The effect of Habrobracon hebetor venom on the activity of the prophenoloxidase system, the generation of reactive oxygen species and encapsulation in the haemolymph of Galleria mellonella larvae

The cellular and humoral immune reactions in haemolymph of the wax moth Galleria mellonella larvae naturally injected by venom of ectoparasitic wasp Habrobracon hebetor were analyzed. A strong decline of phenoloxidase (PO) activity in the haemolymph and the number of haemocytes with PO activity of envenomated wax moth was observed. In addition, it has been shown that the rate of capsule melanization in the envenomated larvae was half that of the control. Also production of reactive oxygen species (ROS) in the haemolymph of envenomated larvae decreased. The obtained data casts light on the suppression of the main immune reactions in G. mellonella larvae during natural envenomation by H. hebetor.

Highlights► The suppression of main immune reactions in wax moth larvae during natural envenomation by H. hebetor is found. ► The poison of H. hebetor suppresses the phenoloxidase activity in the haemolymph. ► The poison of H. hebetor suppresses the rate of encapsulation in haemolymph. ► The reduction of reactive oxygen species generation in the envenomated larvae is detected. ► The decline of the haemocytes with phenoloxidase activity in the envenomated larvae is registered.