Biological Fitness Cost, Demographic Growth Characteristics, and Resistance Mechanism in Alpha-Cypermethrin-Resistant Musca domestica (Diptera: Muscidae)

Abstract

Musca domestica L., a pest of animals and humans, has developed resistance to alpha-cypermethrin, a pyrethroid insecticide commonly used to control medically important pests in many countries, including Saudi Arabia. We investigated the mechanism underlying the development of alpha-cypermethrin resistance and life history characteristics of alpha-cypermethrin–susceptible (Alpha-SS) and alpha-cypermethrin-resistant (Alpha-RS) M. domestica using the age-stage, two-sex life table theory, which is crucial for developing a future rational management strategy and minimizing the negative effects of alpha-cypermethrin on the environment. Our results showed that Alpha-RS M. domestica had a 405.93-fold increase in resistance to alpha-cypermethrin relative to Alpha-SS M. domestica. This increase in the resistance toward insecticide was attributed to metabolic enzymes, such as glutathione S-transferases, specific esterases, and cytochrome P450 monooxygenases. Furthermore, Alpha-RS M. domestica exhibited lower relative fitness (0.50), longevity, survival rate, life expectancy, reproductive values, intrinsic rate of increase, net reproductive rate, fecundity, maternity, and finite rate of increase, along with shorter larval, female preadult, and adult durations than Alpha-SS M. domestica, indicating fitness costs associated with most parameters. However, no significant differences were found between the strains in the following parameters: egg, pupa, and male preadult durations; adult preoviposition, total preoviposition, and oviposition periods; female ratio; and total generation time. Additionally, Alpha-RS M. domestica had a markedly lower intrinsic rate of increase, net reproductive rate, and finite rate of increase than Alpha-SS M. domestica. The results of this study suggest that alpha-cypermethrin resistance may lead to dominant fitness costs in M. domestica. Overall, these findings will aid in the development of rational control strategies for M. domestica as well as help to reduce pesticide pollution.

Lack of fitness costs associated with resistance to permethrin in Musca domestica

“…The observed fitness advantage of biological parameters of permethrin resistant strains suggest that permethrin resistance was not energetically costly, and there might be an absence of a trade-off in the distribution of physiological resources to overcome insecticide resistance and to perform biological activities 24 . Previously, in contrast to the present study, it has been reported that pyrethroid insecticides induce fitness costs in insect pests 46 , 48 . However, studies also revealed that the phenomenon of fitness cost is not a consistent phenomenon; rather it changes from species to species, among insecticides within the same class and/or strains of the same species with different geographical origins.…”