Harvester ant microbiome is associated with reproductive role

Host-associated microbes can impact host fitness, and it is therefore important to uncover the drivers of variation among hosts in their associated microbes. In social insects, microbiome composition differs based on both reproductive role and behavioral task. Here, we asked whether reproductive role or behavioral task is more important in determining the diversity and composition of host-associated microbes in the harvester ant Veromessor andrei. Specifically, we compared the bacterial communities between workers and reproductives by sequencing the 16S rRNA gene region. We further compared the bacterial communities between workers that are foragers and those that perform nest maintenance, as well as between reproductives that are male alates and those that are female alates. We found that reproductive role was a better predictor of bacterial communities than behavioral task. Workers and reproductives differed in their bacterial communities. However, different types of workers (foragers and nest maintenance workers) and different types of reproductives (males and females) did not differ from one another. Our findings suggest that morphological differences are a better predictor for differences in microbial communities than behavioral differences.