Insect-plant relationships predict the speed of insecticide adaptation

Area of Science:

• Ecology
• Evolutionary Biology
• Pest Management

Background:

• Herbivorous insects face challenges from plant chemical defenses and synthetic insecticides.
• The pre-adaptation hypothesis suggests insecticide resistance evolves by co-opting pre-existing adaptations to plant defenses.
• Systematic testing of this hypothesis has been limited.

Purpose of the Study:

• To systematically test the pre-adaptation hypothesis regarding insecticide resistance in herbivorous insects.
• To identify factors influencing the rate of insecticide resistance evolution.
• To develop a predictive framework for pest resistance to insecticides.

Main Methods:

• Survival analysis was used to examine over 17,000 herbivore-insecticide interactions.
• Statistical models were applied to assess the relationship between diet breadth, chemical similarity, and resistance evolution.
• Macro-evolutionary and population genetic processes were considered.

Main Results:

• Insecticide resistance evolution accelerated with broad, but not excessively broad, herbivore diets.
• Resistance evolution was faster when insecticides and plant defensive chemicals exhibited moderate similarity.
• Diet breadth and chemical similarity are key factors in predicting resistance evolution.

Conclusions:

• The study provides empirical support for the pre-adaptation hypothesis in insecticide resistance.
• A complex interplay exists between evolutionary history and current population genetics in pest resistance.
• The findings offer a framework to predict which pests may develop resistance to specific insecticides.