Left: Schematic representation of Drosophila (A), Tribolium (B), and Nasonia (C) embryos showing distribution of maternally provided mRNAs. Right: representation of resulting protein gradients. Red curves in left panel on A and B represent the distribution of tsl expression, and correspond with the red bars at right representing the resulting activation of MAP kinase in the embryo. Question marks for Otd and Hb in panel B indicate their now doubted role in providing positional information to the early embryo. Ah=anterior head, Gn=gnathal, Tx=thorax, Ab=abdomen, Tl=telson, Gz=growth zone.