Butterflies first appeared about a hundred million years ago. A study published in Nature Ecology and Evolution traces their global spread, with evidence pointing to western North America and Central America as early centers of diversification.
A large team of scientists, including Spanish researchers, rebuilt the butterfly tree of life by analyzing DNA from more than 2,300 species across 90 countries. This expansive effort covers roughly 92 percent of all families and genera known today.
Butterflies emerged near the end of the Cretaceous period. The Barcelona Institute of Botany and the Institute of Evolutionary Biology, along with other collaborators, emphasize that this overview marks the first time the group has been linked to legume feeding in their evolution.
Current evidence suggests a native origin in the Americas, particularly western North America or Central America. Yet the researchers caution that the North American origin is not definitively proven.
Butterflies originate from North or Central America. These conclusions come from a broad comparison of fossils and living species and are supported by extensive DNA data and paleontological records.
About 100 million years ago, a lineage of moths began to fly by day, exploiting new nectar-rich flowers that co-evolved with bees. This shift helped set the stage for the modern diversity of butterflies.
Large-scale DNA analyses, completed in recent years, challenged earlier hypotheses about the timing of butterfly evolution. They indicate that the evolution of butterflies was not solely driven by bat predation after the dinosaur extinction about 66 million years ago, but involved multiple factors and rapid bursts of diversification.
The fossil record includes 11 rare butterfly fossils. These delicate wings and filamentous structures are rarely preserved, and the available specimens were essential for building a fuller picture of butterfly history.
According to the Florida Museum of Natural History, which coordinated the research, the results reveal a dynamic story marked by bursts of diversification, periods of stagnation, and unexpected disjunctions in lineages over time.
Expansion all over the world
Some butterfly groups traveled astonishing distances while others remained relatively localized. Landmasses such as continents, mountains, and rivers have shifted in space, yet butterflies moved with them, adapting to new climates and habitats along the way.
In earlier eras, North America was divided by a sweeping seaway, and today a long arc connects what is now Mexico with the United States, Canada, and even distant regions like Russia, a testament to the long journeys butterflies undertook.
Butterflies did not need a continuous land bridge to migrate. They crossed open oceans and narrow straits when opportunities arose, expanding their range across continents.
North and South America were still separated by ocean barriers until the Isthmus of Panama formed. Even so, butterflies crossed the early ocean gaps with relative ease, spreading beyond their initial homes.
Butterflies later entered Asia via the Bering land bridge and then spread rapidly through Southeast Asia, the Middle East, and the Horn of Africa. They even reached India, a region long isolated by sea distances from other landmasses.
Surprisingly, butterflies made their way to Australia as well, a landmass that remained attached to the supercontinent of Antarctica for much of deep time. It is possible that butterflies traveled across warmer periods when Antarctica was more hospitable, moving toward Australia before the continents drifted apart.
Late arrival in Europe
Further north, butterflies persisted in distant western Asia for tens of millions of years before appearing in Europe. Akito Kawahara, lead author from the Florida Museum of Natural History, notes that the reasons for this extended delay remain unclear, but the consequences are evident in today’s butterfly distributions across the continent.
Europe hosts far fewer butterfly species compared with other regions. Some species that are common elsewhere are found in different places like Siberia and parts of Asia, reflecting complex biogeographic patterns over time.
Today there are about 19,000 butterfly species globally. To reconstruct their history, researchers needed extensive data on current distributions and host plants. Much of this information had to be compiled from diverse sources because centralized databases were incomplete, prompting the creation of new, integrated data resources.
In summary, the study paints a picture of rapid diversification, regional stasis, and unexpected breaks in lineages as butterflies spread around the world. The research highlights how life on Earth responds to climate shifts, geography, and ecological opportunities over millions of years.
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