Why has there been an increase in clothes moth populations?

• A. Increased use of bed nets
• B. Lower humidity levels
• C. More house plants
• D. Loss of chlorinated hydrocarbon insecticides

Answer: (D)

The situation hinges on how chemical controls shape pest populations. Chlorinated hydrocarbon insecticides were broad-spectrum and long-lasting, meaning they didn’t just target a single pest but helped keep many household pests, including clothes moths, under stronger mortality pressure. When the use of these persistent chemicals declined or stopped, that extra layer of control disappeared. With less chemical pressure, clothes moths can survive and reproduce more readily, leading to higher populations.

Other options don’t align with why clothes moth numbers would jump. Bed nets mainly reduce mosquitoes and aren’t a factor for fabric-feeding moths. Lower humidity tends to create drier conditions that can slow moth development, not boost it. More house plants don’t provide the same direct food source for clothes moth larvae, which feed on natural fibers rather than plant matter. The key idea is that removing those longtime, broad-spectrum insecticides removes a major hurdle for clothes moths, allowing their populations to rise.