Reintroduced the great endangered blue butterfly

blue butterfly

The blue butterfly has returned to England.

Not a common type of butterfly, of course, but blue butterflies that were thought to be extinct, and which only a great effort by private companies and ecological associations could prevent.

The blue butterfly

The name of the butterfly comes from Menelaus, the king of ancient Sparta.

The adult butterfly feeds on rotten fruit juice with the long spirotromba, has tactile sensors on its legs and perceives the chemical substances present in the air thanks to its antennae.
It also feeds on the body fluids of dead animals and fungi; this makes it important for the dispersion of fungal spores.

The danger of extinction

The great endangered blue butterfly was introduced to Rodborough Common in Gloucestershire last year after five years of landscape preparation.

In what has been described by many as the largest insect conservation project, running from 1984 to 2008, the number of Phengaris Arion has increased dramatically and now numbers thousands.

The large blue butterflies have a remarkable life cycle, the butterfly larvae trick a particular species of red ant into bringing them into their nest, so the butterfly larvae can feed on ant larvae before becoming butterflies the following year.

The species was declared extinct in Britain in 1979, was first reintroduced by the continent’s populations almost 40 years ago and has been found in many places in southern England.

The work not only touched the butterflies but an entire habitat, which had to be changed to allow the reintroduction of these magnificent specimens into the wild.
Thus, thyme and marjoram bushes, the primary source of food for the blue butterfly larvae, were planted and Myrmica sabuleti ants were introduced, working symbiotically to protect the larvae from danger.

About 1,100 larvae were taken from other locations in the West Country and released last August on the 867-acre site owned by the National Trust.

It is estimated that around 750 butterflies emerged successfully during the summer, and team members monitoring the scheme recorded large blue matings and eggs laid on thyme and marjoram.

A human effort to correct human mistakes then, a great conservation project that teaches us once again that we must not only preserve great animals but also insects so that our children and grandchildren can continue to enjoy their beauty.

Blue butterfly life cycle

For its reproduction the blue butterfly depends on a particular species of ant (Myrmica).
Female butterflies lay their eggs on thyme flowers.
When the eggs hatch, the caterpillars eventually fall to the ground where they secrete chemicals that attract ants that mistake them for ant larvae.
The ants then transport the caterpillars inside the anthill and look after them for ten months.
At the beginning of June the caterpillars turn into chrysalises near the entrance to the colony and after two weeks they appear on the surface as butterflies.

The researchers observed that the grass in the butterfly habitat had grown too tall.
Farmers had stopped grazing their livestock and wild rabbits – victims of a viral infection in the 1950s – had stopped grazing the grass.
Because of the grass that was too high in the ant habitat, the soil temperature decreased and with it the ant population, and the blue butterflies also decreased.


Preparation of the site has been carried out by partners including National Trust, Butterfly Conservation, Limestone’s Living Legacies Back from the Brink project, Natural England, Royal Entomological Society (RES) and Minchinhampton and Rodborough Committees of Commoners.

Small temporary grazing areas were created using electric fences to allow cows, including Luing, Hereford and long-horned cattle, to graze on the slopes to provide the right conditions for ants, and a scrub control programme was carried out.

David Simcox said: “The butterfly needs high densities of the Myrmica sabuleti heat-loving red ant, which has a crucial role to play in the butterfly’s life cycle.

Myrmica sabuleti
Myrmica sabuleti

The grazing cows create ideal conditions for them by keeping the grass low so that sunlight can reach the ground to warm it, creating perfect conditions for the ants, who are cold-blooded and therefore need heat“.

In summer, butterfly larvae trick the ants into believing they are their young and bringing them into the nest to complete their life cycle by feeding on the larvae until they are ready to pupate and emerge.

The legend of the blue butterfly

A man who lived many years ago, remained a widower with two daughters to take care of.
The two girls were extremely curious, intelligent and eager to learn.
To satisfy their hunger for knowledge, they were constantly filling their father with questions.
Sometimes he gave them wise answers, but it was not always easy to convince the two girls or to answer their questions correctly.

Noting the anxiety of his two daughters, the man decided to send them on holiday to a wise man who lived on a hilltop to live together and learn from him.
The wise man showed himself able to answer without hesitation to any questions from the two girls.
One day, however, the two sisters decided to set a cunning trap for the wise man to measure his wisdom.
One night, the two set out to devise a plan: to propose to the wise man a question to which he was unable to answer.

How can we deceive the sage? What question could we ask him in order to catch him unprepared? – asked the younger sister.

Wait here, I’ll show you right away. – answered the elder one.

The elder sister went down the hill, and after an hour, she came back with her apron closed like a sack, hiding something.

What have you got there? – asked the little sister.

The older sister put her hand in her apron and showed the little girl a beautiful blue butterfly.

How wonderful! What are you going to do with it?

This will be the weapon that will allow us to fool the master with a trick question.
We will look for it and, once found, I will keep the butterfly hidden in one hand.
I will then ask the sage to tell me whether the butterfly in my hand is alive or dead.
If he tells me that it is alive, I will shake his hand and kill it.
If he answers that it is dead, I will let it go free.
Whatever his answer will therefore always be wrong
. –

Accepting the proposal of the older sister, both girls set out in search of the essay.

– “Wise,” said the older sister, “could you tell us whether the butterfly in my hands is alive or dead?

To which the wise man, with a shrewd smile, replied: “It depends on you, it is in your hands“.