Morphology of Insect Wings and Airflow Produced by Flapping Insects

This article describes the results of some experiments concerning wing morphology and flight performance of some flying insects: cicadas, dragonflies, and gadflies. First, the wing structures of these insects are measured down to the minutest detail by a three-dimensional curve-shaped measuring system. The surface shapes of the insect wings are mapped by distinct three-dimensional images. From the three-dimensional images, correlation coefficients are calculated by comparisons of the distribution of undulation on the wings. The surface shapes and the correlation coefficients show a difference in functions for flapping flight between each wing. Second, the distribution of velocity fields around a flapping cicada and a flapping dragonfly are visualized with a PIV system to identify the airflow generated by the wings. The distribution of velocity vectors for one stroke of a dragonfly wing is explained in the article. Additionally, the difference of airflow around the wings of a dragonfly and a cicada are revealed. It is found that the flapping forewing of the dragonfly carries out an important motion in its highly efficient flight.