Rare Two-Sexed Butterfly Hatched in UK


On its left, the butterfly’s wings glisten like polished black leather. On its right, they flash colorfully, edged with leopard-gold spots, slashes of mottled silver and a bright red teardrop. The striking asymmetry is extremely rare in butterflies, not only for its beauty but for its cause. Genetically, this mismatched creature is both male and female.

Recently hatched in London’s Natural History Museum, the butterfly is technically classified as a gynandromorph. The BBC reports that its unique traits are caused by a failure of the butterfly’s sex chromosomes to separate during fertilization. Only .01% of hatched butterflies are gynandromorphs.

The genetic condition has been noted in other species, including crabs, lobsters, spiders and chickens. According to the BBC, experts believe gynandromorphy occurs throughout nature but can be difficult to observe in species where sexual dimorphism, or visual and behavioral differences between males and females, is less pronounced.

“It is a complete split; part-male, part-female… welded together inside,” Luke Brown, a butterfly enthusiast who works with the Natural History Museum, told the BBC.

This gynandromorph butterfly, a species native to Asia called the Great Mormon (Papilio memnon), gets its darker wings from its male side, while the brighter, bolder set come from its female traits. The creature also has male and female sex organs, which means it is infertile, and even its antenna are different lengths. Brown, who has hatched over 300,000 butterflies, has only seen two others like it.

“I was bouncing off of the walls when I learned [about it],” Brown said. He reported to The Guardian that the butterfly was feeding and flying well. At three and a half weeks old, it is already considered middle-aged. After the butterfly dies, the Natural History Museum will preserve it as part of its rare butterfly collection.

“The gynandromorph butterfly is a fascinating scientific phenomenon, and is the product of complex evolutionary processes,” Blanca Huertas, the museum’s butterfly curator, told The Guardian. “It is fantastic to have discovered one hatching on museum grounds, particularly as they are so rare.”

Click here to see a photograph of the gynandromorph butterfly.


Related Stories

Female Butterflies Use Their Wings to Tell Males “Not Available”

Monarch Butterflies Use Plants As Medicine (Video)

The Plight of the Butterflies

Image credit: Miranda P.


W. C
W. C2 months ago


William C
William C2 months ago

Thank you.

Cheryl B.
Cheryl B5 years ago


KrassiAWAY B.
Krasimira B6 years ago

Noted with interest.

SeattleAnn S.
Ann S6 years ago

Fascinating article. Thanks for sharing.

Carrie Anne Brown

very interesting! thanks for sharing :)!

Jane R.
Jane R6 years ago

Very Pretty!!!

James Campbell
James Campbell6 years ago

Addendum to previous post:

Different from AIS, the condition known as 5 Alpha Reductase Deficiency (5-ARD) occurs due to an autosomal defect (on a chromosome other than the X or Y chromosomes) and requires *two* altered genes, one from the father and one from the mother. neither of whom present with an intersex condition.

James Campbell
James Campbell6 years ago

@Joseph B.
I my comment, I was referring to intersex conditions in-general. The butterfly in the article is an example of one form of intersex that is infertile, but any reference to intersex being a 'dead end' is only applicable if all intersex lifeforms were found to be infertile. There is a wide variation of intersex conditions affecting many lifeforms, including human These variations are triggered by a complex aetiology and several individuals present as fertile. My reference to adaptation is accurate in that during gestation, an organism adapts to the prevailing conditions (for example translocation of a chromosome) or dies. When this adaptation succeeds the resultant life form survives.
With regard to an intersex condition being inherited, many are, but since the factors which lead to most conditions are not dependent on one factor it is not as straightforward as "intersex breeds intersex". For instance, in the condition Androgen Insensitivity Syndrome (AIS) the mother (who is not intersex) of an AIS individual is a carrier, and her XY children have a 1/2 chance of having AIS. Her XX children have a 1/2 chance of carrying the AIS gene. In the condition known as Congenital Adrenal Hyperplasia (CAH) which is the most prevalent cause of intersex among people with XX chromosomes, about 1 in 10,000 to 18,000 children are born with congenital adrenal hyperplasia, but it does not cause intersex in those with XY chromosomes, Different from AIS, the condition known as 5 Al


Isn't nature FASCINATING?!! I DO wish that butterlies, ( not just rare ones like this but ALL butterflies,) lived for WEEKS instead of days.. They are far too beautiful to just flitter around for such a little while. I am dying to see the picture of THIS one. Thanks for the post Miranda.