New species take longer to arise in the Amazon

October 22, 2019

Amazonia is home to the greatest number of species on earth, many now threatened, but a new study published October 22 in the open-access journal PLOS Biology by Jason Weir from the University of Toronto and Trevor Price from the University of Chicago hammers home Amazonia's importance, showing that it is not only a place with many species, but one where it has taken an exceptionally long time for new species to form.

Working in Peru and Brazil, Weir recorded songs from a population of birds in one region and played them back to male birds from a related population in another distant location. A major function of song is to advertise territories, so males typically respond aggressively to playback of their own species' song, believing it to be an intruder; sometimes they come right up to the speaker and try to look in.

For many of the 51 pairs of populations Weir studied in Amazonia, males responded aggressively to songs from the distant population, implying they continue to view them as members of the same species. Using DNA sequence differences to estimate how long these pairs of populations have been separated, Weir and Price estimated it takes about 3 million years of separation for levels of aggression (e.g. how closely birds come to the playback) to decline to half of that seen in response to their own population.

For comparison, Weir conducted an identical study on 58 pairs of populations in North America. The corresponding time to loss of aggression was much quicker -- about half a million years. Why might this be? One factor apparently maintaining responses for a long time in Amazonia is that, unlike in temperate North America, males of many Amazonian species defend their territories all year round, even against other species. It is these species in which males tend to respond especially aggressively to songs from distant, related populations.

The project took several visits, and involved encounters with jaguars, poisonous snakes, chiggers, several thousand ticks, and botfly infestations, yet, according to Weir, was exceptionally rewarding fieldwork that provides a salutary lesson. While one may argue that extinction of a species in Amazonia is potentially recoverable on a similar timescale to that induced by glaciations in North America (a 'mere' one to two million years), the new study's findings imply that the special, warm and aseasonal environments of the tropics slow that rate. The build-up of species in the tropics has apparently occurred over very long timescales, where slow speciation rates have been matched by even slower extinction rates, making them especially important repositories of biodiversity.
Peer-reviewed; Experimental Study; Animals

In your coverage please use this URL to provide access to the freely available article in PLOS Biology:

Citation: Weir JT, Price TD (2019) Song playbacks demonstrate slower evolution of song discrimination in birds from Amazonia than from temperate North America. PLoS Biol 17(10): e3000478.

Funding: Funding supplied by a National Geographic Waitt Grant (, Natural Sciences and Engineering Research Council of Canada (NSERC, Discovery Grants 402013-2011 and RGPIN-2016-06538, and NSERC Discovery Accelerator Grant 492890 to JTW and a National Science Foundation Grant ( 0640139 to TP. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing Interests: The authors have declared that no competing interests exist.


Related Birds Articles from Brightsurf:

In a warming climate, can birds take the heat?
We don't know precisely how hot things will get as climate change marches on, but animals in the tropics may not fare as well as their temperate relatives.

Dull-colored birds don't see the world like colorful birds do
Bengalese finches -- also called the Society finch -- are a species of brown, black and white birds that don't rely on colorful signals when choosing a mate.

Some dinosaurs could fly before they were birds
New research using the most comprehensive study of feathered dinosaurs and early birds has revised the evolutionary relationships of dinosaurs at the origin of birds.

If it's big enough and leafy enough the birds will come
A new study from the Cornell Lab of Ornithology highlights specific features of urban green spaces that support the greatest diversity of bird species.

How do birds understand 'foreign' calls?
New research from Kyoto University show that the coal tit (Periparus ater) can eavesdrop and react to the predatory warning calls of the Japanese tit (Parus minor) and evokes a visual image of the predator in their mind

Microelectronics for birds
Ornithologists and physicists from St Petersburg University have conducted an interdisciplinary study together with colleagues from Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences and the Biological Station Rybachy of the Zoological Institute of the Russian Academy of Sciences.

Birds of a feather better not together
A new study of North American birds from Washington University in St.

Not-so-dirty birds? Not enough evidence to link wild birds to food-borne illness
Despite the perception that wild birds in farm fields can cause food-borne illness, a WSU study has found little evidence linking birds to E. coli, Salmonella and Campylobacter outbreaks.

Birds are shrinking as the climate warms
After 40 years of collecting birds that ran into Chicago buildings, scientists have been able to show that the birds have been shrinking as the climate's warmed up.

Diving birds follow each other when fishing
Diving seabirds watch each other to work out when to dive, new research shows.

Read More: Birds News and Birds Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to