Sex-based variation in insecticide susceptibility and tolerance related biochemical parameters in tea mosquito bug Helopeltis theivora

摘要

Helopeltis theivora, one of the major pests of tea from North east India, reported to acquire tolerance against commonly used synthetic pesticides. Study on relative toxicity of both sexes of H. theivora along with their detoxifying enzyme levels were carried out to assess developemnt of sex-based tolerance of pest against the pesticides. The present study showed that female develop more tolerance among H. theivora population than male. Relative toxicity tests showed that LC50 was higher in female than male H. theivora. This result reflects in general, sex level difference in tolerance status of the pest along with corresponding changes in the quantities of detoxifying enzymes. Female of H. theivora showed significantly higher general estearse and glutathione-S-transferase activities than that of male; however there was no significant difference in cytochrome P450 activity. The total body lipid content was also found to be higher in female than male, which indicated female attribute to be more tolerant than male. Body weight of female was significantly higher than that of male, which showed positive correlation with general esterase and glutathione-S-transferase. Hence, on application of recommended dose of pesticide, chance of survivability of female is better in field, leading to addition of more tolerant forms.