Are parasites a good model to study evolution?
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University of Utah biologists experimentally triggered adaptive radiation; they used host-specific parasites isolated on individual pigeon "islands." The scientists showed that descendants of a single population of feather lice adapted rapidly in response to preening, the pigeons' main defense. They found that preening drives rapid and divergent camouflage in feather lice (Columbicola columbae) transferred to different colored rock pigeons (Colombia livia). Over four years and 60 generations, the lice evolved heritable color differences that spanned the full color range of the lice genus found on 300 bird species worldwide.
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