at a primordial stage. We refute this hypothesis by showing that nodules and mushroom primordia are macro- and microscopically different structures and by showing that in the absence of workers, primordia do, and nodules do not grow out into mushrooms. It remains to be tested whether termite control of primordia formation or of primordia outgrowth mitigates the reproductive conflict.

尽管每个定义的共生共生体对于相互作用的物种都是有益的，但如果伴侣独立繁殖，可能会发生冲突。我们解决这一冲突的生殖如何在真菌生长白蚁的专互惠共生调控蚁巢菌类。即使白蚁及其真菌共生体独立地散布以建立新的菌落，散布仍与时间相关。真菌共生菌通常在菌落产生分散的骨板后数周形成蘑菇。人们认为，这个时机是由于后期和工人生产之间的权衡所致。后期生产会减少可用于工人生产的资源。随着工作人员食用真菌，减少工作人员的数量将使蘑菇从宿主菌落中“逃脱”。在这里，我们测试该假设的一个特定版本：在所有Termmitomyces物种中发现的典型无性结构“结节”是蘑菇的未成熟阶段，通常是白蚁在原始阶段收获的。我们通过证明结节和蘑菇原基在宏观和微观上是不同的结构，并通过证明在没有工人的情况下，原基确实存在，并且结节不会长成蘑菇来反驳这一假设。白蚁对原基形成或原基生长的控制能减轻生殖冲突仍有待测试。