Killing of parasitoid wasp eggs does not require Toll signaling in the fat body or hemocytes, but the outcome of infection is correlated to Toll activation in the fat body.

<p><b>A</b>. Percentage of killed parasites, as seen in dissected larvae 48–50 hours after infection. No consistent effect is seen after suppressing Toll signaling with the fat body driver <i>FB-Gal4</i> (<i>FB</i>>) or with the double hemocyte driver <i>Hml^Δ-Gal4 He-Gal4</i> (<i>HH</i>>), crossed to <i>MyD88</i> RNAi constructs (><i>MyD88^IR</i>) <i>MyD88^GD25399</i> (399) or <i>MyD88^GD25402</i> (402), or to a <i>pelle</i> RNAi construct (><i>pll^IR</i>), <i>pll^GD2889</i>. <b>B</b>. The percentage of parasitized larvae that have visible black capsules 27–29 hours after infection (genotypes are the same as in A). Suppressing Toll signaling with the double hemocyte driver <i>Hml-Gal4 He-Gal4</i> (<i>HH</i>>) does significantly enhance the encapsulation response, whereas suppressing Toll signaling with the fat body driver <i>FB-Gal4</i> (<i>FB</i>>) does not have any effect on encapsulation. <b>C</b>. Activation of Toll signaling in the fat body of parasitized larvae, as visualized with the <i>Drs-GFP</i> reporter and ApoTome imaging. Most larvae show no activation (GFP^-) 48–50 hours after infection, some show weak activation, mainly in the posterior end (GFP⁺), and a few show strong generalized activation (GFP⁺⁺). <b>D</b>. Correlation between Drs-GFP activation and the encapsulation response, as seen after dissecting larvae 48–50 hours after infection. The dissected larvae were divided into four categories, depending on the outcome of the infection: “live, no capsule” (living wasp larvae and no melanization), “live encapsulated” (living wasp larvae and destroyed melanized capsules), “dead encapsulated” (dead, melanized wasp larvae or melanized wasp eggs), and “stung, no egg” (fly larvae with a clear ovipositor wound but without a parasite). The bars show the percentage of larvae within each category with no, weak, or strong GFP expression. Average +/− standard error of the mean, from three independent experiments with more than 200 larvae in each experiment, * <i>p</i><0.05, ** <i>p</i><0.01, *** <i>p</i><0.001. The total number of larvae in each category is indicated.