Early Learning and the Recognition of Conspecific Cocoons by Carpenter Ants (Camponotus spp.)

Groups of newly‐eclosed workers of two carpenter ant species (Camponotus floridanus and C. tortuganus) were reared in the presence of conspecific cocoons, cocoons of the other species, or were kept without cocoons. Groups of older workers (> 20 days), previously exposed to conspecific brood in their natal nest, were familiarized with either conspecific or heterospecific cocoons. After 14 days of exposure, groups were subjected to short‐term (5 min) and long‐term (10 day) preference tests. Young and older workers retrieved and retained many cocoons of both species, familiar and unfamiliar. However, a pattern of non‐exclusive discrimination emerged: (1) Young workers exposed to conspecific cocoons picked up and retrieved conspecifics before unfamiliar heterospecifics, and retained conspecifics longer. (2) Young workers generally required experience with conspecifics to develop this preference, as those exposed to only heterospecifics and those deprived of cocoons were impartial in short‐term tests. However, in long‐term tests (5–10 days), naive young workers significantly preferred unfamiliar conspecifics. (3) Older workers preferred conspecific cocoons, whether familiar or unfamiliar, in short‐term tests, but their tolerance for heterospecifics in the longer term (5 days) could be increased by recent familiarization. In no case did young or older ants significantly prefer familiar heterospecifics to conspecifics. These results confirm a role for early learning in brood recognition by carpenter ants, but suggest that it is less important than in Formica species studied by previous authors. 1987 Blackwell Verlag GmbH