Lisa G. Crozier, Mark D. Scheuerell, Richard W. Zabel, "Using Time Series Analysis to Characterize Evolutionary and Plastic Responses to Environmental Change: A Case Study of a Shift toward Earlier Migration Date in Sockeye Salmon." http://www.jstor.org/stable/10.1086/662669
Predators Keep Local Frogs In Uniform
Peruvian poison dart frogs of the genus Ranitomeya are jewels of the rainforest, renowned for the diversity of vivid colors they display, which vary greatly from region to region. Obviously, these colors have not evolved for our amazement, but rather to warn predators that they will be greatly ill if they dare taste them. But how do predators keep track ofand learn to avoidso many color patterns. And why do poison-dart frogs maintain such a high diversity of color patterns? Researchers from the University of Montreal have recently showed that diversity in poison-dart frogs is maintained locally due to the predators avoiding only one color pattern and quickly eliminating all others. Using hundreds of life-sized clay models painted to resemble the distinct color patterns of poison dart frogs, the researchers found that avian predators avoided models with the local coloration, but attacked models with non-local colors. The results show that the local predators have come to recognize and avoid the local frogs. "Being exotic is, in this case, not advantageous at all, as the frogs' vivid coloration make them more easily detected by predators that have not learned to recognize them," said Dr. Chouteau. These results highlight the close relationship between the colorful amphibians and their predators, and demonstrate that the geographic diversity of color patterns is maintained by the learning experience of a distinct predator community.
Mathieu Chouteau, Bernard Angers, "The Role of Predators in Maintaining the Geographic Organization
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