Behaviour of intranidal and extranidal major workers of the African carpenter ant Camponotus maculatus Fabricius (Hymenoptera: Formicidae) during dyadic nestmate reunion tests

摘要

Behavioural differences between intranidal and extranidal major workers from a laboratory colony of an African carpenter ant species Camponotus maculatus reared from a foundress captured in Cameroon were investigated by means of dyadic nestmate reunion tests. Prior to the test, the ants were subjected to social isolation (48 h) in test tubes containing water reservoirs and carbohydrate food. Each test (20 min) involved a confrontation between a dyad of nestmates (two intranidal workers or two extranidal ones) placed in a set of two connected test tubes in which they had been isolated. Intranidal major workers showed higher propensity for resting behaviour and lower propensity for behavioural responses to elements of physical environment than extranidal ones. Similar behavioural differences between intranidal and extranidal minor workers (nurses and foragers) from the same colony were reported earlier in a companion study by our group. However, in contrast to minor nurses and foragers, intranidal and extranidal major workers of C. maculatus did not differ with respect to propensity for locomotion, self-grooming and social behaviour. Our findings provide a new clear-cut example of behavioural differences between nestmates related to differences in both worker morphology and worker specialisation in intranidal versus extranidal tasks.