Resistance occurs when a pest...

Resistance occurs when a pest...

• A. Pest is not exposed to pesticides.
• B. Pest survives pesticide exposure.
• C. Pests are attracted to pesticides.
• D. Pesticide effectiveness increases over time.

Answer: (B)

Pest resistance occurs when a population under pesticide pressure shifts as a result of natural selection. When a pesticide is applied, most individuals die, but a few carry genetic traits that let them survive. Those survivors reproduce and pass the resistance traits to their offspring. Over multiple generations, the population becomes more able to withstand the pesticide, making control harder. So the statement that the pest survives pesticide exposure best captures how resistance develops. The other ideas don’t fit this process: if pests aren’t exposed, there’s no selective pressure to favor resistance; simply being attracted to a pesticide doesn’t create heritable tolerance; and if pesticide effectiveness increased over time, that would imply the opposite of resistance rather than its development.

Pest resistance occurs when a population under pesticide pressure shifts as a result of natural selection. When a pesticide is applied, most individuals die, but a few carry genetic traits that let them survive. Those survivors reproduce and pass the resistance traits to their offspring. Over multiple generations, the population becomes more able to withstand the pesticide, making control harder. So the statement that the pest survives pesticide exposure best captures how resistance develops.

The other ideas don’t fit this process: if pests aren’t exposed, there’s no selective pressure to favor resistance; simply being attracted to a pesticide doesn’t create heritable tolerance; and if pesticide effectiveness increased over time, that would imply the opposite of resistance rather than its development.