Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Global warming may cause songbirds to avoid certain foods

27.01.2004


URI student researcher: Chickadees avoid caterpillars that eat leaves exposed to high levels of CO2



In yet another example of the far-reaching impact of global warming, a University of Rhode Island student found evidence that suggests some songbirds may avoid eating insects that consume leaves exposed to high levels of carbon dioxide.

URI senior Martina Müller of Kingston, working in cooperation with Associate Professor Scott McWilliams, Ph.D. candidate David Podlesak and colleagues at the University of Wisconsin, studied the food preferences exhibited by black-capped chickadees.


"When plants are grown in conditions of higher carbon dioxide, they produce increased levels of several secondary compounds -- tannins and phenolics -- that they use to defend against herbivory," said the 23-year-old wildlife conservation and biology major. "Those secondary compounds are absorbed by gypsy moth caterpillars that feed on the plant’s leaves, which other researchers have found reduces the caterpillar’s growth rates. We wanted to see if the chickadees can detect the secondary compounds in the caterpillars and if they have preferences for caterpillars that fed on different types of leaves."

Using chickadees captured in Kingston and acclimated for three days, Müller and McWilliams fed the birds a choice of caterpillars that were high in tannins or phenolics and other caterpillars low in those compounds.

"It was clear that the birds could tell the difference between the different caterpillars and they had strong preferences," Müller said. "They’re intelligent birds with a keen capacity to learn."

While the birds showed a distinct preference for caterpillars low in tannins and phenolics, they also showed a preference for foods they had eaten previously. "Previous experience does affect their preferences," Müller said.

So what does all this mean? According to McWilliams, it could mean a great deal in a world that is growing warmer due to increasing levels of carbon dioxide in the atmosphere. "These results provide a much more complete and realistic picture of how elevated atmospheric CO2 might affect ecological systems."

Since increased carbon dioxide leads to elevated levels of secondary compounds in plant leaves and decreased growth rates of caterpillars that eat those leaves, McWilliams said "birds that primarily eat herbivorous insects like caterpillars may find themselves without enough to eat as atmospheric CO2 levels increase. In short, chemicals in the caterpillar’s food influences the likelihood of predation by birds."

In addition, he said that if birds avoid feeding on gypsy moth caterpillars, for instance, an uncontrolled population of the caterpillars could result in more severe forest defoliation.

McWilliams also sees a connection between Müller’s results and the current mad cow disease concerns in the U.S. "We know that mad cow disease can be transmitted to humans if we eat beef from cows that have eaten feed with the disease. So to safeguard our beef, we feed cows food that does not contain the disease. Birds seem to pay attention to this same rule: know what the food you are eating has eaten, because it can affect your health. In the case of birds, however, they seem to be one step ahead of us in that they are able to detect the secondary compounds in the food and change their feeding behavior accordingly."


Funding for this research was provided by the National Science Foundation, the URI Agricultural Experiment Station, and the URI Coastal Fellows program, a unique program designed to involve undergraduate students in addressing current environmental problems. The caterpillars and aspen leaves used in the project were provided by Professor Richard Lindroth and Ph.D. candidate Jack Donaldson at the University of Wisconsin.

Todd McLeish | URI
Further information:
http://www.news.uri.edu/releases/html/04-0126-05.html

More articles from Ecology, The Environment and Conservation:

nachricht Robotic fish to replace animal testing
17.06.2019 | Otto-von-Guericke-Universität Magdeburg

nachricht Marine oil snow
12.06.2019 | University of Delaware

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: The hidden structure of the periodic system

The well-known representation of chemical elements is just one example of how objects can be arranged and classified

The periodic table of elements that most chemistry books depict is only one special case. This tabular overview of the chemical elements, which goes back to...

Im Focus: MPSD team discovers light-induced ferroelectricity in strontium titanate

Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.

Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...

Im Focus: Determining the Earth’s gravity field more accurately than ever before

Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.

The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...

Im Focus: Tube anemone has the largest animal mitochondrial genome ever sequenced

Discovery by Brazilian and US researchers could change the classification of two species, which appear more akin to jellyfish than was thought.

The tube anemone Isarachnanthus nocturnus is only 15 cm long but has the largest mitochondrial genome of any animal sequenced to date, with 80,923 base pairs....

Im Focus: Tiny light box opens new doors into the nanoworld

Researchers at Chalmers University of Technology, Sweden, have discovered a completely new way of capturing, amplifying and linking light to matter at the nanolevel. Using a tiny box, built from stacked atomically thin material, they have succeeded in creating a type of feedback loop in which light and matter become one. The discovery, which was recently published in Nature Nanotechnology, opens up new possibilities in the world of nanophotonics.

Photonics is concerned with various means of using light. Fibre-optic communication is an example of photonics, as is the technology behind photodetectors and...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

Uncovering hidden protein structures

18.06.2019 | Life Sciences

Monitoring biodiversity with sound: how machines can enrich our knowledge

18.06.2019 | Life Sciences

Schizophrenia: Adolescence is the game-changer

18.06.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>