What began with photographing butterflies soon became a passion for studying them.
“I use butterflies and moths as a lens to understand how climate and habitat changes affect tropical insects.”
Dr Yuet Fung LING
• Postdoctoral Fellow, School of
Biological Sciences, HKU
• PhD in Ecology and
Biodiversity, HKU
• BSc (double major in
Environmental Science and
Geography), HKU
At first glance, butterflies seem like carefree drifters, fluttering lightly from flower to flower as though life were nothing more than a sunlit stroll. To most of us, they embody beauty, fragility, and grace. Yet behind those shimmering wings lies a very different truth. “People often think of butterflies as delicate,” says Dr Yuet Fung LING, Postdoctoral Fellow at the School of Biological Sciences. “But they are strong flyers, and at the same time, powerful indicators of climate change.”
Science Behind the Wings
Ling’s journey into the world of insects began with an unlikely houseguest: a praying mantis that flew into his home when he was a child. Rather than shooing it away, his family chose to care for it, and before long, he watched it lay eggs and hatch a brood of young.
“Through caring for it, I learned a lot about insects’ biology and ecology,” he recalls. “The experience sparked my curiosity and deepened my interest in nature.”
That childhood encounter planted a seed that never faded. His passion for nature eventually led him to the Faculty of Science at HKU, where he majored in Environmental Science. During his undergraduate years, frequent hikes brought him face-toface with Hong Kong’s butterflies. His early admiration, first expressed through photography, gradually deepened into a fascination that steered him toward the serious study of insects. “Butterflies are not only beautiful, but they are also important parts of the ecosystems and are vulnerable to changes in the environment,” he says. That realisation led him into doctoral research on the ecophysiology of butterflies and moths, and eventually, to his postdoctoral research exploring how climate and habitat changes are transforming tropical insect communities.
The Chestnut Tiger (Parantica sita),
captured in Repulse Bay on December 21,
2024, was tagged in Japan on August 18,
2024.
Photo courtesy: Yuet Fung Ling.
Ling’s research explores how insects adapt to a changing environment: from testing butterflies’ tolerance to heat and hunger, to comparing day- and night-active species, to understanding the range expansion of tropical species into Hong Kong. Each study adds to the picture of how climate change is reshaping biodiversity.
However, the most astonishing insights have come from his research on butterfly migration. Since 2021, Ling, together with Professor Timothy BONEBRAKE, Director of the School of Biological Sciences, PhD student Emily JONES, volunteers, and the public, has tracked the seasonal movements by tagging nearly 16,000 butterflies across 13 species at 32 sites in Hong Kong. The project yielded 1,503 recoveries, more than half reported by the public and 78 movement records within the city. Each tiny sticker, carefully affixed to a wing, carries a website address for the public to report sightings, an ingenious way to turn the community into collaborators.
Then came the discovery that redefined expectations: in December 2024, they found a Chestnut Tiger butterfly that had flown 3,016 kilometres from Fukushima, Japan, to Hong Kong, the longest recorded journey for the species.
“I was both shocked and excited,” Ling recalls. “The Chestnut Tiger is very rare in Hong Kong in winter, and in three years of fieldwork, we hadn’t seen one. I was aware of a case in 2011, but I thought it was a once-in-a-lifetime event. Out of more than 15,000 butterflies we tagged, this was our first international recovery!”
Why Does It Matter?
Danaid butterflies formed a spectacular winter cluster, clinging to branches for shelter.
Photo taken in Pui O, 2023.
These findings challenge the perception of butterflies as fragile creatures, revealing them instead to be resilient, long-distance travellers and vital indicators of environmental change.
“Butterflies are a good study system for understanding climate change and conservation due to their sensitivity to the environment,” Ling explains. Their biology is also relatively well studied, and their unique connection with the public makes them powerful tools for education and outreach. “By studying butterflies, we can gain insights into the responses of other insects, using them as umbrella species to guide conservation strategies,” he says.
Ling now turns his attention to moths, another vital yet often overlooked group of insects, to explore how urbanisation and light pollution are reshaping their lives. His ambition is to bridge the gap between science and society, to produce research that informs conservation while sparking awareness among the wider public. “Ultimately, I hope that even for the general public, my work can inspire greater awareness of the environmental changes we are facing and action for conservation,” he says. In the delicate lives of these creatures lies a quiet strength–one that may yet shape the world of tomorrow.
Q&A with Dr Yuet Fung LINGSport a Danaid butterfly? Report it here
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