23 June 2022

Tresnakova and colleagues 2022

Logo for journal "Biology"

Tresnakova N, Kubec J, Stara A, Zuskova E, Faggio C, Kouba A, Velisek J. 2022. Chronic toxicity of primary metabolites of chloroacetamide and glyphosate to early life stages of marbled crayfish Procambarus virginalis. Biology 11: 927. https://www.mdpi.com/2079-7737/11/6/927




Degradation products of herbicides, alone and in combination, may affect non-target aquatic organisms via leaching or runoff from the soil. The effects of 50-day exposure of primary metabolites of chloroacetamide herbicide, acetochlor ESA (AE; 4 µg/L), and glyphosate, aminomethylphosphonic acid (AMPA; 4 µg/L), and their combination (AMPA + AE; 4 + 4 µg/L) on mortality, growth, oxidative stress, antioxidant response, behaviour, and gill histology of early life stages of marbled crayfish (Procambarus virginalis) were investigated. While no treatment effects were observed on cumulative mortality or early ontogeny, growth was significantly lower in all exposed groups compared with the control group. Significant superoxide dismutase activity was observed in exposure groups, and significantly higher glutathione S-transferase activity only in the AMPA + AE group. The gill epithelium in AMPA + AE-exposed crayfish showed swelling as well as numerous unidentified fragments in interlamellar space. Velocity and distance moved in crayfish exposed to metabolites did not differ from controls, but increased activity was observed in the AMPA and AE groups. The study reveals the potential risks of glyphosate and acetochlor herbicide usage through their primary metabolites in the early life stages of marbled crayfish.  


Open access


15 June 2022

SyFy article spreading the word

There’s been an uptick in my Google Alerts because of a new article about Marmorkrebs on SyFy Wire.


At first, I though the article was recycled from the big burst of coverage when the marbled crayfish genome was sequenced. A good chunk of the article discusses the 2018 paper, and it uses a press photo that came out at that time.


But as I saw back in 2018, when one popular news site does a story, many more will pick it up.


External links


Cloned crayfish accidentally created in an aquarium are conquering the world

01 June 2022

Marn and colleagues 2022

Conservation Physiology cover

Marn N, Hudina S, Haberle I, Dobrović A, Klanjšček T. 2022. Physiological performance of native and invasive crayfish species in a changing environment: insights from Dynamic Energy Budget models. Conservation Physiology 10(1): coac031. https://doi.org/10.1093/conphys/coac031



Crayfish are keystone species important for maintaining healthy freshwater ecosystems. Crayfish species native to Europe, such as Astacus astacus and Austropotamobius torrentium, are facing decline and are increasingly endangered by changing climate and invasions of non-native crayfish, such as Pacifastacus leniusculus and Procambarus virginalis. The success of these invasions largely depends on differences in ontogeny between the native species and the invaders and how changes in the environment will affect the ontogeny. Dynamic Energy Budget (DEB) models can be used to investigate such differences because the models capture dependence of metabolism, and therefore ontogeny, on environmental conditions. We develop DEB models for all four species and investigate key elements of ontogeny and metabolism affecting interspecific competition. We then use the DEB models to predict individual growth and reproduction in current and new conditions that are expected to arise from climate change. Although observations suggest that P. leniusculus poses the major threat to native species, our analysis identifies P. virginalis, in spite of its smaller size, as the superior competitor by a large margin—at least when considering metabolism and ontogeny. Our simulations show that climate change is set to increase the competitive edge of P. virginalis even further. Given the prospects of P. virginalis dominance, especially when considering that it is able to withstand and spread at least some crayfish plague strains that severely affect native species, additional research into P. virginalis is necessary.


Open access


13 May 2022

Convicted by crayfish

Super quick because I’m in the middle of something, but I have to share this new story of a woman convicted of selling marbled crayfish in the United States.



Update, 18 May 2022: I never, ever, thought I would see the day when Marmorkrebs would be mentioned in a US Department of Justice press release. The press release contains more details of the scale of the operation.

Between August 2020 and June 2021, (Alison) Spaulding sold marbled crayfish in 96 different transactions to buyers in 36 states for approximately $2,812.

According to The Guardian article linked above, Spaulding faces “faces a maximum penalty of a year in prison and up to $100,000 in fines, although a federal judge is set to consider a lesser penalty under a plea deal.”

19 April 2022

Bohman and colleagues 2022

Crayfish News

Bohman P, Edsman L, Mrugała A. 2022. Is this a Swedish signal crayfish or an alien marbled crayfish? Crayfish News 44(1): 1, 3-6. https://pub.epsilon.slu.se/27549/1/bohman-p-et-al-220414.pdf




Without abstract. Edited excerpt:


Marble-coloured signal crayfish may superficially look similar to another non-native crayfish species, the Marmorkrebs (the marbled crayfish, Procambarus virginalis), and may therefore be incorrectly identified as that species. Both crayfish species are on the European Union’s list of invasive alien species of Union’s concern (EU regulation 1143/2014) and thus highly unwanted in Sweden. The first illegally introduced Marmorkrebs in natural waters in Sweden was found in 2012. During 2013, several additional marble-coloured morphs of juvenile signal crayfish were discovered in Sweden. Therefore, to properly manage invasive alien species and to take correct and swift mitigation actions, it is imperative to have tools for quick and unambiguous species identification.

26 March 2022

Retained European Union law says you can’t retain Marmorkrebs in the United Kingdom

Dalek with Union Jack livery
I ran across this article of “pets you can’t have in the United Kingdom” and was a little surprised to see Marmorkrebs on the list. It is banned, along with four other crayfish species (Louisiana red swamp crayfish, signal crayfish, spiny-cheek crayfish, and virile crayfish).

It turns out the regulatory situation in England and Wales (but not Scotland or Northern Ireland?) is a little complicated.


Marmorkrebs were banned in 2016 as part of a European Union intiative. When the United Kingdom left the European Union, the regulations against Marmorkebs stayed as part of “retained EU law.” 

While the government website lists exemptions that people “may” be able to invoke to keep existing pets, it seems none of them would apply to Marmorkrebs. In particular, the “grandfather clause” allowing people to keep existing pets should not apply since Marmrokrebs don’t live as long as the regulations have been in effect.

I also have to snicker a bit about the rule that says if you have one of these animals, you must not let it reproduce. I’m not sure how you are supposed to prevent that in a parthenogenetic animal.

External links


The animals banned as pets in the UK - complete list


Invasive non-native (alien) animal species: rules in England and Wales


Form CRAY2: Application for a licence to keep non-native crayfish

18 March 2022

Katayama and colleagues 2022

COver to journal bioorganic Chemistry
Katayama H, Toyota K, Tanaka H, Ohira T. 2022. Chemical synthesis and functional evaluation of the crayfish insulin-like androgenic gland factor. Bioorganic Chemistry 122: 105738. hhttps://doi.org/10.1016/j.bioorg.2022.105738




Insulin-like androgenic gland factor (IAG) from the marbled crayfish Procambarus virginalis is an insulin-like heterodimeric peptide composed of A and B chains and has an Asn-linked glycan at the B chain. IAG is considered to be a male sex hormone inducing the sex differentiation to male in decapod crustacean, although there is no report on the function of IAG peptide in vivo. In order to characterize P. virginalis IAG, we chemically synthesized it and evaluated its biological function in vivo. A and B chains were prepared by the ordinary solid-phase peptide synthesis, and three disulfide bonds were formed regioselectively by dimethyl sulfoxide oxidation, pyridylsulfenyl-directed thiolysis and iodine oxidation reactions. An IAG disulfide isomer was also prepared by the same manner. Circular dichroism spectral analysis revealed that the disulfide bond arrangement affected the peptide conformation, which was similar to the other insulin-family peptides analyzed so far. On the other hand, the glycan moiety attached at the B chain had no effect on the peptide secondary structure. Injection of the synthetic IAG and its disulfide isomer to female crayfish did not induce male characteristics on the external morphology, but both peptides suppressed the oocyte maturation in vivo. These results suggest that IAG has a pivotal role on the suppression of female secondary sex characteristics.


Keywords: Insulin-like androgenic gland factor •  Procambarus virginalis • peptide synthesis • masculinization

Synthetic insulin-like androgenic gland factor suppressed oocyte formation in marbled crayfish