Relative mRNA expression levels of Cshsp19.8, Cshsp21.4, Cshsp21.5, Cshsp21.7a, and Cshsp21.7b in different developmental stages of Chilo suppressalis. Abbreviations: E eggs, L1 first instar larvae, L2 second instar larvae, L3 third instar larvae, L4 fourth instar larvae, L5 fifth instar larvae, L6 sixth instar larvae, P pupae, A adults