Abstract: 【Aim Insects’ ability to adapt to new environment is closely related to their tolerance to different temperatures. Heat shock proteins HSP70 and HSP90 play important roles in improving stress resistance in insects, especially the thermo tolerance. Different whitefly species and different cryptic species of Bemisia tabaci complex show different tolerance to temperature stress, which may be related to the difference in the copy numbers of the Hsp genes of these species. 【Methods】 The copy numbers of hsp70 and hsp90 in Trialeurodes vaporariorum and three cryptic species (two invasive species MED and MEAM1, and one native species Asia Ⅱ 1) of B. tabaci complex were detected by using absolute real-time quantitative PCR. 【Results】 The results showed that there was great difference in the copy numbers of both hsp70 and hsp90 among different species. The copy numbers of hsp70 and hsp90in MED and MEAM1 cryptic species were much higher than those in T. vaporariorum and Asia Ⅱ 1, and those in Asia Ⅱ 1 were the lowest. Moreover, for the same species the copy numbers of hsp70 and hsp90 in female whiteflies were 2-fold as high as those in male adults. 【Conclusion】 There is a relationship between the copy numbers of Hsp genes and thermal tolerance in B. tabaci cryptic species and T. vaporariorum. The results provide further information in understanding the mechanisms of different heat tolerance for different species or different sexes of whiteflies

Key words: Bemisia tabaci;Trialeurodes vaporariorum, heat shock gene, thermal tolerance, real-time PCR, copy number 