Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Robo-lizards help prove long-standing signaling theory

25.11.2008
UC Davis researchers using robotic lizards in a Puerto Rico forest have shown that in noisy visual environments, animals can use body language to alert neighbors to forthcoming information-rich messages

Like teachers who rap a ruler before announcing homework in noisy classrooms, Puerto Rican anole lizards perform eye-catching pushups before beginning head-bobbing displays that advertise their territory and status, according to a new study by researchers at the University of California, Davis.

With the help of robotic lizards that mimic their flesh-and-blood counterparts, research associate Terry Ord and professor emerita Judy Stamps, both with the Department of Evolution and Ecology, have shown for the first time that animals in noisy environments can use visual displays to grab their neighbors' attention before initiating a more information-rich performance. The study will be published in the November 24 Proceedings of the National Academy of Sciences (PNAS).

"What's really interesting is that the anoles are in some way assessing the environmental variables that are likely to affect the detection of their signals," Ord said, "and they are tailoring their behavior accordingly."

The work confirms a nearly 30-year-old hypothesis that when the environment is noisy, animals might use conspicuous signals, or "alerts," to let neighbors know that a message is forthcoming.

Audible alerts, like trills or barks, have been documented in only one species, towhees, but studies suggest that coyotes and tree frogs also issue them. Until now, however, no one has shown that mute species can use body language to do the same thing, said Ord, who also holds a postdoctoral fellowship at Harvard University's Museum of Comparative Zoology.

"It's a real formidable task for animals to be communicating out in the real world," Ord explained. "Not only is there a lot of acoustic noise, but there's visual noise, as well. The trouble for an animal that tries to send an information-rich signal under low-light conditions or when the wind is blowing branches and leaves around is that the signal will not transmit very far. To solve that conundrum, the theory goes, you start the communication with a conspicuous component to attract the attention of your receivers."

Scientists working with audible alerts have the advantage of being able to use recorded songs and calls in the field. But to study body language in yellow-chinned anoles (Anolis gundlachi) living in Puerto Rico's deep, shaded forests, Ord had to design and build realistic models that could dip, bend and unfurl flaps of skin on their chins, known as dewlaps. His hand-painted latex constructions were so realistic they fooled humans and anoles alike.

Ord housed small motors powered by packs of AA batteries in a box below his robotic lizards, then programmed the models to precisely imitate the typical four-legged pushups and head-bobbing displays performed by anoles. He also programmed two alternate sequences: displays with head bobs only (no pushups), and displays that began with quick dewlap extensions, a behavior not typically performed by this species.

Then the researcher planted his creations in a Puerto Rican forest and observed how neighboring anoles responded to the various displays. After viewing and analyzing more than 300 responses, Ord and Stamps concluded that pushups are an alert that the lizards mostly use only when necessary, such as when their neighbors are far away or when the light is dim.

They also found that both the pushups and rapid dewlap extensions prompted neighboring lizards to orient themselves more quickly to the displaying robots than when head bobs were performed without these alerts. The fact that the lizards responded to the atypical, but eye-catching dewlap extensions confirmed the hypothesis that any high-speed movement at the onset of a display could function as an effective alert.

By adding animals that use visual alerts to the roster of species already suspected of using audible alerts, the case can be made that alert signals represent a significant example of evolutionary convergence, Ord noted.

"This is interesting," he said, "because it's an example of very different species converging on a similar strategy."

Liese Greensfelder | EurekAlert!
Further information:
http://www.ucdavis.edu

More articles from Studies and Analyses:

nachricht Europe’s Demographic Future. Where the Regions Are Heading after a Decade of Crises
10.08.2017 | Berlin-Institut für Bevölkerung und Entwicklung

nachricht Scientists reveal source of human heartbeat in 3-D
07.08.2017 | University of Manchester

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

On the way to developing a new active ingredient against chronic infections

21.08.2017 | Life Sciences

Smart Computers

21.08.2017 | Information Technology

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>