Records of aggregation formation of four groups of 24 female cockroaches (Blaptica dubia) using the same shelter. Each file covers a single group for a single day. Each line in the data represents the confident detection of a single individual, hence the name of the aggregation/photograph is repeated over multiple lines if there were multiple individuals in that photograph. The cockroaches were kept in an incubator at 50%, then 40%, then 30% relative humidity for four days each. After experiencing the three humidities, groups were randomly re-formed and the run repeated. This was then done twice more, giving four replicates in total (16 unique groups). Cockroaches in the same shelter, and therefore in the same photograph, were assumed to be in the same aggregation and so associating in that instance. These data can be used to understand how patterns of social associations change with humidity. Full details about this nonGeographicDataset can be found at https://doi.org/10.5285/64467180-c8e0-467e-865a-f42495a89019