Relative fertility in miRNA KO lines. After mating with either wild-type or miRNA KO males, females are permitted to lay eggs for 7 d. (A) Number of progeny in the first 2 d. (B) Number of progeny in days 3–7. Overall, the fertility differences between wild-type and KO males are small. The three older miRNAs seem to have a larger impact on days 3–7, whereas the younger miRNAs do not show a consistent pattern. Except for mir-977, none of the differences is significant: (**) P < 0.01, Student's t-test. (C,D) Day-to-day fertility analyses of mir-977 for egg laying and progeny count, respectively. Mean ± SEM is shown. Fertility differences between wild-type and KO males are significant in later days (multiple t-tests with the Holm-Sidak correction, P = 0.0009 on day 5 and P = 0.011 on day 7). (E,F) Day-to-day fertility analyses of mir-978. There is a slight but insignificant decrease during the first 2 d and a slight increase in subsequent days for the KO line.