In termites, it was predicted that the MEKRE93 pathways contribute to caste differentiation (Korb and Belles, 2017 Miura and Maekawa, 2020 Oguchi et al., 2021), and although JH related genes (Met and Kr-h1) were investigated in detail (e.g., Zhou et al., 2007 Saiki et al., 2014 Masuoka et al., 2015Masuoka et al.,, 2018Milacek et al., 2021), the roles of these pathways especially in the neotenic differentiation were not fully understood.Ĭaste development in social insects requires the coordination of molting and metamorphosis during postembryonic development. Specifically, the antimetamorphic action of Kr-h1 is reciprocally repressed by the expression of E93, which is regulated by ecdysone and its receptor (EcR) and the master trigger of imaginal molt and neoteny (Ureña et al., 2014 Bell es and Santos, 2014 Kayukawa et al., 2017 Chafino et al., 2018 Vea et al., 2019). Briefly, after JH binds to the receptor Methoprene-tolerant (Met), this complex upregulates the expression of Krüppel-homolog 1 (Kr-h1), which is known as the transducer of the antimetamorphic signal of JH (Minakuchi et al., 2008(Minakuchi et al.,, 2009Charles et al., 2011 Jindra et al., 2021 Kayukawa et al., 2012).
