Mitochondrial and myofibrellar development in the flight muscle of locusta migratoria l. (Orthoptera: Acrididae)‎

Abstract EN

The fine structure of the median indirect dorsal longitudinal flight muscles have been examined throughout the first week of Locusta migratoria adult life.

During this period, muscle colour changed from white to reddish-brown and the banding pattern, characteristic of mature adult flight muscles, was established.

Associated with these changes, there was an increase in myofibril size and the mean number of myosin filaments per myofibril; no significant change was observed in the actin: myosin ratio.

There were indications that the number of myofibrils per muscle fibre increased by "longitudinal splitting" of the myofibrils existing in the first four days of adult life.

A marked increased in mitochondrial size and complexity was noted with increasing age.

The increase in mitochondrial size is probably attributed, partly, to fusion of adjacent mitochondria which become gradually arranged in straight columns between the myofibrils by the 5th day of adult life.

The developmental changes observed in the fine structure of myofibrils and mitochondria are important in explaining the improvement in flight performance noted in the developing adult locusts.