Neural investment patterns reflect task specialization in the leaf-cutting ant Acromyrmex subterraneus

Leaf-cutting ants are excellent models for studying the relationship between behavior and brain investment because their pronounced division of labor is associated with worker differentiation. In Acromyrmex subterraneus, division of labor is linked to worker size, defining three subcastes - minor, media, and major - that typically perform tasks with distinct sensory demands. We investigated brain investment under the hypothesis that task performance is associated with differential allocation to distinct brain regions. Medias, whose intermediate size allows participation in a wide range of tasks, showed greater investment in the olfactory processing region, the antennal lobes. Majors, which engage in foraging, exhibited increased investment in the visual processing region, the optic lobes. Brain centers involved in learning and memory (the mushroom body) did not differ significantly among subcastes. These results suggest that sensory processing regions are shaped by task-specific demands, whereas similar investment in the mushroom-body may support flexible task repertoires across worker subcastes.