19 July 2016

Jackson, 2016

Jackson CJ. 2016. Characterization of locomotor response to psychostimulants in the parthenogenetic marbled crayfish (Procambarus fallax forma virginalis): a promising model for studying the epigenetics of addiction. Master’s thesis, Department of Biology, Bowling Green State University, Bowling Green, Ohio. https://etd.ohiolink.edu/!etd.send_file?accession=bgsu1467967151&disposition=inline


Chapter I: Epigenetic regulation has been implicated as an important factor in understanding the molecular mechanisms of drug addiction. This is due to the life -long behavioral changes that commonly afflict addicted individuals long after drug exposure has been extinguished. Invertebrates, such as crayfish, offer excellent model systems to study these molecular mechanisms because they retain the ancestral neural reward circuit that is evolutionarily conserved across taxa, possess relatively few, large neurons, and have an accessible, modularly organized nervous system. The marbled crayfish (Procambarus fallax forma virginalis), in particular, has potential as a model for epigenetic studies because it is parthenogenetic, and thus all individuals are genetic clones. To provide the foundation of this model system for parsing the epigenetic mechanisms of drug addiction, here I characterize the locomotor response of juvenile P. f. f . virginalis exposed to the psychostimulant, d-amphetamine sulfate. Custom video-tracking software was used to record the movement patterns of juveniles exposed to water infused with varying concentrations of d-amphetamine sulfate. ANOVA demonstrated that crayfish locomotion was significantly impacted by drug concentration. These psychostimulant effects, along with the non-invasive mode of drug delivery, which avoids potential epigenetic changes resulting from the stress of direct injection into the hemolymph, set the stage for using P. f. f . virginalis as an animal model for epigenetic studies.

Chapter II: With the rising interest in using invertebrate models for behavioral epigenetic studies, and the tissue- specific nature of epigenetic changes, there is a need for effective methods of extracting genomic DNA from neural tissue. Invertebrates, such as crayfish, represent useful models in which to parse out the basic underlying epigenetic changes because of the relatively simplified anatomical structure of their nervous system. The parthenogenetic marbled crayfish (Procambarus fallax forma virginalis) offers a particularly elegant system because it reproduces asexually and produces large numbers of genetically identical offspring. However, the low DNA yield of fatty neural tissue combined with small sample size represent technical challenges in using invertebrate brains. The present study seeks to support the use of the marbled crayfish as a model for studying the mechanisms of behavioral epigenetics by providing an optimized method for genomic DNA extraction from invertebrate neural tissue.

Keywords: None provided.

22 June 2016

Chucholl, 2016b

Chucholl C. 2016b. The bad and the super-bad: prioritising the threat of six invasive alien to three imperilled native crayfishes. Biological Invasions 18(7): 1967-1988. http://dx.doi.org/10.1007/s10530-016-1141-2


Multiple species invasions and limited resources for management require prioritisation of deleterious effects of invaders on imperilled native species. This study prioritises the threat of six non-indigenous crayfish species (NICS) to three indigenous crayfish species (ICS) in southwestern Germany, a European region with high diversity of crayfish species and freshwater habitats. Using multivariate statistical analyses and niche-based species distribution models, the (1) contemporary and potential range overlap, (2) habitat overlap, and (3) rate of spread of the nine species were assessed. Predicted and contemporary range overlap with ICS was consistently the highest for the alien signal crayfish. Environmental niches of ICS tended to be associated with cooler temperatures (except for white-clawed crayfish), lower Human Influence Index, and higher terrain slope than that of alien Orconectes and Procambarus species, but were mostly similar to that of signal crayfish. Habitat overlap was found to be the highest between signal crayfish and ICS. In contrast to Orconectes and Procambarus species, signal crayfish also invade headwaters, where the most ICS populations occur. Range expansion during the past 15 years was the highest for signal crayfish, followed by Orconectes species. Because of the great potential to invade as-yet isolated refuge areas and spread at a high rate, signal crayfish is of the highest concern for conservation of ICS and should be primarily targeted by prevention and control measures. However, it merely represents the ‘worst of the worst’, since all NICS of North American origin are natural reservoirs of crayfish plague, a fatal disease of ICS.

Keywords: aquatic invaders • risk assessment • Crustacea • distribution models • habitat association

Lipták and colleagues, 2016

Lipták B, Mrugala A, Pekárik L, Mutkovic A, Grula D, Petrusek A, Kouba A. 2016. Expansion of the marbled crayfish in Slovakia: beginning of an invasion in the Danube catchment? Journal of Limnology 75(2): 305-312. http://dx.doi.org/10.4081/jlimnol.2016.1313


The marbled crayfish, Procambarus fallax f. virginalis, is a taxon widely available in the aquarium pet trade, which has been introduced to open waters in several European countries and in Madagascar. Recent studies confirmed this parthenogenetically reproducing crayfish as a high-risk invasive species, and vector of the crayfish plague pathogen, Aphanomyces astaci. It has been first discovered in Slovakia in 2010, but the status of the local population was not studied since then. Due to enlarged sampling area around the first report and one locality, where we presupposed the crayfish occurrence, we identified new marbled crayfish populations. Here, we report presence of three newly established marbled crayfish populations in Slovakia. Two populations are located critically close to the Váh River, a major tributary of the Danube River; one of them being directly connected to the Váh River via a side channel during occasional floods. The third established marbled crayfish population was found at the mouth of a thermal stream flowing into the Nitra River, a tributary of the Váh River. In this stream, crayfish coexist with other exotic fish and gastropod species of aquarium origin. We presume that the reported localities may serve as a source for further expansion of the marbled crayfish in the mid-part of the Danube catchment. Floods, active dispersal (including overland), passive dispersal by zoochory or anthropogenic translocations are among the major drivers facilitating the marbled crayfish colonization. We have not detected the crayfish plague pathogen in any of the studied populations. However, if spreading further, the marbled crayfish will encounter established populations of crayfish plague carriers in the Danube River, in which case they may acquire the pathogen by horizontal transmission and contribute to spread of this disease to indigenous European crayfish species.

Keywords: aquarium pet trade • crayfish plague • freshwater crayfish • Procambarus fallax f. virginalis • species introductions

11 June 2016

Chatila, 2016

Chatila Z. 2016. Lentiviral GFP transfection of the parthenogenic crayfish species, Procambarus fallax: a tool for examining the source of neural precursor cells in crayfish. Undergraduate honors thesis, Neuroscience, Wellesley College. http://repository.wellesley.edu/thesiscollection/345/


The thesis is embargoed online until 22 April 2018. I am attempting to get a copy of the abstract to place here earlier than that.

31 May 2016

Kouba and colleagues, 2016

Kouba A, Tíkal J, Císar P, Veselý L, Fort M, Príborský J, Patoka J, Buric M. 2016. The significance of droughts for hyporheic dwellers: evidence from freshwater crayfish. Scientific Reports 6: 26569. http://dx.doi.org/10.1038/srep26569


Freshwater biodiversity is globally threatened by various factors while severe weather events like long-term droughts may be substantially devastating. In order to remain in contact with the water or stay in a sufficiently humid environment at drying localities, the ability to withstand desiccation by dwelling in the hyporheic zone, particularly through vertical burrowing is crucial. We assessed the ability of three European native and five non-native crayfish as models to survive and construct vertical burrows in a humid sandy-clayey substrate under a simulated one-week drought. Three native species (Astacus astacus, A. leptodactylus, and Austropotamobius torrentium) suffered extensive mortalities. Survival of non-native species was substantially higher while all specimens of Cherax destructor and Procambarus clarkii survived. The native species and Pacifastacus leniusculus exhibited no ability to construct vertical burrows. Procambarus fallax f. virginalis and P. clarkii constructed bigger and deeper burrows than C. destructor and Orconectes limosus. In the context of predicted weather fluctuations, the ability to withstand desiccation through constructing vertical burrows into the hyporheic zone under drought conditions might play a significant role in the success of particular crayfish species, as well as a wide range of further hyporheic-dwelling aquatic organisms in general.

Keywords: behavioural ecology • biodiversity • hydrology • limnology

03 May 2016

Lőkkös and colleagues, 2016

Lőkkös A, Müller T, Kovács K, Várkonyi L, Specziár A, Martin P. 2016. The alien, parthenogenetic marbled crayfish (Decapoda: Cambaridae) is entering Kis-Balaton (Hungary), one of Europe’s most important wetland biotopes. Knowledge and Management of Aquatic Ecosystems 417: 16. http://dx.doi.org/10.1051/kmae/2016003


The marbled crayfish or Marmorkrebs, Procambarus fallax (Hagen, 1870) f. virginalis, a parthenogenetic freshwater crayfish belonging to the North American cambarids, was recorded in Hungary for the first time. Several specimens of this potentially invasive crayfish were caught at different locations in the thermal Lake Hévíz and its outflows in the western part of the country. Captured individuals covered a wide size range (5.5 to 50.5 mm carapace length) and one was carrying eggs and recently hatched offspring, which suggests that this organism has established a stable and self-sustaining population in the warm habitats of Lake Hévíz area. This finding is of great significance because these habitats belong to the catchment of the Danube River including Lake Balaton, and thus, a significant further spread of the marbled crayfish is likely to happen in Central Europe. Furthermore, the expansion of this crayfish already reached the Kis-Balaton, one of the landscape protection areas of the Balaton Uplands National Park, what could have currently yet unpredictable consequences for this unique wetland biotope.

Keywords: non-indigenous crayfish species • pet trade • illegal release • crayfish plague • thermal lake

Note: One of the latitude and longitude coordinates in Table 2 is incorrect. The coordinates for Lake Hévíz should be N 46° 47.252', E 17° 11.501'. The corresponding author confirmed this.

02 May 2016

African crayfish

The Conversation hosts a good post by Ana Nunes about the introduction of crayfish into Africa. Marmorkrebs make a brief cameo appearance (with an incomplete name):

Another species that bears mentioning is the marbled crayfish or “Marmokrebs” (Procambarus fallax) (sic). It was introduced to Madagascar for mysterious reasons, but there may be a link with a road building project carried out by foreign contractors in 2003/2004. In 2005, biologists at the University of Antananarivo noticed it being sold in markets close to the capital.

This particular crayfish has a peculiar history: nobody knows where it comes from. It simply appeared in the German aquarium trade in about 1995. It is also the only decapod in the world known to be able to reproduce by parthenogenesis – a female is able to reproduce without being fertilised by a male. This means that a single individual is sufficient to start a whole new population. As such, this species seems very likely to pose a serious threat to freshwater biodiversity in Madagascar.

Even though it focuses on one continent, it is a very nice lay summary of the issues around crayfish introductions.

External links

Freshwater crayfish: the forgotten invaders wreaking havoc across Africa

Pictured: Lake Naivasha, site of a Procambarus clarkii introduction. Picture from here.