The dragonfly is an extremely unique insect, both in the shape of its body, and its 4 independent wings. Lets start with its eyes. The dragonfly, like many insects, has nearly 30,000 eyes, called compound eyes(1). This doesn’t work well for traditional sight it gives the dragonfly a 360 degree motion detector of sorts. This is critical because the dragonfly uses that motion detector to find prey and it enables the dragonfly to use its supreme mobility to hunt down what it saw.
Lets get into that mobility, as it is where the dragonfly really shines. Birds can fly only in one direction because of the requirement of having air flow over their wings to generate lift. While there is a humming bird that can fly backwards it nowhere nears the acrobatics of a dragonfly. With 4 wings it can fly up, down, sideways, forward, and backward without changing its orientation (1). These amazing insects can hover in one spot with no motion in any direction or fly upwards of 38 mph depending on the species (2).
The secret to this maneuverability is the dragonfly’s 4 wings. They enable it to quickly change direction, slow down, or accelerate extremely rapidly. Recent studies by Cornell Physicists looked into different ways of pairing and flapping the wings affected flight and energy use. The dragonfly can use both pairs of wings flapping in tandem to obtain the fastest acceleration and directional changes while by flapping the wings at the same rate but out of phase the dragonfly could conserve energy while hovering. Out of phase means when the front pair of wings are at the top of the flap the back pair are at the bottom and vice versa. Below is a simulation put together of a dragonfly flapping and the airflow generated.
There are currently projects going on to develop robotic dragonflies to use as spy cams along with other things. Their light frame, amazing flight abilities, and small size make robotic versions of them extremely appealing. There currently has been little progress made considering the complications associated with 4 independent wings and complicate flight maneuvers(4). However, there are toy versions currently on the market if you are looking to pick one up such as the WowWee Dragonfly pictured below.