Giant Fibre Activation of Direct Flight Muscles in Drosophila

1. Electrical stimuli delivered to the brain were used to activate the giant fibre of Drosophila. 2. The giant fibre drove a prominent wing opening movement. 3. Intracellular microelectrode recordings from direct wing opener muscle fibres showed that giant fibre activation of an anterior pleural muscle, pa3, was responsible for the wing opening movement. 4. The giant fibre drove a slight wing elevation movement. 5. Intracellular recordings from direct wing elevator muscle fibres showed that these muscles were not activated by the giant fibre. 6. It is suggested that giant fibre-driven wing elevation movements were mediated by the tergotrochanter muscle (TTM).