Figure 1.

Mortality caused by DCV decreases when infection occurs later in larval development: larvae of the w¹¹¹⁸ and Champetières fly lines were picked from rearing plates and orally challenged with lysates of DCV- or PBS-injected flies at 4 different times post ecclosion, and transferred to individual test plates (A). At least 4 biological replicates were done, each containing 2-PBS- and 3-DCV-challenged groups of larvae, per time point. Mortality was calculated from the proportion of adults that emerged from the larvae transferred to each test plate, for each PBS or DCV feeding challenge. A two-way ANOVA analysis was used to compare the effect of infection and the time (of larval development) at which the challenge was done. Using Šídák’s test for multiple comparisons, the survival between PBS and DCV at each time point was compared, to determine that L0, L2, and L2 larvae were susceptible to lethal DCV infection compared to their uninfected controls; and Tukey’s test was used to compare the mortality after PBS or DCV feeding across instars, to determine that the mortality caused by DCV decreased significantly between the L0-L1, L1-L2, and/or L2-L3 times of infection ((B,C); statistical analysis results are detailed in Table S1; * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001).