北京时间7月15日消息，最近，伦敦自然历史博物馆孵化出一只双性蝴蝶。这只美凤蝶身上的这种奇特现象被称作“雌雄嵌性”(gynandromorph)。它也因此成为该馆内所收集的450万份蝴蝶标本中仅有的200例此类畸形样本之一。
双性蝴蝶 雌雄特征各半
“雌雄嵌性”(gynandromorph)这个词的“Gyn”部分源于希腊语，意为雌性，而“Andro”部分指雄性。如果你仔细观察，很快就会注意到这只蝴蝶拥有明显的雌雄两性特征——一边的翅膀是雄性特有的暗色，而另一侧则是雌性特有的偏浅色调，上面点缀着蓝色，红色和黄褐色斑纹。
正如其翅膀色彩所反映的那样，这只蝴蝶正是一半雄性一半雌性的。它拥有雌雄各一半的生殖器官。BBC报道说：甚至连它的两个触须长度都不一样！
博物馆工作人员解释说：“如果昆虫的受精卵在首次分化时其性染色体未能正确分离，则可能会出现雌雄嵌性畸形体。也有一种情况是卵子同时被两个精子受精，因此其中同时含有两种性染色体，而不是通常的一种。”
生物学家已经在自然界观察到双性的龙虾，蜘蛛和螃蟹。
这次蝴蝶展将一直持续开放至今年9月11日，不过蝴蝶们可能并不能一直活那么久。博物馆方解释说：“蝴蝶的生命周期很短，因此要想目睹这种罕见的现象，参观者可能时间有限。随后这只蝴蝶就会被制成标本收录，存放进该馆世界级的鳞翅目昆虫标本库。”
生物探索推荐英文报道
A rare he-she butterfly is born in London's NHM
A half-male, half-female butterfly has hatched at London's Natural History Museum.
A line down the insect's middle marks the division between its male side and its more colourful female side.
Failure of the butterfly's sex chromosomes to separate during fertilisation is behind this rare sexual chimera.
Once it has lived out its month-long life, the butterfly will join the museum's collection.
Only 0.01% of hatching butterflies are gynandromorphs; the technical term for these strange asymmetrical creatures.
"So you can understand why I was bouncing off of the walls when I learned that... [it] had emerged in the puparium," said butterfly enthusiast Luke Brown from London's Natural History Museum.
Mr Brown built his first butterfly house when he was seven, and has hatched out over 300 thousand butterflies; this is only his third gynandromorph.
Half and half
It is not only the wings that are affected, he explained. The butterfly's body is split in two, its sexual organs are half and half, and even its antennae are different lengths.
"It is a complete split; part-male, part-female... welded together inside," he told the BBC.
The dual-sex butterfly is an example of a Great Mormon, Papilio memnon - a species that is native to Asia.
With a shortage of butterfly-specific gender neutral pronouns, the butterfly is being referred to as "it", and is already middle-aged at three and a half week's old.
So the public has only a narrow window of opportunity to see it alive.
Though rare, gynandromorphy isn't unique to butterflies; individual crabs, lobsters, spiders and chickens have all been found with a mix of two sexes.
There are likely many more cases in the natural world, but sexual chimeras are more difficult to spot in animals where females and males look alike.
