Understanding how social groups function requires studies on how individuals move across the landscape and interact with each other. Ant supercolonies are extreme cooperative units that may consist of thousands of interconnected nests, and their individuals cooperate over large spatial scales. However, the inner structure of suggested supercolonial (or unicolonial) societies has rarely been extensively studied using both genetic and behavioral analyses. We describe a dense supercolony-like aggregation of more than 1300 nests of the ant Formica (Coptoformica) pressilabris. We performed aggression assays and found that, while aggression levels were generally low, there was some aggression within the assumed supercolony. The occurrence of aggression increased with distance from the focal nest, in accordance with the genetically viscous population structure we observe by using 10 DNA microsatellite markers. However, the aggressive interactions do not follow any clear pattern that would allow specifying colony borders within the area. The genetic data indicate limited gene flow within and away from the supercolony. Our results show that a Formica supercolony is not necessarily a single unit but can be a more fluid mosaic of aggressive and amicable interactions instead, highlighting the need to study internest interactions in detail when describing supercolonies.

See article.

Microsatellite data
(”microsatellite data.txt” and ”microsatellite data Särkkilen 4 parts.txt”)

The microsatellite data is given in the Genepop format. Subpopulation abbreviations: LG = Lillgård; Sar = Särkkilen; SG = Storgård; SS = Storsand. Separate files are given for the supercolony site (Särkkilen) as one population, and divided into its four parts (SarI, SarII, SarIII, and SarIV).

Coordinates
(coordinates.csv)

Coordinates for all nests. Coordinate system: EPSG: 4326, WGS 84.

Behavioral data
(behavioral_data.csv)

Column explanations
video: identifier of video file
host: nest id of the nest with 15 workers, the reactions of which were recorded.
host_part: the part (I–IV) of the supercolony site that the host nest belongs to
guest: nest id of the introduced worker
guest_part: the part of the supercolony site that the guest nest belongs to.
treatment: see article for descriptions of treatment classes.
timeinsight: the total time (milliseconds out of 120 000) that the introduced ant was in sight and not e.g. under nest material
trotime: trophallaxis time (milliseconds)
aggrtime: aggressive time (milliseconds)
anttime: antennation time (milliseconds)
dist: internest distance (km)

The reactions toward the introduced ant were recorded for one minute, but as the videos were watched at half speed, we scored behaviors for two minutes, and the total time for each replicate is thus two minutes (120 000 milliseconds) in the data.