Fig. 6From: Post-zygotic selection against parental genotypes during larval development maintains all-hybrid populations of the frog Pelophylax esculentus Survival in hybrid (grey) and parental (black) offspring. In (a) the time course of tadpole survival prior to metamorphosis is shown on a weekly basis for medium (circles) and low (triangles) food treatment. Survival under the high food treatment was measured only once after 9Â weeks; the corresponding values for hybrid and parental offspring are indicated by grey and black stars, respectively. In (b) only survival of metamorphs emerging from the medium food treatment is shown, because tadpoles from the high and low food treatments were not reared beyond metamorphosisBack to article page