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The Mutant All-Female Crayfish, Which Reproduces by Cloning Itself, Is Filling Europe at Alarming Speed (atlasobscura.com)
The marbled crayfish looks much like any other freshwater crustacean. It has two claws, ten legs, and an attractive blue-brown marbled shell. Yet this six-inch creature, found in streams and lakes around the world, is far more sinister than you might expect. From a report: Its new scientific name gives a few clues: Procambarus virginalis. Every marbled crayfish, known as a marmorkreb in German, is female -- and they reproduce by cloning themselves. Frank Lyko, a biologist at the German Cancer Research Center, first heard about the marbled crayfish from a hobbyist aquarium owner, who picked up some "Texas crayfish" at a pet shop in 1995. They were strikingly large, and they laid enormous batches of eggs -- hundreds, in a single go. Soon, the New York Times reports, the hobbyist was beset with so many crayfish he was giving them away to his friends. And soon after that, marmorkrebs were showing up in pet stores upon Europe.
There was something very strange about these crayfish. They were all female, and they all laid hundreds of eggs without mating. These eggs, in turn, hatched into hundreds more females -- with each one growing up fully able to reproduce by herself. In 2003, scientists sequenced their DNA and confirmed what many owners already believed to be the case: Each baby crayfish was a clone of its mother, and they were filling Europe's fishtanks at alarming speed. Just 25 years ago, the marbled crayfish did not exist at all. Now, they can be found in the wild by the millions in Germany, the Czech Republic, Hungary, Croatia, the Ukraine, Japan, and Madagascar.
There was something very strange about these crayfish. They were all female, and they all laid hundreds of eggs without mating. These eggs, in turn, hatched into hundreds more females -- with each one growing up fully able to reproduce by herself. In 2003, scientists sequenced their DNA and confirmed what many owners already believed to be the case: Each baby crayfish was a clone of its mother, and they were filling Europe's fishtanks at alarming speed. Just 25 years ago, the marbled crayfish did not exist at all. Now, they can be found in the wild by the millions in Germany, the Czech Republic, Hungary, Croatia, the Ukraine, Japan, and Madagascar.
https://www.nature.com/article... Nobody knows. Best hypothesis is that it was a lucky mutation.
Wasn't there supposed to be some sort of replicative fading where the telomeres or some such got shorter over time until the clones were not viable?
Yes : *body* cell lines have such kind of control to avoid cells replicating too much.
But eggs are formed from *germ* cell lines, which are (by Nature's "design" - as its supposed to be the way a specie reproduce) not having any replication limit.
These are not "dolly the sheep"-style clones (a body cell used to form a new clone by transfering the nucleus, and might inherit some of the replication limits of the body cell).
These are parthenogenesis-style (see christian mythology about virgin mary) clones : some how, an non-fertilized egg-cell managed to grow into a full grown individual (usually, in other species, there's some kind of bug in the "meiosis" - the process is supposed to split the normally "diploid" genome into half "haploid". The wikipedia mentions that they are "triploid" - so having triplets instead of chromosome pairs - so it's quite a big bug in the meiosis procedure).
But it is an egg cell (although a chromosomaly abnormal one) that produces the whole individual, so no telomeres problems nor any other cell division limitations.
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When the colonists first came to the Americas, the coastal areas were overflowing with Lobsters, with stories of 100s washing up on the shore at a time. By the late 1700s, lobsters were considered "prison food", because there was so many of them. Lobsters begin to rot almost immediately when killed which is why they are cooked alive in the pot, and the shells horribly stink... in a culture without refrigeration and modern sanitation, these would quickly turn into a strong negative.
After the US Civil war (1860s), canning was invented and cooked lobster would last for a long time. With the expansion of the railroads, the interior and west coast of the US began to demand canned lobster for its high-protein value. Then they realized that it tastes even better live, and with refrigeration, lobsters began to ship live all over the country. After that, the demand for lobsters skyrocketed, and we have the high prices we see today.
Since the 1990s, apparently the Maine lobster crops have been booming, some say proportional to the rising sea temperatures, combined with sustainability policies restricting farming of female (only chicks that have not yet spawned, male or female, are allowed to be legally caught). Also, humans have overfished the cod stocks in the northeast, which have been known to eat lobster for food. By killing the predators, we've turned lobsters into the chickens of the sea.
Apparently they're tasty. From the article in Nature:
"Julia Jones, a conservation scientist at Bangor University, UK, who first identified4 marbled crayfish in Madagascar in 20074, says that the species’ spread is due largely to their popularity as a food source. In 2009, she met a man on a bus carrying a plastic bag full of them that he planned to dump into his rice fields in the hope of creating a sustainable stock, she says.
"Stopping their spread in Madagascar will be “almost impossible”, says Lyko. Collaborators there have begun campaigns urging people not to transport them or release them into rice fields. The message is a hard sell in a country where poverty levels are high and marbled crayfish are a cheap and popular source of protein. Lyko’s colleague brought a few dozen that she had caught to a family barbecue. “This went down quite well,” he says."
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