Question

D

Question 10
10 pts
Bed bugs might sound like an old-fashioned problem, but now they are back with a vengeance. Fifty
years ago, the blood-sucking pests were nearly eradicated in the United States thanks in part to the
use of pesticides like DDT. Today, they are creeping over sheets and tormenting sleepers across the
country. New York was recently declared America's most bed-bug-infested city in America. In the
past, we countered the bed bugs by using pesticides called pyrethrins and pyrethroids. These
compounds work by attacking the nervous system. Insects have channels in the membranes of their
nerve cells that can be opened to allow sodium into the cells, triggering a nerve impulse. Pyrethrins
and pyrethroids alter the nervous system by binding to the sodium channels, locking them in the
open position. This allows sodium to pour into the cell continuously, causing the nerve to fire
repeatedly and eventually leading to paralysis. Todays bed bugs seem to be more resistant to the
chemicals that previously killed them. Cases of resistance have been reported in all classes of pests:
crop diseases, human diseases, weeds, rodents, and insects, with crises in insect control beginning
shortly after the introduction of pesticide use in the 20th century.
Why do insect pests become resistant so readily to the pesticides used for control?
O Mutation in only a single gene can lead to the evolution of a resistant organism.
An effective way to reduce pesticide resistance is to develop new pesticides.
We often rely almost exclusively on pesticides for pest control and this decreases selection pressure towards
resistance.
O Insect exoskeletons reduce the effectiveness of pesticides and the death rate is much lower than was ever
expected.

Answer 1

Answer: In summary, the process of natural selection, widespread and frequent use of pesticides and genetic variation within the insect population all contribute to the rapid evolution of resistance to pesticides.

Step-by-step explanation:

Insect pests become resistant to pesticides because of the process of natural selection. When pesticides are used to control insect populations, the insects that are most susceptible to the pesticides die off, leaving behind those that are less susceptible. Over time, these less susceptible insects reproduce and pass on their resistance to their offspring.

Additionally, the widespread and frequent use of pesticides can accelerate this process of resistance development. When pesticides are used on a large scale and with high frequency, the population of pests that are resistant to these pesticides will increase. As these insects are more likely to survive and reproduce, the resistant population will grow more quickly than the susceptible population.

Another reason for the rapid evolution of resistance to pesticides is the genetic variation that exists in insect populations. Some insects have genetic mutations that make them resistant to pesticides. When these insects are exposed to pesticides, the resistant insects will survive, reproduce, and pass on their resistance genes to their offspring.