Mechanism of physiological resurgence affecting recovery of susceptibility in fenvalerate-resistant strains of the diamondback moth Plutella xylostella.

建立了一株对氰戊菊酯产生抗性的小菜蛾（DBM），研究了亚致死剂量对小菜蛾卵大小和繁殖力的影响。选择菌株的卵明显小于未选择菌株的卵。选择菌株的雌虫繁殖力倾向于高于非选择菌株。选择菌株的存活率低于未选择菌株。为了确定赤眼蜂抗性发育和减小卵大小的遗传方式，对正交F_1代与亲本进行了这些性状的比较。还比较了正交F1后代以及抗性和易感系之间的几个适合度成分，以检测母体对卵大小等成分的影响。雌雄敏感系（SR）和雌雄敏感系（RS）杂交F_1的剂量-死亡率回归曲线大致，介于亲本（SS）和亲本（RR）之间。这一结果表明，对氰戊菊酯的抗性遗传方式既不是完全显性遗传，也不是完全隐性遗传，没有性别连锁。RR系的卵大小显著小于SS系。RS系和SR系的卵大小与其母系相近。虽然选择实验表明，这些参数之间存在负相关响应，但可以认为抗性遗传方式与卵大小遗传方式不同。在严酷的饲养条件（Harsh lines）和最优的饲养条件（Optimal lines）下，通过10代的试验，检测了DBM抗性品系对丁伐雷酯的敏感性恢复情况。在所有世代中，严酷系的LD_<50>值均低于最优系。经过10代，两系的卵大小逐渐增大。对这两种品系的比较表明，在早期世代中，“严酷”品系的卵大小比“最佳”品系增大得更快。在这些条件下饲养的严酷系和最优系的未成熟存活率比较表明，严酷系个体存活率显著低于最优系个体存活率。这些结果表明，由于卵小的抗性昆虫的敏感性低于卵正常的敏感昆虫，因此在“严酷”品系中，敏感性恢复可能比在“最佳”品系中更快。少

A diamondback moth (DBM) strain resistant to fenvalerate was established and the effects of sublethal dose of the insect on egg size and fecundity were examined. The eggs of the selected strain were significantly smaller than those of non-selected strain. The fecundity of females of the selected strain tended to be higher than that of the non-selected strain. The survival rate of the selected strain was lower than that of the non-selected strain.To determine mode of inheritance of resistant development and of reduction of egg size in DBM, F_1 offspring of reciprocal crosses were compared with their parental lines for these traits. Several fitness components were also compared between F1 offspring of reciprocal crosses as well as the resistant and susceptible lines to detect maternal effects on the components including egg size. The dose-mortality regression lines of the F_1 hybrid of susceptible females and resistant males (SR) and resistant females and susceptible males (RS) were roug … More hly intermediate between that of parental lines, i.e., SS and RR. This result indicates that the mode of inheritance of fenvalerate resistance was neither complete dominant nor recessive with no sex-linkage. The egg size of RR lines was significantly smaller than that of the SS lines. The RS and SR lines have an egg size close to that of their own matrilineage. It was considered that the mode of inheritance of resistance and that of egg size were different from each other, although the selection experiment showed that there is a negative correlated response between these parameters.The recovery of susceptibility to fenvarelate in resistant strains of DBM was examined through 10 generations after freeing then from insecticide selection under harsh-rearing (Harsh lines) and optimal-rearing conditions (Optimal lines). The LD_<50> values were lower for the Harsh lines than for Optimal lines in all the generations. Egg size of both lines increased gradually through 10Generations. Comparisons of these two lines show that the egg size increased more rapidly in Harsh lines than in Optimal lines in early generations.Comparison of immature survivability of Harsh and Optimal lines reared under those conditions showed that the survivability of Harsh line individuals was significantly lower than for those of Optimal lines. These results suggest that susceptibility might recovery more quickly in Harsh lines than in Optimal lines because resistant insects with small eggs had lower susceptibility than susceptible insects with normal eggs. Less