View Full Version : Crayfish cloning
20th February 2003, 10:07 AM
(ScienceNow - subscription only)
A crayfish species discovered in the fish tanks of German aquarists is the first of its kind to reproduce asexually.
It's not clear exactly where the crayfish comes from, but was first noticed in the fish tanks of hobbyists in the 1990s. Aquarists were baffled when they noticed that even single crayfish could reproduce: None of the 10,000 species of decapods--a group that includes shrimp, lobster, and crayfish--are known to reproduce without using sperm to fertilize an egg.
Scientifically, [Keith Crandall] wonders whether the parthenogenetic crayfish is some kind of "aquarium beast" that evolved in captivity, or whether there are natural populations that reproduce this way.
22nd February 2003, 01:24 PM
What did Darwin say about some small, warm pond...? Pretty good description of a fishtank.:)
24th February 2003, 01:35 PM
Here's a non-subscription link.
Self-cloning crayfish threatens native species
GERMANY: February 21, 2003
LONDON - A mysterious self-cloning female crayfish, popular with German aquarium owners, could pose a threat to native European species if it were released into the wild, scientists said.
The marbled crayfish, called Marmorkrebs, is probably related to a North American species although scientists at Humboldt University in Berlin admit they do not know exactly where it originated.
But they are sure that it can reproduce without mating.
Parthenogenesis, a form of self-cloning, is found in creatures such as snails and water fleas but is unusual in crayfish.
The Marmorkrebs' ability to produce 20 or more clones of itself in six months could be a danger and a competitor to crayfish in the wild, according to Gerhard Scholtz, a comparative zoologist at the university.
"It might pose a threat to European native crayfish," he told Reuters.
Marmorkrebs, which can be bought for about five euros ($5) in Germany, may also be able to transmit a deadly crayfish plague to other less robust species, according to Scholtz, who published his findings in the science journal Nature.Weeeeeeird stuff.
24th February 2003, 06:31 PM
Thanks for the link.
There is a kind of gecko lizard living on some South Sea islands that reproduces by parthenogenesis. There is also a species of cichlid fish that reproduces this way. The fish, curiously, still needs stimulation from a male to spawn, so they use males of a closely related species.
Reproduction purely by parthenogenesis, as I understand it, is ultimately a genetic dead end. Since there is no mixing of genes, the species tends to have a hard time adapting to changing conditions. It wasn't clear from the article if the crayfish spawned this way exclusively. If it can reproduce sexually as well, I guess it would be a tough competitor.
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