Rachel Neumeier

Fantasy and Young Adult Fantasy Author

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Best headline of the year?

Escaped cloned female mutant crayfish take over Belgian cemetery

That cannot possibly be as great an article as this headline makes it seem. There is no way.

Hundreds of the duplicating crustaceans, which can dig down to up to a metre and are always female, pose a deadly threat to local biodiversity after colonising a historic Antwerp graveyard.

“Duplicating” is a ridiculous word for reproducing. I guess they must be parthenogenic? Reproducing parthenogenically is not quite the same thing as cloning. The meiotic process introduces some genetic variation.

Are crayfish — in certain areas, you may know them as crawdads — are they often parthenogenic? Or is that just these special cloned mutant crayfish?

Ah! No, it’s just this kind, which is called the marbled crayfish . This is not exactly a species — it was “discovered in the pet trade” and is not known from any wild populations. ??? That’s what it says! On Wikipedia, so it must be true. “Information provided by one of the original pet traders as to where the marbled crayfish originated was deemed “totally confusing and unreliable.”

How interesting! So this strange parthenogenic crayfish turned up in the pet trade and has now — of course — been released into all sorts of streams where it is thriving. I don’t at once see anything about other parthenogenic decapod crustaceans, just poking around on Google. A quite different crustacean, the water flea, Daphnia similoides, alternates parthenogenic and sexual generations. So, once you get outside the crustaceans, does the common aphid, which is why aphid populations can explode so fast in your garden. So this is not unknown in arthropods more broadly.

Well, I would say that it sounds like the marbled crayfish is here to stay, and likely to be very successful in all sorts of freshwater streams. The linked article says, “It is particularly prevalent in Madagascar where its rapid spread in less than a decade is because of its popularity as a cheap source of protein. Researchers have found that the marbled crayfish could out-compete seven native crayfish.”

I bet. If at some point someone really wants to get rid of them, I expect the way to do it would be to find a disease or parasite that attacks them. A population like this probably does not have the genetic variability to evolve resistance, while crayfish that reproduce sexually are more likely to have that kind of genetic variability.

Anyway: fantastic headline. If anyone has a headline that comes anywhere close to that neat, drop it in the comments so we can all admire it!

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