Biologists have discovered a special ‘superfast’ muscle in a group of tropical birds that allows them to move their wings at exceptional speeds. According to a recent study, the red-capped and golden-crowned manakins, found in the tropical rainforests of South America, have one of the fastest limb muscles ever recorded in a vertebrate animal.
The experiment involved implanting electrodes into the wing muscles of the birds while they were anaesthetized. The scientists then measured and analyzed the speed at which they could relax and contract the wing muscle when stimulated with an electrical current.
The researchers found that these birds can move their wings at more than twice the speed required to get airborne. It is around 6-8 times faster than that of a professional athlete during the course of a 100-meter sprint. While the professional sprinters can move their legs at a speed of 8-hertz (Hz), some of the tropical birds can attain wing movement speed in excess of 60-hertz (Hz). Not surprisingly though, the superfast movements of their wings go undetected with the naked human eyes.
Further studies conducted on this group of tropical birds revealed that only the male manakins have developed this ‘superfast’ muscle, while the females are devoid of such a special quality. This lead the researchers to dig further down the evolution process of their limb muscles.
To their surprise, the biologists found that the muscle which powers the exceptionally fast wing display of male manakins – the main humeral retractor muscle – has evolved purely to help them win a female partner. The rapid clapping or snapping noise produced by the movement of wing muscles acts as a catalyst in attracting the attention of potential female mates, the scientists concluded.
The scientists who were a part of this study believe that the findings could enable them to uncover the physiological secrets behind faster limb movements. The research could also help in developing new therapies for motor disorders, including the dwindling muscle performance experienced in cancer and HIV patients.
The researchers are now exploring whether male hormones have a role to play in the development of these superfast humeral retractor muscles. In-case they are successful in establishing a link between the two, then it can offer a great deal of insight on how rapid limb movements are regulated in accordance with the species’ reproductive environment.
This study was published in the journal eLife.