In areas of the American Wheat Belt and American Corn Belt in the midwest, certain insect species are quickly becoming resistant to continuous application of specific chemical insecticides. The increase in the number of insecticide-resistant insects is due to
natural selection
variability through asexual reproduction
inheritance of acquired traits
geographic isolation
natural selection
The increase in the number of insecticide-resistant insects in the American Wheat Belt and American Corn Belt in the midwest is primarily due to natural selection. Natural selection is the process through which organisms with advantageous traits have a greater chance of survival and reproduction, passing on those traits to future generations. In this case, the application of specific chemical insecticides is selecting for insects that have genetic variations that make them resistant to the insecticides. Over time, the resistant insects become more prevalent in the population, leading to an increase in insecticide resistance.
Variability through asexual reproduction and inheritance of acquired traits are not significant factors in the development of insecticide resistance. In asexual reproduction, offspring are produced from a single parent organism, often resulting in little genetic variation within the population. Acquired traits, which are traits acquired during an individual's lifetime, are typically not inherited and therefore do not contribute to the evolution of resistance in subsequent generations.
Geographic isolation, on the other hand, refers to the physical separation of populations and is not directly related to the development of insecticide resistance. While geographic isolation can lead to the development of new species over long periods of time, it does not play a significant role in the development of resistance to insecticides.