Myrmecochory is a widespread mutualism in which plants benefit from seed dispersal services by ants. Ants might also be providing seeds with an additional byproduct benefit via reduced plant pathogen loads in the ant nest environment through their antimicrobial glandular secretions. We investigate this byproduct benefit by identifying fungal communities in ant nests and surrounding environments and quantifying fungal community change (1) through time, (2) between different nest substrates, and (3) as a function of average ant activity levels within nests (based on observed ant activity at nest entrances throughout the summer). We split fungal communities by functional guild to determine seed-dispersing ant-induced changes in the overall fungal community, the animal pathogen fungal community, the plant pathogen fungal community, and the myrmecochore pathogen fungal community. Nest substrate (soil or log) explained much of the variation in fungal community dissimilarity, while substrate occupation (ant nest or control sample) and time had no influence on fungal community composition. Average ant activity had no effect on the community turnover in fungal communities except for the myrmecochore pathogenic fungal community. In this community, higher ant activity throughout the summer resulted in more fluctuation in the pathogenic community in the ant nest. Our results are not consistent with a byproduct benefit framework in myrmecochory, but suggest that nest substrate drives dissimilarity in fungal communities. The influence of nest substrate on fungal communities has important implications for seeds taken into ant nests, as well as ant nest location choice by queens and during nest relocation.

防霉菌是一种普遍存在的共生关系，在这种共生关系中，植物从蚂蚁的种子传播服务中受益。蚂蚁还可能通过减少其抗菌腺分泌物而减少蚂蚁窝环境中的植物病原体负荷，从而为种子提供额外的副产品收益。我们通过确定蚁巢和周围环境中的真菌群落并量化真菌群落变化（1）随时间变化，（2）不同巢基质之间的变化以及（3）作为巢内平均蚂蚁活性水平的函数来调查这种副产品的益处（基于整个夏季在巢穴入口处观察到的蚂蚁活动）。我们按功能协会划分真菌群落，以确定种子分散蚂蚁诱导的总体真菌群落，动物病原体真菌群落，植物病原体真菌群落的变化，和线虫病菌的真菌群落。巢底物（土壤或原木）解释了真菌群落差异的许多变化，而底物的占用（蚁巢或对照样品）和时间对真菌群落组成没有影响。除线虫病原性真菌群落外，平均蚂蚁活性对真菌群落的群落更新没有影响。在这个群落中，整个夏季较高的蚂蚁活动导致蚂蚁巢中的致病群落更多波动。我们的结果与防线虫的副产品效益框架不一致，但表明巢底物在真菌群落中驱动异源性。巢底物对真菌群落的影响对于进入蚂蚁巢中的种子具有重要意义，