Abstract
Dysdercus koenigii is an economically important cotton-staining pest in Asia. The population of D. koenigii in Pakistan showed resistance to emamectin benzoate, a semi-synthetic pesticide used for the control of several pests. To investigate the biological fitness cost of emamectin benzoate resistance in D. koenigii, the biological traits of emamectin benzoate-resistant (EMB-RR), -susceptible (EMB-SS), hybrid (RS1, EMB-RR male x EMB-SS female), and hybrid (RS2, EMB-RR female x EMB-SS male) D. koenigii strains were compared using the established life table based on age, stage, and two sex patterns. Compared with the EMB-SS strain, the relative fitness of the EMB-RR, RS1, and RS2 D. koenigii strains were 0.538, 0.545, and 0.424, respectively, with substantial decreases in the net reproductive rate, fecundity, age-stage reproductive value and life expectancy, gross reproduction rate, and generation time. The development durations of nymphs, male total longevity, female total longevity, and total preoviposition period were significantly shorter, whereas female's preoviposition period was prolonged in the EMB-RR, RS1, and RS2 D. koenigii strains. No significant difference was observed in reproductive female ratio, female ratio, and intrinsic and finite rates of increase among the strains. The findings of current study suggest that emamectin benzoate resistance may lead to dominant fitness costs in D. koenigii. Also they provided valuable data for facilitating the rational strategies for controlling D. koenigii.