Comparison of the behavior of nurses and foragers of the carpenter ant, Camponotus melanocnemis, during dyadic nestmate reunion tests carried out after a period of social isolation (Hymenoptera: Formicidae)

摘要

We compared the behavior of minor laboratory-reared nurses and foragers of the African carpenter ant species Camponotus melanocnemis Santschi during dyadic nestmate reunion tests carried out after 48 h of social isolation during which the ants had access to water and carbohydrates as food. During a 20 min test a dyad of nestmates (two nurses or two foragers) was placed together in a set of two connected test tubes. Nurses showed higher readiness to engage in some forms of social contacts (mostly antennal contacts and trophallaxis and, to a lesser degree, licking of a nestmate's legs and thorax) and in some forms of resting behavior (complete immobility and resting with movements of antennae). The behavior of foragers was characterized by a higher readiness to engage in interactions with various elements of their physical environment, including various subcategories of active interactions with the humid cotton plugs closing the water reservoirs, licking of the inner surface of the test tubes in which they were confined, and antennal exploration of the junction between the two tubes. Self-grooming behavior depended on behavioral status of the tested ants in a complex way. If nurses decided to self-groom their antennae and their gasters, they devoted more time to these activities than foragers, which in turn showed higher readiness to engage in self-grooming of both antennae and legs. This is the first direct comparison of behavior of ant nurses and foragers during their encounters with nestmates after a period of social isolation. Our results provide yet another example of profound behavioral differences between nurses and foragers of social insects and demonstrate once more that behavioral polymorphism of social insect workers is related not only to the requirements of the organization of work in their colonies, but may be expressed in other important contexts as well.