30 July 2015

Beard, 2012

Beard LS. 2012. Responses to predator recognition odors in Marmorkrebs. Master’s thesis, Department of Biology, The University of Texas-Pan American, ProQuest, UMI Dissertations Publishing. http://search.proquest.com/docview/1152525739?accountid=7116


Marmorkrebs is a parthenogenetic crayfish with no indigenous populations. They have been introduced in several countries and could become an invasive species. Individuals introduced in Germany had longer, sharper spines, suggesting an adaptation to predators via developmental plasticity. This was tested by exposing juveniles to the odor of a predatory fish over their development and comparing them to controls. No difference in spine length or sharpness was found between the experimental and control groups.

Other crayfish detect predators via an alarm cue, hemolymph, and exhibit avoidant behavior in response. I hypothesized that Marmorkrebs would also treat hemolymph as an alarm cue. Adult crayfish were exposed to three conditions: food, fish odor, and hemolymph and recorded for behavioral measures. Results showed no difference across conditions indicating that Marmorkrebs do not use hemolymph or fish odor as cues.

Keywords: None provided.

29 July 2015

Lyko, 2015

Lyko F. 2015. DNA methylation patterns of arthropod genomes. Presentation given at Ninth Annual Arthropod Genomics Symposium, Kansas State University, Manhattan, Kansas, 17-19 June 2015. Abstract and program book, p. 11. http://www.k-state.edu/agc/images/symposium/Abstracts-ProgramBook.pdf


Eukaryotic species use (cytosine-5) DNA methylation to facilitate phenotypic adaptation to their environments, which can include both the modulation of developmental and adaptive gene expression programs. Variations in the complement of cytosine methyltransferase enzymes have been interpreted to reflect multiple versions of a toolkit for phenotypic adaptation. During evolution, specific parts of this toolkit could have been contracted or expanded to facilitate specific requirements for genome regulation. We are using whole-genome bisulfite sequencing to investigate this hypothesis and to establish genome methylation maps of various model systems at single-base resolution. Our results define three groups of arthropod methylomes with fundamental differences that will be discussed in detail: The first group is defined by Drosophila and is characterized by the complete absence of recognizable DNA methylation patterns. The second group is defined by the honeybee and is characterized by the highly selective methylation of specific CpG residues. The third group is characterized by pervasive genome-wide methylation and we will present the marbled crayfish (Procambarus virginalis) as a novel model system to understand the relevance of DNA methylation for phenotypic variation.

Keywords: None provided.

Gutekunst and colleagues, 2015

Gutekunst J, Falckenhayn C, Raddatz G, Lyko F. 2015. Assembly and annotation of the marbled crayfish genome. Poster presented Ninth Annual Arthropod Genomics Symposium, Kansas State University, Manhattan, Kansas, 17-19 June 2015. Abstract and program book, p. 23. http://www.k-state.edu/agc/images/symposium/Abstracts-ProgramBook.pdf


Marbled crayfish are the only freshwater crayfish known to reproduce by cloning (apomictic parthenogenesis). Notably, among genetically identical offspring raised in the same environment phenotypic differences can be observed. Such non-genomic characteristics render the marbled crayfish an interesting laboratory model, especially for the field of epigenetics. We experimentally determined the genome size at approximately 3.8 Gbp by k-mer analysis and flow cytometry. Two individual females (Koelle, Steuerwald) were sequenced using shotgun sequencing with various insert sizes generating 350 Gbp and 196 Gbp of data respectively. High coverage sequencing data of Koelle was used to produce a first de novo draft assembly with a length weighted median contig size (N50) of 809 bp and scaffold N50 of 41 kb. To unambiguously demonstrate clonal reproduction in the marbled crayfish we are currently evaluating sequencing data from the second individual (Steuerwald). Transcriptome data provides additional information for quality control and assembly refinement. Genome wide comparisons to other arthropods will allow us to define characteristic features of decapods as ecologically and economically keystone species.

Keywords: None provided

28 July 2015

Scholtz, 2016

Scholtz G. 2016. Happy birthday! The first decade of Marmorkrebs research—results and perspectives. In: T Kawai, Z Faulkes, G Scholtz, eds. Freshwater Crayfish: A Global Overview, pp. 3-12. Boca Raton: CRC Press. https://www.crcpress.com/Freshwater-Crayfish-A-Global-Overview/Kawai-Faulkes-Scholtz/9781466586390


This brief review of the past 10 years of Marmorkrebs research reveals that we know a great deal more about many aspects of the biology of this very special crustacean. Both the similarity to other crayfish species and the unique aspects of Marmorkrebs biology offer excellent perspectives for the Marmorkrebs as a model system.

Keywords: None provided.

Related posts

Kawai and colleagues (editors), 2016

23 July 2015

Award-winning crayfish

Marmorkrebs are an integral part of a new aquaponics project at Western Michigan University.

In March, five Western Michigan University students won a $15,000 Wege Prize—a national sustainability award—for their aquaponics system.

Marmorkrebs get used in this project because:

Instead of buying regular fish food, the team will raise spirulina algae and marbled crayfish—both of which are easy to raise.

You can tell from the bit about Marmorkrebs on the infographic that this is a university project run by academics.

Marbled crayfish
This recently-discovered crustacean species reproduces through parthenogenesis, an asexual process in which a single female creates genetically identical clones. As an all-female species, marbled crayfish reproduce exponentially and are less aggressive than other species, which makes them better suited for aquaculture. They are fed spirulina algae and BSFL frass. Being omnivorous scavengers, the crayfish can also process undigested waste as supplemental feed. In this system, they are used as a feed component, but could be raised for human consumption if demand exists.

How can I tell this was written by an academic? Not because of the fancy word “parthenogenesis,” but because only an academic would refer to a species that appeared in the scientific literature twelve years ago as “recently described.”

I’m also a doing a bit of an eyebrow raise over this statement, “As an all-female species, marbled crayfish reproduce exponentially and are less aggressive than other species...”. It’s worded in such a way that might suggest the alleged lower levels of aggression are due to them being female, which is absolutely not the case. Female crayfish fight just as hard as males, and study after study has repeatedly found no strong effects on sex on outcome of fights.

Finally, I think it’s a little unlikely that Marmorkrebs are likely to have much demand for food for people. They’re a small species, and you’ve not going to get much meat off them compare to, say, Louisiana red swamp crayfish or redclaw crayfish.

External links

WMU Students To Build Sustainable Aquaponics Farm
Local Loop Farms

22 July 2015

Kawai and colleagues (editors), 2016

Kawai T, Faulkes Z, Scholz G (eds.). 2016. Freshwater Crayfish: A Global Overview. CRC Press: Boca Raton. http://www.crcpress.com/product/isbn/9781466586390

Table of contents


Section 1: Marbled Crayfish—A New Model Organism for Biology

  • 1. Happy birthday! The first decade of Marmorkrebs research—results and perspectives — Gerhard Scholtz
  • 2. Predicting the distribution of crayfish species: a case study using marble crayfish — Teresa Patricia Feria and Zen Faulkes
  • 3. Marble crayfish as a new model organism and a new threat to native crayfish conservation — Zen Faulkes
  • 4. A preliminary study on the tolerance of marble crayfish Procambarus fallax f. virginalis to low temperature in Nordic climate — Katrin Kaldre, Anton Meženin, Tiit Paaver and Tadashi Kawai
  • 5. Reproductive biology: Parthenogenesis: mechanisms, evolution, and its relevance to the role of marbled crayfish as model organism and potential invader — Peer Martin
  • 6. Aquarium: Marbled crayfish gaining ground in Europe: the role of the pet trade as invasion pathway — Christoph Chucholl
  • 7. Cell biology research on stem cells, aging, cancer resistance, and epigenetics in marbled crayfish and relatives: potential benefits for human biology and medicine — Günter Vogt

Section 2: Crayfish: New Developments

  • 8. Aquaculture: Developing markets for a new product: aquacultured redclaw in Mexico — Antonio Garza de Yta
  • 9. The biology of crayfish plague pathogen Aphanomyces astaci: current answers to most frequent questions — Svetlana Rezinciuc, Jose V. Sandoval-Sierra, Birgit Oidtmann and Javier Diéguez-Uribeondo
  • 10. A review of current techniques for sampling freshwater crayfish — Stephanie Parkyn
  • 11. Behavior: Behavioral ecology of crayfish: its contribution to conservation and management — Elena Tricarico
  • 12. Chaos and adaptation in the pathogen-host relationship in relation to the conservation: the case of the crayfish plague and the noble crayfish — Japo Jussila, Ivana Maguire, Harri Kokko and Jenny Makkonen
  • 13. Crayfish as tools of water quality monitoring — Pavel Kozák and Iryna Kuklina
  • 14. Phylogenetic estimate of the freshwater crayfish (Decapoda: Astacidea) using morphology and molecules — David Stern and Keith A. Crandall

Section 3: Global Overview of Freshwater Crayfish Biology

  • 15. Asia — Tadashi Kawai, Gi-Sik Min, Evgeny Barabanshchikov, Vjacheslav Labay and Hyun Sook Ko
  • 16. The crayfish fauna of Canada and the United States in North America — Roger Thoma
  • 17. Historical biogeography of Pacifastacus crayfishes and their branchiobdellidan and entocytherid ectosymbionts in Western North America — Eric R. Larson and Bronwyn W. Williams
  • 18. The crayfish of middle America — Fernando Alvarez and José Luis Villalobos
  • 19. The native South American crayfish (Decapoda: Parastacidae) — Erich Harry Rudolph and Mauricio Pereira Almerão
  • 20. Oceania: the freshwater crayfish of the Oceania Region — James M. Furse, Quinton F. Burnham, Kathryn L. Dawkins and Alastair M.M. Richardson
  • 21. Crayfish of Africa — Christopher B. Boyko
  • 22. Crayfish in Europe: Biogeography, Ecology and Conservation — Leopold Füreder
  • 23. Global Overview of Branchiobdellida (Annelida: Clitellata) — Stuart R. Gelder and Bronwyn W. Williams


Note: Although the release date of this book was released in 2015, the publication date within it is consistently given as 2016 throughout the book.

09 July 2015

The Francesca Gherardi Memorial Prize for 2016

The Francesca Gherardi Memorial Prize of €5,000 is awarded annually by the Department of Biology at the University of Florence to a young researcher who demonstrates outstanding ability in the fields of crustacean behaviour and/or invasion biology. The prize money is donated by the Gherardi family in memory of their beloved relative. The professors of zoology of the Department of Biology of University of Florence serve as the award committee.

The winner gives a lecture on the subject of his/her research and receives the award at the annual memorial honouring Francesca Gherardi at the Department of Biology, University of Florence, in May 2016.

Application Guidelines

Applications for the 2016 prize for research in crustacean behaviour are open to researchers under the age of 40, of all nationalities, lacking permanent positions. The deadline for submissions is 30 November 2015.

The application should be written in English, and include a CV, three articles published in peer-reviewed journals, a letter attesting that the applicant holds no permanent research or teaching position, and a copy of his/her identity card.

Send submissions in electronic format to Prof. Felicita Scapini, felicita.scapini@unifi.it.

More information at http://www.bio.unifi.it/vp-118-francesca-gherardi-prize.html.

08 July 2015

Hanging out for a ride

Spotted here.

07 July 2015

Support for doctoral students studying aquatic invaders

The project Marie Curie ITN Aquainvad-ED offers eight Ph.D. fellowships on early detection, control, and management of aquatic invasive species.

The main research goal of the project is to exploit novel molecular advances combined with the power of crowd data sourcing (citizen science) to develop innovative methods of early detection, control and management of aquatic invasive species. This will be achieved via a multi-disciplinary network of experts in invasion biology, ecology, marine and fresh-water biotechnology, citizen science and environmental policy working in three different countries: the United Kingdom (3 positions), Spain (3 positions), and Italy (2 positions).

Deadline for applications is 22 July 2015 for positions in Italy (ESR4, ESR7) and 14 August 2015 for positions in Spain (ESR5, ESR6, ESR8) and UK (ESR1, ESR2, ESR3). For more details on individual projects and how to apply, click on each one of the Fellow links (ESR1-8) in the following website: http://www.aquainvaded.com/individual-projects

For more information, contact Elena Tricarico (email: elena.tricarico@unifi.it).