Nest Contents and Colonial Adult Productivity in a Common Hornet, Vespa simillima simillima SMITH, in Northern Japan (Hymenoptera, Vespidae)

The contents of 19 nests of Vespa simillima simillima were described and the number of adults produced was estimated. The nests were collected in August and September in Hokkaido. They had three to ten combs, one to three of which were totally or partly composed of small cells, and the others composed of large cells. Workers and queens respectively were reared in small and large cells, while males were reared in either type of cells. Mean cell number was 1, 382 in August and 1, 997 in September. Almost no reproductive adults were present in August, while during September more than 30% adults were reproductives. Estimates of colonial adult production, based on cocoon numbers and meconial counts of nests collected in September, were 593 workers, 325 males, and 222 new queens on average, far fewer than in the southern subspecies V. simillima xanthoptera. The colonial characteristics and adult production schedule were compared between the two subspecies.