Fig. 1

Distinction between within-generational plasticity (WGP) and transgenerational plasticity (TGP), and their additive or interactive effects. Additive effect: (a) offspring phenotype is independently affected by offspring environment (WGP) and parental environment (TGP). Interactive effect: (b) the parental environment only alters the slope of the offspring reaction norm or (c) the parental environment alters the offspring reaction norm direction, producing an opposite response for a same offspring environment. 1 et 2 are two disctinct environments where the phenotype of the offspring is measured. The black and dashed lines represent offspring reaction norms for two different parental environments