Insect chitinases are necessary hydrolytic enzymes for chitin degradation, insect molting and metamorphosis. In this study, five chitinases encoded in the genome of Spodoptera exigua (SeCHIT7, SeCHIT11, SeCHIT12, SeCHIT13 and SeCHIT14) were identified by reverse transcription PCR. Phylogenetic analysis indicated that SeCHIT7 belonged to Group III, and SeCHIT11/12/13/14 belonged to Group VIII. Real-time quantitative PCR analyses showed that SeCHIT7 had an extensive transcription at the fourth- and fifth-instar larval and pupal stages, while SeCH...