Coevolution happens when the genetic development between two or more species affects the evolution of each other. An example would be hummingbirds and bird-pollinated (ornithophilous) flowers. The ornithophilous flowers give nourishment to the birds with their nectar that has high sugar content. The birds in return aids in the pollination of these flowers.
...decrease in population until the fall season, where leaves are orange to suit the orange beetles
Answer: When your hypothalamus senses that you're too hot, it sends signals to your sweat glands to make you sweat and cool you off. When the hypothalamus senses that you're too cold, it sends signals to your muscles that make your shiver and create warmth. This is called maintaining homeostasis.