FGF signalling is vital for early development in vertebrates and invertebrates. I studied the function of various FGF signalling components during embryogenesis of the beetle Tribolium castaneum. I found that Fgf1b, which is absent in Drosophila, is crucial for organising the early anterior fate of the beetle along the AP-axis. I further show that, like in Drosophila, Fgf8 in Tribolium is critical for mesoderm morphogenesis. However, unlike Drosophila, the single FGF-receptor in Tribolium integrates with both the ligands Fgf8 and Branchless during mesoderm and tracheal formation respectively.
