Resistance to insecticides

Definition

The heritable capacity of an arthropod population to survive exposure to a dose of insecticide that would be lethal to individuals from a susceptible strain of the same species. Resistance arises through selection of pre-existing or de novo genetic variants affecting target-site insensitivity, metabolic detoxification, behavioral avoidance, or reduced penetration/cuticular thickening. It is distinct from tolerance (innate, non-heritable variation in susceptibility among individuals) and from resistance management (the deliberate strategy to delay its evolution).

Etymology

Example

Populations of the malaria vector Anopheles gambiae in West Africa have developed target-site resistance to pyrethroids through mutations in the voltage-gated sodium channel (kdr alleles), while metabolic resistance through elevated cytochrome P450 activity allows some strains of the cotton bollworm Helicoverpa armigera to detoxify organophosphates and carbamates.

Synonyms

• Insecticide resistance

Related Terms

• Cross-resistance
• Multiple resistance
• Resistance management
• Acetylcholinesterase
• Voltage-gated sodium channel
• Cytochrome P450
• Knockdown resistance
• Integrated Pest Management
• Susceptibility baseline
• Selection pressure

Usage Notes

Specialists distinguish resistance (population-level, heritable) from tolerance (individual variation, not heritable). 'Cross-resistance' refers to resistance to one chemical conferring resistance to another; 'multiple resistance' involves independent mechanisms protecting against different classes. The term is sometimes misapplied to behavioral changes (e.g., resting outdoors to avoid treated surfaces), which are more precisely called 'behavioral avoidance' unless the behavior has a genetic basis and is selected.