Wings and Flight in Insects – Direct & Indirect flight Muscles & More

Wings & Flight in Insects

The ability to fly is one of the elements responsible for the biological and evolutionary success of insects. The wings are flattened areas of the integument, occurring dorsolateral in between the nota and pleura of the meso- and metathoracic sections.

Wings in living insects serve a variety of functions, including active flying, moving, parachuting, elevation stability while leaping, thermoregulation, and sound production. These are extremely useful in identification. The wings are more or less triangular in form and certain areas might be recognized.

Cross-section through the wing

The membrane is two layers of the integument. Veins consisting of nerve, blood area, and tracheae. Wings do not include muscle.


Irregular network of veins found in primitive insects. Longitudinal veins with restricted cross-veins common in numerous pterygote groups. Extreme decrease of all veins typical in small insects. Longitudinal veins concentrated and thickened towards the anterior margin of the wing. This offers increased performance and support.


Dark area on forewing in Hymenoptera, Psocoptera, Megaloptera, and Mecoptera and on both wings in Odonata. Functions as an inertial mass in flight. Reduces wing flutter throughout sliding in odonates, thus increasing flight effectiveness. Offers passive control of the angle of attack in small insects, which improves effectiveness during flapping flight.


Wing folding

Flexion lines lower passive deformation and boosts the wing as an aerofoil. Fold lines utilized in the folding of wings over back.

Flight in Insects

The capability for flight in bugs is believed to have actually developed some 300 million years ago, and at first, consisted of simple extensions of the cuticle from the thorax. The success of insects throughout the evolution of flight was because of their small size.

Naturally, not all insects have developed wings, including such groups as spring-tails and silverfish. Some parasitic groups are thought to have actually lost their wings through evolution. When wings are present in insects, they frequently include two sets. These consist of grasshoppers, bees, wasps, dragonflies, real bugs, butterflies, moths, and others. Some bugs with big wings, such as Dobsonflies and Antlions, are reasonably poor fliers, while bees and wasps with smaller wings are good fliers.


True flies are a large group of insects with only one set of wings, although they have small stabilizing organs called halteres where a second pair of wings may develop. The halteres vibrate with the wings and sense changes of direction. Flight is one of the main reasons that insects have succeeded in nature. Flight assists insects in the following ways:

  • Escaping from threat
  • Discovering food
  • Finding mates
  • Exploring for new locations to live
Insect Wing Movement

In a lot of insects, the forewings and hindwings operate in tandem. Throughout the flight, the front and rear wings remain locked together, and both go up and down at the same time. In some insect orders, most especially the Odonata, the wings move separately during flight. As the forewing raises, the hindwing lowers.

Insect flight requires more than a basic upward and downward movement of the wings. The wings likewise move on and back, and turn so the leading or tracking edge of the wing is pitched up or down. These complex movements assist the insect to attain lift, lower drag, and perform acrobatic maneuvers.

Flight muscles

Insects have one of two various arrangements of muscles used to flap their wings:

Direct flight muscles

Direct flight muscles are found in insects such as dragonflies and cockroaches. The wings pivot up and down around a single pivot point. The wings are raised by a contraction of muscles connected to the base of the wing inside (toward the middle of the insect) the pivot point. The wings are then brought down by a contraction of muscles that attach to the wing beyond the pivot point.


Indirect flight muscles

Indirect flight muscles are found in more advanced insects such as true flies. Indirect flight muscles are linked to the upper (tergum) and lower (chest bone) surface areas of the insect thorax. The second set of muscles connect to the front and back of the thorax. The wings are raised by the muscles attached to the upper and lower surface of the thorax contracting.

This brings the top surface of the thorax down and, along with it, the base of the wings. As a result, the wingtips pivot upwards. The wings are then lowered by a contraction of the muscles connected to the front and back of the thorax. This forces the upper surface of the thorax to raise and the wings pivot downwards.


Synchronous and asynchronous muscle
  • Insects that beat their wings less than one hundred times a second use synchronous muscle. Synchronous muscle is a type of muscle that contracts once for every single nerve impulse.
  • Insects that beat their wings more rapidly utilize asynchronous muscle. This is a kind of muscle that contracts more than once per nerve impulse. This is attained by the muscle being stimulated to contract once again by a release in tension in the muscle. This can occur more quickly than through basic nerve stimulation alone.