The RoboBee has landed. Well, actually, it has perched, which is even more impressive.

The RoboBee is an insect-size robot that weighs less than four thousandths of an ounce. And it flies, which is a giant achievement for such a tiny machine.

Until recently, however, it didn’t perch, and perching is the next frontier for tiny flying machines because robots, like birds, bats and insects, can keep going longer if they conserve energy by resting.

Most micro aerial vehicles, or MAVs as they are called, are bigger than the RoboBee, but still are measured in inches and ounces rather than feet and pounds. They have power enough to fly for 10 minutes to a half-hour or so, but the tasks they are designed for, like searching for disaster survivors or doing environmental monitoring, require hours of activity, not minutes.

Nature also encountered the energy demands of flight during the course of evolution. And so it should be no surprise that most flying creatures can rest up high, where they can keep looking for whatever it is they look for — tasty mice, delectable flowers — or just rest.