does not give an advantage to the ectoparasitoid (Say, 1836) when it develops on an infected host.

The effect of on the viability and antimicrobial activity of the ectoparasitoid was evaluated in laboratory experiments. Two lines of the parasitoid, -infected (W+) and -free (W-), were used. Parasitoid larvae were fed with a host orally infected with a sublethal dose of (Bt) and on the host uninfected with Bt. Parasitoid survival was assessed at developmental stages from second-instar larvae to adults. At all developmental stages, there were no statistically significant differences in survival between lines W+ and W-, regardless of host Bt infection. In both W+ and W- lines, the expression of lysozyme-like proteins, antimicrobial peptides (AMPs), and genes was analysed in fourth-instar larvae fed with an infected and uninfected host. In addition, lysozyme-like activity and antibacterial activity were evaluated. The expression of AMPs was significantly higher in W- larvae and did not get induced during the feeding on the Bt-infected host. mRNA expression of lysozyme-like proteins and lysozyme activity were significantly higher in W+ larvae than in W- larvae and did not get induced when the larvae were fed with the infected host. In whole-body homogenates of larvae fed with the uninfected host, antibacterial activity against gram-positive bacteria ( and ) was significantly higher in the W+ line and did not get induced during the feeding with the Bt-infected host. Therefore, there is no obvious immunostimulatory effect of in larvae when they feed on a host infected with an entomopathogenic bacterium.