Thursday, March 09, 2006
"AUSTIN, Texas--Studying neotropical poison dart frogs, biologists at the University of Texas at Austin uncovered a new way that the frog species can evolve to look similar, and it hinges on the way predators learn to avoid the toxic, brightly colored amphibians.
In the Mar. 8 issue of Nature, Catherine Darst and Molly Cummings show that a harmless, colorful frog living in the Amazonian rainforest gets protected from predators not by mimicking its most poisonous neighbor, but by looking like a frog who's poison packs less punch.
The Texas biologists studied three species of poison dart frogs--one highly toxic species, one less toxic species and one harmless species. All live in the same area and are brightly colored, which warns predators that they may be poisonous.
In a series of predator learning experiments, the researchers found that the frogs' predators--in this case birds--learned to avoid anything remotely resembling the most toxic species."