Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Host Shift Triggers Cascading Effect on Ecosystem

09.02.2009
A major cause for biodiversity may be biodiversity itself, says evolutionary ecologist Andrew Forbes of the University of California, Davis, whose newly published research shows that when the apple maggot shifted hosts from the hawthorn to the apple, that triggered a cascading effect on the ecosystem.

Forbes and his colleagues found that a parasitic wasp (Diachasma alloeum) that attacks the apple maggot (Rhagoletis pomonella) has “formed new incipient species as a result of specializing on diversifying fly hosts, including the recently derived apple-infesting race of R. pomonella.”

The apple maggot, native to North America, shifted from its ancestral hawthorn host (Crataegus spp.), to introduced European apples less than 250 years ago. “The two populations,” Forbes said, “have since become partially reproductively isolated due to a number of host-related adaptations and are now distinct host races, on their way to becoming separate species.”

A host race is a group of organisms in the process of becoming a new species due to its close association with a particular host (plant or animal).

In this new study, Forbes and his co-authors showed that the wasp D. alloeum is undergoing the same evolutionary changes.

“The research shows the process of speciation in action and might tell us more about why certain groups of organisms are more diverse than others.” said Forbes, now a postdoctoral researcher in professor Jay Rosenheim’s laboratory in the UC Davis Department of Entomology. “It also suggests why certain areas and/or biotic regions may have more species than others.”

The research, “Sequential Sympatric Speciation Across Trophic Levels,” published Feb. 6 in the journal Science, provides insight into what Forbes calls “the tangled bank of life.”

“As new species form, they create new opportunities for others to exploit which, in turn, begets ever more new species,” he said. “And all this is happening right before our eyes in our own backyards.”

The scientists, led by Forbes, studied genetic differences, diapause length and fruit odor preferences for apple-associated populations of D. alloeum wasps collected from numerous Midwestern sites. They collected the same measurements for D. alloeum in hawthorn, blueberry and snowberry.

Their work showed that D. alloeum associated with apple has genetic, phenological and ehavioral differences that isolate it from the other wasp populations. “D. alloeum attacks only R. pomonella complex flies found on these four host plants,” Forbes said, “so we can be fairly confident that the apple wasp is derived from one of the other wasp populations and has rapidly evolved into this new race.”

In its larval form, the apple maggot is a major pest of apples throughout the United States. Other Rhagoletis species attack cherries, walnuts and blueberries. The female apple maggot fly deposits her eggs in ripe fruit. The eggs then develop into larvae (maggots), which later leave the fruit to pupate and overwinter in the soil.

The parasitic wasp D. alloeum lays its eggs directly into the larva of the apple maggot as it feeds inside the fruit. The developing wasp eats the maggot and emerges the following year from its pupa.

Forbes published the work in Science with co-authors Thomas H. Q. Powell and Jeffrey Feder, University of Notre Dame; Lukasz Stelinski of the University of Florida Citrus Research and Education Center; and James J. Smith, Department of Entomology, Michigan State University.

The research was funded by a National Science Foundation Doctoral Dissertation Improvement Grant and an American Museum of Natural History Theodore Roosevelt Fund Grant.

Media contacts:
Andrew Forbes, Entomology, (530) 752-4481, aaforbes@ucdavis.edu
Kathy Keatley Garvey, Entomology, (530) 754-6894, kegarvey@ucdavis.edu

Kathy Keatley Garvey | EurekAlert!
Further information:
http://www.ucdavis.edu
http://entomology.ucdavis.edu/news/andrewforbesresearch.html

More articles from Ecology, The Environment and Conservation:

nachricht Upcycling of PET Bottles: New Ideas for Resource Cycles in Germany
25.06.2018 | Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF

nachricht Dry landscapes can increase disease transmission
20.06.2018 | Forschungsverbund Berlin e.V.

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Global study of world's beaches shows threat to protected areas

19.07.2018 | Earth Sciences

New creepy, crawly search and rescue robot developed at Ben-Gurion U

19.07.2018 | Power and Electrical Engineering

Metal too 'gummy' to cut? Draw on it with a Sharpie or glue stick, science says

19.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>