Differences in Forage-Acquisition and Fungal Enzyme Activity Contribute to Niche Segregation in Panamanian Leaf-Cutting Ants
Principal Component Analyses (PCA) using either the five enzyme groups of Figure 2 (A and B) or the five forage material categories of Figure 1 (C and D) as predictor variables (black arrows). Red arrows represent response vectors for forage material (A) or enzymes (C). The B and D panels complement the respective A and C panels by plotting PCA’s scores across the fungus garden measurements (B, 45 for Atta and 32 for Acromyrmex) the sampled ant trails (D, 30 for Atta and 21 for Acromyrmex; Table 1), largely separating the ant genera along the x-axes, confirming that Atta primarily focuses on tree-leaf material (compare panels C and D) and Acromyrmex on herbaceous leaves, flowers and (less pronounced) fruit. Comparison of the A and B panels illustrates that enzyme activity was generally higher in Acromyrmex (towards the right).