Are you familiar with the butterfly called the "Great Mormon"?
The Great Mormon butterfly is designated as the prefectural butterfly of Okinawa, and is one of the largest butterflies in Japan, with a wingspan of 13 to 15 cm.
Outside of the cold season (December to February), you can see the large white butterfly (Idea leuconoe) fluttering about.

The sight of the Great Mormon butterfly soaring through the sky, with its feathers falling from above, is so elegant that in some regions it is called the "Lady of the Southern Islands."
Furthermore, it is said that when it is in its pupal stage, it shines with a golden light and "brings happiness to those who see it."

I tried raising one of Japan's largest butterflies, the Great Mormon, until it became a butterfly!
I also looked into the reasons behind its striking pattern, why it turns into a golden chrysalis, and why it flies so gracefully!

<Table of Contents>
1. A larva with conspicuous markings and horns.
2. Into a golden pupa
3. The largest adult insect in Japan with white mottled markings.
4. Places where you can see the Great Mormon butterfly

Show all table of contents

1. A larva with conspicuous markings and horns.

First, we went to look for the larvae of the Great Mormon butterfly.

The larvae of the Great Mormon butterfly feed exclusively on a poisonous plant called "Hourai-kagami," so they head towards areas where this plant grows.
This time, we headed to a park near Shuri Castle. There are *Hourai Kagami* trees planted in Shuri Castle Park, so you can see the Great Mormon butterfly there as well.

As soon as we arrived at the park, we spotted a butterfly laying eggs on a Ficus microcarpa flower!

The growth cycle of the Great Mormon butterfly is as follows: It takes about a month from egg to larva to pupa to adult, but during that time, its appearance changes dramatically.

	Status	Size
Day 0	Eggs are laid	2mm
Day 4	incubation	4 mm
↓	Larva	Approximately 5cm
Day 24	Turns into a chrysalis
Day 36	Becomes an adult	13-15 cm

This time, I brought home four healthy larvae.

The larvae of the Great Mormon butterfly have a striking appearance, with their entire body being black with white vertical stripes, red spots lining both sides of their body, and six long, slender black horns on the head side and two on the tail side.

Many larvae blend in with the colors of branches and leaves to avoid being eaten by natural predators like birds, so why do these have such conspicuous patterns?

This is related to the fact that the "Hourai-kagami" plant, which the larvae of the Great Mormon butterfly eat, is poisonous.

Larvae that eat poisonous leaves will also develop toxins in their own bodies.

So, it seems they're trying to warn people with their "poisonous" appearance, as if to say, "I'm poisonous! Don't eat me!"

The larvae eat leaves at an incredible rate and grow larger and larger as they repeatedly molt.

Since they only eat fresh leaves, prepare some lush green leaves of the *Hourai Kagami* plant.

2. To the golden pupa

Around 20 days after becoming a larva, when it reaches a length of about 5 cm, it is time to transition to pupation.

As they approach pupation, their movements slow down and they become still.
Then, they hang upside down, their rear ends attached to a string and suspended from a cage or branch.

After one day in this form, it begins to molt and becomes a pupa.
It wriggles and moves skillfully, shedding its skin, and an orange-colored object emerges from inside.

The next day, it had transformed into a beautiful pupa, somewhere between yellow and gold in color.

As the days go by, it shines more and more golden. It gets this dark gold.

Why are the pupae of the Great Mormon butterfly golden in color?

It is said that there are mainly three reasons for this.

① To warn others, "Don't eat me, I'm poisonous!" (Warning coloration)
② To reflect light like a mirror and blend into its surroundings, thus avoiding detection (camouflage).
③ Birds dislike metallic colors.

After investigating, it seems that reason ② is the most plausible.
It appears strikingly golden to the human eye, but it's not the same to the eyes of birds or insects.

From the perspective of birds and insects, the pupa doesn't appear as a shiny golden pupa,
It's possible that it's a "pupa that's difficult to spot because it reflects the surrounding scenery."

Especially in places like forests where sunlight filters through the trees, the pupae blend in with the scenery.

3. The largest adult insect in Japan with white mottled markings.

On the 11th day after pupation, a dark greenish-black color began to emerge, likely on the wing portion.
By the morning of the 12th day, it had completely emerged from its pupa.
Its body was still plump like a caterpillar, and its wings were wrinkled.

After letting the feathers dry thoroughly for a day, they stretched out and the patterns on the wings became beautifully visible.

So, what is the reason why the Great Mormon butterfly has large wings and flies so gracefully?
The reason for this, too, lies in the 'poison'.

Thanks to the *Hypochaeris erythrosora* they ate as larvae, the *Idea leuconoe* butterfly retains toxins in its body even as an adult.
Thanks to its poison, it was less likely to be preyed upon by birds and other animals, which allowed it to grow to a large size.
Furthermore, its striking patterns and graceful flight are said to be a way of advertising that it possesses "poison."
*Please rest assured that there is no danger in simply touching it!

The Great Mormon butterfly lays 100 to 180 eggs at a time, but only about 2% of them survive to become larvae.
To survive from there and become an adult...the natural world is harsh.

The wings of the Great Mormon butterfly are very beautiful because they become translucent when light shines through them.
The Great Mormon butterfly, having grown up successfully, flew off energetically towards the blue sky!
I hope we live long enough to bump into each other again somewhere.

4. Places where you can see the Great Mormon butterfly

In Okinawa, butterflies have long been believed to protect living people and ward off evil spirits, and have been depicted on baby clothes, fans, and kimonos.

After hearing that, seeing the large white butterfly fluttering about feels strangely surreal.

Wouldn't you like to see such a mystical butterfly in Okinawa?

While a chance encounter is wonderful, there are also plenty of places where you're guaranteed to meet someone.

You should definitely go and meet them!

Places to see the Great Mormon butterfly in Okinawa

Okinawa Peace Memorial Park, Kiyora Butterfly Garden
■Address: Mabuni, Itoman City, Okinawa Prefecture
■ Fee: Free ■ Parking: Available
■ TEL: 098-997-3011
■ URL:http://www.okinawakyoukai.jp/publics/index/30/

Butterfly Garden at Manko Park
■Location: Next to the Manko Park Management Office
■ Fee: Free ■ Parking: Available
■TEL:098-951-3239
■ URL:https://www.city.naha.okinawa.jp/shisetsu/kankyo/gakusyunature.html#cmschocho

Tedako Butterfly House
■Location: 1-9 Nakama, Urasoe City, Okinawa Prefecture (near Urasoe Art Museum)
■ Admission Fee: Free ■ Parking: Available (Urasoe City Culture Park Parking Lot)

Ryugu Castle Butterfly Garden
■Location: 390-1 Yamakawa, Motobu-cho, Kunigami-gun, Okinawa Prefecture
■ Admission Fee: Adults (16 years and older) 500 yen, Children (3 to under 16 years old) 250 yen ■ Parking: Available
■ TEL: 0980-48-3456
■ URL:http://www.ryugujo.net/user_data/park-house.php

Tropical Dream Center Victoria Greenhouse
■Location: 424 Ishikawa, Motobu-cho, Kunigami-gun, Okinawa Prefecture
■Price: Adults 760 yen, Children free ■Parking: Available
■ TEL: 0980-48-2741
■ URL:https://oki-park.jp/sp/kaiyohaku/inst/38/40

OKINAWA Fruit Land
■Location: 1220-71 Tamata, Nago City, Okinawa Prefecture
■Price: Adults 1000 yen, Children 600 yen ■Parking: Available
■ TEL: 0980-52-1568
■ URL:https://www.okinawa-fruitsland.jp/
*Temporarily closed

The courtyard at Ishigaki Airport
■Location: Inside Shin-Ishigaki Airport
■ Fee: Free ■ Parking: Available
■ TEL: 0980-87-0468
■ URL:https://www.ishigaki-airport.co.jp/spend/fun/lightcourt.html

Final thoughts

Raising the Great Mormon butterfly, I was amazed by the resilience of life in creatures that manage to survive by changing their bodies three times.

Over many years, the Great Mormon butterfly has grown beautifully large in Okinawa's blessed natural environment.

Please come and see them soaring gracefully and majestically under the blue skies of Okinawa.

I hope that encountering the Great Mormon butterfly will become one of the highlights of your trip.