Insecticide resistance and dominance levels.

Area of Science:

• Insecticide resistance
• Population genetics
• Pest management

Background:

• Dominance in insecticide resistance is traditionally assessed using dose-lethal concentration (DLC), dose-lethal mortality (DML), or fitness in treated areas (DWT).
• These metrics are influenced by genetic background and environmental conditions, and are not always directly related.
• Existing studies often prioritize DLC, which offers limited insight into the efficacy of pest management programs.

Purpose of the Study:

• To propose a generalized formula for estimating dominance on a scale of 0 to 1.
• To highlight the importance of fitness dominance (DWT) over other metrics for resistance management.
• To emphasize the need to re-evaluate dominance assessment in insecticide resistance studies.

Main Methods:

• Development of a general formula for dominance estimation.
• Analysis of the relationship between DLC, DML, and DWT.
• Examination of how pest management strategies can influence DWT through dominance modifiers.

Main Results:

• A unified scale for dominance estimation (0 = complete recessivity, 1 = complete dominance) was proposed.
• DLC, DML, and DWT were shown to be independent and context-dependent.
• Pest management strategies can inadvertently increase DWT by selecting for dominance modifiers.

Conclusions:

• Fitness dominance (DWT) is a more relevant measure for resistance management than DML or DLC.
• The high dose/refuge strategy relies on assumptions about recessivity (low DML) that may not align with fitness impacts.
• Future research should prioritize assessing fitness dominance in both the presence and absence of insecticides for effective pest control.