"I couldn't believe it," said study co-author
Each of the 12 species lives in and along streams running down the mountains on several different islands of
They usually eat algae or lichen, and build silk cases — which one species even adorns with bird feathers — for shelter and camouflage. They spin silk drag lines to withstand the high pressure of fast flood waters.
Unlike other amphibious creatures that can survive underwater on stored oxygen but must come back up for air, these caterpillars can spend several weeks without ever breaking the surface, according to the paper, which was published online Monday in Proceedings of the National Academy of Sciences.
It isn't yet clear how the insects do it. Rubinoff and co-worker
The trait appears to have evolved more than once, Rubinoff said. After analyzing the DNA of the 12 amphibious species, the scientists found that three separate lineages of moth had developed the ability to breathe underwater at different points in the past.
Why they evolved this trick isn't clear, but animals
and plants are known to often evolve in surprising directions after
arriving at new, sparsely populated habitats such as islands, said
In a new environment, released of the pressure of having to fight for food sources or evade predators, they are freer to expand into new niches.
"When the pressures on an environment are released, what crazy things are animals capable of doing?" said
"You just wonder ... do all animals have that potential?"
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