The protein identification and iTRAQ quantification were carried out as previously described using a MASCOT engine (Matrix Science, London, UK; version 2.2) embedded into Proteome Discoverer 1.3 (Thermo Electron, San Jose, CA.)25. Briefly, the database search was performed against the lepidopteran (Uniprot)database. The corresponding parameters were set as follows: Peptide mass tolerance = 20 ppm, MS/MS tolerance = 0.1 Da, Enzyme = Trypsin, Missed cleavage = 2, Fixed modification: Carbamidomethyl (C), iTRAQ 8plex(K), iTRAQ8plex(N-term), Variable modification:Oxidation(M), thorough search effort and detected protein threshold(False discovery rate, FDR) < 0.01. The ProGroup algorithm in the software was used to eliminate redundancy from the grouping of identified proteins.