Consider the Dragonfly
Most of the dragonflies we see at a pond or lake will be males. Each male tries to establish a territory that he aggressively defends against any other males of his species. Once this is done, most of each day will be spent defending his territory. This requires a lot of energy, therefore he must also eat large amounts of flying insects, such as mosquitoes. He also needs the energy of the sun to keep his muscles warm. This is why you will not see many dragonflies on cool cloudy days! His reward for successfully defending his territory is the opportunity to mate with every female that enters his territory. His lifestyle requires sharp vision and swift wings. Without them he will fail to acquire enough energy to successfully defend a territory, and will not pass on his genes to a new generation of dragonflies.
The females do not need to defend a territory, but they do need to acquire the energy and nutrients to produce thousands of eggs. The production of so many eggs requires that females eat large numbers of small flying insects, just like the males. The females do most of their hunting away from the water to avoid harassment by the males until they are ready to lay eggs.
There are 67 species of dragonflies and damselflies known to reside in Idaho.