Preening
drives divergent camouflage in feather lice on both micro- and
macro-evolutionary timescales
Date: March 5, 2019
Source: University of Utah
When
naturalist Charles Darwin stepped onto the Galapagos Islands in 1835, he
encountered a bird that sparked a revolutionary theory on how new species
originate. From island to island, finches had wildly varied beak designs that
reflected their varied diets. The so-called Darwin's finches are an emblem of
adaptive radiation, which describes when organisms from a single lineage evolve
different adaptations in response to competitors or predators.
Scientists
think that adaptive radiation generates much of the biodiversity on Earth, yet
most studies focus on groups that have already diversified. A new study took
the opposite approach.
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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