OLFACTORY CUES IN HOST NEST DETECTION BY THE SOCIAL PARASITE POLISTESSULCIFER (HYMENOPTERA, VESPIDAE)

Sometimes the nests of the paper wasp Polistes dominulus are parasitiz ed by the obligate social parasite Polistes sulcifer. It is not known how, in the spring, this parasite searches for established nests of it s host species. This study investigates the capacity to detect the hos t nest by olfactory cues alone. In laboratory experiments P. sulcifer females were allowed to choose different options hidden from view: hos t nest and dummy, various portions of the host nest (larvae, pupae and material), nests or immature brood pertaining to different sympatric species (P. dominulus, P. nimpha and P. gallicus). The parasites prove d to be capable of perceiving nest odour and of discriminating between different species of Polistes. The odour of the immature host brood, rather than the nest material, elicits the greatest response in the pa rasites.