Review of adult diapause in ichneumonid wasps (Hymenoptera, Ichneumonidae)

The mechanisms and ecological circumstances of adult diapause in Ichneumonidae are poorly studied. An overview is presented of what observations and research have been carried out on ichneumonid diapause to date, and new ecological and distributional data are presented. The new data primarily concerns species that hibernate in association with trees, based on observations made in Belgium and the Netherlands. A preliminary checklist of the 50 species that are now known to hibernate is provided for both these countries. Auberteterus alternecoloratus (Cushman, 1929), Dicaelotus montanus (de Stefani, 1885), Dicaelotus pictus (Schmiedeknecht, 1903) and Orthocentrus sannio Holmgren, 1858 are reported as adult hibernators for the first time. Four species are newly recorded for the Belgian or Dutch faunas.