Cockroach social network position does not influence dispersal tendency

In group-living organisms, we might expect relationships between social position and dispersal, such as if certain patterns of social associations lead to dispersal or if certain personality types both link different groups and are more likely to disperse. However, directly testing these ideas is challenging as dispersal is hard to track in the field and is a difficult trait to measure in the laboratory. Furthermore, invertebrate dispersal is less commonly quantified as their small size makes them hard to track. Here we quantified social networks in multiple groups of the gregarious cockroach Blaptica dubia in the laboratory and related three measures of social network position (representing overall sociability, connectedness in local cliques, and connectedness to the wider network) to two different measures of dispersal. We found none of the social network measures related to either of the measures of dispersal, which were themselves not correlated. We also found that sociability and connectedness to the wider network were negatively correlated, with males falling towards the low-sociability/high global connectedness part of the continuum compared to females. We found no effects of mass, but there were differences between the two blocks our experiments were performed in, suggesting some effect of observer variability. Overall, our results suggest assays of dispersal may not effectively capture the underlying trait we hope to quantify, that cockroaches differ in the social behaviour along a syndrome integrating sociability and the tendency to move between groups, and that study replication should be encouraged so we can be confident identified trends are robust.