24 May 2024

Burggren and colleagues 2024

Cover to "Physiology" journal supplement.
Burggren W, Martinez Bautista G, Göpel T, Padilla P. 2024. Lack of genetic variation in low heterozygosity and clonal animals creates lack of physiological variation. Physiology 39:S1. https://doi.org/10.1152/physiol.2024.39.S1.1477


Data variability frequently complicates reproducibility and interpretation of experimental results. Such variability arises from numerous sources such as differences in procedures or not accounting for key biological factors (e.g. sex, biological rhythms, prandial state). Making the situation more problematic, variation in physiological performance is often viewed as highly labile, easily and rapidly influenced by environmental stressors, development, etc., making it diffcult to pin down a source for variation. Undeniably, however, unknown (or ignored) genetic variation among and within strains/lines can also be a significant source of data variability in published physiological measurements, though surprisingly this has not been extensively investigated as a specific source of physiological variation. We hypothesized that variation in physiological performance is correlated with the intrinsic degree of genetic variability of the subject animal. To test this hypothesis, we employed two animal models: 1) Inbred lines (e.g., NHGRI-1) derived from wild type strains of the zebrafish (Danio rerio), with an estimated 15% of the genetic heterozygosity of wild type AB zebrafish, and 2) the parthenogenetically reproducing marbled crayfish (Procambarus virginalis), all specimens of which are genetically identical clones. For these two animal models, we measured both physiological variables (e.g. heart rate, stroke volume, cardiac output, oxygen consumption) and morphological variables (e.g. yolk-chorion ratio, body mass, embryo mass, total length, condition factor, specific growth rate) during development. We subjected the two animal models to environmental stress in the form of both temperature and hypoxia to stimulate physiological responses that could be compared and contrasted among populations. From these data we then calculated the resultant coeffcients of variation for measured variables for wild type and low/zero heterozygosity populations and/or species. In zebrafish, both the wildtype AB and NHRGI-1 lines showed similar developmental trajectories characterized by similar mean values for physiological and morphological variables. Additionally, similar mean values for physiological and morphological variables were recorded in the face of temperature and hypoxia challenge. Yet, importantly, the coeffcient of variation for each measured variable was significantly lower in NHGRI-1 than AB larvae for >90% of the assessed endpoints. In the clonal crayfish, genetically identical early stage marbled crayfish reared in different temperatures or oxygen levels show major acclimation responses, but generally showed less morphological and physiological variation about the mean than sexually-reproducing species crayfish with inherently much greater genetic variation, as evident from comparisons of calculated coeffcients of variation. A key question regarding the clonal crayfish is how can there be any morphological or physiological variation between individuals? We suggest that variability that persists may arise from microenvironmental differences during rearing (e.g. egg position during incubation on the mother’s pleon) and/or stochastic differences in gene expression (e.g. due to random epimutations) in this clonal species. In conclusion, genetic diversity clearly contributes to physiological variability. For future experiments, low heterozygosity lines and/or clonal species may be useful for decreasing inter-individual variation, thus aiding interpretation of results and enhancing reproducibility. In any event, scientific documentation of physiological studies should include as much information on (genetic) background of the experimental animals as possible.

Keywords: None provided.

Note: This is the full abstract presented at the American Physiology Summit 2024 meeting. There are no additional versions or additional content available for this abstract.

Sánchez and colleagues 2024

Cover to Evology and Evolution, Volume 4, number 5.
Sánchez O, Oficialdegui FJ, Torralba-Burrial A, Arbesú R, Valle-Artaza JM, Fernández-González Á, Ardura A, Arias A. Procambarus virginalis Lyko, 2017: A new threat to Iberian inland waters. Ecology and Evolution 14(5): e11362. https://doi.org/10.1002/ece3.11362


An eco-monitoring programme to assess faunal biodiversity in the main rivers of the northern Iberian Peninsula (Spain) reveals the first occurrence of the marbled crayfish Procambarus virginalis (Decapoda: Cambaridae) in Iberian inland waters. Iberian specimens have been identified by combining morphological and genetic traits. We discuss the most plausible pathways and introduction vectors, its potential invasiveness and subsequent impacts on host localities. Our preliminary results raise concern about the potential threat of P. virginalis to native fauna and ecosystem dynamics, as P. virginalis was found in an area of great cultural and ecological importance with relevant populations of endangered species. Due to the invasive history of the marbled crayfish, eradication of these individuals is urgent. This study confirms the importance of early warning systems for exotic species, keeping the population, forest guards and field technicians informed about potential invasive species to execute a rapid and effective response.  

Keywords: None provided.

Open access

28 April 2024

Marmorkrebs on Great Lakes Now

The first ten minutes of this video from Great Lakes Now is an excellent mini-documentary on the discovery of Marmorkrebs in North America and steps taken to try to eliminate it.

There’s also a short news article.

External links

Warning waters and mutant crayfish

Marbled crayfish raises eyebrows, and concerns

08 April 2024

Yanai and colleagues 2024

BioInvasion Records cover
Yanai Z, Guy-Haim T, Kolodny O, Levitt-Barmats Ya, Mazal A, Morov AR, Sagi A, Truskanov N, Milstein D. 2024. An overview of recent introductions of non-native crayfish (Crustacea, Decapoda) into inland water systems in Israel. BioInvasions Records 13(1): 195-208. https://doi.org/10.3391/bir.2024.13.1.17


Crayfish are known to effectively invade freshwater systems worldwide. Whilst no native crayfish species exist in Israel, three exotic species have been documented in recent years, and their introduction details are hereby discussed. Three of these introduction events, one of each species, were previously reported; one was established, one failed to establish, and the third was successfully eradicated. However, more recently, invasive crayfish have been independently detected multiple times, involving a variety of natural and artificial habitats. Altogether, three invasive crayfish species currently inhabit Israeli freshwaters: Cherax quadricarinatus, Procambarus clarkii, and Procambarus virginalis. They were found in fourteen independent cases, and at least five of them represent established populations. Similar to other crayfish invasions around the globe, we speculate that the invasive populations in Israel result from the intentional release of aquarium inhabitants, as well as from aquaculture escapees. The import and trade policy of aquatic organisms in Israel requires thorough revision to prevent future invasions. Thought should also be given to the prevention of the spread of the existing invasive populations as well as to their eradication, if possible.

KeywordsCherax quadricarinatusProcambarus clarkiiProcambarus virginalis • aquarium release • invasive species • Levant

Open access

21 February 2024

Minnesota bans Marmorkrebs

Map highlighting Minnesota in US.
Minnesota has become the latest North American jurisdiction to ban Marmorkrebs. Effective yesterday (20 February 2024):

It is unlawful to possess, import, purchase, transport or introduce prohibited invasive species, except under a DNR-issued permit for disposal, decontamination, control, research or education.

External links

News release: Minnesota DNR classifies 13 invasive plants, animals as prohibited – Minnesota Department of Natural Resources

13 new 'high-risk' invasive species prohibited in MinnesotaBring Me the News

Minnesota DNR Classifies 13 Invasive Plants + Animals As Prohibited – KFRO 

Hear (sic) are Minnesota DNR’s 13 Newest High-Risk Invasive Species – KDHL

28 January 2024

Legrand and colleagues 2023

Legrand C, Andriantsoa R, Lichter P, Raddatz G, Lyko F. 2023. Time-resolved, integrated analysis of clonally evolving genomes. PLOS Genetics 19(12): e1011085. https://doi.org/10.1371/journal.pgen.1011085


Clonal genome evolution is a key feature of asexually reproducing species and human cancer development. While many studies have described the landscapes of clonal genome evolution in cancer, few determine the underlying evolutionary parameters from molecular data, and even fewer integrate theory with data. We derived theoretical results linking mutation rate, time, expansion dynamics, and biological/clinical parameters. Subsequently, we inferred time-resolved estimates of evolutionary parameters from mutation accumulation, mutational signatures and selection. We then applied this framework to predict the time of speciation of the marbled crayfish, an enigmatic, globally invasive parthenogenetic freshwater crayfish. The results predict that speciation occurred between 1986 and 1990, which is consistent with biological records. We also used our framework to analyze whole-genome sequencing datasets from primary and relapsed glioblastoma, an aggressive brain tumor. The results identified evolutionary subgroups and showed that tumor cell survival could be inferred from genomic data that was generated during the resection of the primary tumor. In conclusion, our framework allowed a time-resolved, integrated analysis of key parameters in clonally evolving genomes, and provided novel insights into the evolutionary age of marbled crayfish and the progression of glioblastoma. 

Keywords: None provided.

Open access

Neculae and colleagues 2024

Neculae A, Barnett ZC, Miok K, Dalosto MM, Kuklina I, Kawai T, Santos S, Furse JM, Sîrbu OI, Stoeckel JA, Pârvulescu L. 2024. Living on the edge: Crayfish as drivers to anoxification of their own shelter microenvironment. PLOS ONE 19(1): e0287888. https://doi.org/10.1371/journal.pone.0287888


Burrowing is a common trait among crayfish thought to help species deal with adverse environmental challenges. However, little is known about the microhabitat ecology of crayfish taxa in relation to their burrows. To fill this knowledge gap, we assessed the availability of oxygen inside the crayfish shelter by series of in-vivo and in-silico modelling experiments. Under modeled condition, we found that, except for the entrance region of the 200 mm, a flooded burrow microenvironment became anoxic within 8 h, on average. Multiple 12-hour day-night cycles, with burrows occupied by crayfish for 12 h and empty for 12 h, were not sufficient for refreshing the burrow microenvironment. We then examined the degree to which crayfish species with different propensities for burrowing are tolerant of self-created anoxia. From these experiments, primary and secondary burrowers showed best and most consistent tolerance—exhibiting ≥ 64% survival to anoxia and 25–91% survival of ≥ 9 h at anoxia, respectively. Tertiary burrowers exhibited little to no tolerance of anoxia with 0–50% survival to anoxia and only one species exhibiting survival (2%) of ≥ 9 h at anoxia. Results suggest that moderate to strongly burrowing crayfish can quickly draw down the dissolved oxygen in burrow water but appear to have conserved a legacy of strong tolerance of anoxia from their monophyletic ancestors–the lobsters–whereas tertiary burrowers have lost (or never evolved) this ability.

Keywords: None provided.