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This study was designed to assess the impact of the mixture of cadmium (Cd) and zinc (Zn) on the bioaccumulation and the ultrastructural changes in the hepatopancreas of Porcellio laevis (Latreille, 1804) after 4 weeks of exposure to contaminated Quercus leaves under laboratory conditions. For each metal, four concentrations were used with four replicates for each concentration. Metal concentrations in the hepatopancreas and the rest of the body were determined using atomic absorption spectrometry. From the first week until the end of the experiment, a weight gain in P. laevis was observed particularly between the first and the end of exposure from 93.3 ± 18.22 mg fw to 105.22 ± 16.16 mg fw and from 106.4 ± 22.67 mg fw to 125.9 ± 23.9 mg fw for Mix1 and Mix4, respectively. Additionally, the determined metal trace elements (MTE) concentrations in the hepatopancreas were considerably higher compared to those in the rest of the body and seem to be dose-dependent. Using transmission electron microscopy (TEM), some alterations were highlighted in the hepatopancreas. The main observed alterations were (a) the destruction of the microvilli border in a considerable portion of cells, (b) the increase of the lipid droplets with different shapes and sizes, (c) the increase in the number of the mitochondria, and (d) the appearance of TE in the form of B-type granules. The obtained results confirmed the ability of P. laevis to deal with high amounts of MTE, suggesting its possible use in future soil's biomonitoring programs.

Effects of trace elements on the hepatopancreas ultrastructure and on the locomotor activity rhythm were investigated in the amphipod talitrid Orchestia gammarellus collected from Bizerte lagoon banks situated in the north of Tunisia. Animals were exposed to a series of contaminated soil with different concentrations of cadmium and zinc. The locomotor activity rhythm was studied under constant darkness. Histopathological analysis showed that the trace elements, especially the Cd, induced significant changes in the morphology and in the ultrastructural organization of hepatopancreatic cells. The significant alterations obtained were dose dependent. Concerning the behavioral response, results revealed the presence of two components whatever the experimental conditions. In addition, a great inter-individual variability of the locomotor rhythm was observed. Patterns were in majority bimodal for the control individuals and became unimodal and multimodal when exposed under Cd and Zn, respectively. Furthermore, ultradian and circadian periods were determined. The circadian period lengthened after Zn exposure. In addition, the locomotor activity rhythm was more stable for control individuals. However, those exposed to Cd were less active.

To estimate trace element bioaccumulation in Armadillo officinalis, specimens were collected then exposed to contaminated sediments with copper and zinc for three weeks.

The hepatopancreas of crustacean species has been recognized as an important target organ for studying the toxic effects of trace metals (TM). This dynamic organ, with its capability of detoxifying trace metals, often indicates distinct pathological disturbances. This study dealt with the evaluation of the histological alterations in the hepatopancreas of the supralittoral amphipod Orchestia montagui Audouin, 1826 exposed to a mixture of copper and zinc. After exposure, the hepatopancreas was dissected and its ultrastructure was observed using transmission electron microscopy. The obtained results showed that the body mass differed from the control organisms depending on the nominal metal concentration to which they were exposed. The hepatopancreas of unexposed and exposed animals were compared for the detection of histological changes. Significant dose-dependent alterations were noted in all the treatment groups. Among these histological changes of the hepatopancreas in O. montagui, we noted the loss of cell structure, especially cell remoteness and border lyses, a reduction in the nuclear volume, an increase in cytoplasm density with trace metals in both nucleus and vacuoles, a disorganization and destruction of microvilli and a condensation of the majority of cell organelles, and mitochondria swelling. Through this study, O. montagui could be a good indicator providing measurable responses. It could be an attractive candidate for the biochemical study of TM toxicity in coastal ecosystems.

This study was conducted to compare metals bioaccumulation in the Talitrid O. mediterranea collected from the banks of Bizerte lagoon. Individuals were exposed to a series of contaminated soil with...

Terrestrial isopods have adapted to land life by diverse morphological, physiological and behavioral changes. Isopod species exhibit a large variety of preferences ranging from moist to dry habitats. Isopod cuticle is an interesting model for studying adaptations to terrestrial life. The cuticle consists of a hierarchically organized material which provides protection and sites for muscle attachment. The present paper aimed to investigate the structure of the cuticle in three isopod species in order to relate some peculiar features to an adaptive process to environmental constraints. Results showed that general thickness of Ligia italica cuticle was quite similar to that observed in Porcellio lamellatus. Nevertheless, this cuticle was half as thick as in Porcellio laevis. Although the positive relationship found between total body lengths and the total thickness of the cuticle, the exocuticle did not show any differences between the three species. However, it is the development of a thicker endocuticle in P. laevis which make its total cuticle thickness more important.

Environmental DNA (eDNA) is a powerful method for assessing the presence and distribution of invasive aquatic species. We used this tool to detect and monitor several invasive crayfishes Procambarus clarkii, Orconectes limosus and Pacifastacus leniusculus present in, or likely to invade, the ponds of the Brenne Regional Natural Park. A previous study showed that the eDNA method was not very efficient in detecting P. clarkii. In the present study, we explored new improvements in the detection of invasive crayfish. We designed specific primers for each crayfish species, and set up an experimental mesocosm approach to confirm the specificity of the primers and the sampling protocol. We analysed samples taken from ponds in 2014 and 2015. We compared two qPCR protocols involving either SybrGreen or TaqMan assays. Using these same primers, we were able to detect crayfish eDNA with both assays during the mesocosm experiment. However, crayfish from field samples could only be detected by performing qPCR with a SybrGreen assay. We successfully monitored the presence of three invasive species of crayfish using eDNA. This method is a powerful tool for establishing the presence or absence of invasive species in various freshwater environments.

In Tunisia, while wetlands are considered as remarkable habitats for their faunal and floral diversity, few studies on the biogeography and the diversity of terrestrial isopods were performed. To fill this gap, we carried out a field study in the supralittoral zone of 146 Tunisian wetlands belonging to eight types (lagoon, river, lake, sebkha, dam, hill reservoir, beach and chott) and to five bioclimatic zones (humid, subhumid, semi-arid, arid and Saharan). Field work was carried out in spring 2010. Terrestrial isopods were collected in the morning by hand search each time with the same sampling effort. During the study, 22 species of terrestrial isopods belonging to nine families were collected. Porcellio variabilis, Porcellio laevis, Chaetophiloscia elongata and Armadillidium pelagicum are the most common species identified. From the northern to the southern regions, a gradual decrease in species richness has been shown. The identified species belonged to different biogeographical categories: Mediterranean, Mediterranean-Atlantic, North Africa with circum-Sicilian islands, semi-arid and Saharan species. Some of these species are endemic to Tunisia (Porcellio dominici) or to North Africa (Armadillidium sulcatum, Armadillidium tunisiense, Porcellio marginenotatus and P. variabilis). Terrestrial isopod species differ according to wetland type and bioclimatic zone.

To estimate trace element bioaccumulation in Armadillo officinalis, specimens were collected from Ghar El Melh lagoon then exposed for 3 weeks in contaminated sediments with copper, zinc, and cadmium. From the first week until the end of the experiment, a decrease in A. officinalis growth related to the increase of Cd concentration in the sediment was recorded. However, a mass gain was highlighted under Cu and Zn exposures. At the end of experiment, body metal concentrations were measured using flame atomic emission spectrometry. Results of the bioaccumulation factor showed that the species could be considered as a macroconcentrator of copper (BAF > 2) and a deconcentrator of zinc (BAF

1. Groundwater ecosystems represent the greatest proportion of unfrozen freshwa- ter on Earth and harbour high numbers of rare taxa with restricted distributions. Stygofaunal abundance, species richness, and ecology play essential roles in groundwater ecosystem services and functioning, as well as providing an impor- tant contribution to global biodiversity. However, as global depletion and contam- ination of groundwater pose serious and often irreversible threats to stygofauna, more information is urgently needed about the ecology of rare groundwater spe- cies to guide effective strategies for their conservation or restoration. 2. In this study, analyses of carbon and nitrogen stable isotopes were used to com- pare and evaluate trophic niches and diets of a vulnerable stygobiont isopod, Gallasellus heilyi living in sympatry in French groundwater ecosystems with the isopod Caecosphaeroma burgundum and the amphipod Niphargus ladmiraulti. 3. Stable isotope results showed trophic niche partitioning among the three sty- gobiont species and indicated that G. heilyi and C. burgundum occupy the role of primary consumers and N. ladmiraulti that of predator. Moreover, although G. heilyi and C. burgundum were shown to rely on the same food sources, indicat- ing similar diets, and their trophic niches did not overlap, suggesting trophic specialization. 4. The results suggest that detritus (i.e. decaying organic material) is an important food source for G. heilyi, and its availability could determine the survival of this endangered species. As a practical conservation measure for G. heilyi and the whole stygofauna community, we suggest reconnecting surface and subterranean ecosystems, as they probably were before natural sinks and many wells were filled up or closed. Funding information: Agence de l’Eau Adour-Garonne; Centre National de la Recherche Scientifique; DREAL Nouvelle-Aquitaine; Estonian Ministry of Education and Research, Grant/Award Number: IUT 21-2; Estonian Research Council, Mobilitas Pluss, Grant/Award Number: MOBJD29; Foundation LISEA Biodiversité; Regional Council of Nouvelle-Aquitaine; University of Poitiers. Funding information: Agence de l’Eau Adour-Garonne; Centre National de la Recherche Scientifique; DREAL Nouvelle-Aquitaine; Estonian Ministry of Education and Research, Grant/Award Number: IUT 21-2; Estonian Research Council, Mobilitas Pluss, Grant/Award Number: MOBJD29; Foundation LISEA Biodiversité; Regional Council of Nouvelle-Aquitaine; University of Poitiers.

Terrestrial isopods (Oniscidea) are crustaceans whose ancestors have left the water to conquer land even in arid regions where Hemilepistus reaumurii is living. This species is the only terrestrial isopod conducting a real sub-social life as a monogamous semelparous species forming families. The chemical signature of five family units from this population was investigated by gas chromatography. Results showed highly significant differences among the family units according to: (i) the cuticular chemical profiles which confirm that the cuticle is one of the most important organs involved in family chemical signature and recognition; (ii) the cuticular chemical distances and (iii) the faeces chemical profiles which suggest that these droppings help individuals of the same family to find their burrows and deter intruders. Moreover no significant correlation was shown between faeces chemical distance and the distance between burrows from where the family units were collected.

To evaluate the influence of wetland types on the distribution of terrestrial isopods, species richness, relative abundance and diversity indices were studied in the supralittoral zone of 95 wetlands in the north-western of Tunisian dorsal, belonging to six types: lagoon, hill reservoir, river, dam, lake and sebkha. We tested the following hypothesis: (i) is isopod diversity influenced by wetland types? (ii) is isopod diversity influenced by bioclimatic zones? and (iii) what are the environmental factors influencing isopod distribution? A total of 3255 individuals belonging to twenty species of terrestrial isopods were captured. Species richness differs significantly between wetland types. A highly significant positive relationship between species richness and both humidity and altitudinal gradient was described. The dendrogram of similarities showed a divergence of the lagoons compared to the remaining wetland types.

This study deals with the evaluation of trace element bioaccumulation and histological alterations in the hepatopancreas of the supralittoral amphipod Orchestia montagui Audouin, 1826 due to the exposure to cadmium, copper, and zinc. Orchestia montagui individuals were maintained during 14 days in soils contaminated with different trace elements namely cadmium, copper, and zinc; a control was also prepared. Our results show that the mortality and the body mass vary according to the metal and the nominal concentration used. In general, the mortality increases from the seventh day. However, the body mass shows a decrease with cadmium exposure and an increase with copper and zinc exposures. Furthermore, the concentration factor highlights that this species is considered a macroconcentrator for copper and zinc. The hepatopancreas of unexposed and exposed animals were compared to detect histological changes. Our results show significant alterations in the hepatopancreas of the exposed animals after the experiment. The degree of these alterations was found to be dose-dependent. Among the histological changes in the hepatopancreas in O. montagui, a loss of cell structure was noted, especially cell remoteness and border lyses, the reduction of nuclear volume, an increase in the cytoplasm density with the presence of trace element deposits in both the nucleus and vacuoles, a disorganization and destruction of microvilli, and a condensation of the majority of cell organelles and mitochondria swelling. Through this study, we have confirmed that O. montagui can be a relevant model to assess trace metal element pollution in Tunisian coastal lagoons with the aim of using it in future biomonitoring programs.

Mate choice is an important process in sexual selection and usually prevents inbreeding depression in populations. In the terrestrial isopod Armadillidium vulgare, the close physical proximity between individuals may increase the risk of reproducing with siblings. Moreover, individuals of this species can be infected with the feminizing bacteria of Wolbachia, which influence male mate choice. However, little is known about the kinship or familiarity assessment of the selected partner that occurs when a male can choose between females with or without Wolbachia. To investigate the potential mechanisms leading to mate choice and the potential impact of the parasite, we performed behavioral choice tests on males where they could choose between sibling vs. nonsibling females, familiar vs. unfamiliar females, and sibling familiar vs. unfamiliar nonsibling females. To investigate the costs of inbreeding, we compared the reproductive success of both sibling and nonsibling mates. Our results revealed that male copulation attempts were higher for familiar females and for nonsibling females when both females were Wolbachia-infected, but the duration was longer when both females were Wolbachia-free. When males mated with a sibling female, their fecundity was severely decreased, consistent with inbreeding depression. Overall, we observed copulations with all types of females and demonstrated discrimination capacities and potential preferences. We highlight the complexity of the tradeoff between kinship, familiarity and parasite transmission assessment for mate choice.

This study was designed to evaluate the copper and zinc bioaccumulation in Orchestia montagui Audouin, 1826 which was exposed to a contaminated soil during three weeks and to determine the ultrastructural changes in the hepatopancreas of this species. Individuals were weekly weighed and the metals body burdens were determined at the end of the experiment. Furthermore, the bioaccumulation factor (BAF) was calculated showing that this species is considered as a macroconcentrator of these two metals. The highest concentrations of copper and zinc induced significant changes in the ultrastructural organization of S and B cells in the hepatopancreas.

Biological invasions are a major cause of biodiversity loss, and early action in these cases is more cost-effective than dealing with widespread invasions. Thus, understanding possible consequences of invasions is essential for control and management actions. Given the early stage of invasion of South America by Procambarus clarkii, a potentially harmful crayfish, we investigated aggressive interactions between this invasive crayfish and the native Parastacus brasiliensis to understand potential impacts of the invader on native species before they encounter each other in nature. We paired size-matched crayfish for two experiments: one with Pr. clarkii males and females against Pa. brasiliensis; and another with Pr. clarkii intraspecific interactions. We starved the crayfish then allowed to interact in the presence of food. In interspecific fights we compared the number of attacks, time with the resource, frequency of won interactions of each species and the first species to reach the resource. Regarding the interspecific fights, Pr. clarkii attacked more often, spent more time with the resource, won more interactions and reached the resource first more often than Pa. brasiliensis. Interspecific fights escalated faster than intraspecific fights. The invasive crayfish’s ability to win might be enhanced due to ownership effects, and its impact is likely to be severe because of its life-history traits. We conclude that Pr. clarkii is definitely a threat for native crayfish, requiring that immediate actions be taken, such as dam construction and manual removal of Pr. clarkii.

This study reports new records of Procambarus clarkii Girard, 1852 in Southeastern Brazil and investigates its possible pathways of introduction. The Brazilian crayfish pet trade was surveyed with regard to species’ availability and price, reporting its persistence, even though illegal. An invasion risk analysis was performed by applying a protocol developed specifically to invasive freshwater invertebrates (FI-ISK). Procambarus clarkii has confirmed occurrences from urban and non-urban areas in the state of Sao Paulo, including the Jaragua State Park, an Atlantic Forest conservation area. The pet trade is an important introduction vector but some subsequent translocation can also be due to the release of live bait by anglers. Besides passive dispersal, these newly discovered populations, especially those located in non-urban areas, are likely to naturally disperse further through active spread and river drift of juveniles. Although confirmed colonized areas are all located in the state of Sao Paulo, the invasive risk analysis showed that P. clarkii is a potential highly invasive species for Brazil. These introductions have unknown consequences; however, many impacts are associated with this species establishment around the world, underlining the urgency to understand the invasion process in Brazil and develop efficient management techniques.

In many species, males increase their reproductive success by choosing high‐quality females. In natural populations, they interact with both virgin and mated females, which can store sperm in their spermatheca. Therefore, males elaborate strategies to avoid sperm competition. In the terrestrial isopod Armadillidium vulgare, females can store sperm and produce several clutches. Moreover, this species can be parasitized by Wolbachia, which feminizes genetic males, transforming them into functional females. Our study compared attractiveness and mate choice when a male is exposed to both virgin and experienced females (i.e., females who have produced offspring and rested for 6 months), with or without Wolbachia. Our results revealed that males are more attracted to virgin females than experienced females, even if these virgin females are parasitized. Moreover, the chemical analysis highlighted different odors in females according to their reproductive and infection (Wolbachia‐free or vertically Wolbachia‐infected) status. Males attempted copulation more frequently and for longer with virgin females, even if Wolbachia‐infected, while experienced females refused further copulation. The evolutionary consequences of both male choice and female resistance on their fitness are discussed in this study.

South America is considered a world biodiversity hotspot, especially for freshwater ecosystems where there is significant biodiversity and endemism across different taxonomic groups. Native South American crayfishes are characterized by small range distributions, high levels of endemism and specific habitat requirements. Although this group may be considered one of the most threatened among South American freshwater crustaceans, IUCN Red List assessments for most of these species are ‘data deficient’. IUCN assessments are technical evaluations of species risk of extinction based on biological indicators of population features, thereby providing a ‘conservation status’ for each species based on common and international standards. Attempts to assess the conservation status of native South American crayfishes have been limited mainly owing to a lack of fundamental data and also misinterpretations of present information. Thus, a revision of the state of knowledge of native South American crayfishes (taxonomy, phylogeny and distribution, genetics, ecology and threats) was carried out coupled with IUCN assessments of conservation status. Globally, the lack of information on the biology of these species is still the major obstacle to making reliable conservation status assessments. For this reason, the Data Deficient (DD) category is still appropriate for many species. However, based on the Extent of Occurrence (EOO) and severely fragmented populations, number of locations and decline in area, extent or quality of habitat, it is recommended that some species (especially Virilastacus spp.) should be moved to threatened categories (VU, EN or CR). The data suggest that others are appropriately in the Near Threatened (NT) category, because they almost reach the thresholds for threatened categories. The assessment of conservation status is essential to support future conservation actions, especially for species allocated to threatened categories. This study has identified new species under threat and also areas for future study to provide relevant data for conservation assessment for ‘data deficient’ species. Copyright © 2014 John Wiley & Sons, Ltd.

In 2007, the invasive crayfish Procambarus clarkii (Girard 1852) was identified for the first time in the “Parc Naturel Regional de la Brenne” (Indre department, Centre region, France). Ten infestation sites were found in the park, with 62 fishponds colonised. To better understand how the fishponds could be affected, and changes in invaded ponds, we followed crayfish burrowing activity in recently drained fishponds in two areas. Weekly investigations of burrowing activity by analysing their density, occupation and location with respect to the banks, and micro-habitat features were carried out for 2 months in spring. Burrow densities of 1.16 and 1.05 burrows m–2 were found at Le Terrier Blanc and Coudreau 3 respectively. Procambarus clarkii sought humid soil in a dry pond and preferred burrowing on silt substrates. While no statistical differences were found between sites, some differences were observed among weeks independently of the sites. The mean mouth diameter of burrows in the two sites was 5.7 cm (...

International audience; : Mitochondrial DNA (mtDNA) is usually depicted as a circular molecule, however, there is increasing evidence that linearization of mtDNA evolved independently many times in organisms such as fungi, unicellular eukaryotes, and animals. Recent observations in various models with linear mtDNA revealed the presence of conserved inverted repeats (IR) at both ends that, when they become single-stranded, may be able to fold on themselves to create telomeric-hairpins involved in genome architecture conversions. The atypical mtDNA of terrestrial isopods (Crustacea: Oniscidea) composed of linear monomers and circular dimers is an interesting model to study genome architecture conversions. Here, we present the mtDNA control region sequences of two species of the genus Armadillidium: A. vulgare and A. pelagicum. All features of arthropods mtDNA control regions are present (origin of replication, poly-T stretch, GA and TA-rich blocks and one variable domain), plus a conserved IR. This IR can potentially fold into a hairpin structure and is present in two different orientations among the A. vulgare populations: either in one sense or in its reverse complement. This polymorphism, also observed in a single individual (heteroplasmy), might be a signature of genome architecture conversions from linear to circular monomeric mtDNA via successive opening and closing of the molecules.

SUMMARY 1. Climate warming often leads to shifts in the strength and sign of agonistic interactions amongspecies, which in turn may change their distribution ranges. Notwithstanding the ubiquity of thisphenomenon, there is scant literature about how interspecific agonistic behaviour changes withaltered thermal regime, especially for invasive species such as three widespread North Americancrayfishes in Europe (Orconectes limosus, Procambarus clarkii and Pacifastacus leniusculus).2. We conducted a laboratory study to analyse some descriptors of agonistic behaviour in fightingdyads of similarly sized males of the three species’ combinations, both at 20 °C (the current maxi-mum water temperature in the study area, central France) and 27 °C (the maximum expected in thenext 80 years under the more pessimistic IPCC greenhouse gas emission scenario).3. The results showed significantly different responses to warming by the three crayfishes. At 27 °C,O. limosus spent more time motionless and P. leniusculus was more often the subordinate, indepen-dent of the opponent. On the contrary, the agonistic strategy of P. clarkii did not change with temper-ature: when engaged in fighting, this species outcompeted both O. limosus and P. leniusculus.4. Caution should be taken when extrapolating laboratory studies to the field, but these results,combined with outputs of previous modelling exercises, suggest that European catchments willbecome dominated by P. clarkii with climate warming. Ultimately, this might lead to impoverishedbiodiversity, simplified food webs and altered ecosystem services.Keywords: agonistic behaviour, alien species, interspecific competition, North American crayfishes,temperature

International audience; In Tunisia, while wetlands are considered as remarkable habitats for their faunal and floral diversity, few studies on the species diversity of terrestrial isopods were performed. To fill this gap, the spatio-temporal distribution of Oniscidea at Ghar El Melh lagoon (north-east of Tunisia) was analysed. Sampling was carried out with 50 × 50 cm quadrats along a perpendicular transect to the shoreline. Nine species of terrestrial isopods belonging to seven genera were identified. Chaetophiloscia elongata Dollfus, 1884 was the most abundant species in all seasons except for summer; its relative abundance ranged from 38.9% to 77% in summer and autumn, respectively. Hill diversity indices ranged from 0.86 to 0.94 and equitability indices from 0.33 and 0.68. The statistical analysis showed a significant difference of isopod species and plant associations among seasons. En Tunisie, si les zones humides sont considérées comme des habitats remarquables pour leur diversité faunistique et floristique, peu d'études ont été faites sur la diversité des isopodes terrestres. Pour combler cette lacune, nous avons étudié la distribution spatio-temporelle des Oniscidea de la lagune de Ghar El Mehl (au nord-est de la Tunisie). L' échantillonnage a été effectué avec un quadrat 50 x 50 cm, le long d'un transect perpendiculaire à la ligne de rivage. Neuf espèces d'isopodes terrestres appartenant à sept genres ont été identifiées. Quelle que soit la saison, Chaetophiloscia elongata Dollfus, 1884 est l'espèce la plus abondante exception faite pour la saison d'été; son abondance relative varie de 38,9 à 77 % en été et en automne respectivement. L'indice de diversité de Hill varie de 0,86 à 0,94 et l'équitabilité de 0,33 à 0,68. L'analyse statistique montre une différence significative de la distribution saisonnière des isopodes terrestres en fonction des associations végétales

International audience; This field study aimed at determining the effect of metal-polluted environments on fluctuating asymmetry (FA) level of Porcellio scaber as a measure of developmental stability (DS). For this, woodlice and litter were collected on 8 sites of northern France located either away from metal pollution source or near metallurgical smelters. Physico-chemical parameters such as pH, C/N ratio and CaCO(3) were measured in litter since they could have potential effects on woodlouse population. Moreover, Cd, Pb, and Zn concentrations in litter were determined to evaluate the contamination degree of each site. The metal body burdens were determined in woodlice to evaluate their impregnation degree. Fluctuating asymmetry levels on males and gravid females were performed on 9 traits (the 2nd and the 3rd articles of antennae, the 1st flagellum segment of the antennae, and the merus, carpus and propodus of the 6th and the 7th pereiopods) according (1) to each site and (2) to two habitat types (cf. metal-contaminated and uncontaminated habitats). Results showed close correlations between litter metal concentrations and metal body burdens in woodlice. However, contrary to the initial hypothesis that metal pollution would induce an increase of the FA level, this seemed to be lower for individuals from metal-contaminated habitats than for those from uncontaminated habitats, and particularly for males. The role of antennae and pereiopods on the foraging behavior and reproduction processes on woodlice were discussed and could explain these observations. (C) 2012 Elsevier Ltd. All rights reserved.

International audience; Nowadays, the distribution of the European native white-clawed crayfish (Austropotamobius pallipes) is restricted, fragmented and mainly located in headwater streams. To preserve this indigenous species, it is necessary to characterize its habitat preferences. Although this species is endangered, little was known about its ecological requirements until recently. Recent studies conducted throughout its distribution area indicate that water pollution is the main cause of its disappearance. In particular, A. pallipes seems very sensitive to organic pollution. However, no study has focused on the macroinvertebrate assemblages that co-occur with A. pallipes. In this study, seven streams located in the Deux-Sevres Departement (western France) containing wild populations of A. pallipes were qualitatively sampled in April 2004 and Ephemeroptera were identified to species level. These sites were also sampled according to the French biotic index "IBGN" during the summer of 2004. Several chemical parameters were also analyzed e.g. Dissolved Oxygen, pH, Ca, Turbidity, UV254mm, Conductivity, Total Organic Carbon (TOC) and Total Suspended Solids (TSS) The objectives of this study were: 1) to analyze the benthic invertebrate assemblage by determining the IBGN index in both reference zone (presence of A. pallipes) and zone without crayfish, 2) to identify the Ephemeroptera community in both zones to find some match with the presence of A. pallipes. The applied issue of this study is to use both physico-chemical criteria and Ephemeroptera communities to select suitable streams for a crayfish relocation program in the Poitou-Charentes region of France. It was found that (i) the IBGN scores did not separate the sites with/without A. pallipes (ii) Ephemeroptera diversity is statistically higher in sites with crayfish than in sites without (iii) there was a strong correlation between A. pallipes, species of Ephemeroptera mainly of Leptophlebiidae family (Habrophlebia fusca, Habrophlebia lauta and Paraleptophlebia submarginata) and dissolved oxygen at the study sites.

Summary 1. Habitat fragmentation of stream ecosystems often results in decreased connectivity between populations and lower population sizes. Hence, understanding how habitat fragmentation affects genetic erosion is important for the preservation of freshwater biodiversity, in particular, as small populations suffer from loss of genetic diversity through genetic drift and loss of fitness because of inbreeding, increasing the risk of extinction. 2. Here, we assess the impact of demographic factors on population differentiation in the endangered freshwater crayfish Austropotamobius pallipes by analysing population genetic structure, estimating effective population sizes and comparing levels of polymorphism at five microsatellite loci with density estimates of 10 populations within a small French catchment that has become progressively confined to headwaters over the last six decades. 3. Levels of expected heterozygosity and allelic richness per population were relatively low (0.214–0.396 and 1.6–2.6, respectively). We found strong genetic differentiation between these geographically close populations (FST = 0.283), with weak statistical evidence for a pattern of isolation by distance. Estimates of effective population size were low (

International audience; This study aimed at determining, in the laboratory, the effects of poplar litter collected in woody habitats contaminated by heavy metals on growth and metal accumulation in the terrestrial isopod Porcellio scaber. Cd, Pb, and Zn pseudototal and CaCl(2)-extractable concentrations in litter types were determined using AAS. Juveniles were fed ad libitum, individually, for 28 days with four litter types presenting an increasing gradient of metal contamination. Individuals were weighed every week and metal body burdens were determined at the end of the experiment. From the first week until the end of the experiment, a decrease in P. scaber growth related to the increase of metal concentration in litter types was recorded. Significant correlations were observed between metal body burdens and metal concentrations in litter types. However, Cd accumulation in woodlice appeared to be related to the Cd/Zn concentration ratio in litter types. All these results showed the potential of weight gain in P. scaber as a suitable indicator for litter quality assessment with ecological relevance.

International audience; As part of the Austropotamobius pallipes species complex, the crayfish Austropotamobius italicus is a species of community interest whose preservation requires the designation of Special Areas of Conservation (SACs) (Annex II, EU Habitats Directive). This study aimed at (1) assessing the conservation status of this threatened indigenous species by stock assessment in central Italy and (2) identifying some aspects of its elective habitat.

As intensive land-use practices may reduce available leaf litter, woodlice-important decomposers of leaf litter-may show a loss of biomass and a decrease in number of species. Their diversity as grassland detritivores could thus be a potential guide to ecosystem activity in natural and cultivated grasslands. Woodlice diversity was studied in different grassland types at three sites in Western France: Avon, with semi-natural grasslands; Fors, with mixed farming; Lusignan, with intensive farming. Woodlice were collected by hand in plot centres, borders and field boundaries. Isopod numbers were higher at Fors than at Lusignan; species assemblages were dominated by Philoscia muscorum at Lusignan whereas this species is less numerous at Fors than Armadillidium vulgare and Armadillidium nasatum. These results also differ with grassland type, with higher species diversity or number of individuals in temporary and permanent grasslands at Fors. Hedges were important in increasing isopod diversity within plots. Assemblages reflect grassland quality with high densities and diversity of woodlice in the permanent grasslands at Avon. (c) 2005 Elsevier SAS. All rights reserved.

One of the goals of the European network CRAYNET - entitled "European crayfish as keystone species-linking science, management and economics with sustainable environmental quality" - is to identify current crayfish protection programmes carried out in individual countries. During this roundtable held at the CRAYNET meeting in Innsbruck 2004, we tried to evaluate the projects that aimed directly at crayfish conservation or at habitat improvement in order to protect crayfish environments. Different approaches and new skills were discussed in order to increase understanding of the advances and positive results obtained on the management of native populations (species status, habitat, population, control of aliens, diseases etc.).

Native European freshwater crayfish (Astacida, Decapoda) are under severe pressure from habitat alteration, the introduction of nonindigenous species, and epizootic disease. Crayfish plague, an acute disease of freshwater crayfish caused by the fungus-like agent Aphanomyces astaci, was introduced into Europe in the mid-nineteenth century and is responsible for ongoing widespread epizootic mortality in native European populations. We reviewed recent developments and current practices in the field of crayfish pathology. The severity of crayfish plague has resulted in an overemphasis on it. Diagnostic methods for detecting fungi and fungal-like agents, and sometimes culturing them, are frequently the sole techniques used to investigate disease outbreaks in European freshwater crayfish. Consequently, the causes of a significant proportion of outbreaks are undetermined. Pathogen groups well known for causing disease in other crustaceans, such as viruses and rickettsia-like organisms, are poorly understood or unknown in European freshwater crayfish. Moreover, the pathogenic significance of some long-known pathogens of European freshwater crayfish remains obscure. For effective management of this culturally significant and threatened resource, there is an urgent need for researchers, diagnosticians, and resource managers to address the issue of disease in European freshwater crayfish from a broader perspective than has been applied previously.

A nucleotide sequence analysis of a portion of the mitochondrial large ribosomal subunit was performed to define the phylogeography of the threatened crayfish Austropotamobius (Decapoda; Astacidae) in Italy. We collected 61 specimens from 31 localities across the Italian peninsula. For the phylogenetic inference, we combined the 61 Austropotamobius spp sequences obtained from this study with 18 sequences deposited in GenBank and corresponding to Italian, French, Irish, Swiss, and Slovenian locations. Among the analysed sequences, 34 distinct haplotypes were detected. Our results confirmed the presence of both A. pallipes and A. italicus in the Italian peninsula and the existence within the latter species of a strong intraspecific genetic variation, due to the occurrence of four subspecies with a well-defined geographic distribution. From a conservation viewpoint, Italy, with its high haplotype variability, may be considered a 'hot spot' for the genetic diversity of the European native crayfish Austropotamobius. We suggest that re-introduction programs should be conducted with extreme caution in Italy, since not only the two Austropotamobius species but also the four A. italicus subspecies are genetically and taxonomically separate units and require independent conservation plans.

In the past, conservation programmes for a given species consisted in restoring the habitat and in translocating individuals without knowledge of their taxonomic status. Even if managers wanted to be informed, the “traditional taxonomy”, based on morphological characters, was discouraging because it could indicate several types of classification. This is the case for Austropotamobius pallipes, considered as a species complex. Today, conservation genetics aims to maintain, on one hand, the genetic specificity of populations (genetic integrity principle) and, on the other hand, the genetic diversity within and between populations (biodiversity principle), these basic principles being considered both at the level of protection measures and management measures. As an endangered species, A. pallipes is subjected to a loss of genetic diversity, a result of deterioration of water quality responsible for habitat fragmentation, with populations being confined to headwaters of the catchments. Consequently a certain degree of genetic variability must be maintained within the species because it governs the adaptation potential: the populations must be capable of responding to new environmental conditions. In A. pallipes, recent studies from several countries attempt to first describe the distribution of the present natural populations and secondly, by studying mitochondrial DNA, to clarify the taxonomy (number and identification of the present species and subspecies by phylogenetic inferences) and to assess the biogeographical history. These two preliminary steps are fundamental before defining conservation units and working at the catchment level, using highly polymorphic nuclear markers. The new approach has provided a good framework for research, with more frequent dialogues between geneticists and managers.

Since 1973, the red swamp crayfish, Procambarus clarkii, native to south-central United States and northeastern Mexico, has spread throughout Europe. Here, we surveyed the genetic variability of five European populations of the species using RAPD markers. Genetic variation was found to be so high as to uniquely fingerprint most of the surveyed individuals. Analysis of molecular variance (AMOVA) of the RAPD markers showed that 1) a large part of the genetic variation can be attributed to the differentiation among localities, and 2) the differentiation was mainly due to the separation of the samples from Louisiana with respect to the European set. A hypothesis emerged in which subsequent introductions of crayfish from different sources were performed. This hypothesis might explain the high genetic diversity observed within each population and the genetic differentiation among populations, as the result, respectively, of the introduction of different sets of crayfish and the casual bias of introductions. Although preliminary, our results suggest that RAPDs could be helpful in providing information about human-mediated introduced populations.

The phylogenetic relationships of the genus Austropotamobius were reviewed by the compilation of two recent genetic studies based on the partial nucleotide sequence of the mitochondrial RNA 16S gene. The results showed a well-resolved phylogeny revealing four distinct clades: A1, A2, A3 and B, supported by high bootstrap values. The clades A (including A1, A2, A3) and B are separated by a high genetic divergence (5%). In accordance with morphological and nuclear data, two species could be defined: A. italicus and A. pallipes, respectively. The average of genetic divergence within the major group A and B was 2.1% ± 1.2 and 0.9% ± 0.6 respectively. Three clades A1, A2 and A3 correspond mainly to crayfish sampled from Austria-Switzerland, South of Balkans and Italy-Spain respectively. On the basis of morphological, genetic and distribution data, a new systematic - based on two species A. pallipes and A. italicus with 3 subspecies A. i. carinthiacus, A. i. carsicus and A. i. italicus - could be proposed for the white-clawed crayfish species complex. We rejected the specific status of A. berndhauseri and A. i. lusitanicus given to the Swiss and Spanish crayfish respectively.

The white-clawed crayfish, Austropotamobius pallipes, an endangered species in Europe, was surveyed for genetic and morphological variation as part of a larger project aimed at clarifying its French stock structure. Analysis from four morphological characters discriminated two groups, one including the 8 stream populations and the other comprising a single pond population. Total mitochondrial DNA variation was examined by RFLP analysis using 11 restriction enzymes for 120 animals sampled from these 9 populations located in Poitou-Charentes region. Among the three haplotypes revealed, two were found in animals sampled from brook populations and the third haplotype was only found in individuals from the pond population. Mitochondrial DNA nucleotide diversity values within species ranged from 0.57 to 1.31%. The analysis of genetic variance showed no structuring of genetic variation by hydrographic basins and could reflect the impact of translocations by man although other explanations are possible.

Here we report a high level of mtDNA variationfrom RFLP analysis within A. p. pallipes from 21 French and 4British populations. Seventeen haplotypes were recorded among 269individuals. Nucleotide sequence divergence (p) among mtDNAhaplotypes ranged from 0.0019 to 0.0425. Nucleotide diversity (π)ranged from 0.01 to 0.006 (mean = 0.0031) and from 0 to 0.001(mean = 0.00037) for populations located in southern and northernFrance, respectively. Graphical representation from principalcoordinate analysis based on Nei's genetic distance values amongpopulations showed two groups, cluster A, including the 16populations sampled in the north-western and north-easternFrance, England and Wales and cluster B containing 9 populationssampled in the central and southern of France. No geneticdifferences were noted among the most northern French and Englishpopulations whereas marked interpopulation genetic diversity wasobserved in southern populations. Such genetic heterogeneityamong populations of A. p. pallipes appears to be related tohabitat fragmentation and subsequent recolonizations fromrefugial areas during the Pleistocene. Implications for theconservation of A. p. pallipes are discussed.

Summary The characterization of photoperiodic induction of sexual rest in Armadillidium vulgare females (a cosmopolitan species) shows that the photoperiodic curves relating to the cessation of reproduction are representative of long-days type species. Experiments made on photophase maintenance or reduction show that females are sensitive not only to such reduction but also to its magnitude. Furthermore, the photophase value is relative and depends on previous conditions experienced by the female and there is evidence for the existence of a circannual endogenous cycle in A. vulgare.

Under particular conditions of photoperiod and temperature, Armadillidium vulgare females, originating from a single population, might exhibit individual differences in the onset of reproduction and duration of the breeding period. In a population issued from a strain from middle latitudes, some females underwent only one parturial moult (northern tendency) and others three parturial moults (southern tendency). Females with an atypical northern phenology are the most numerous and tend to be found near the Danish population. In the latter, there is an asymmetrical response to laboratory selection (favourable to females with a longer breeding period). The asymmetrical variation in atypical individuals acts as a safety device against the unpredictability of the environment. The adaptation of this species, originally from the Mediterranean periphery, to a northern environment has led to a reduction in its capacity to breed over long periods of time. Populations from middle latitudes can undergo one or several parturial moults which enables the species to successfully colonize even far-away countries. These intrapopulation differences have an essential role and explain why Armadillidium vulgare is one of the most widely distributed species among Oniscidea.

This study presents a revised method for the extraction of mitochondrial genome (mtDNA) from crayfish species of aquacultural interest, Pacifastacus leniusculus. The mean size of the mitochondrial genome is approximately 18,000 bp. Restriction fragment length polymorphism (RFLP) analysis performed on the mtDNA has revealed extensive genetic variability within this species. The estimated percentage of nucleotide sequence divergence among the four haplotypes found for P. leniusculus ranges from 1.16 to 3.99%. These data suggest that RFLP analysis of mtDNA may provide greater resolution than protein electrophoresis for population identification among signal crayfish populations. This marker offers new avenues for aquaculture and for understanding the genetic structure and evolutionary history of crayfish populations.

1. The white-clawed crayfish Austropotamobius pallipes has a widespread distribution in Europe, but since the last century its distribution has been severely affected by a combination of factors, particularly the disease crayfish plague, introduced by foreign crayfish species. At present A. pallipes is considered as vulnerable and endangered and measures are being taken in a number of countries to conserve it. 2. The application of genetics to conservation is of practical value particularly where restocking is being considered. This study assesses levels of genetic differentiation from an analysis of mitochondrial DNA (mtDNA) variation by restriction fragment length polymorphism of four populations sampled on a European scale. Six different composite haplotypes were detected among sixty-four crayfish representing the four populations. mtDNA nucleon diversity values within species ranged from 0.63% to 12.35%. A close genetic similarity was found between British and French populations of A. pallipes. 3. Results show that mtDNA can be as a suitable diagnostic marker for measuring genetic diversity between crayfish populations and that such information is of use in planning crayfish conservation strategies.

If recovery programmes are to be initiated in England and Wales, it is very important to obtain information on how genetic variation is partitioned between the remaining populations for the endangered species Austropotamobius pallipes pallipes. A survey of the mtDNA genome, using 12 restriction enzymes revealed 3 haplotypes in 4 British populations. The study reveals a low level of genetic variation amongst four geographically distant populations. Moreover, the most widespread haplotype found in the British populations is also similar to those found in French populations; one of the rare haplotypes found in one English population is also widespread in French populations. Management of crayfish stocks may be possible at a national level however, a more extended study of mtDNA variation is needed to prove this conclusively.

L'ecrevisse a pattes blanches Austropotamobius pallipes pallipes a encore une large repartition en France mais, depuis le siecle dernier, les populations ont ete serieusement reduites a cause de la degradation des habitats suite a l'activite humaine et ont egalement ete decimees par la peste de l'ecrevisse, suite aux introductions d'especes d'ecrevisses exotiques. Si des actions de conservation d'A. pallipes sont urgentes a mettre en place, elles ne peuvent se faire sans une estimation prealable de la variabilite genetique des populations chez cette espece actuellement en voie de disparition. La variabilite de l'ADN mitochondrial (ADNmt) dans les populations naturelles est examinee par polymorphisme de la longueur des fragments de restriction a partir d'echantillons issus de quinze populations francaises et de six populations europeennes representatives de la repartition des trois sous-especes observees chez Austropotamobius pallipes, ceci afin d'examiner l'etendue de la variabilite genetique au sein de l'espece. Des considerations biogeographiques sont faites a partir des distances genetiques obtenues entre les trois sous-especes. L'etude revele un faible niveau de variabilite genetique au sein des populations anglaises, galloises et la plupart des populations francaises, ce qui correspond a une certaine homogeneite genetique du stock parmi les populations d'A. pallipes pallipes. En effet, les deux seules populations francaises presentant un haut niveau de variabilite genetique sont en fait des populations mixtes. La comparaison avec les resultats obtenus chez les populations europeennes montre que l'une est composee des deux sous-especes A. pallipes pallipes et A. pallipes italicus et la deuxieme d'A. pallipes italicus et A. pallipes lusitanicus. Les resultats prouvent que quelques tentatives de repeuplement, faites dans le passe a partir d'individus d'A. pallipes italicus et supposees avoir echoue, peuvent avoir reussi et que le stock astacicole francais ne doit pas correspondre a la seule sous-espece A. pallipes pallipes. Une premiere analyse realisee au niveau regional montre qu'il n'existe pas de structuration genetique entre les bassins hydrographiques, ce qui pourrait traduire l'intervention de l'homme pour des transferts de populations entre bassins. En consequence, l'ADNmt est un bon marqueur pour mesurer la variabilite genetique au sein des populations d'ecrevisses, pour cartographier precisement comment les trois sous-especes sont reparties en France et quelle est l'importance de chacune avant d'entreprendre toute operation de repeuplement de l'ecrevisse autochtone.

This paper describes patterns of sex and size dimorphism and allometric growth in a French population of the native crayfish species, Austropotamobius pallipes pallipes. The threatened status of this species shows the necessity to establish a suitable management to protect it. An efficient management requires an increase in our knowledge about existing populations. By using allometric relationships, we characterized the size at the onset of sexual maturity in both sexes and evaluated sexual dimorphism in this population. The size at the onset of sexual maturity appeared to be different in both sexes (20.1 mm POL in males and 18.17 mm POL in females). The sexual dimorphism, shown by the variables of claw length and abdominal width, was not closely related to the puberal moult. The growth rates of this population were very different from those shown by other European populations. Discriminant analysis was performed on the data, but it did not separate the juveniles of both sexes. This study provides fundamental results concerning the relative growth of A. pallipes which could be used to compare several French populations in the future.

Size at sexual maturity was determined by the allometric equation in three populations of Austropotamobius pallipes pallipes from the Poitou-Charentes region, France. Seven morphological characters were measured and POL (post orbital length) was used as a reference parameter. The puberal moult was identified by changes in the relative growth of CW (claw width) and CL (claw length) in both sexes. Males have shown variation of the relative growth of CW and CL at 19.15 mm of POL for the Gatineau (Gat) stream, 20.1 mm of POL for the Magnerolle (Mag) and 20.3 mm for the Fontaine Saint-Pierre (Fsp) populations, respectively. Sexual maturity of females occurred at 16.17 mm POL for the Fsp, 18.2 mm for the Mag and for the Gat. Geographic variation in A. pallipes was investigated using multivariate analysis of five morphometric characters on mature specimens. By canonical discriminant analysis, the Mag population was distinct from the other two populations. Results are discussed with regard to restocking strategy.

Several species of land snails, including Helix pomatia and Helix lucorum are consumed as food products. The main source of commercial competition is an imported African snail, Achatina fulica. The only way to distinguish between these species has been morphologically. We hypothesized a reliable method for identifying canned snails could be based on using PCR-RFLP analysis of mito-chondrial DNA. The molecular weights of the amplified fragments were perfectly identical, regardless of low extraction (fresh snails or cooked and canned samples). The whole amplified products (16S rRNA and 12S rRNA) made it possible to check any fraudulent label and identify the three species using four restriction enzymes (RFLP).