Parabiotic ants: the costs and benefits of symbiosis

1. Mutualisms are important drivers of co-evolution and speciation. However, they typically imply costs for one or both partners. Each partner consequently tries to maximise benefits and minimise costs. Mutualisms can therefore develop towards commensalism or parasitism if one partner fails to provide sufficient benefits. This is particularly likely in diffuse interactions, where multiple species can associate with each other. If costs and benefits of a species vary with the identity of the partner species, this may result in a geographical mosaic of co-evolution. 2. In the present study, inter-specific interactions in two parabiotic associations of ants were studied (Hymenoptera: Formicida…