Convergent Evolution in Poison Frogs - Yahoo! News:
Scientists have discovered one of the most intricate examples of convergent evolution with the help of South American "poison" frogs and ants and their cousins in Madagascar.
Poison frogs can't make their own poison--they steal it from ants. Poison frogs secrete a variety of chemicals called alkaloids to create a poisonous defense against predators. Since they can't produce alkaloids on their own, these frogs maintain a steady diet of specific alkaloid-rich ants to keep up their defense.
Now, Valerie Clark of Cornell University and her colleagues have detailed two instances of convergent evolution--the process in which organisms not closely related independently acquire similar characteristics while evolving in separate ecosystems--between frogs and ants on two continents.
Convergent evolution and a test of evolutionary hypotheses.