The seven foraging substrate preference categories (leaves, insect frass, flowers, seeds, wood, fruits, other) are presented either in shades of green (for ants collecting mainly fresh plant-material) or shades of yellow/red/brown (for ants collecting mainly dried plant material or animal-waste), roughly representing changes in foraging from the base to the crown in the attine ant tree (Figure 3B). The plotted datapoints are averages of proportional foraging substrate prevalences across ant colony samples (n) (see Materials and methods). The best segregating foraging substrate preferences were leaves (mostly acquired by Atta and Acromyrmex leaf-cutting ants), flowers (mostly acquired by Acromyrmex leaf-cutting ants, but also observed for Trachymyrmex and Sericomyrmex species in more open habitats in Gamboa; J.J. Boomsma, pers. obs.), and insect frass (mostly acquired by the lower attine ants). Analyses with a (zero-inflated) negative binomial regression model (see Materials and methods) showed that leaf-cutting ants, the almost exclusive carriers of EntAcro1 bacteria, forage significantly more on fresh plant material (leaves, seeds and flowers; Tukey's post hoc, z = 3.97, p=0.005, z = 3.38, p=0.045 and z = 3.71, p=0.015, respectively), while the non-leaf-cutting ants, which only have EntAcro10 (particularly S. amabilis and T. zeteki), forage significantly more on insect frass, dry wood and ‘other’ substrates (Tukey's post hoc, z = −5.93, p<0.001, z = −4.84, p<0.001 and z = −5.24, p<0.001, respectively).