# Salvinia molesta - attack of the clones



## Cavan Allen (Jul 22, 2004)

I've been reading the excellent A Natural History of Ferns by Robbin Moran. One of the chapters is about _Salvinia molesta_. If you've been around the hobby for long, and especially ponds, you probably seen it before (especially if you live in the southern states or certain areas of the tropics). It's the large _Salvinia_ that has multiplied out of control in warm areas and caused incredible economic damage by clogging waterways and choking the life out of ponds.

Once its natural range was finally discovered, a biological control was finally found, that being a weevil that eats nothing else. The most interesting thing, at least to me, is that _Salvinia molesta_ is a clone species. That means that *every* little bit of it the world over is genetically identical. Because the fern's reproductive parts are not functional, there is no sexual reproduction. How might something like that come about? I really don't know. Could it be that all of that species died out except for that one little piece that spread around?

There are all-female salamander species. Can anyone comment on this?

http://www.timberpress.com/books/isbn.cfm/0-88192-667-1


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## Gumby (Aug 1, 2005)

I found a website that talks about the all-female salamanders. It's got a hypotheis on how these species evolved and their reproductive behavior.

http://www.naturenorth.com/spring/creature/bluespot/blspot2.html

Scroll down to the "Really weird stuff" section.


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## david lim (Mar 30, 2004)

I remember writing a research paper in college about S. molesta and it's eradication methods. This stuff could get to be 3-4 feet thick. Crazy... and yea it doesn't sexually reproduce. Why did this come about? Who knows? Maybe a mutation occurred that prevented the plant's development of viable spores. Then, through competition, this subspecies outcompeted its sexual couterparts. I dunno. 

David


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## mrbelvedere138 (Jan 18, 2006)

So if every single piece was identical could a disease theoretically wipe out the entire species?


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## filipnoy85 (Jan 26, 2006)

Yeah, I think so... That actually happened with bananas. The variety commonly sold today in supermarkets is not the same as the variety from the middle of the last century. That variety was wiped out by a disease. We'll be getting a new banana soon too, the current variety is under attack by a similar disease in asia.


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