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 Safeguarding sustainability through forest certification mapping
27.06.2017 | International Institute for Applied Systems Analysis (IIASA)

nachricht Dune ecosystem modelling
26.06.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

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: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

NASA looks to solar eclipse to help understand Earth's energy system

21.07.2017 | Earth Sciences

Stanford researchers develop a new type of soft, growing robot

21.07.2017 | Power and Electrical Engineering

Vortex photons from electrons in circular motion

21.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>