Figure 17.9 Reduction in bacteria by mutualistic ants. The presence of the mutualistic ant (P. ferrugineus) causes a large reduction in the abundance of bacteria on the leaves of the acacia tree. In contrast, the presence of a nonmutualistic ant (P. gracilis) has no effect on bacterial abundance. Error bars are standard errors.

Data from M. González and M. Heil, Pseudomyrmex ants and Acacia host plants join efforts to protect their mutualism from microbial threats, Plant Signaling and Behavior 5 (2010): 890–892.