Nature notes

hermaphrodite butterfly

A couple of items from BBC’s Nature feed have caught my eye. First, London’s Natural History Museum has hatched out an extremely rare butterfly genotype: a half male, half female. And I mean literally half and half.

[Luke] Brown built his first butterfly house when he was seven, and has hatched out over 300 thousand butterflies; this is only his third gynandromorph.

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 genetic variation, which occurs in 0.01% of hatching butterflies, is a result of the sex chromosomes failing to separate during fertilization. Nor is it limited to butterflies, having also been observed in crabs, lobsters, spiders and chickens.

The other item, somewhat less visually stunning but still fascinating to geeks, is the discovery by a Japanese team of researchers that certain small snail species have a unique way of achieving geographic dispersal: they get eaten by birds. Now, I’m familiar with the bird vector for seed dispersal, but this is the first I’ve heard of it for snails! The survival rate of the snails isn’t great — around 15% — but it’s enough to get them places they couldn’t go on their own.

One snail in particular helped researchers identify how numerous snails could travel over distances via bird droppings.

“One of the snails fed to the bird gave birth to juveniles just after passing through the gut,” [researcher Shinichiro] Wada told the BBC.

The main factor allowing the snails to survive being eaten is their small size, according to the scientists.

At an average of 2.5mm the micro snails fared much better than larger species in previous studies whose shells were severely damaged when eaten by birds.

Amazing.

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About Fletcher DeLancey

Socialist heathen and Mac-using author of the Chronicles of Alsea, who enjoys pondering science, politics, well-honed satire (though sarcastic humor can work, too) and all things geeky.
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8 Responses to Nature notes

  1. Inge says:

    To be honest i’m not so much impressed by the snails as by the gynandromorph (i speaked) butterfly. How can those two sides be fused? I mean, yes most organs are in more or less the same place, but some differ widely.. or is it different in a butterfly’s body?

  2. JR says:

    So, I tried to pin my partner down on this gynandromorph thing, since she works at a research institute for sex, gender and reproduction, but she pointed out that as the art curator, she’s not required to know the same things as the research scientists. However, we were both curious (especially about the chicken!), so I did some informal reading. This blog entry (http://scienceblogs.com/grrlscientist/2010/03/sex_bird_gynandromorph_somatic.php) describes the division of the organs in the gynandropmorph chickens: the distribution of sex organs is different from from bird to bird.

    I also found a really great article on gynandromorph butterflies in an issue of the Journal of Experimental Zoology from 1925, describing all the organ fusion, omissions and connections. “Complicated” doesn’t even being to describe the situation, but now that I’ve read the article a few times, I could probably draw a table of the organ distribution on a napkin at a cocktail party.

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