Thanks to a pair of University of Houston researchers who found a possible new solution to a 163-year-old puzzle, ecological factors can now be added to physiology to explain why animals grow bigger in the cold.
Their results were published in the February issue of the American Naturalist, offering new insight to Bergmann's rule that animals grow larger at high, cold latitudes than their counterparts closer to the equator. While traditional explanations have been based on body temperature being the driving force of this phenomenon, this group of community ecologists hypothesize that better food makes high-latitude animals bigger.
Chuan-Kai Ho, a Ph.D. graduate from UH in ecology and evolution, his adviser and UH professor of biology and biochemistry Steven Pennings, and their collaborator Thomas Carefoot from the University of British Columbia opened up a new line of study into Bergmann's rule. The research program in Pennings' lab over the last decade has offered the most extensive work done on the general problem of latitudinal variation in plant-herbivore interactions. This latest finding from Pennings' groundbreaking research at UH on this subject came from one of Ho's doctoral dissertation chapters.
"Because the American Naturalist is one of the top journals in our field, publishing at this level is a mark of great success for a Ph.D. student," Pennings said. "It's also a reflection of the strength of our graduate program in the ecology and evolution division of UH's department of biology and biochemistry."
Ho, now a postdoctoral student at Texas A&M at Galveston's Armitage & Quigg Laboratory, also has another chapter from his UH dissertation on salt marsh food webs published in Ecology, another top journal in the field. Pennings received a doctoral dissertation improvement grant for Ho in 2007-2008 from the National Science Foundation that provided funding for Ho to run chemical analyses on leaves from different latitudes to assess their nutritional content.
Studying three different plant-eating species – grasshoppers, planthoppers and sea snails – collected from along the Atlantic coast to Japan, respectively, the researchers fed these herbivores plants from both high and low latitudes and found that they all grew better when fed plants from the higher latitudes. This indicates that Bergmann's rule could reflect that plants from high latitudes provide better food than those from low latitudes. These latest findings, according to Ho, indicate that studies of Bergmann's rule should consider ecological interactions in addition to the more traditional theories of physiology based on responses to temperature.
Over the years, work in Pennings' lab has shown that, although low-latitude plants are less nutritious and better protected by chemical defenses, they experience heavy damage from herbivores, which are more abundant at low latitudes. Future study, Pennings adds, should focus on why there are more herbivores at lower latitudes despite the lower-quality food sources. A likely explanation is that herbivore populations are limited at high latitudes by a short growing season and high death rates during cold winters.
"While the explanations discovered in our current study only apply to herbivores, it may be that carnivores and omnivores also might grow larger as a consequence of eating larger herbivores," Ho said. "Examining such patterns and underlying mechanisms in nature will help us understand what currently is going on and what might happen down the line to our ecosystems."
About the University of Houston
The University of Houston, Texas' premier metropolitan research and teaching institution, is home to more than 40 research centers and institutes and sponsors more than 300 partnerships with corporate, civic and governmental entities. UH, the most diverse research university in the country, stands at the forefront of education, research and service with more than 37,000 students.
About the College of Natural Sciences and Mathematics
The UH College of Natural Sciences and Mathematics, with 170 ranked faculty and approximately 4,500 students, offers bachelor's, master's and doctoral degrees in the natural sciences, computational sciences and mathematics. Faculty members in the departments of biology and biochemistry, chemistry, computer science, earth and atmospheric sciences, mathematics and physics conduct internationally recognized research in collaboration with industry, Texas Medical Center institutions, NASA and others worldwide.
For more information about UH, visit the university's Newsroom at http://www.uh.edu/news-events/.
To receive UH science news via e-mail, visit http://www.uh.edu/news-events/mailing-lists/sciencelistserv.php.
For additional news alerts about UH, follow us on Facebook at http://tinyurl.com/6qw9ht and on Twitter at http://twitter.com/UH_News
Lisa Merkl | EurekAlert!
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 WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
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,...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
21.11.2017 | Physics and Astronomy
21.11.2017 | Physics and Astronomy
21.11.2017 | Life Sciences