Identification of bracovirus particle proteins and analysis of their transcript levels at the stage of virion formation.

Polydnaviruses (PDVs) are unique symbiotic viruses associated with parasitic wasps; they replicate only in the calyx cells of a wasp's ovaries and are transferred at oviposition along with the parasitoid egg into the lepidopteran host. The DNA packaged in the viral particles encodes factors that manipulate the host's immune defences and development to benefit the parasitoid. PDVs are found in two subfamilies of ichneumonids (ichnoviruses) and in braconids of the microgastroid complex (bracoviruses).

Venom of the egg-larval parasitoid Chelonus inanitus is a complex mixture and has multiple biological effects.

The egg-larval parasitoid Chelonus inanitus injects bracoviruses (BVs) and venom along with the egg into the host egg; both components are essential for successful parasitoid development. All stages of eggs of its natural host, Spodoptera littoralis, can be successfully parasitized, i.e.

Stage dependent influences of polydnaviruses and the parasitoid larva on host ecdysteroids.

In the solitary egg-larval parasitoid Chelonus inanitus (Braconidae) both polydnavirus and the parasitoid larva manipulate host development. Parasitization leads to a premature drop in juvenile hormone titre and a precocious onset of metamorphosis in the 5th larval instar. The C.

Influence of the parasitoid Chelonus inanitus and its polydnavirus on host nutritional physiology and implications for parasitoid development.

Chelonus inanitus is a solitary egg-larval endoparasitoid, which feeds on host haemolymph during its internal phase. Parasitization induces in the host Spodoptera littoralis a precocious onset of metamorphosis and a developmental arrest in the prepupal stage. At this stage the parasitoid larva emerges from the host and consumes it.

Changes in the haemolymph proteome of Spodoptera littoralis induced by the parasitoid Chelonus inanitus or its polydnavirus and physiological implications.

The egg-larval parasitoid Chelonus inanitus induces in its host Spodoptera littoralis two major developmental effects, namely a precocious onset of metamorphosis followed by a developmental arrest in the prepupal stage. Along with each egg, the wasp injects polydnavirus and venom into the host egg. The polydnavirus has been shown to play a major role in inducing the developmental arrest while the parasitoid larva is instrumental in inducing the precocious onset of metamorphosis.

Titres of juvenile hormone I, II and III in Spodoptera littoralis (Noctuidae) from the egg to the pupal moult and their modification by the egg-larval parasitoid Chelonus inanitus (Braconidae).

Physico-chemical analysis of juvenile hormones (JHs) of Spodoptera littoralis revealed highest quantities in the second half of embryonic development and in newly hatched 1st instar larvae. At these stages, mostly JH II, JH I and little JH III were found, while in later stages only JH II and JH III were found. Titres fluctuated in a similar manner in all larval instars, being lowest during the moults.

Analysis of endoparasitoid-released proteins and their effects on host development in the system Chelonus inanitus (Braconidae)-Spodoptera littoralis (Noctuidae).

Having shown earlier that the larva of C. inanitus is essential in inducing the precocious onset of metamorphosis in polydnavirus/venom containing S. littoralis, we here analysed release of proteins by parasitoid larvae and their effects on host development.

Physiological and endocrine changes associated with polydnavirus/venom in the parasitoid-host system Chelonus inanitus-Spodoptera littoralis.

As shown earlier, parasitization by the egg-larval parasitoid C. inanitus causes in its host the precocious onset of metamorphosis in the 5th instar followed by developmental arrest in the prepupal stage. Polydnavirus/venom were shown to be responsible for the developmental arrest.

Overview of parasitism associated effects on host haemocytes in larval parasitoids and comparison with effects of the egg-larval parasitoid Chelonus inanitus on its host Spodoptera littoralis.

In the first part we review the effects of larval endoparasitoids and their polydnavirus and venom on the immune system of their hosts. In all systems investigated, haemocyte spreading and encapsulation activity was reduced; in some cases effects on total (THC) or differential (DHC) haemocyte count as well as modification of haemocyte morphology and ultrastructure were also documented. In many cases polydnavirus (and venom) were shown to play a major role in abrogation of the host's immune reaction.

Polydnavirus of the parasitic wasp Chelonus inanitus (Braconidae): characterization, genome organization and time point of replication.

Ultrastructural analysis of the polydnavirus of the braconid wasp Chelonus inanitus revealed that virions consist of one cylindrical nucleocapsid enveloped by a single unit membrane. Nucleocapsids have a constant diameter of 33.7 +/- 1.