麻豆影视

Skip to main content

Rare fossils reveal the butterfly 'tree of life' over the past 100 million years

The blue morpho is one of the largest butterflies in the world. (Kristen Grace/Florida Museum of Natural History) The blue morpho is one of the largest butterflies in the world. (Kristen Grace/Florida Museum of Natural History)
Share

The world鈥檚 largest butterfly tree of life is helping researchers determine where the winged insects originated when they first appeared on Earth about 100 million years ago.

During the age of the dinosaurs, some moths transitioned from flying at night to daytime, evolving to take advantage of the nectar from flowers that developed alongside bees.

Scientists first uncovered how this single shift to daytime activity served as the evolutionary turning point for all butterfly species. But researchers had yet to uncover the full history of the nearly 19,000 species of butterflies that exist around the world.

A global team of scientists began working on an ambitious project in 2015 to assemble a detailed model tracing the evolutionary history and species relationships for butterflies. Together, the researchers collected DNA from nearly 2,300 species from 90 countries that represent all butterfly families.

The researchers used four supercomputers in Europe and the United States to process the data, tracing the feeding habits and migrations of the butterfly species over time.

The team鈥檚 findings, published Monday in the journal , showed that butterflies first originated in what鈥檚 now North and Central America.

The research is a first step in a larger project concerning butterfly species, and it can act as a resource for future studies, said lead study author Akito Kawahara, curator of lepidoptera at the Florida Museum of Natural History.

Butterflies face many threats due to the climate crisis, including habitat destruction and global warming, which is causing some species to migrate to new environments. Understanding different populations and species of butterflies can better help scientists and conservationists protect the insects and their habitats.

SCARCE EVIDENCE IN THE FOSSIL RECORD

The geographical origins of butterflies were unexpected because previous hypotheses had supported the idea that they came from current-day Australia or Asia.

At the heart of the study were rare butterfly fossils. These precious remains of early butterflies are difficult to find because the insects have thin, fragile wings and threadlike hairs, neither of which preserve nearly as well as bones do in the fossil record.

The fossil specimens provided the researchers with genetic mile markers, helping them determine when critical events happened in butterfly evolution.

鈥淲e used multiple fossils for the study in order to calibrate particular parts of the tree,鈥 Kawahara said. 鈥淏ut most butterfly fossils are poorly preserved, so we could only include about 10-15 fossils in our study that we trusted based on paleontological research.鈥

Butterfly DNA painted a dramatic portrait of how the winged insects came to exist around the world over time. While some populations travelled seemingly impossible distances, others remained in place as the continents shifted around them.

When butterflies first appeared in Central America and western North America, a vast seaway divided North America into two regions. North and South America were also separated by the sea, and Mexico, the US, Canada and Russia were all joined together by land.

GLOBAL MIGRATION

Some butterfly species took an extended scenic route to Africa by moving across the Bering Land Bridge from North America and taking root first in Asia, where they spread across Southeast Asia, then migrated to the Middle East and the Somali Peninsula in East Africa. Butterflies also reached India, an isolated island at the time, despite the fact that it was surrounded by open sea.

Butterflies lived on the edge of western Asia for a lengthy amount of time, possibly as long as 45 million years, before migrating to Europe. While the researchers aren鈥檛 sure what caused the delay, the elongated pause is still evident.

鈥淓urope doesn鈥檛 have many butterfly species compared to other parts of the world, and the ones it does have can often be found elsewhere,鈥 Kawahara said. 鈥淢any butterflies in Europe are also found in Siberia and Asia, for example.鈥

The researchers were also surprised to find that butterflies reached Australia, which was still attached to Antarctica when the insects appeared there. Given that Antarctica was once a warmer environment millions of years ago due to hotter global temperatures, it鈥檚 likely that butterflies once lived there and crossed into Australia before it separated into its own continent.

Scientists were also interested in learning about the plants butterflies relied on for their survival, since the evolution of these plants would also impact how the insects changed over time. But there was no singular resource on plants for the researchers鈥 work, so they painstakingly assembled their own.

鈥淚n many cases, the information we needed existed in field guides that hadn鈥檛 been digitized and were written in various languages,鈥 Kawahara said. 鈥淚t鈥檚 also the most difficult study I鈥檝e ever been a part of, and it took a massive effort from people all over the world to complete.鈥

The database, now available to the public, is the result of translated and transcribed information from books, web pages and museum collections.

BUTTERFLIES EVOLVED WITH PLANTS

Most of the modern butterfly families were already around about 66 million years ago when dinosaurs went extinct due to an asteroid strike.

Butterflies diversified alongside the plants they relied on 鈥 and the butterfly families all seemed to gravitate to a specific plant group.

鈥淲e looked at this association over an evolutionary timescale, and in pretty much every family of butterflies, bean plants came out to be the ancestral hosts,鈥 Kawahara said. 鈥淭his was true in the ancestor of all butterflies as well.鈥

Over time, bean plants have become attractive to bees, hummingbirds, flies and mammals, and butterflies have since diversified their diet to include a wealth of plants. But the early relationship between butterflies and bean plants helped the winged insects become one of the world鈥檚 largest groups of insects, according to study co-author Pamela Soltis, distinguished professor and curator at the Florida Museum of Natural History.

鈥淭he evolution of butterflies and flowering plants has been inexorably intertwined since the origin of the former, and the close relationship between them has resulted in remarkable diversification events in both lineages,鈥 Soltis said in a statement.

For Kawahara, the monumental endeavour also represented his own evolutionary path.

鈥淭his project was a childhood dream,鈥 Kawahara said. 鈥淚 have loved looking at butterflies since I was very young and was fortunate to be able to do this project with so many amazing butterfly scientists from around the world. I hope more kids spend time outside to observe nature and continue to follow their dreams. Dedication can lead to great things!鈥

CTVNews.ca Top Stories

Canadian musician Jacob Hoggard has been found not guilty of sexually assaulting a young woman in northeastern Ontario eight years ago. The former Hedley frontman had pleaded not guilty to sexual assault.

Police have arrested a Toronto woman in connection with three recent homicides and investigators say that they believe two of the victims may have been 'randomly targeted.'

The body of a British Columbia mountain climber has been located and recovered after the 39-year-old man was reported missing during a solo climb on Washington state's Mount Baker earlier this week.

A teen charged with the murder of another teen on Prince Edward Island last year has pleaded guilty to a lesser charge of manslaughter.

A Saskatchewan man living in the United States has pleaded guilty to possessing child pornography after he unknowingly provided disturbing videos to an FBI agent he thought was a pedophile.

Local Spotlight

Chantal Kreviazuk is set to return to Winnipeg to mark a major milestone in her illustrious musical career.

From the beaches of Cannes to the bustling streets of New York City, a new film by a trio of Manitoba directors has toured the international film festival circuit to much pomp and circumstance.

A husband and wife have been on the road trip of a lifetime and have decided to stop in Saskatchewan for the winter.

The grave of a previously unknown Canadian soldier has been identified as a man from Hayfield, Man. who fought in the First World War.

A group of classic car enthusiasts donated hundreds of blankets to nursing homes in Nova Scotia.

Moving into the second week of October, the eastern half of Canada can expect some brisker fall air to break down from the north

What does New Westminster's t蓹m蓹sew虛tx史 Aquatic and Community Centre have in common with a historic 68,000-seat stadium in Beijing, an NFL stadium and the aquatics venue for the Paris Olympics? They've all been named among the world's most beautiful sports venues for 2024.

The last living member of the legendary Vancouver Asahi baseball team, Kaye Kaminishi, died on Saturday, Sept. 28, surrounded by family. He was 102 years old.

New data from Greater Vancouver and the Fraser Valley shows a surge in supply and drop in demand in the region's historically hot real estate market.