Figure 1.

Mapping traits onto the attine phylogenetic tree (from Schultz & Brady 2008) shows the independent recurrence of a reduction in visibly cultured Pseudonocardia bacteria, which is associated with increased MG grooming rates (black lines). Mapped traits are mean rates of MG grooming following exposure to conidia of Penicillium sp. 1, proportion of workers with visible bacteria and estimated colony sizes. Data are presented as mean±s.d., except estimated colony size. Letters of nodes in the phylogeny correspond to those in the inset of figure 2.