26 February 2021

Heroes release zeroes

The Illinois-Indiana Sea Grant has started a new campaign against invasive species. The aquatic species arm of the campaign is Release Zero.


I particularly appreciate the point that it’s hard to be a responsible pet owner when so many providers don’t know or provide scientific names. There are hundreds of species of crayfish with different invasive potential, so just selling “crayfish” is irresponsible. There is a great need for quick, high quality ways of identifying species in the pet trade.


Marmorkrebs are not featured on the main webpage, but are species of concern for the Great Lakes, as the project’s Twitter account points out.


Wild marbled crayfish populations are established across Europe and elsewhere. They have NOT been found in the Great Lakes! 🙌 Aquarium owners, anglers and others can help keep it that way.

We need way more education on this, so I hope this campaign is very successful!

External links


Release Zero website

24 February 2021

Marmorkrebs talk online, 26 February 2021

Seminar announcement poster featuring Saisupritha Talasu is presenting “Identifying various biogenic amine receptors in Procambarus virginalis”
Wolfgang Stein announced a seminar about Marmorkrebs will be held on Zoom!

Saisupritha Talasu is presenting “Identifying various biogenic amine receptors in Procambarus virginalis” at 12:00 pm (noon) Central time on Friday, 26 February 2021. The Zoom meeting ID is 630 494 073.

It will be followed by a talk on escape responses, species unknown.

19 February 2021

Invasive Species Week is coming...

 Mark your calendars for 24 May, 2021. That will be the start of Invasive Species Week.

Invasive Species Week, 24-30 May 2021.

This blog will be participating, naturally!

External links


Invasive Species Week

15 February 2021

Wen 2020

Swedish University of Agricultural Sciences logo
Wen Y. 2020. Characterization of MITF gene in crayfish and their possible role in innate immunity. Master’s thesis, Department of Animal Breeding and Genetics, Sveriges lantbruksuniversitet (Swedish University of Agricultural Sciences). http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-s-16418


Microphthalmia-associated transcription factor (MITF) is a tissue-specific transcription factor (TF), with a basic helix-loop-helix leucine zipper (bHLH-LZ) domain, which binds to the canonical E-box sequence (5’-CANNTG-3’) in the promoter region of target genes. In this study, the MITF-like protein was identified in the marbled crayfish (Procambarus virginalis). The full-length cDNA coding sequence of the most similar gene to MITF from marbled crayfish is 1284bp (427 amino acids). In the secondary and tertiary structure of the deduced amino acid sequence, a conserved functional structure of bHLH-LZ was shown, which could bind to E-box. In the phylogenetic analysis, this obtained MITF-like gene showed a lager evolutionary distance to all the vertebrates and some invertebrates like lancelet (Branchiostoma belcheri), starfish (Acanthaster planci), sea urchin (Paracentrotus lividus) and (Lytechinus variegatus), but is closer than worms (Caenorhabditis elegans). The bHLH-LZ domain is located in exon 6, exon 7, exon 8, and exon 9 in the MITF gene and has a similar structure as the corresponding exons in human. Besides, in this study, a comparison of exon-intron structure of MITF between human, mouse, fruit fly and marbled crayfish was performed, it was shown that the splicing sites of the bHLH-LZ domain in MITF gene might be conserved across species. To evaluate the possible role of MITF as a TF in innate immune system regulation, a similar prophenoloxidase (proPO) DNA sequence was analysed for the presence of E-box. The proPO gene is responsible for trapping and myelinization of pathogens in invertebrate. The proPO-like gene of marbled crayfish contains eight CANNTG sequences. In addition, anti-apoptotic factor (BCL-2)-like gene was found in marbled crayfish and four CANNTG sequences were found. Our results provided evidence of the presence of MITF-like gene in crayfish species and may provide knowledge on the role of MITF in innate immune activation.

Keywords: Microphthalmia-associated transcription factor • basic Helix-Loop-Helix Leucine Zipper • crayfish • Aphanomyces astaci • immunity

12 February 2021

Marmorkrebs continue advance in Asia

Map of China showing Macao.
Marmorkrebs have been found near the mainland of the People’s Republic of China, according to the Macao Daily Times.

The news article is short on details, like how many crayfish or exactly where they were found, with the newspaper simply referring to a “leisure area” on Taipa in Macau. Taipa is technically an island, but sits so close to the mainland that it is connected by reclaimed land. 

The impact of Marmorkrebs in China could be immense. The Louisiana red swamp crayfish was embraced by the restaurant business and is now one of the most popular dishes in China, so there is clearly money to be made on crayfish.

But one of the interesting points of the article is that the concern about invasive species it lists is different than other countries. The article raises the fear that invasive will remove natives that are used for... traditional Chinese medicine.

The map of Marmorkrebs introductions has been updated.

Update: The Macau Post Daily has an article with a little more detail. It sounds like it was a single individual. It also gave a more precise location: “the ecological pond in the Camellia Garden.” Which, unfortunately, I cannot find on Google Maps yet.


There is no information up at the Municipal Affairs Bureau yet. At least not on the English site. 


More update: Ah, here’s the park with Camellia Garden. And this seems to be the person who found them.


External links

Foreign species of crayfish, hazardous to local ecology, found in Taipa

Invasive marbled crayfish found on Big Taipa Hill: IAM

10 February 2021

van Kuijk and colleagues 2021

Scientific Reports

van Kuijk T, Biesmeijer JC, van der Hoorn BB, Verdonschot, PFM. 2021. Functional traits explain crayfish invasive success in the Netherlands. Scientific Repprts 11: 2772. https://doi.org/10.1038/s41598-021-82302-4




Biological invasions by nonindigenous species can have negative effects on economies and ecosystems. To limit this impact, current research on biological invasions uses functional traits to facilitate a mechanistic understanding of theoretical and applied questions. Here we aimed to assess the role of functional traits in the progression of crayfish species through different stages of invasion and determine the traits associated with invasive success. A dataset of thirteen functional traits of 15 species currently occurring or available for sale in the Netherlands was evaluated. Six of these crayfish appeared invasive. Important traits distinguishing successful from unsuccessful invaders were a temperate climate in the native range, a medium to high egg count and producing more than one egg clutch per year. The most successful invaders had different functional trait combinations: Procambarus clarkii has a higher reproductive output, can migrate over longer distances and possesses a higher aggression level; Faxonius limosus is adapted to a colder climate, can reproduce parthenogetically and has broader environmental tolerances. Using a suit of functional traits to analyse invasive potential can help risk management and prevention. For example, based on our data Procambarus virginalis is predicted to become the next successful invasive crayfish in the Netherlands.


Keywords: None provided.

Open access

04 February 2021

VeselĂ˝ and colleagues 2021

Cover of Hydrobiologia, volume 848, issue 3.
Veselý L, Ruokonen TJ, Weiperth A, Kubec J, Szajbert B, Guo W, Ercoli F, Bláha M, Buřič M, Hämäläinen H, Kouba A. 2021. Trophic niches of three sympatric invasive crayfish of EU concern. Hydrobiologia 848(3): 727737. https://doi.org/10.1007/s10750-020-04479-5




The spread of non-native species results in novel and often unexpected assemblages. Using stable isotopes, we disentangled the trophic relationships between three invasive crayfish species at two sites of a small thermal tributary of the Barát stream, Hungary. We studied Procambarus virginalis and Faxonius limosus living in sympatry in the upper section of this thermal tributary, and then an assemblage in a lower section also containing P. clarkii. The two species in the upper section largely shared trophic niches, although P. virginalis was more carnivorous than F. limosus, which fed more on detritus and aquatic plants. In the lower section, P. clarkii had a distinctive trophic niche, being more carnivorous than the other species and also preying on other crayfish and fish. The trophic niches of the other two species shifted slightly, being narrower and more overlapping in the presence of P. clarkii. It seems that the presence of P. clarkii affects the feeding habits and trophic niches of the other two crayfish. Our results also indicate that the species have somewhat distinctive feeding niches, which suggests that the ecosystem effects of these species are likely to be at least partially additive in the shared localities.


Keywords: biological invasion • Faxonius limosus • Procambarus virginalisProcambarus clarkii • sympatry

29 January 2021

Ranja Andriantsoa interview

Ranja Andriantsoa

Rowan Moore Gerety, author of the excellent Harper’s article on Marmorkrebs in Madagascar, continues his coverage of the story with another outstanding piece. This is an interview with Ranja Andriantsoa.

The article also has a nice video which is one of the best I’ve seen for giving a sense for just how abundant Marmorkrebs are in Madagascar.

External links


Invasion of the crayfish clones: Q&A with Ranja Andriantsoa

22 January 2021

Maiakovska and colleagues, 2021

Communications Biology logo.
Maiakovska O, Andriantsoa R, Tönges S, Legrand C, Gutekunst J, Hanna K, Pârvulescu L, Novitsky R, Weiperth A, Sciberras A, Deidun A, Ercoli F, Kouba A, Lyko F. 2021. Genome analysis of the monoclonal marbled crayfish reveals genetic separation over a short evolutionary timescale. Communications Biology 4(1): 74. https://doi.org/10.1038/s42003-020-01588-8



The marbled crayfish (Procambarus virginalis) represents a very recently evolved parthenogenetic freshwater crayfish species that has invaded diverse habitats in Europe and in Madagascar. However, population genetic analyses have been hindered by the homogeneous genetic structure of the population and the lack of suitable tools for data analysis. We have used whole-genome sequencing to characterize reference specimens from various known wild populations. In parallel, we established a whole-genome sequencing data analysis pipeline for the population genetic analysis of nearly monoclonal genomes. Our results provide evidence for systematic genetic differences between geographically separated populations and illustrate the emerging differentiation of the marbled crayfish genome. We also used mark-recapture population size estimation in combination with genetic data to model the growth pattern of marbled crayfish populations. Our findings uncover evolutionary dynamics in the marbled crayfish genome over a very short evolutionary timescale and identify the rapid growth of marbled crayfish populations as an important factor for ecological monitoring.


Keywords: None provided. 

Open access

Additional: Blog post by two of the authors about this paper:

Tönges S, Lyko F. 2021. Population growth and utilization of clonal marbled crayfish. Nature Ecology and Evolution. https://natureecoevocommunity.nature.com/posts/population-growth-and-utilization-of-clonal-marbled-crayfish-18289693-c2e2-4213-b624-26c114b5b428 2021.

19 January 2021

Harper’s magazine features Marmorkrebs in Madagscar

Harper's February 2021 cover
Rowan Moore Gerety has just published the best article ever written about Marmorkrebs.


“Stowaways” appears in the February 2021 issue of Harper’s magazine. It’s a feature-length examination of the invasion of Marmorkrebs on Madagascar. It was prompted by conversation with Julia Jones and was almost two years in the making.


There is some science, but the bulk of the article is a nuanced, detailed examination of the complexities of living with environmental change.


Over and over again, people are ambivalent to Marmorkrebs. People recognize the crayfish is a pest... but it’s a cheap meal. In a place where most people are living on the equivalant of a couple of US dollars a day, that matters.

In the hills above town, where rice cultivation depends on rainfall for irrigation, farmers complain that the levees of their terraced paddies spring leaks without warning, sparking arguments when valuable rainwater drains into their neighbors’ fields instead. Most realize that crayfish burrows are to blame, but suspicions linger all the same. “The tsi pe’peo is an enemy of agriculture,” Ramandrosoa told me. Nevertheless, he hesitated to advocate for its eradication. For families without even enough money to pay their children’s school fees, he said, “It’s kerosene, it’s sugar, it’s soap. It’s the basic necessities.” In the lean months, Ramandrosoa explained, “People collect crayfish so they don’t have to sell their rice.”

I also love the illustrations by Barry Falls. Look at this gem:

Illustration of marbled crayfish overlaying a map of Madagascar

I’ll forgive that the abdomen probably can’t bend quite that much.


I will probably be rereading this many times. It’s a rich and insightful part of a story that I know from the published literature, but this shows just how little of the story makes it into journal articles.


Highly recommended.

External links

Gerety RM. 2021. Stowaways. Harper’s 342(2049): 72-79. https://harpers.org/archive/2021/02/stowaways-crayfish-madagascar/

04 January 2021

Stein and colleagues, 2020

The Journal of Undergraduate Neuroscience Education logo
Stein W, Talasu S, Vidal-Gadea A, DeMaegd ML. 2020. Physiologists turned Geneticists: Identifying transcripts and genes for neuronal function in the marbled crayfish, Procambarus virginalis. The Journal of Undergraduate Neuroscience Education 19(1): A36-A51. https://www.funjournal.org/wp-content/uploads/2020/11/june-19-36.pdf




The number of undergraduate researchers interested in pursuing neurophysiological research exceeds the research laboratory positions and hands-on course experiences available because these types of experiments often require extensive experience or expensive equipment. In contrast, genetic and molecular tools can more easily incorporate undergraduates with less time or training. With the explosion of newly sequenced genomes and transcriptomes, there is a large pool of untapped molecular and genetic information which would greatly inform neurophysiological processes. Classically trained neurophysiologists often struggle to make use of newly available genetic information for themselves and their trainees, despite the clear advantage of combining genetic and physiological techniques. This is particularly prevalent among researchers working with organisms that historically had no or only few genetic tools available. Combining these two fields will expose undergraduates to a greater variety of research approaches, concepts, and hands-on experiences. The goal of this manuscript is to provide an easily understandable and reproducible workflow that can be applied in both lab and classroom settings to identify genes involved in neuronal function. We outline clear learning objectives that can be acquired by following our workflow and assessed by peer-evaluation. Using our workflow, we identify and validate the sequence of two new Gamma Aminobutyric Acid A (GABAA) receptor subunit homologs in the recently published genome and transcriptome of the marbled crayfish, Procambarus virginalis. Altogether, this allows undergraduate students to apply their knowledge of the processes of gene expression to functional neuronal outcomes. It also provides them with opportunities to contribute significantly to physiological research, thereby exposing them to interdisciplinary approaches.


Keywords: undergraduate • peer-mentoring • GABA • Marmorkrebs • neurophysiology • gene annotation • decapod • crustacean


Open access