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Foraging and spatial ecology in a competitive environment: Polydomous carpenter ants (Camponotus leydigi) in a tropical savanna

Citation

Soares Jr., Hélio; Oliveira, Paulo (2021), Foraging and spatial ecology in a competitive environment: Polydomous carpenter ants (Camponotus leydigi) in a tropical savanna, Dryad, Dataset, https://doi.org/10.5061/dryad.z34tmpg9z

Abstract

Carpenter ants (genus Camponotus) are considered to be predominantly omnivorous, mixing several feeding habits that include predation, scavenging of animal matter, and plant-derived resources. Nitrogen acquisition is crucial for the nutritional ecology of ant colonies since growing larvae require sustainable protein provisioning. Here, we investigate the foraging ecology and the spatial nesting structure of the carpenter ant Camponotus leydigi in Brazilian cerrado savanna. By marking workers from different nests with distinct colors, we revealed that C. leydigi occupies physically separated but socially connected nests (up to 30 m apart), a phenomenon known as polydomy. Data on internest movements in C. leydigi corroborate cooperative exchanges between nest units and confirm several types of social connections, including internest transfer of liquid and solid food, transport of colony members (brood, workers), movement of solitary workers, and internest recruitment. Polydomous C. leydigi allocate foragers throughout 1,700 m2, feeding mostly on termites and plant-derived exudates. Influx of exudates is threefold higher compared to solid food. Uric acid pellets excreted by lizards comprise 20% of the solid diet in C. leydigi, a first quantitative assessment of this peculiar type of nitrogen complementation in ants. We hypothesize that nest decentralization in C. leydigi may reduce foraging constraints caused by overt interference by its main competitor, the aggressive ant Ectatomma brunneum that regularly blocks nest entrances. Our field study enhances the importance of natural history data to clarify selective pressures underlying the evolution of particular behavioral patterns (nutritional and nesting habits) in social insects.