Visit Blog Website

18 posts · 18,308 views

News and views about the all-female parthenogenetic marbled crayfish, Marmorkrebs.

Zen Faulkes
18 posts

Sort by: Latest Post, Most Popular

View by: Condensed, Full

  • July 11, 2013
  • 12:51 PM

Celebrate diversity: Rare boys

by Zen Faulkes in Marmorkrebs

Artemia have featured on this blog before, mostly as possible food for Marmorkrebs. But like Marmorkrebs, there are parthenogenetic Artemia that reproduce asexually.


Maccari and colleagues show that Artemia sometimes produce little baby boy Artemia. There’re at low numbers; about 1% of offspring. I am impressed by just how many Artemia they looked at to determine this:

415 666 diploid parthenogenetic Artemia specimens were sexed in this experiment(.)

But while rare overall, a fe........ Read more »

Maccari M., Gómez A., Hontoria F., & Amat F. (2013) Functional rare males in diploid parthenogenetic Artemia. Journal of Evolutionary Biology. DOI: 10.1111/jeb.12191  

  • July 10, 2012
  • 06:52 PM

Where are the Procambarus clarkii clones?

by Zen Faulkes in Marmorkrebs

Some years back, a paper came out purporting to have identified genetically identical red swamp crayfish (Procambarus clarkii) in China (Yue et al. 2008). At the time, this was a rather remarkable claim, given that there have been no shortage of labs looking at this species. You would have expected that if P. clarkii could reproduce by parthenogenesis, someone would have noticed by now.

The plausibility of that claim went up, in my mind, with the discovery of facultative parthenogensis in spiny........ Read more »

Li Y, Guo X, Cao X, Deng W, Luo W, & Wang W. (2012) Population genetic structure and post-establishment dispersal patterns of the red swamp crayfish Procambarus clarkii in China. PLoS ONE, 7(7). info:/10.1371/journal.pone.0040652

  • November 22, 2011
  • 08:00 AM

The curious case of crustacean colours

by Zen Faulkes in Marmorkrebs

From time to time, you will see news of a lobster being caught with some unusual colour, like orange, blue, or calico. Some even become celebrities, of sorts. And within the pet trade, brightly coloured variations of crayfish (typically bright blue) are widely prized.

What determines colour in crustaceans generally? It’s a complicated mix.

The most dramatic colour variants are caused by genetics. In crayfish, several colour morphs are due to simple recessive genes (Black and Huner 1980), of ........ Read more »

  • October 25, 2011
  • 12:49 PM

Celebrate diversity: Absent fathers might not be missing fathers

by Zen Faulkes in Marmorkrebs

That you don’t see males around when a female gives birth or lays eggs doesn’t mean that a male wasn’t involved. Females of many species can store sperm for long periods, sometimes their entire lives. Queen honeybees, for instance, go on a single “nuptial flight”, and the the sperm they gain on that flight is enough for the rest of her life, which can be several years.

A rattlesnake (Crotalus adamanteus) is making the news with this point. A female that had been isolated for five year........ Read more »

  • October 20, 2011
  • 05:57 PM

Tracking your colony: SAPling

by Zen Faulkes in Marmorkrebs

Where was this when I started my Marmorkrebs colony?

A new article in The Journal of Experimental Biology describes a software package called SAPling that is intended to track the pedigree of entire colonies of asexually reproducing animals. You can find the software at:

I’ve downloaded the software, which is written in Java. I have not quite figured out how to run the program yet, though. There’s no standard *.exe file to run. If a........ Read more »

  • August 16, 2011
  • 08:00 AM

An Achilles’ heel?

by Zen Faulkes in Marmorkrebs

Last week, at my Ecological Society of America talk, one of the questions asked afterwards was, “Could the fact that Marmorkrebs are genetically identical be exploited to control introduced, unwanted populations?”

I said, “No.”

One of the things I admire about crayfish is that they are tough little survivors. Unfortunately, this means that they are hard to get a handle on once they’re loose.

I think it’s fair to say that the weapons used to control crayfish populations are blunt i........ Read more »

  • July 5, 2011
  • 08:00 AM

Bad bait

by Zen Faulkes in Marmorkrebs

On the Marmorkrebs home page, I added the following text in bold a couple of months ago:

Marmorkrebs should not be kept in outdoor tanks or ponds, used for bait, or used in any other situation where they could be released into natural ecosystems.
I was pleased to see that this piece of advice was cited in this thread on a fishing forum when someone asked if there were laws concerning the use of Marmorkrebs as bait. But it occurred to me that I should provide more information in support of th........ Read more »

DiStefano RJ, Litvan ME, & Horner PT. (2009) The bait industry as a potential vector for alien crayfish introductions: problem recognition by fisheries agencies and a Missouri evaluation. Fisheries, 34(12), 567-597. info:/10.1577/1548-8446-34.12.586

  • May 31, 2011
  • 06:57 PM

Another (occasionally) parthenogenetic crayfish

by Zen Faulkes in Marmorkrebs

I not sure how to describe the sound I made when I saw the title of this paper, but it was not a quiet sound. I immediately thought, “This is huge.”

A new paper in PLoS ONE reports that spinycheek crayfish (Orconectes limosus) can reproduce by parthenogenesis. Unlike a previous report of Procambarus clarkii reproducing by parthenogenesis, which based its claim on similar DNA from adults and no actual observed instances of reproduction, this paper claims to have isolated females that have re........ Read more »

  • April 26, 2011
  • 08:00 AM

Looking for hope

by Zen Faulkes in Marmorkrebs

When I went to the International Association for Astacology meeting last year, the first couple of days were largely concerned with crayfish as invasive species. The phrase that kept kept popping into my head was, “horror show.”

A new review article taps into that concern, asking flat out, “Is there a hope?” in the title. Note the use of the singular. Things are so bad, we are just looking for one hope.

Marmorkrebs make a brief cameo appearance in the paper:

Today, it is extremely eas........ Read more »

Gherardi F, Aquiloni L, Diéguez-Uribeondo J, & Tricarico E. (2011) Managing invasive crayfish: is there a hope?. Aquatic Sciences, 73(2), 185-200. DOI: 10.1007/s00027-011-0181-z  

  • October 12, 2010
  • 08:00 AM

Like a virginalis, named for the very first time

by Zen Faulkes in Marmorkrebs

The new paper by Martin and colleagues is a significant one for the Marmorkrebs research community, because it seems to settle the problem of the species most closely related to Marmorkrebs pretty definitively. Marmorkrebs are most closely related to slough crayfish, Procambarus fallax. The picture at right compares the two; P. fallax is on top (Fig. 1 from Martin et al.)

It’s also noteworthy for being the first to tackle the thorny issue of a species name for Marmorkrebs. Martin and colleagu........ Read more »

Martin P, Dorn NJ,, Kawai T, van der Heiden C, & Scholtz G. (2010) The enigmatic Marmorkrebs (marbled crayfish) is the parthenogenetic form of Procambarus fallax (Hagen, 1870). Contributions to Zoology, 79(3), 107-118. info:/

  • October 5, 2010
  • 08:00 AM

Celebrate diversity: The fish that fertilizes itself

by Zen Faulkes in Marmorkrebs

It’s almost another marbled clone.

There are parthenogenetic vertebrates (some of which have been featured on this blog), but the Mangrove killifish, Kryptolebias marmoratus, is the only vertebrate that regularly self-fertilizes. Most individuals have male and female reproductive organs. Obviously, this allows you to have individuals that are not quite clones, but certainly have much more limited variation than most sexual species.

But, because sex is rarely simple, some individuals in this ........ Read more »

  • August 17, 2010
  • 08:00 AM

Celebrate diversity: Old female salamanders

by Zen Faulkes in Marmorkrebs

Imagine, if you will, a line of ancient females, who trick males into having sex with them, so that the females can continue living indefinitely.

I know, you’ve seen it before in a dozens of movies, books, and television episodes. Who hasn’t seen a vain sorceress stealing youth, particularly from young men?

Something like this goes on in some salamanders, except that no one salamander is living unusually long. The evolutionary line of salamanders, though, is showing surprisingly longevity......... Read more »

  • July 27, 2010
  • 08:00 AM

North American crayfish diversity threatened

by Zen Faulkes in Marmorkrebs

When I recently attended the International Association of Astacology meeting, it was ground into my face how bad things are for crayfish.

In Europe, crayfish are being beaten up by exotic North American species. If competition doesn’t get them, the crayfish plague that the exotics carry will.

In North America, the home to the greatest diversity of crayfish species in the world, non-indigenous species are playing a role in some regions, but habitat degradation is the bigger concern. At the As........ Read more »

  • July 13, 2010
  • 08:00 AM

Asexual species identifications

by Zen Faulkes in Marmorkrebs

Marmorkrebs are difficult beasts. As I’ve mentioned before, there is no species name for them yet, partly because of how people define species. At the practical level, most crayfish are identified by the sex organs of the males (which Marmorkrebs don’t have). At the conceptual level, many people define species by interbreeding populations (which parthenogenetic organisms don’t do).

Birky and colleagues recently proposed a way to define species for parthenogenetic organisms. As near as I c........ Read more »

  • June 30, 2010
  • 01:03 PM

Celebrate diversity: Lesbian lizard sex

by Zen Faulkes in Marmorkrebs

I have a hard time remembering the name Aspidoscelis uniparens, because when it first broke into the limelight, it was Cnemidophorus uniparens. Sort of like how everyone continued calling Prince “Prince” even after he changed his name to a squiggle. If only he’d been known as a squiggle first when he released “Little Red Corvette”...

Regardless of the genus name, I love this lizard. This was probably the first parthenogenetic animal that made an impression on me, when I was an undergr........ Read more »

Crews D, & Fitzgerald KT. (1980) "Sexual" behavior in parthenogenetic lizards (Cnemidophorus). Proceedings of the National Academy of Sciences of the United States of America, 77(1), 499-502. PMID: 16592761  

  • April 29, 2010
  • 10:31 PM

Celebrate diversity: Parthenogenesis in white tipped bamboo shark

by Zen Faulkes in Marmorkrebs

A few years ago, a bonnethead shark made the news because one had given birth. Giving birth is not unusual for sharks... except that the female in question had grown up in isolation. Good evidence for parthenogenesis.

Shortly after that, another shark species (blacktip) was autopsied and found to have an embryo that was genetically identical to the mother. Clearly, parthenogenesis in sharks was not happenstance. But in both cases, the parthenogenetic offspring didn’t live long. Are the off........ Read more »

Feldheim, K., Chapman, D., Sweet, D., Fitzpatrick, S., Prodohl, P., Shivji, M., & Snowden, B. (2010) Shark Virgin Birth Produces Multiple, Viable Offspring. Journal of Heredity, 101(3), 374-377. DOI: 10.1093/jhered/esp129  

  • December 8, 2009
  • 11:30 AM

Genome research: good idea, bad idea

by Zen Faulkes in Marmorkrebs

Good idea: A paper in the Journal of Heredity proposes sequencing 10,000 genomes...

Bad idea: ...of vertebrates.

A news article in Science characterized this in the title as, “No genome left behind.” But of course, it leaves a tremendous number of genomes behind, namely, every single invertebrate. What are the current estimates for number of vertebrate species? Maybe 60,000 or so? The crustaceans alone probably have about the same number of species. The number of vertebrate species is not ........ Read more »

  • September 15, 2009
  • 07:00 AM

An experiment gone wrong in Hong Kong?

by Zen Faulkes in Marmorkrebs

I was re-reading the recent paper on the introduction of marbled crayfish in Italy, and noticed this:

"The authors even raised the hypothesis that Procambarus sp. is a transgenic species created by laboratories in Hong Kong."

I’d like to think I would have remembered a claim that marbled crayfish were the result of a scientific experiment gone wrong.... Read more »

Marzano FN, Scalici M, Chiesa S, Gherardi F, Piccinini A, & Gibertini G. (2009) The first record of the marbled crayfish adds further threats to fresh waters in Italy. Aquatic Invasions, 4(2), 401-404. DOI: 10.3391/ai.2009.4.2  

join us!

Do you write about peer-reviewed research in your blog? Use to make it easy for your readers — and others from around the world — to find your serious posts about academic research.

If you don't have a blog, you can still use our site to learn about fascinating developments in cutting-edge research from around the world.

Register Now

Research Blogging is powered by SRI Technology.

To learn more, visit