Figure 1.

Mean ± s.e. frequency with which ants treated with either the fungal parasite Metarhizium (shaded columns) or a control solution (clear columns) were allogroomed for (a) 18 naive mini-nests that had not previously had contact with the parasite, and (b) 18 immunized mini-nests that had previously been exposed to the parasite. Ants were placed in mini-nests for behavioural observation either immediately after treatment or 2 days after treatment. Both naive and immunized mini-nests consisted of three mini-nests from each of six colonies.