Thus, our first objective was to focus on the cis‐regulatory structure of the yellow gene in B. mori, which is associated with melanin pigmentation and is widely investigated in both lepidopteran (Futahashi et al., 2008; Zhang et al., 2017) and other insect species (Wittkopp et al., 2002; Arakane et al., 2010). The yellow gene has been previously identified in B. mori, and has been shown to be homologous to yellow from other insect species (Futahashi et al., 2008; Ferguson et al., 2011). A Δyellow mutant of B. mori (k12) was isolated (Toyama, 1909), and the mutated genomic region identified (Futahashi et al, 2008). Using this mutant, previous studies revealed that the yellow gene is associated with the hair, epidermis, trachea, spiracle, pupal colour and head capsule in fifth‐instar larvae and adults (Table 1).