Fitness costs in Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae) associated with laboratory-selected resistance to imidacloprid

Abstract

The use of insecticides is widespread for the management of insect pest populations. Injudicious use of insecticides is responsible for rapid development of resistance, environmental pollution and human health problems. Insecticide resistance is a great problem in managing insect pest populations of different crops using insecticides. The evolution of resistance may also affect other fitness parameters of resistant insects. In our study, the impact of imidacloprid resistance development on the fitness parameters of Oxycarenus hyalinipennis Costa (Hemiptera: Lygaeidae) and resistance stability was evaluated. After undergoing 19 generations of development selecting for resistance to imidacloprid, the imidacloprid selected (Imida-Sel) strain of O. hyalinipennis developed 55.30-fold and 146.50-fold resistance compared to UNSEL and susceptible strain, respectively. Imidacloprid resistance was found unstable and the resistant strain reverted towards susceptibility after cessation of insecticide selection pressure for eight generations. The value for Rf (relative fitness) was 0.41 for Imida-Sel with a significant reduction in mean relative growth rate (MRGR), intrinsic rate of natural increase (Rm) and net reproductive rate (Ro). Values of Rf for C1 and C2 were 0.85 and 0.77, respectively. The present study was designed to propose a comprehensive strategy for suppression of O. hyalinipennis. O. hyalinipennis exhibits potential for developing imidacloprid resistance, but the resistance was unstable and manageable with insecticide rotation. In addition, the fitness disadvantage associated with imidacloprid resistance may also slow down field evolution of imidacloprid resistance.