Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A tale of 2 species

28.03.2014

Scientists identify factors limiting hybridization of closely-related woodrat species

A pair of new studies from the Wildlife Conservation Society, Idaho State University, and the University of Nevada Reno look at the surprising variety of factors that prevent two closely related species of woodrats from becoming a single hybrid species despite the existence of hybrid individuals where the two species come into contact.


This photo shows a woodrat emerging from its den at dusk. The small tags in each ear indicate that this individual had been previously captured and genetic material was sampled as part of a study to understand the dynamics of the hybrid zone in southern California.

Credit: Quinn Shurtliff

After finding that two closely related species, the desert and Bryant's woodrats, could interbreed and produce hybrid offspring, scientists set out to determine why only 14 percent of the population in a "contact zone" had genetic signatures from both species. (If the two species were similar enough to interbreed, what was keeping them from merging into a single hybrid species?)

In the study, "Ecological segregation in a small mammal hybrid zone: Habitat-specific mating opportunities and selection against hybrids restrict gene flow on a fine spatial scale," which appears in the March print edition of the journal Evolution, the authors discuss the factors driving these mating dynamics in a hybrid zone in southern California.

... more about:
»Conservation »mammal »species »woodrats

Trapping and handling hundreds of woodrats (also known as packrats), the scientists found that the two species are highly associated with different habitat types, though they may live within meters of each other along the boundary. Their research showed that 98 percent of Bryant's woodrats occupied a boulder-strewn hillside comprised of coastal / Sierra vegetation, while 93 percent of the desert woodrats occupied the adjacent valley floor consisting of Mojave desert scrub and a sandy substrate. This, in spite of the fact that both habitats were theoretically available to both species.

"Mating opportunities between species are limited because the two species make their homes and forage in very distinct habitats, even though those habitats are right next to each other," said lead author of both studies, Quinn Shurtliff of the Wildlife Conservation Society and Idaho State University.

Another reason why interbreeding between species is limited: personality conflicts. The scientists brought wild-caught woodrats into the laboratory to test female mate preferences.

They found that Bryant's woodrat females selected either Bryant's woodrat males or desert woodrat males with equal preference. Desert woodrat females, however, almost always mated with males of their own species.

The reason? The desert woodrat females were intimidated by Bryant's woodrat males due to their larger body size and aggressive nature. In contrast, Bryant's females, themselves larger, were open to mating with the smaller, more docile desert woodrat males as well as the males of their own species.

Another factor shown to be determining the number of hybrids is that hybrid offspring do not survive to adulthood as well as do the other two species. Higher proportions of Bryant's woodrats survived to their first year of adulthood than did the hybrids (33 percent vs. 10 percent). The same was the case for the desert woodrats (22 percent vs.10 percent percent). Once the hybrids reached their first year of adulthood, however, they fared as well as the purebreds.

The reason for the low juvenile hybrid survivability, the authors say, may lie in the lack of aggressiveness and ability to compete with purebred males for denning sites and in winning territorial battles. This may necessitate greater dispersal for the male hybrids pushing them out of range of female hybrids and exposing them to greater predation pressure.

Shurtliff said, "These studies offer further insight into the behavioral and ecological dynamics of hybrid zones.

Understanding these unique areas is important because there are many examples of naturally occurring hybrid zones, and new hybrid zones will form in the future as climate change and human impacts cause species distributions to shift and come into contact. For example, scientists have documented hybrid zones between introduced and native species, and climate change has already been linked to hybridization among flying squirrels in eastern North America. It is important to understand these relationships so that we can predict, and where necessary, mitigate their negative impacts."

###

"Experimental evidence for asymmetric mate preference and aggression: behavioral interactions in a woodrat (Neotoma) hybrid zone," appears online on BioMed Central. Authors include: Quinn R. Shurtliff of the Wildlife Conservation Society; Peter J. Murphy and Marjorie D. Matocq of the University of Nevada, Reno; and Jaclyn D. Yeiter of Idaho State University.

"Ecological segregation in a small mammal hybrid zone: Habitat-specific mating opportunities and selection against hybrids restrict gene flow on a fine spatial scale," appears in the March print edition of the journal Evolution. Authors include: Quinn R. Shurtliff of the Wildlife Conservation Society; Peter J. Murphy and Marjorie D. Matocq of the University of Nevada, Reno.

Scott Smith | EurekAlert!
Further information:
http://www.wcs.org

Further reports about: Conservation mammal species woodrats

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: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

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....

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

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>