Flower Evolves Shape for Bird Pollination, Spreads Across Asia

Lipstick vine species Aeschynanthus acuminatus defies long-standing botanical model by adapting to new pollinators on mainland and Taiwan

Jan. 27, 2026 at 9:23pm

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Researchers have discovered that a lipstick vine species called Aeschynanthus acuminatus has evolved shorter, wider, yellowish-green flowers to accommodate shorter-beaked birds as pollinators, rather than the long-beaked sunbirds that pollinate its tube-shaped red flower cousins. This contradicts the long-held Grant-Stebbins model that predicts plants will evolve new species when they colonize areas with different pollinators. The study found that A. acuminatus actually originated on the Asian mainland, where sunbirds live, and later adapted to shorter-beaked birds when it spread to the sunbird-less island of Taiwan.

Why it matters

This discovery challenges a foundational botanical model and provides new insights into how plants can evolve to adapt to different pollinators, even in the presence of their ancestral pollinators. It highlights the importance of field research and direct observation of ecological interactions, rather than relying solely on theoretical models, in understanding plant evolution.

The details

Aeschynanthus acuminatus, a member of the lipstick vine group, has evolved shorter, wider, yellowish-green flowers compared to its red, tube-shaped cousins. While the red flowers attract long-beaked sunbirds as pollinators, A. acuminatus is pollinated by a variety of shorter-beaked birds, even in areas where sunbirds are present. Researchers used DNA analysis and camera traps to determine that A. acuminatus actually originated on the Asian mainland, where sunbirds live, and later adapted to the shorter-beaked birds when it spread to the sunbird-less island of Taiwan.

  • The study was published in the journal New Phytologist in January 2026.

The players

Jing-Yi Lu

The lead author of the study and a research associate at the Field Museum who recently graduated with a PhD from the University of Chicago.

Rick Ree

A curator at the Field Museum's Negaunee Integrative Research Center and the senior author of the study.

Aeschynanthus acuminatus

A species of lipstick vine that has evolved shorter, wider, yellowish-green flowers compared to its red, tube-shaped cousins.

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What they’re saying

“Compared to the rest of its genus, this species has weird, unique flowers.”

— Jing-Yi Lu, Lead author (Mirage News)

“At the heart of our study is a question of where species originate. There must have been a switch when this species evolved, when it went from having narrow flowers for sunbirds to wider flowers for more generalist birds. Where and when did the switch occur?”

— Rick Ree, Senior author (Mirage News)

What’s next

The researchers plan to continue investigating the evolutionary history and ecological interactions of Aeschynanthus acuminatus to better understand the factors that drove its adaptation to different pollinators.

The takeaway

This study challenges a long-standing botanical model and demonstrates the importance of field research and direct observation in understanding plant evolution, rather than relying solely on theoretical frameworks. It provides new insights into how plants can adapt to changing pollinator communities, even in the presence of their ancestral pollinators.