Ultrastructure of the natural and factitious host eggs of Trichogramma galloi Zucchi and Trichogramma pretiosum Riley (Hymenoptera : Trichogrammatidae)

The surface and structure of the chorion of eggs of Diatraea saccharalis (F .) (Lepidoptera: Crambidae), Anticarsia gemmatalis (Huebner), Heliothis vir escens F., Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae), Sitotrog a cerealella (Oliver) (Lepidoptera: Gelechiidae), Ephestia kuehniella Zelle r and Corcyra cephalonica Stainton (Lepidoptera: Pyralidae), that are hosts of Trichogramma galloi Zucchi and Trichogramma pretiosum Riley (Hymenopter a: Trichogrammatidae) were studied on SEM and TEM. Other characteristics of these eggs, such as changes in their color during embryonic development, s ize and volume were also recorded. Sculpturing and texture of the surface o f the chorion greatly varied among the species studied, as well as the numb er of layers of the chorion and their thickness. Eggs of the factitious hos ts were among the smallest and their volume was very close to each other. A ll these characteristics would provide basic information for a better under standing of the host selection behavior and are useful for the development of a suitable artificial host egg for the in vitro rearing of these egg par asitoids. (C) 1999 Elsevier Science Ltd. All rights reserved.