The use of insecticides in agricultural settings often exerts negative effects on nontarget species. Methomyl, a broad-spectrum carbamate insecticide, is recommended to manage a number of insect pests of the cotton crop. Recently, Musca domestica, which is a nontarget insect species in cotton fields, has shown resistance to methomyl in Pakistan. The present study tried to assess resistance-risk assessment, rapidity of resistance development to methomyl, cross-resistance potential to other insecticides, resistance heritability and to forecast the projected rate of resistance development under field conditions. For this purpose, a field strain of M. domestica with 186 fold resistance to methomyl was re-selected in the laboratory for eight consecutive generations. Consequently, LD₅₀ values increased rapidly (126.64 ng/fly to 3112.79 ng/fly) compared to those before selection experiments. Similarly, RR values increased from 186 to 3113 fold as a result of the selection process. However, resistance to methomyl did not remain stable when the selected strain (Meth-SEL) reared for the next five generations in a pesticide free environment. The Meth-SEL strain also developed cross-resistance to permethrin. The realized heritability (h²) value for the Meth-SEL strain was 0.39 with 27% average mortality of M. domestica. Assuming the standard deviation (σp) value 0.27 and the h² value 0.39 for eight generations of continuous exposure to methomyl, then five, seven, eight, ten and twelve generations at 90, 80, 70, 60 and 50% selection intensity, respectively, would be required for a tenfold increase in the LD₅₀ value of methomyl. In conclusion, the Meth-SEL strain of M. domestica exhibited a high risk of resistance development to methomyl under continuous selection pressure. Resistance increased rapidly during selection experiments that reflect the probability of resistance development under field conditions if M. domestica receive exposures to methomyl during its applications for the management of target pest species.

在农业环境中使用杀虫剂通常会对非目标物种产生负面影响。灭多威是一种广谱氨基甲酸酯杀虫剂，建议用于防治棉花作物的多种害虫。最近，巴基斯坦棉田非靶标昆虫家蝇对灭多威表现出抗药性。本研究试图评估抗性风险评估、灭多威抗性发展的速度、与其他杀虫剂的交叉抗性潜力、抗性遗传力，并预测田间条件下抗性发展的预计速率。为此，在实验室中连续八代重新选择了对灭多威具有186倍抗性的家蝇田间菌株。因此，与选择实验之前相比，LD _{50值迅速增加（126.64 ng/fly 至 3112.79 ng/fly）。}同样，由于选择过程，RR 值从 186 倍增加到 3113 倍。然而，当所选菌株（Meth-SEL）在无农药环境中培育接下来的五代时，对灭多威的抗性并没有保持稳定。Meth-SEL 菌株还对氯菊酯产生了交叉耐药性。Meth-SEL 菌株的实现遗传力 ( h ² ) 值为 0.39，家蝇平均死亡率为 27% 。假设八代连续暴露于灭多威的标准偏差( σp )值为0.27，h ²值为0.39，则分别在90%、80%、70%、60%和50%选择强度下的五代、七代、八代、十代和十二代，需要灭多威的 LD ₅₀值增加十倍。总之，家蝇Meth-SEL 菌株在持续选择压力下表现出对灭多威产生抗性的高风险。在选择实验期间，抗性迅速增加，这反映了如果家蝇在用于管理目标害虫物种期间接触灭多威，则在田间条件下产生抗性的可能性。