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Rare Two-Sexed Butterfly Hatched in UK

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.


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Image credit: Miranda P.

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8:56PM PDT on Jun 5, 2012


1:09PM PDT on Aug 7, 2011

Noted with interest.

9:15PM PDT on Jul 30, 2011

Fascinating article. Thanks for sharing.

6:52AM PDT on Jul 28, 2011

very interesting! thanks for sharing :)!

2:45PM PDT on Jul 25, 2011

Very Pretty!!!

11:15AM PDT on Jul 25, 2011

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.

11:14AM PDT on Jul 25, 2011

@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

5:05AM PDT on Jul 25, 2011

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.

5:01AM PDT on Jul 25, 2011

@James C

How is it a natural adaptation? The very fact that these so called "intersex" creatures are infertile tells me that nature does not intend for these creatures to be able to pass on their intersex characteristics. Natural selection weeds these creatures out of the gene pool when they appear. If they were an intentional adaption that was somehow beneficial to the survival of the creatures' species, then shouldn't they be able to pass it on to future generations?

7:21AM PDT on Jul 24, 2011

Too bad the picture was not a part of the article. It certainly is a beautiful butterfly though. Well worth the wait to get to the picture on my so slow dial up.

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