Fig. 4. Mandible opening response (MOR) mean (± s.e.m.) for each of the four assayed species. The responses significantly differed among stimuli (F_4,384=28.43; P<0.0001). Species effect (F_3,96=1.03; P=0.38) and interaction between both effects (F_12,384=0.95; P=0.50) were non-significant. Stimuli: solvent (SOL), or extracts from nestmate (NM); non-nestmate of the same species (NNM); different species of the same genus (SG); different genus (DG). Different letters indicate significant differences (Scheffé's post-hoc test, P<0.03 in all cases).