Tropical birds have superfast and strong wing muscles, and they are using it to attract mates, a new study has found.
With more than twice the speeds needed for flying, the said limb muscles are the fastest for any animal with a backbone. The impressive show of speed and strength has become a way for the birds to pull off over-the-top courtship practices.
The birds endowed with this ability are male red-capped and golden-crowned manakins. The wing movements of these birds cannot be detected by the naked eye. For comparison, the speed is six to eight times faster than that of Olympian Usain Bolt when he moves his legs during a 100-meter sprint.
Bird Courtship: Faster Is Better
Courtship practices among different species involve fast limb movements. For example, birds run across lakes and hares box fast in March to attract mates.
A particularly interesting example is when Uraeginthus cyanocephalus birds move their feet so fast when attracting mates that it looks like they performing a tap dance.
Speed is not the only important factor when it comes to courtship displays. Force is valuable too. Being able to show both is the desired outcome, but it is not really easy. Therefore, under normal circumstances, one feature has to be let go.
Some animals, however, are exceptions to this rule as they can perform both, leaving scientists baffled as to how they do it.
Manakins Stand Out
To find out how some species can exert both speed and force in their movements, scientists from the Wake Forest University and the University of Utah studied the twitch speeds of forelimb muscles of wild-caught golden-collared manakins, red-capped manakins, blue-crowned manakins, the dusky antbird and the house wren.
"Of the species studied, the golden-collared and red-capped manakins produce exceptionally rapid wing movements as part of their acrobatic courtship displays," says study lead author Matthew Fuxjager.
To further investigate, the team looked into how fast the muscles of the five species are stimulated to contract.
The golden-collared and red-capped manakins stood out, exhibiting superfast wing contractile movements.
The other two muscles that produced flight force are also the same among the two leaders, signifying that they have been readied to show the needed strength for flying.
Together, these abilities allow the species to keep both speed and force, without sacrificing one for the other.
Applications Of The Study Results
The study results may help develop treatments for motor impairments, specifically those that involve reduction in muscle performance due to diseases such as HIV and cancer.
The study was published in eLife on April 12.
