Flies in the flight simulator

Written by Thomas Hesselberg

Friday, 10 August 2007

Article Index
Flies in the flight simulator
Page 2
Page 3
Page 4
Page 5

Page 2 of 5

The halteres. Part A shows a fruit fly during tethered flight in a flight simulator. The fly is viewed from below and the arrows point to the location of the halteres. Part B. The club shaped halteres in a close-up.

A further difference between the two type of insects is that the where dragonflies have direct flight muscles, where the muscles directly move the wings, the flies have indirect flight muscles, where the muscles move the entire outer skeleton. This means that the wings move up and down by mechanical contractions of the exoskeleton and by making use of the elastic protein resilin. This, combined with several muscle contractions per nerve impulse, result in a very high wing beat frequency of up to 200 Hz in fruit flies.

Vision and flight
Vision plays an important role for stabilisation during fast and directional movement in many animals, including humans. When we walk blindfolded or in darkness it is much more difficult to move fast. Similarly vision plays a crucial role for maintaining stable flight in insects. In flies, however, the halteres also play an important role and they are actually capable of flying fairly stable even in darkness. Removal of the halteres, however, results in total loss of stable flight. The insects use sensory feedback from the eyes to determine their own motion relative to the surroundings. Their eyes are compound eyes which give them a much large field of view than our eyes – flies for instance have a field of view of up to 300° without moving their head.

Contrast differences, caused by objects in the surroundings, in the eye’s visual image show the direction in which the visual field is moving. The visual inputs from both eyes are then compared and used to determine how the insect is moving. If the visual image from the right eye for instance is moving clockwise (front to back) and the image from the left eye moves counter-clockwise the animal must be moving forward. If both images, however, moves counter-clockwise the animal must be rotating to the right.

<< Prev - Next >>