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
How does the loss of species alter ecosystems?
18.05.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig
Excess diesel emissions bring global health & environmental impacts
16.05.2017 | International Institute for Applied Systems Analysis (IIASA)
Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.
Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
26.05.2017 | Life Sciences
26.05.2017 | Life Sciences
26.05.2017 | Physics and Astronomy