Interaction with refuse piles drives co-occurrence of core gut microbiota in workers of the ant Aphaenogaster picea

Comparing the diversity of gut microbiota between and within social insect colonies can illustrate interactions between bacterial community composition and host behavior. In many eusocial insect species, different workers exhibit different task behaviors. Thus, these workers may benefit from symbiotic relationships with certain bacteria that augment the metabolic processes underlying their specific behaviors. Evidence of compositional differences between core microbiota in different worker types could suggest a microbial association with division of labor among workers. Here we present the core microbiota of Aphaenogaster picea ant workers with different task behaviors. The genus Aphaenogaster is abundant worldwide, yet the associated microbiota of this group is unstudied. Bacterial communities from A. picea gut samples in this study consist of 19 phyla, dominated by Proteobacteria, Cyanobacteria, and Firmicutes. Analysis of 16S rRNA gene sequences reveals distinct similarity clustering of A. picea gut bacterial communities in workers that have more interactions with the refuse piles. Though gut bacterial communities of nurse and foraging ants are similar in overall composition and structure, the worker groups differ in relative abundances of dominant taxa. Interaction with fecal matter via refuse piles seems to have the greatest impact on taxa distribution, and this effect appears to be independent of worker type. This is the first report surveying the gut microbiome community composition of Aphaenogaster ants.