Figure 1.

3-MeC₃₁ is a condition-dependent queen pheromone that affects worker physiology and behaviour in L. niger. (a) The cuticular hydrocarbon profile of queens contains a 6 times higher proportion of 3-MeC₃₁ than that of a worker, while the egg profile has 9 times more; see also electronic supplementary material, table S1. (b) Supplementation of queenless groups of workers with synthetic 3-MeC₃₁ negatively affected ovarian activation relative to controls. Bars show the frequency distributions of ovary activation on a categorical scale from 1 (no activation) to 4 (highest activation). (c) Glass model queens coated with 3-MeC₃₁ were attacked by workers less often than controls. (d) A lipopolysaccharide immune challenge reduced the proportion of 3-MeC₃₁ on the cuticle of queens. (a,c,d) Means ± 1 s.e.; shared letters indicate that two groups are not significantly different. Sample size is shown inside the bars.