Biogeography of biotic interactions. Expected overlap of the geographic ranges of interacting species, considering different kinds of interactions and intensities of the interactions A competition: both competing species have a negative outcome and with high levels of competition exclude each other geographically B predation: one species has a positive outcome (blue) and the other species has a negative outcome (gray) as in the interactions predator/prey, parasite/host, herbivore/plant, Batesian mimic/model C mutualism: both interacting species have a positive outcome and (almost) complete geographic overlap is expected when the interaction is obligate D commensalism: one species has a positive outcome (blue) and the other species is neutral (gray) E higher range overlap is expected between obligate ant-following bird species and army ants than between facultative ant-following bird species and army ants.

Bayesian regression models show that the intensity of the interaction between army ants and ant-following birds (obligate vs. facultative) is not reflected in the overlap of geographic ranges between the army ants and the birds A obligate ant-following birds do not have higher estimated overlap of geographic ranges than facultative ant-following birds B facultative ant-following birds do not have wider expected geographic ranges than obligate ant-following birds.

Overlap of species distribution models of two species of army ants (columns; Eciton burchellii, carmine color, and Labidus praedator, caramel color) and five species of obligate ant-following birds (rows, amethyst color). Range overlap between army ants and ant-following birds is shown in lime color, and the percentage of overlap is represented numerically for each ant-bird species pair. Photo credits: G. bicolor (Melton 2023a), P. mcleannani (Melton 2023b), D. anabatina (NDMR), D. sanctithomae (PG), E. penicillata (NDMR).

Overlap of species distribution models of two species of army ants (columns; Eciton burchellii, carmine color, and Labidus praedator, caramel color) and five species of facultative ant-following birds (rows, teal color). Range overlap between army ants and ant-following birds is shown in lime color, and the percentage of overlap is represented numerically for each ant-bird species pair. Photo credits: A. spadiceus (PG), S. griseicapillus (Carlos Echeverría), R. melanurus (NDMR), H. leucosticta (RAJ), H. fuscicauda (NDMR).