The research, by University of Michigan evolutionary biologists Tom Duda and Taehwan Lee, is scheduled to be published online May 20 in the open-access journal PLoS ONE.
In the study, Duda and Lee explored ecological release, a phenomenon thought to be responsible for some of the most dramatic diversifications of living things in Earth's history. Ecological release occurs when a population is freed from the burden of competition, either because its competitors become extinct or because it colonizes a new area where few or no competitors are found. When this happens, the "released" population typically expands its diet or habitat, taking over resources that would be off-limits if competitors were present. This expansion is believed to drive the evolution of adaptations for taking advantage of the new resources, such as venoms tailored to a broader array of prey.
"Although there are plenty of examples of populations expanding into a variety of niches after experiencing ecological release, little is known about the evolution of genes associated with this phenomenon," said Duda, an assistant professor in the U-M Department of Ecology and Evolutionary Biology.
To investigate the process, Duda and Lee took advantage of a natural experiment involving a species of cone snails (Conus miliaris), which is found in shallow waters of tropical to subtropical environments from the Red Sea and eastern shores of Africa in the western Indian Ocean to Easter Island and Sala y Gómez in the southeastern Pacific. In most areas where the species is found, C. miliaris has lots of competitors and preys on only three species of marine worms. But on Easter Island, where it has virtually no competition, the snail's diet is much broader, incorporating many additional species of worms.
Cone snails paralyze their prey with venom made up of various "conotoxins." Because different species---or in some cases even different populations---of cone snails have both distinct prey preferences and distinctly different venom compositions, Duda has speculated that natural selection has shaped particular species' venoms to most effectively paralyze their favored prey.
To test this hypothesis, Duda and Lee looked at two conotoxin genes and compared patterns of variation found in the Easter Island snails with those of snails from Guam and American Samoa, where the snails have not experienced ecological release.
"On Easter Island, where the snails are eating far more things than they're eating elsewhere, we see that different toxins predominate, suggesting that natural selection has operated at these toxin genes," said Duda, who also is a research associate with the Smithsonian Tropical Research Institute. "These results imply that ecological release is associated with strong selection pressures that are associated with the evolution of new ecologies."
The research was funded by the National Geographic Society's Committee for Research and Exploration and the National Science Foundation.
For more information:
Thomas Duda: www.eeb.lsa.umich.edu/eeb/people/tfduda/index.html
Smithsonian Tropical Research Institute: www.stri.org/
PLoS ONE: www.plosone.org/home.action
Link to paper: http://dx.plos.org/10.1371/journal.pone.0005558
Nancy Ross-Flanigan | Newswise Science News
Scientists team up on study to save endangered African penguins
16.11.2017 | Florida Atlantic University
Climate change: Urban trees are growing faster worldwide
13.11.2017 | Technische Universität München
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
20.11.2017 | Earth Sciences
20.11.2017 | Earth Sciences
20.11.2017 | Life Sciences