Inverted Flight
摘要
A male Blue Hawker (Aeshna cyanea) escapes an attacking conspecific rival (white ovals in the photos on the right) by using an unusual avoidance tactic (image sequences from top to bottom): it turns on its back and thus accelerates strongly downwards. It reaches a downward speed of 3.4 m/s (bottom left image) in 0.07 seconds from flying on the spot. It achieved this by benefiting from the earth’s gravitational pull and also by flapping its wings upwards to move air upwards.