Dragon flies with radio tags

Very little is known about dragonfly migration. Now a study is underway in USA, which is being led by Martin Wikelski, a professor of ecology and evolutionary biology at Princeton University .The first radio tags were attached in September. The transmitters, which weigh .0.3 gram and are about 1 centimetre long, are glued to the insects' undersides Wikelski puts the receiver in his plane and follow the insects. Uncertainties exist on how dragonflies navigate. Do they use their big eyes as an aid in navigation? Or do they have an internal compass? Scientists are intrigued.