25 April 2012

Martin and Scholtz, 2012

Martin P, Scholtz G. 2012. A case of intersexuality in the parthenogenetic Marmorkrebs (Decapoda: Astacida: Cambaridae). Journal of Crustacean Biology 32(3): 345-350. http://dx.doi.org/10.1163/193724012X629031


We describe an intersex specimen of the Marmorkrebs, the only obligate parthenogenetic freshwater crayfish with an all-female population. The individual was a fully functional female which possessed male-like first pleopods. Nevertheless, it reproduced successfully and the offspring were normally developed parthenogenetic females, lacking any trace of male traits. The general rarity of aberrant sexual traits in freshwater crayfishes, in particular in Procambarus, is discussed. We suggest that a dysfunction of the sex determining system, which controls the anlagen of the androgenic glands during development, caused the partial male-like phenotype of this Marmorkrebs specimen. The application of this organism for investigations of sex determination and differentiation is recommended.

Keywords: aberrant secondary sexual characteristics • androgenic gland • gonochorism • gynandromorphy • hermaphroditism

23 April 2012

Soedarini and colleagues, 2012

Soedarini B, Klaver L, Roessink I, Widianarko B, van Straalen NM, van Gestel CAM. 2012. Copper kinetics and internal distribution in the marbled crayfish (Procambarus sp.). Chemosphere 87(4): 333–338. http://dx.doi.org/10.1016/j.chemosphere.2011.12.017


Metal pollution e.g. copper, in water bodies occurs worldwide. Although copper is an essential trace metal, at certain levels it is still considered as pollutant. The aim of this study was to investigate the effect of exposure concentration on copper bioaccumulation in marbled crayfish (Procambarus sp.) by determining uptake and elimination kinetics. Crayfish were exposed to sub-lethal copper concentrations (average measured concentrations of 0.031 and 0.38 mg Cu L−1) for 14 d and transferred to copper-free water for another 14 d. At different time points during the uptake and elimination phases copper concentrations were measured in five organs (exoskeleton, gills, muscle, ovaries and hepatopancreas). At 0.031 mg Cu L−1, copper levels in the crayfish organs were not significantly increased compared to the control animals, suggesting effective regulation. Exposure to 0.38 mg Cu L−1 did lead to not significantly increased copper levels in muscles and ovaries, while the gills and exoskeleton, which are in direct contact with the water, showed significantly higher copper concentrations. In these four organs, copper showed fast uptake kinetics with equilibrium reached within 10 d of exposure. Copper accumulation was highest in the hepatopancreas; uptake in this storage organ steadily increased with time and did not reach equilibrium within the 14-d exposure period. Copper accumulation levels in the marbled crayfish found in this study were hepatopancreas > gills > exoskeleton > muscle.

Keywords: copper • toxicokinetics • bioaccumulation • hepatopancreas • marbled crayfish

19 April 2012

Crawling out of the swamp May 1st!

Get your donations ready!

10 April 2012

SciFund 2: Return of the Marmorkrebs!

You may recall that last year, I had a Marmorkrebs project in the inaugural SciFund Challenge.

I’m pleased to report that Marmorkrebs and I will both be back in the next SciFund challenge, starting in May.

But not together.

Kyle MacLea will be carrying the banner for Marmorkrebs in Round 2. To learn more, you should follow Kyle’s blog, By Way of Science. He’s also on Twitter and Google Plus.

This is an opportune time to update people on the status of the project I successfully launched in round 1. I contacted some experts on Procambarus fallax in Florida, and the answer I got was consistent. The best time to collect for that species was... November. News will be slow on the first #SciFund project, then.

As for my own project in SciFund 2, you can read about it over at my other blog, NeuroDojo.

05 April 2012


Last year, I live-blogged the announcement that Gerhard Scholz had been award The Crustacean Society’s Excellence in Research Award. He was not at the meeting to accept his award, but the latest issue of Journal of Crustacean Biology discusses his research contributions in more detail and allows him to reply. I am pleased to see it does not leave out Marmorkrebs.

In 2003, Gerhard reported the first parthenogenetic decapod, a cambarid crayfish (Marmorkrebs) found in the aquarium trade. It was subsequently shown that these animals originated in Florida, and molecular evidence revealed that they were in fact a form of Procambarus fallax that has established itself in several European countries as well as Madagascar, thus uncovering a harmless pet primed to become a devastating invasive species.

In his comments, Dr. Scholz offers this bon mot:

Life without crustaceans is possible, yet pointless!


McLay C, Boyko CB, Schram FR. 2012. Gerhard Scholtz Recipient of the Crustacean Society Excellence in Research Award. Journal of Crustacean Biology 32(2):341-344.