Irrespective of the exact mechanism, dominance is intrinsic to oscillatory cAMP signalling. Group 4 species have larger fruiting bodies because their cAMP oscillators are better at suppressing competitors. Two aspects of cAMP signalling are specific to group 4: (1) oscillatory cAMP signalling occurs much earlier in development than in groups 1-3, and (2) the cAMP receptor gene was duplicated three times, and both expression and affinity of the daughter cARs were altered. It is conceivable that either of these novelties may have ''improved'' cAMP signalling to allow it to control larger numbers of cells and make it generally more robust.