The researcher’s methodology was rather unusual: on three occasions over three days, at two different sites, Chouteau investigated the number of attacks that had been made on fake frogs, by counting how many times that had been pecked. Those that were attacked the least looked like local frogs, while those that came from another area had obviously been targeted.
Mathieu Chouteau, Université de Montréal
Research published in the American Naturalist by Université de Montréal's Mathieu Chouteau links the colours and patterns of poison dart frogs to their predators.
The brightly coloured frogs that we find in tropical forests are in fact sending a clear message to predators: “don’t come near me, I’m poisonous!” But why would a single species need multiple patterns when one would do? It appears that when predators do not recognize a poisonous frog as being a member of the local group, it attacks in the hope that it has chanced upon edible prey. “When predators see that their targets are of a different species, they attack. Over the long term, that explains how patterns and colours become uniform in an area,” said Bernard Angers, who directed Chouteau’s doctoral research.
A total of 3,600 life-size plasticine models, each less than one centimetre long, were used in the study. The menagerie was divided between two carefully identified sites in the Amazon forest. “The trickiest part was transporting my models without arousing suspicion at the airport and customs controls,” Chouteau said. He chose plasticine following a review of scientific literature.
“Many scientists have successfully used plasticine to create models of snakes, salamanders and poison dart frogs.” The Peruvian part of the forest proved to be ideal for this study, as two radically different looking groups of frogs are found there: one, living on a plain, has yellow stripes, and the other, living on a mountain, has green patches. The two colonies are ten kilometers apart. 900 fake frogs were placed in each area in carefully targeted positions. Various combinations of colours and patterns were used.
Chouteau was particularly surprised by the “very small spatial scale at which the evolutionary process has taken place.” Ten kilometers of separation sufficed for a clearly different adaptation to take place. “A second surprise was the learning abilities of the predator community, especially the speed at which the learning process takes place when a new and exotic defensive signal is introduced on a massive scale,” Chouteau said.
This process could be at origin of the wide range of colour patterns that are observed not only in frogs but also many species of butterflies, bees, and other animals. Mathieu Chouteau is in fact currently undertaking post-doctoral research into the Heliconius genus of butterfly. “Considering that this kind of project requires regular field work, I have taken up residence in the small town of Tarapoto, where I am responsible for the opening of a research centre that will facilitate the study of neotropical butterfly mimicry,” he said.
• Département de sciences biologiques de l'Université de Montréal : www.bio.umontreal.caMedia contact:
William Raillant-Clark | Newswise Science News
Study shines light on brain cells that coordinate movement
26.06.2017 | University of Washington Health Sciences/UW Medicine
New insight into a central biological dogma on ion transport
26.06.2017 | Aarhus University
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
26.06.2017 | Life Sciences
26.06.2017 | Physics and Astronomy
26.06.2017 | Information Technology