抄録
Factitious hosts are needed for mass-propagation in crop pest management. Egg parasitoids are considered as effective biocontrol agents of lepidopterous pests because they kill host eggs and can usually be easily mass propagated on factitious hosts. However, previous studies indicated that parasitoids which had been reared on a factitious host changed host preference and did not parasitize the native host. In the present report, Trichogramma dendrolimi were collected from egg masses of Mamestra brassicae in cabbage fields maintained without insecticides. T. dendrolimi was maintained in the laboratory for 12 successive generations on Ephestia kuehniella. After the 12 successive generations, the parasitoid females still preferred M. brassicae to E. kuehniella for oviposition. T. dendrolimi, that emerged from M. brassicae eggs were larger in size and laid twice as many eggs as those from E. kuehniella during their lifetime. These results suggest that T. dendrolimi parasitizes the native host without losing host preference even after 12 successive generations on a factitious host.
