Insects are the most diversified organisms in the world. They are vital to the functioning of the ecosystem and biosphere, and neither of these systems can operate effectively without insect interactions. Insects are regularly subjected to stressors related to increasing anthropogenic activities, including chemicals and climatic changes that induce major stresses. Depending on the species and the particular stress affecting it, insect populations respond by increasing or decreasing in numbers. Researchers have assessed the responses of insect populations to various direct and indirect environmental stresses. Some insect populations increase, while others decline. The reponses were determined by the particular environmental stress, the insect species, and he stage at which they were exposed to the stress.