How do halteres help true flies maintain balance during flight?

In true flies (order Diptera), the hind wings are modified into club-shaped organs known as halteres. These structures vibrate in synchronization with the functional forewings and serve as biological gyroscopes to maintain stability during flight.12

When a fly experiences changes in its flight path—such as yawing, rolling, or pitching—the halteres maintain their original plane of movement. This action causes the stalks of the halteres to twist at their bases. Special nerve cells located at these bases detect the mechanical strain caused by the twist, allowing the fly to sense its orientation and make the necessary adjustments to correct its flight attitude.1