How does pesticide resistance primarily develop within pest populations?

Pesticide resistance primarily develops through the selective survival and reproduction of resistant individuals. When a pesticide is applied, it creates a selection pressure on the pest population. Individuals that have genetic traits allowing them to survive the pesticide exposure are more likely to live longer and reproduce. Over time, as these resistant individuals pass on their genes to the next generation, the population as a whole becomes increasingly resistant to the pesticide.

This process can occur rapidly, especially if the pesticide has a specific mode of action that targets certain physiological or biological functions of the pests. With each subsequent application of the pesticide, the proportion of resistant individuals continues to grow, leading to a situation where the pesticide becomes less effective over time.

In contrast, sudden climate changes do not directly cause resistance but can influence pest behavior and reproduction. The integration of new chemical compounds may help manage resistance but does not inherently cause it. Enhanced predator populations can reduce pest numbers but do not directly induce resistance within the pest population.