Fig 3. Pharmacologically increasing brain concentrations of 5-HT and OA (ISO-NON-NM+5-HTP and ISO-NON-NM+OA) increased fighting levels by isolated (ISO-NEST) ants (n = 20), which lacked a recent history of interaction with nestmates, when they met isolated non-nestmate ants (ISO-NON-NM).

Black filled bars indicate ants that fought. Unfilled bar indicate ants that did not fight. SOC-NEST are ants that were allowed to interact with nestmates before interacting with nestmate ants in the assay. SOC-NON-NM were ants that were also allowed to interact with nestmates before interacting with non-nestmate ants. Contingency table with a Chi-square test, p < 0.001, df = 75.80, 5; Bonferroni’s correction (α = 0.009).