WINSTON-SALEM, N.C., April 12 (UPI) -- Scientists have discovered a special muscle in two tropical bird species that allows them to move their wings at tremendous speeds. The "superfast" muscles and the movements they enable are key to courtship for male red-capped and golden-crowned manakins.
In addition to offering insights into the evolution of tropical birds, the discovery may enable scientists to uncover the physiological secrets of stronger, faster muscles.
"This could be important for developing therapies for motor disorders, particularly those characterized by decreases in muscle performance that result from diseases such as cancer and HIV," lead researcher Matthew Fuxjager, a biologist with Wake Forest University, said in a news release.
Researchers revealed the superfast muscles by comparing the muscle contractions and courtship routines of several tropical bird species.
Normally, species must sacrifice another physical advantage to adopt a more rigorous courtship routine. But male red-capped and golden-crowned manakins have avoided a trade-off of speed and force -- or speed and coordination -- by evolving a special muscle.
Most of the muscles used to control flying are largely the same among the tropical bird species analyzed by Fuxjager and his colleagues. Only red-capped and golden-crowned manakins have developed a superfast version of the muscle that retracts the humerus. This allows them to beat their wings at superfast speeds without giving up the ability perform precise movements.
"Further studies could now explore how this one muscle can create such superfast wing movements and whether male hormones, such as testosterone, play a role in regulating the muscle's speed," Fuxjager explained. "If we discover whether steroids regulate the muscle's ability to contract at superfast speed, we would be uncovering how hormones can 'turn on' or 'turn off' its extraordinary ability."
Researchers shared their latest discovery in the journal eLife.