Pre-imaginal flight motor pattern in Locusta

In a wind stream, larval stages of Locusta usually show a tonic muscle activity but they can also exhibit a rhythmic motor output. With ageing such a pattern can be released sooner, the trains become longer. The basic rhythm of 10 Hz does not change. The initial co-contraction of specific muscles is substituted later in development by an antagonistic recruitment. This activity resembles the flight motor pattern of young locusts which lack phasic sensory feedback from the wing region. Azadirachtin, an insect growth regulator, has been used to produce a permanent 5th larval instar. However, the extension of the last larval stage does not lead to a further development of the motor pattern to a level comparable to mature animals.