Ant social network structure is highly conserved

The ecological dominance of social insects makes studying their colony organization fundamentally important to scientists studying collective systems. The recent combination of automated behavioral tracking and social network analysis has deepened our understanding of many aspects of colony social organization. We know how social organization is influenced by group size, genetic heterogeneity, pathogens and symbionts. However, because studies have typically investigated the influence of a given variable on the social network structure of a particular species, we know little about interspecific variation in network structure. Here we conduct a comparative network analysis across five ant species from five sub-families, separated by >100 MY. We find that social network structure is highly conserved. All species form modular networks, with two social communities, a similar distribution of individuals between the communities, and a similar mapping of task performance onto the communities. The deeply conserved two-community structure highlights that the most fundamental behavioral division of labor in social insects is between workers that stay in the nest to rear brood, and those that leave the nest to forage. This division has parallels across the animal kingdom in systems of biparental care and likely represents the most readily evolvable form of division of labor.

Methods
For each of 25 colonies (1 queen & 100 workers) we performed 1 week of automated tracking, extracting coordinates and orientations for each tag multiple times per second.

Around each tag we annotated a head region and used overlap of head regions to infer pairwise social interactions.

We quantified each individuals space-use (in particular time distribution between nest and foraging boxes)