4

Flight Morphology and Flight Muscles

47

Fig. 4.6 Illustrating the direct muscle action in an insect

Wing Coupling, Folding and Wing Movements

1.

In many insect species, the fore and hind wings are coupled together on each

side, which improves the aerodynamic efficiency of flight.

2.

In Hymenoptera (Bees and Wasps) and Trichoptera (Caddis flies), a row of

small hooks called “hamuli” located at the front margin of hind wings lock on

to the forewing; thus, both the wings are held together.

3.

In some other insects such as butterflies, the jugal lobe of the forewing covers

a portion of the hind wing.

4.

Also, in other insects, margins of the fore and hind wing overlap or the hind

wing bristles or frenulum hook up in the forewing.

5.

When at rest, wings are held over the back in most insects causing longitudinal

or transverse folding of the wing membrane.

6.

Normally, there will be radial fold lines to the base of the wing allowing the

adjacent wing to be folded over or under each other.

7.

In cockroaches and locusts, the anal part of wings is folded like a fan along

the veins.