KURASHIKI, Okayama Prefecture--Bug-loving high school student Yuri Adachi stopped in front of a vending machine and couldn't believe her eyes.

Lying on the ground was a moth that she thought looked pretty weird--and it was.

It turned out to be an extraordinarily rare gynandromorph moth, meaning it was half-male and half-female. The insect was discovered at Kodani service area along the Sanyo Expressway in Higashi-Hiroshima, Hiroshima Prefecture.

The Rhodinia fugax, with a wingspan of about 8.5 centimeters, was perfectly split down the middle with a male deep reddish brown wing and body on the left side of its body, and a female yellow ocher wing featuring a rounded tip on the other.

On closer inspection, Adachi noticed that the left antenna was a totally different shape to the right one. The moth had the leaf-shaped antenna on the left, which is typical of the male, and an extremely narrow female antenna on the other side.

Adachi has another specimen of the same species, but not as remarkable as the one she recently found, which she keeps on her desk at home and studies while it dries out before being mounted.

One in 100,000 to 200,000 Rhodinia fugax are believed to be born with both male and female characteristics.

“But a moth clearly split down its middle is extremely rare,” according to Yuichi Okushima, 48, a curator at the city-run Kurashiki Museum of Natural History where the stunning Rhodinia fugax moth is now on display.

Noticing that its left wing was severely damaged, Adachi gingerly picked it up and put it into a bag to take home.

The expressway service area is known as a perfect observation spot for bug lovers because it is located in a mountain forest district and lit up through the night.

Adachi, a third-year student at Okayama University of Science High School, and her 48 classmates had stopped there for a break Nov. 22 en route to the Miyajima Public Aquarium in Hatsukaichi, Hiroshima Prefecture, for a school event.

As soon as the bus stopped, Adachi began searching for insects.

The day after her find, she took it to the museum where it was mounted.

Adachi said she grew up from a young age liking bugs and liked nothing better than to clasp a chirping cicada in her hand.

She is the only female member of the museum-led Mushi Mushi Tankentai ("hello bug" expedition team). They collect insects with museum staff.

At home, Adachi breeds 15 types of insects, including a wingless cockroach, to study them.

“I made such a rare discovery under my nose. I’m really happy I got involved with insects,” she said.

Gynandromorph moths are believed to be a result of genetic mutation but why is not known.

“The moth might have fallen prey to a bird or would have ended up in the garbage if she had not found it,” said curator Okushima. “It was just a miracle encounter.”

Adachi will study at the Faculty of Biosphere-Geosphere Science at Okayama University of Science from April.

“In the future, I want to be involved in environmental assessments and work to develop a better co-existence between creatures and humans,” she said.