part of muscle invertebrate muscular system asynchronous muscle Asynchronous muscle is that type of muscle which, when turned on by neural input and resulting muscle action potentials, can contract in an oscillatory manner if attached to an appropriate, resonant load such as is offered in life by an insects wings and thorax. The frequency of the oscillatory contractions is different from, and typically much higher than, that of the activating neuronal impulses. Asynchronous muscle is so-named because during oscillation there is no direct correspondence between individual muscle contractions and muscle action potentials, which contrasts with synchronous muscle in which there is a 1:1 correspondence between muscle contractions and muscle action potentials or bursts of action potentials. Asynchronous muscle is only known to occur in insects. The muscles that power flight in dipteran flies, beetles, many of the true bugs and in some, but perhaps not all, bees and wasps are asynchronous muscles, as are the singing muscles of some cicadas. BTO:0001687 BrendaTissueOBO fibrillar muscle myogenic muscle