Fig. 1.

Mutual somatic incompatibility reactions for Acromyrmex and Atta-associated fungal symbionts plotted against genetic distances calculated from genetic variation at AFLP's and ten microsatellite markers, with the size of each circle representing the number of times a particular combination was found. Correlations were significant for Acromyrmex with both (A) AFLP markers (Mantel r = 0.463, p = 0.003) and (B) microsatellites (Mantel r = 0.469, p = 0.003), and for Atta with (D) microsatellites (Mantel r = 0.312, p = 0.032), but not C) AFLP markers (Mantel r = −0.164, p = 0.792). All Mantel tests were performed with 99,999 permutations.