Hummingbirds' 22-million-year-old history of remarkable change is far from complete

Apr 03, 2014

The first comprehensive map of hummingbirds' 22-million-year-old family tree—reconstructed based on careful analysis of 284 of the world's 338 known species—tells a story of rapid and ongoing diversification. The decade-long study reported in the Cell Press journal Current Biology on April 3 also helps to explain how today's hummingbirds came to live where they do.

Part of the secret to the birds' remarkable success lies in the formation of nine principal groups or clades, hummingbirds' unique relationship to flowering plants, and the birds' continued spread into new geographic areas, the researchers say.

"Hummingbirds have essentially been reinventing themselves throughout their 22-million-year history," says Jim McGuire of the University of California, Berkeley.

While all hummingbirds depend on flower nectar to fuel their high metabolisms and hovering flight, coordinated changes in flower and bill shape have helped to drive the formation of new species of both hummingbirds and plants. Remarkably, as many as 25 species are able to coexist in some places.

"One of the really cool features of hummingbird evolution is that they all eat the same thing yet have diversified dramatically," McGuire says. "It really is a big surprise that hummingbirds have divided the nectarivore niche so extensively."

The new, time-calibrated evolutionary tree shows that ancestral hummingbirds split from the swifts and treeswifts about 42 million years ago, probably in Eurasia. By about 22 million years ago, the ancestral species of all modern hummingbirds had made its way to South America, and that's when things really took off.

The Andes Mountains are a particular hotspot for hummingbird evolution, because diversification occurred along with the uplift of those peaks over the past 10 million years. About 140 hummingbird species live in the Andes today.

The availability of new land areas in North America and the Caribbean has also played an important role in the evolution of new hummingbird species. For example, McGuire says, the bee hummingbirds colonized North America about 5 million years ago and consequently experienced rates of speciation that rival textbook examples of adaptive radiation.

The new picture of the birds' past is an important step toward understanding how they have adapted to novel environments, like those found at low-oxygen, high-altitude mountain peaks. It also points to an exciting future.

"Our findings strongly indicate that hummingbirds remain engaged in a dynamic diversification process, filling available ecological and spatial niches across North America, South America, and the Caribbean," the researchers write. "Thus, the dramatic radiation of this unique avian lineage is far from complete."

Explore further: How hummingbirds evolved to fly at high altitude

More information: Current Biology, McGuire et al.: "Molecular phylogenetics and the diversification of hummingbirds." dx.doi.org/10.1016/j.cub.2014.03.016

add to favorites email to friend print save as pdf

Related Stories

Where have all the hummingbirds gone?

May 31, 2012

(Phys.org) -- The glacier lily as it's called, is a tall, willowy plant that graces mountain meadows throughout western North America. It flowers early in spring, when the first bumblebees and hummingbirds ...

Study: Hummingbirds migrating earlier in spring

Feb 18, 2013

(AP)—Ruby-throated hummingbirds are migrating to North America weeks earlier than in decades past, and research indicates that higher temperatures in their winter habitat may be the reason.

Recommended for you

'Red effect' sparks interest in female monkeys

Oct 17, 2014

Recent studies showed that the color red tends increase our attraction toward others, feelings of jealousy, and even reaction times. Now, new research shows that female monkeys also respond to the color red, ...

Roads negatively affect frogs and toads, study finds

Oct 17, 2014

The development of roads has a significant negative and pervasive effect on frog and toad populations, according to a new study conducted by a team of researchers that included undergraduate students and ...

All in a flap: Seychelles fears foreign bird invader

Oct 17, 2014

It was just a feather: but in the tropical paradise of the Seychelles, the discovery of parakeet plumage has put environmentalists in a flutter, with a foreign invading bird threatening the national parrot.

User comments : 0