Factors influencing the adoption of artificial nests in Polistes dominulus (Christ).

Nest recognition is critical to the sociality of wasps. Studies on Polistes have shown that is essentially based on chemoreception. Moreover, wasps are also able to recognise the nest's contents and this could also participate in nest recognition. By the method of the artificial nest adoption, we examined which natural nest stimuli (hydrocarbons from paper nests, hydrocarbons from immature broods or eggs, and the physical presence of both) act consistently in nest recognition. Since these stimuli change with the age of colony, we also considered its maturity. Our results show that the presence of eggs have a stronger effect to induce artificial nest adoption. Surprisingly, the paper nest hydrocarbons alone were weakly attractive. On the contrary, paper nest hydrocarbons combined with immature brood hydrocarbons, increased significantly the adoption of artificial nests. Finally, previous experiences of the wasps and the maturity of the nest they come from appear as influential factors in adoption and probably in nest recognition. In conclusion, some biological and practical implications of these results are discussed that underlined the necessary combination of various nests features to insure nest recognition.

Social hackers: integration in the host chemical recognition system by a paper wasp social parasite.

Obligate social parasites in the social insects have lost the worker caste and the ability to establish nests. As a result, parasites must usurp a host nest, overcome the host recognition system, and depend on the host workers to rear their offspring. We analysed cuticular hydrocarbon profiles of live parasite females of the paper wasp social parasite Polistes sulcifer before and after usurpation of host nests, using the non-destructive technique of solid-phase micro-extraction. Our results reveal that hydrocarbon profiles of parasites change after usurpation of host nests to match the cuticular profile of the host species. Chemical evidence further shows that the parasite queen changes the odour of the nest by the addition of a parasite-specific hydrocarbon. We discuss the possible role of this in the recognition and acceptance of the parasite and its offspring in the host colony.