Remember how Darwin’s finches proved Darwinism – and then the story collapsed in a heap of uncertainty about how different all those “new species” were/are?
Invasive parasites in the Galápagos Islands may leave some Darwin’s tree finches singing the blues.
c The nonnative Philornis downsi fly infests the birds’ nests and lays its eggs there. Fly larvae feast on the chicks’ blood and tissue, producing festering wounds and killing over half of the baby birds. Among survivors, larval damage to the birds’ beaks may mess with the birds’ songs when they’re older, possibly affecting their appeal to potential mates, researchers report June 12 in Proceedings of the Royal Society B. …
For medium tree finches, the deformity meant they sounded similar to a small tree finch with a healthy beak. That may explain why scientists had previously had observed female medium tree finches choosing small male tree finches as partners, instead of males from their own species. The researchers did not observe female small tree finches choosing medium tree finch mates.
Carolyn Wilke, “Parasites ruin some finches’ songs by chewing through the birds’ beaks” at ScienceNews
One evolutionary biologist predicts the “extinction” of the medium tree finch as a result. The insect is thought to have arrived in the Galapagos in about 1960.
The whole story leaves one wondering what role incidental factors played, over many centuries, in the constant, reversible micro-evolution of the once-iconic Darwin’s finches.
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See also: Epigenetics may explain how Darwin’s finches respond to environment