Making new evolutionary innovations: latest butterfly study (Introduction)

by David Turell , Wednesday, February 14, 2024, 23:54 (281 days ago) @ David Turell

Pushes origin back millions of years:

https://www.smithsonianmag.com/science-nature/where-did-butterflies-come-from-scientist...

"This past May, working with nearly 90 co-authors from six continents, he published the results of a massive global study of butterfly evolution, based on DNA samples from 2,300 butterfly species. Not only does it fill in the gaps on the phylogeny chart he saw as a child, but it also presents a completely new origin story for these charismatic insects. Most scientists thought they evolved in Australasia, but it seems most likely that the first butterflies appeared in North and Central America. The ancestor of butterflies was a nocturnal moth that became day-flying here, 101.4 million years ago. (my bold)

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"Moths were the focus of Kawahara’s early career. He remains fascinated by them and likes to point out that butterflies are basically just moths that fly by day. Approximately half of moths have hearing abilities, and he’s particularly interested in a group that can hear bat sonar and make acoustic signals to “jam” the sonar and escape predation.

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"The result is a beautiful, elaborate diagram that looks more like a wheel than a tree. Besides the breakthrough discoveries into where and when butterflies originated, it demonstrates that 36 tribes of butterflies need to be reclassified—and supports Kawahara’s 2019 hypothesis on how and why moths started flying in the day. Since the oldest intact fossilized butterfly was 55 million years old, and bats evolved in the same era, many scientists had thought that a group of moths became day-flying to escape bat predation. Now we know, thanks in large part to Kawahara’s revelatory work, that butterflies originated over 100 million years ago—some 35 million years before bats. Kawahara thinks that it was bees, not bats, that caused the advent of day-flying moths.

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"By assigning a geographic area to every species in the study, and then using the DNA tree and supercomputers to calculate the probability that their ancestors were there in the past, researchers were able to form a hypothesis about the spread of butterflies around the world. First they fluttered east across North America and down into South America. Then they dispersed in waves to Australia, Asia, India, Africa and finally, around 30 million years ago, to Europe. Today there are an estimated 19,500 species, distributed all over the world except Antarctica, even on remote and isolated islands.

"By assigning a geographic area to every species in the study, and then using the DNA tree and supercomputers to calculate the probability that their ancestors were there in the past, researchers were able to form a hypothesis about the spread of butterflies around the world. First they fluttered east across North America and down into South America. Then they dispersed in waves to Australia, Asia, India, Africa and finally, around 30 million years ago, to Europe. Today there are an estimated 19,500 species, distributed all over the world except Antarctica, even on remote and isolated islands.

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"Asked why some butterflies became so beautifully colored, Kawahara offers three generally agreed-upon reasons. “They’re displaying their chemical defense to predators, so birds and lizards, when they see a bright red butterfly, they think, ‘No, I’m not going to eat this thing because it’s toxic.’ Then there’s mimicry. Many butterflies look like the brightly colored toxic ones, but they’re not chemically defended. And lastly for mating. They use their colors to flash and display to the opposite sex.'”

Comment: so, butterflies came from moths that knew the dinosaurs. They pollinate which mean their arrival helped flowering plants which had recently arrived. Their fabulous coloration may be explained as above.