Anatomy of the mouthparts and digestive tract during feeding in larvae of the parasitoid wasp Trichogramma australicum Girault (Hymenoptera : Trichogrammatidae)

In Vitro Rearing of Egg Parasitoids

“…Most of the artificial diets utilized for rearing egg parasitoids were quite diluted, although studies on the larval feeding behavior of Trichogramma indicated the ingestion of solid food particles are common (Jarjees et al 1998). Assays using artificial diets demonstrated that the use of solid particles in the diet improved parasitoid larval growth.…”

Reproduction and Immature Development of Egg Parasitoids

“…It is thus the immature stages that have to deal with the constraints imposed by the host (see Chapter 2). Most egg parasitoid immatures, because of their minute size and their special habitat, are considered as morphologically specialized when compared to other Hymenoptera immatures (Hagen 1964, Jarjees et al 1998). …”

“…Between these two envelopes, free cells with large nuclei can be observed (Volkoff et al 1995). Soon after, the late-stage embryo, still surrounded by the embryonic exuvia, shows vigorous movements of its anterior section (Jarjees et al 1998) that eventually ruptures the chorion. The embryo is then released within the host egg together with the cells that were observed between the chorion and the embryonic exuvia.…”

“…The embryonic membrane remains attached to the posterior end of the larva. Such an attachment could be adaptive by anchoring the larva against the movement of its anterior portion and by preventing the free floating membrane from clogging the mouthparts during feeding (Jarjees et al 1998).…”

Insecticides and Parasitoids

“…However, the different results should be rearranged by difference of nutritional strategy between egg and larval parasitoids. Egg parasitoid ingests egg-yolk of the host soon after hatch as nutritional resource for growth, resulting become distended larval shape (Takada et al, 2000;Jarjees et al, 1998;Hutchison et al, 1990). Egg parasitoids are able to avoid the toxic effect of insecticides through the chorion of the host, using a protective role that is essential to normal development of the host embryo, and can circumvent the accumulation of toxic substance by sucking almost all egg-yolk from host egg at once after hatch.…”