Abstract: In order to study the relationship between resistance and sex in male and female Bombyx mori, Thermo enzyme activity measurement and Real Time fluorescent quantitative RT-PCR were performed to compare differences of the activities of detoxification enzymes in male and female B. mori larvae and their genetic expression of newly exuviated larvae at different instars. The research demonstrated significant differences in detoxification enzymes and their related genes existed between male and female B mori larvae. The activities of glutathione S-transferases（GSTs）and BmGSTe5 showed higher expression in males than those in 1st-3rd instar females, while the opposite phenomena were found in 4th and 5th instar larvae. The ratios of enzyme activity and gene expression in the male and the female were 3.65 and 5.11, respectively, which were attributed to the fast development of testis in 4th instar larvae. The enzyme activities of acetylcholine esterase（AchE） in the male were 1.48，1.34 and 1.40 times compared to those of the female from 2nd to 4th instars, while its gene Bm-ace1 showed insignificant differences between male and female B. mori at 2nd and 3rd instars. The expression amount of gene Bm-ace2 in the male were 1.75，2.17 and 2.40 times as high as that in the female from 2nd to 4th instars, suggesting that Bm-ace2 plays a more important role in sex differences. The enzyme activities of carboxylesterase （CarE） in male were 1.23 and 1.87 times compared to that in female at 2nd and 3rd instars, and the activity ratios in the female and the male were 1.22 and 1.23 at 4th and 5th instars, respectively. The expression of BmCarE-5 and BmCarE-10 showed the opposite trend to enzyme activities between different sexes, i.e., lowlevel gene expression and high carboxylesterase activity. We so speculate that carboxylesterase mutation phenomenon exists in B.mori. These results break a new road for research on modification of genetic expression products and their function, and make further contribution to the study of relations between the gender and the ability of drug resistence in B. mori. 27 Refs. In Chinese.  

Key words: Bombyx mori, sex, resistance, detoxification enzyme, gene expression, enzyme activity