Editor´s choice - Ratios, adaptations, and metabolic capability of avian flight muscles

Submitted by Johan on 13 March 2015.

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Birds trapped in unpredictable events - natural starvation and storm-induced downings helped the authors clarify how changes in the size of flight muscles were achieved in this paper

The adaptive variation in avian body composition has for a long time been interesting from an energy turn-over point of view. Besides being inferred as the basis of variation in basal metabolic rate, such variation is also important for generating work as for example the breast muscles when migrating.

Two flight muscles are commonly distinguished; supracoracoideus (s) which is responsible for lifting the wing and pectoralis major (p) which is responsible for the downstroke. To be able to describe these muscles the ratio s/p are used and the requirement for different kinds of flight will result in different ratios. However, this adaptive variation in the s/p ratio is challenged as a sole explanation for the observed variation by Jehl, Jr in a recent very interesting “point-of-view” paper in J. Avian Biol. They suggest that some of the intraspecific variation in the s/p ratio is due to the high cellular metabolic capacity that is specific to the pectoralis, resulting in a high rate of protein catabolism after both long migration journeys and during starvation. Thus, the pectoralis may serve as an important protein reserve that may be important during the last stage of a long migration bout or when starving.

Jan-Åke Nilsson, Editor in Chief

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Editor´s Choice