Chemical ecological studies for egg discrimination in paper wasps

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We analyzed the mechanism of egg discrimination in a paper wasp, Polistes chinensis antennalts, by using a GC-MS. Dufour gland was immersed in Hexan for l h, and egg was done for 30 min. The cuticular substances of each adult were extracted by washing with Hexan. We used HP-5MS column and temperatures were changed according to the program at 150 ℃ for 2 min, 7 ℃ for l min and 320 ℃ for 5min. There were many extracted hydrocarbons for each sample. The substances extracted from Dufour glands were overlapped with those from eggs, in particular 7 chemicals, namely, (1) 2-MeC_(28), (2) n-C29, (3) 11-, 13-, 15-MeC29, (4) 11-, 13-, 15-, MeC31, (5) 11-, 13-, 15-MeC33, (6) 13-, 15-, 17-MeC35, (7) 13-, 19-deMeC35. These substances were also extracted from the cuticle surfaces.In Polistes snelleai, workers develop their ovaries even when original queen is still alive on the nests. Using a population in Nagano prefecture, we revealed that (1) there was a few mated workers on nests even when original queens were still alive, (2) the mated workers did not develop their ovaries, probably due to physiological suppression by the queens, and could not oviposit, when the queens were on nests, (3) the mated workers became replacement queen when the queens disappeared from the nests, (4) there were not significant differences between colony sizes of queen-right colonies and those of orphan colonies. The last finding strongly suggested that mated workers function as queens and colonies grow well even when queens disappeared. Nliorosatellite DNA analyses revealed that there were colonies with several genetic families, and suggested that polyandry and/or queen turnover take place in this species In addition, early males, which are mating partners of mated workers, function as gene pool in this species.