Microbes are a group of organisms living on and within an animal’s body, but their role in the host is mainly unknown. We are especially interested in whether microbes are associated with social behaviors in ants.

Our study indicates the bacteria composition changed between ants’ colonies in different social behaviors and suggests a potential role of microbes influencing ant’s life.

Social insects (ants, bees, wasps, and termites) are group-living animals whose social behavior, such as grooming and nestmate recognition, is determined by genetic factors. This genetic factor (i.e. social chromosome) determines the fate of ant colonies that will have single or multiple leaders to dominate their kingdom. At the same time, other mechanisms may also involve manipulating social behaviors. One of the neglected factors that may influence social behaviors comes from micro-residences in the body. The composition of micro-residences, called the microbiome, is changing the host in many ways. We are especially interested in whether and how a microbiome manipulates the social behavior of ants.

To figure out whether the microbiome influences social behaviors, we explored the microbiome in ants’ colonies of different social behaviors. We examined the microbe compositions of 670 individuals from both ant colonies dominated by single and multiple leaders by analyzing their genomic data. We were surprised to discover that the overall bacteria diversity is not different between colonies in the desert ant. However, the composition of the bacteria in each social structure varied. The ant colony with intimate social behavior presented a higher chance to carry bacteriophages, which are viruses that only infect and replicate in bacterial cells. One potential hypothesis is the bacteriophages as a component to control and maintain the bacteria community for huge ant colonies. Meanwhile, we observed several bacteria unique to one of the social structures, suggesting potentially special functions of bacteria associated with social behaviors in this ant species.

In all, our study explored the social microbiome in ants and discovered the key difference between bacteria and viruses associated with the complexity of social behaviors. While the role of bacteria in ants was not clear yet, the future experiment that manipulates the bacteria composition will bring us a light to understand the bacteria-host interactions in large, complex societies. 
The research team consists of Chih-Chi Lee, PhD., Aparna Lajmi PhD.,  and Prof. Eyal Privman from the Department of Evolutionary and Environmental Biology,  and Prof. Judith Somekh, from  Department of Information Systems, University of Haifa
We thank DSRC for supporting our research.