A butterfly caught in Kagoshima Prefecture last week had traveled from Taiwan, about 1,000 km away, a group of butterfly enthusiasts said Tuesday.
"We have proved it flew from Taiwan and we hope this will serve as a springboard for cooperation in international research," said Haruo Fukuda, vice chairman of the Kagoshima Konchu Doko-kai (Kagoshima Insect Appreciation Group).
The chestnut tiger butterfly was caught July 2 by Koji Nakamine, a 35-year-old high school biology teacher. The male specimen was found in the town of Kiire on the Satsuma Peninsula, which protrudes from the southern end of Kyushu.
The code "NTU 1032C" was written in oil-soluble ink on the insect's left wing. The group traced the code and confirmed that the butterfly had been part of a research project involving the group and National Taiwan University.
The group had asked students from the university to release butterflies in mid-June on a mountain in Yangmingshan National Park, northern Taiwan.
The chestnut tiger butterfly is known for its migratory patterns. In spring it tends to head north, and in autumn it flies south. During both seasons, it prefers low-elevation areas, while in summer it often heads to higher ground.
The butterflies inhabit East and Southeast Asia, and are found throughout Japan, except in Hokkaido.
Its wings, which measure 8 cm to 12 cm fully extended, are semitransparent with black and brown patches.
Groups throughout Japan conduct research on butterfly migration. In one study, a chestnut tiger caught on Yonaguni Island in Okinawa Prefecture was found to have flown from Osaka Prefecture, about 1,600 km away.
For the past three years, the Kagoshima group has been asking Taiwanese researchers to participate in their butterfly studies. The group hopes last week's discovery will be the start of many years of joint work.