Spatially differential regulation of ATF2 phosphorylation contributes to warning coloration of gregarious locusts

Warning coloration are common defense strategies used by animals to deter predators. Pestilential gregarious locusts exhibit a notable black-brown pattern as a form of warning coloration. However, the mechanisms regulating this distinctive pattern remain largely unknown. Here, we revealed that the black and brown integuments of locusts are governed by varying amounts of β-carotene and β-carotene–binding protein (βCBP) complexes. β CBP expression is regulated by the bZIP transcription factor activation transcription factor 2 (ATF2), which is activated by protein kinase C alpha in response to crowding. Specifically, ATF2 is phosphorylated at Ser 327 and translocates to the nucleus, where it binds to the β CBP promoter and stimulates overexpression. Differential phosphorylation of ATF2 leads to the divergent black and brown coloration in gregarious locusts. The accumulation of red pigments vital for creating the brown sternum depends on βCBP overexpression. The spatial variation in ATF2 phosphorylation enables locusts to rapidly adapt to changing environment for aposematism. Locusts precisely regulate a single transcription factor and effector to implement the warning coloration for group defense.