While their stings are painful or even dangerous, we depend on hymenopterans for our survival. Bees are the main pollinators of the flowering plants that provide most of the world's food supply. Bee adaptations, such as hairy bodies and legs, have evolved for easy pollen collection. Other hymenopterans, such as wasps, are predators that kill insects and spiders. Some hymenopterans are parasites, laying eggs on other "host" insects, which may eventually die from the feeding larvae that hatch out. We benefit from predatory and parasitic hymenopterans that target the many insects that would otherwise be eating crops. Many hymenopterans are social, living in large colonies of related individuals, headed by a queen. Social insects procure their food cooperatively, and humans profit from the way honeybees collect and process flower nectar into honey. The sophisticated chemical senses of hymenopterans support the behaviors, such as nectar collection and pollination, that benefit us.

Insects are the only animals without backbones (invertebrates) that can fly. Wings of insects are flat and paper-thin, supported by a network of veins. They flap their wings at incredible rates, up to about two hundred times per second. Most insects have two sets of wings that work in tandem because they are coupled by a fold, a hook, or other structure that catches the back wing as the front wing beats. Wings are made of two layers of cuticle for strength. The front wing is often hardened to serve as a protective cover, leaving the back wing to provide most of the flying power. Many insects walk around instead of, or in addition to, flying. The good walkers tend to touch three legs to the ground at a time, alternating with other sets of three (tripedal gait). The stable triangles formed by the legs allows them to move quickly without falling over. Some insects "walk" on water or swim.