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

建立了抗氰戊菊酯的小菜蛾品系，研究了亚致死剂量对小菜蛾卵大小和繁殖力的影响。选育品系的卵显著小于非选育品系。选育品系的雌蜂繁殖力趋于高于非选育品系。选择品系的存活率低于未选择品系。为了确定DBM抗性发育和卵大小减少的遗传方式，对正反交F1代与其亲本进行了这些性状的比较。还比较了正反交F1后代以及抗性和感病品系的几个适应度成分，以检测母体对这些成分的影响，包括卵子大小。感病雄株(SR)和抗病雄株(RS)杂交F_1代的剂量-死亡回归系为Roug…HLY介于亲本系SS和RR之间。这一结果表明，氰戊菊酯抗性的遗传方式既不是完全显性的，也不是隐性的，没有性别连锁。RR品系的卵大小显著小于SS品系。RS和SR品系的卵大小接近其母系。抗性的遗传方式和卵大小的遗传方式是不同的，但选择试验表明这些参数之间存在负相关反应。在严酷饲养(苛刻品系)和最佳饲养条件(最佳品系)下，经过10代的筛选，观察了抗性品系对黄粉虫的敏感性恢复情况。在所有世代中，强势品系的LD_(50)值均低于最佳品系。两个品系的卵大小在10代后逐渐增大。两个品系的比较表明，在早期世代中，恶劣品系的卵大小增长速度比最佳品系快，在此条件下饲养的恶劣品系和最佳品系的幼虫存活率比较表明，恶劣品系个体的成活率显著低于最佳品系。这些结果表明，在恶劣品系中比在最佳品系中敏感性恢复得更快，因为具有小卵子的抗性昆虫比具有正常卵子的敏感昆虫具有更低的敏感性。较少

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