The saga continues: Entomology 101: Wing Structure and Wing Venation.
In the last section I introduced insect wings and will now move on to look at wing structure and venation. This post will confine itself to the essentials, with a more detailed look at variations in wing structure when I cover the insect orders in the chapter on diversity.
The wings connect to the thorax at three points, with various forms of axillae, which are stiff plates (sclerites) of cuticle that are activated by muscle movements in the thorax. Wings consist of two layers of cuticular membrane which sandwich a framework of veins through which hemolymph flows. The veins are also sclerotized and provide a strengthening structure to the wing. Other features of the wings include fold lines and lines of flexion. In some orders, the fore and hind wings move together as one when in flight, facilitated by various linking mechanisms.
Wing venation and the lines of folding and flexion all contribute to patterns that can assist in identification. The lines of venation have been ‘mapped’ with a common terminology called the Comstock-Needham system, which recognises the homology of wing veins across the insect orders. The Comstock–Needham system was developed by John Comstock and George Needham in 1898, and today it is variations of that system that are mostly used by entomologists. The Evolution of Insects goes with the Wootton variation (1979) which I follow below, while others may favour the Kukalova´-Peck variation. Continue reading