New research on famous 'supertramp' birds in Southeast Asia offers fresh insights into the evolution of wide-ranging animals
Date:
January 27, 2022
Source:
Trinity College Dublin
Summary:
Beautiful 'supertramp' birds in Southeast Asia are providing
unique insights into how evolution is linked to flight ability
and competition.
New research testing decades-old theories has confirmed that
the isolating effects of islands impact the evolution of even
the species most accomplished at colonizing them -- and in some
surprising ways.
Among the eye-opening findings is the discovery that these birds
settle down more readily than would be expected -- once they have
colonized an island they tend to stay there rather than searching
for others.
FULL STORY ========================================================================== Beautiful "supertramp" birds in Southeast Asia are providing
unique insights into how evolution is linked to flight ability and
competition. New research testing decades-old theories has confirmed that
the isolating effects of islands impact the evolution of even the species
most accomplished at colonising them -- and in some surprising ways.
==========================================================================
The zoologists behind the study, from Trinity College Dublin's School of Natural Sciences, sequenced DNA and took measurements from Island Monarchs (Monarcha cineracens), which are widespread birds that have been studied
by evolutionary biologists for decades. They compared these to a related
bird species, the Pale-blue Monarch, which lives in the same region but
has a different lifestyle.
Among the eye-opening findings is the discovery that these birds settle
down more readily than would be expected -- once they have colonised an
island they tend to stay there rather than searching for others.
In combination, the work confirms there is still much we don't know
about these birds, despite their historic importance to scientific theory.
Fionn O' Marcaigh, first author on the paper and a PhD Candidate in
Trinity's School of Natural Sciences, said: "This study was a great
opportunity to work with one of biogeography's 'star species'. The Island Monarch was studied by famous scientist and geographer Jared Diamond
in the 1970s, when he saw that they occurred on small islands across
a wide range but were entirely missing from larger islands. He named
species with this kind of distribution 'supertramps', hypothesising
that they essentially evolved into specialist island colonisers in
response to their small islands being so unstable. This hypothesis has
been influential ever since, but now we're able to test it using modern
genetic methods and help to evolve it further.
"We found that even though the Island Monarch is clearly good enough at
flying to reach these islands in the first place, it doesn't maintain
this dispersive lifestyle after colonisation. This causes the island populations to diverge from one another, to the point that the Island
Monarch in our study region is probably a different species to the one
Diamond worked with, even though they look the same to the eye.
"Our statistical analyses indicate that this genetic divergence is
linked to the size, elevation, and isolation of the islands, but we
found no evidence that the monarchs get physically worse at flying
between islands. They just choose to stop doing so! "It goes to show how important these island regions are in the evolution of new species. Once
a bird is living on these little islands so far from everywhere else
it's just a matter of time before they start to evolve into something new.
"It seems even supertramp species have to settle down eventually!"
The research, completed with the support of the Irish Research Council
and collaborators in Universitas Halu Oleo, has just been published in Frontiers of Biogeography, the journal of the International Biogeography Society.
The study adds new knowledge to the field of biogeography, the study of
the distribution of species through space and time. Biogeography has been
an important part of evolutionary biology since the very beginning as
both Charles Darwin and Alfred Russel Wallace based their theories on it.
========================================================================== Story Source: Materials provided by Trinity_College_Dublin. Note:
Content may be edited for style and length.
========================================================================== Journal Reference:
1. Fionn O' Marcaigh, Darren P. O'Connell, Kangkuso Analuddin,
Adi Karya,
Naomi Lawless, Caroline M. McKeon, Niamh Doyle, Nicola M. Marples,
David J. Kelly. Tramps in transition: genetic differentiation
between populations of an iconic "supertramp" taxon in the Central
Indo-Pacific.
Frontiers of Biogeography, 2022; 0 (0) DOI: 10.21425/F5FBG54512 ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2022/01/220127104225.htm
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