Du, Louis H., Verneau, Olivier, Gross, Timothy S. (2007): Polystoma floridana n. sp. (Monogenea: ... more Du, Louis H., Verneau, Olivier, Gross, Timothy S. (2007): Polystoma floridana n. sp. (Monogenea: Polystomatidae) a parasite in the green tree frog, Hyla cinerea (Schneider), of North America. Zootaxa 1663: 33-45, DOI: 10.5281/zenodo.179988
We reviewed several published and ongoing studies concerning monogenean communities. Patterns of ... more We reviewed several published and ongoing studies concerning monogenean communities. Patterns of species richness, host specificity, community structure and host-parasite coevolutionary interaction were carefully analysed, and hypotheses of evolutionary processes are proposed. The structuring of monogenean communities seems to be related to both ecological and historical constraints. The database supports an absence of intra- and interspecific competition in monogeneans. Species richness seems to be more due to host characteristics than to parasite interactions. Monogeneans seem to specialise on large hosts, leading to greater species richness on those hosts. The morphometric evolution of attachment and copulatory organs support the hypothesis of a reproductive segregation among conspecifics parasitising the same host(s). It also suggests the existence of concurrent adaptive and non-adaptive processes. The general absence of a coevolutionary pattern between host and parasites also s...
Rivers are representative of the overall contamination found in their catchment area. Contaminant... more Rivers are representative of the overall contamination found in their catchment area. Contaminant concentrations in watercourses depend on numerous factors including land use and rainfall events. Globally, in Mediterranean regions, rainstorms are at the origin of fluvial multipollution phenomena as a result of Combined Sewer Overflows (CSOs) and floods. Large loads of urban-associated microorganisms, including faecal bacteria, are released from CSOs which place public health - as well as ecosystems - at risk. The impacts of freshwater contamination on river ecosystems have not yet been adequately addressed, as is the case for the release of pollutant mixtures linked to extreme weather events. In this context, microbial communities provide critical ecosystem services as they are the only biological compartment capable of degrading or transforming pollutants. Through the use of 16S rRNA gene metabarcoding of environmental DNA at different seasons and during a flood event in a typical Mediterranean coastal river, we show that the impacts of multipollution phenomena on structural shifts in the particle-attached riverine bacteriome were greater than those of seasonality. Key players were identified via multivariate statistical modelling combined with network module eigengene analysis. These included species highly resistant to pollutants as well as pathogens. Their rapid response to contaminant mixtures makes them ideal candidates as potential early biosignatures of multipollution stress. Multiple resistance gene transfer is likely enhanced with drastic consequences for the environment and human-health, particularly in a scenario of intensification of extreme hydrological events.
Madapolystoma n. g. (Monogenea, Polystomatidae), is proposed for a new genus of polystomatid from... more Madapolystoma n. g. (Monogenea, Polystomatidae), is proposed for a new genus of polystomatid from the urinary bladder of the Malagasy poison frogs of the genus Mantella (family Mantellidae), with the description of one new species. This is the second anuran polystome to be described from Madagascar. The parasites are small with a maximum body length of less than 3 mm. The two gut caeca have a few diverticulae but no prehaptoral anastomoses and are confluent posteriorly. The haptor bears six well-developed suckers and one pair of hamuli. A single small ovary lies in mid-body while the single follicular testis lies posteriorly in the body. Vaginae are present. The new genus is unique among all known polystomes in that it apparently has no free-swimming ciliated larvae but instead is characterized by advanced intra-uterine development with larvae developing hamuli and even suckers while still in utero. Based on molecular phylogenetic data, the closest relative of Madapolystoma is the g...
Increasing anthropogenic activities, like agricultural practices, constitute the main causes of t... more Increasing anthropogenic activities, like agricultural practices, constitute the main causes of the loss of water quality and disruption of freshwater ecosystems. High concentrations of pesticides, as shown under experimental conditions, can indeed impact freshwater animals. In Southern France, especially in the Pyrénées-Orientales department, because agricultural activities are mainly based on fruit crops and vineyards, glyphosate and AMPA were detected in some watercourses. Thereby we investigated the effects of degraded waters on the physiology of the endemic endangered freshwater species, namely the Mediterranean pond turtle Mauremys leprosa, in contrasted environments along the same rivers on the one hand and between different rivers on the other. We measured the activity and gene expression of two enzymes involved in the oxidative detoxification processes, namely the Catalase and the Superoxide dismutase. We showed significant variations in the Catalase gene expression and activity within turtles of the Fosseille River depending of their location, i.e. upstream or downstream of the wastewater treatment plants (WTP). Because agricultural environments are similar all along this river, they can no be longer considered as the unique source of turtle stress. The processed waters discharged by the WTP, which contribute to watercourses degradation, could therefore considerably impact the biodiversity of the freshwater environments.
SUMMARY In an interconnected world, the international pet trade on wild animals is becoming incre... more SUMMARY In an interconnected world, the international pet trade on wild animals is becoming increasingly important. As a consequence, non-native parasite species are introduced, which affect the health of wildlife and contribute to the loss of biodiversity. Because the investigation of parasite diversity within vulnerable host species implies the molecular identification of large samples of parasite eggs, the sequencing of DNA barcodes is time-consuming and costly. Thereby, the objectives of our study were to apply the high resolution melting (HRM) approach for species determination from pools of parasite eggs. Molecular assays were validated on flatworm parasites (polystomes) infecting the Mediterranean pond turtle Mauremys leprosa and the invasive red-eared slider Trachemys scripta elegans in French natural environments. HRM analysis results indicated that double or multiple parasitic infections could be detected from wild animal populations. They also showed that the cycle of par...
The North American red-eared slider Trachemys scripta elegans, which is nowadays considered among... more The North American red-eared slider Trachemys scripta elegans, which is nowadays considered among the world’s worst invasive species, could constitute a real threat to native freshwater turtles. Because this species shares the same habitats of the European pond turtle Emys orbicularis since its introduction in the European wetlands, we surveyed populations of both alien and indigenous species in France and Spain in order to determine the diversity of platyhelminth parasites (Monogenea, Polystomatidae) in natural environments and to evaluate the levels of risks associated with parasitism. DNA barcoding procedure based on partial cytochrome c oxydase I sequences revealed ten monogenean parasite species within E. orbicularis populations and/or captive animals among which at least eight could be considered as introduced parasites from American freshwater turtles. Results indicated that host switching could have occurred either in natural environments or in captivity, when indigenous turtles were kept with exotic species, demonstrating that captive turtles could act as reservoirs of parasites. The presence of non-native parasite species within wild populations of E. orbicularis in the European freshwater ecosystems also highlighted the risks that these parasites may pose on the survival of natural turtle’s populations and on the dynamics of native parasites.
Polystomatid flatworms in chelonians are divided into three genera, i.e. Polystomoides Ward, 1917... more Polystomatid flatworms in chelonians are divided into three genera, i.e. Polystomoides Ward, 1917, Polystomoidella Price, 1939 and Neopolystoma Price, 1939, according to the number of haptoral hooks. Among the about 55 polystome species that are known to date from the 327 modern living chelonians, only four species of Polystomoides are currently recognised within the 45 South American freshwater turtles. During 2012, several sites in the vicinity of the cities Cayenne and Kaw in French Guiana were investigated for freshwater turtles. Turtles were collected at six sites and the presence of polystomatid flatworms was assessed from the presence of polystome eggs released by infected specimens. Among the three turtle species that were collected, no polystomes were found in the gibba turtle Mesoclemmys gibba (Schweigger, 1812). The spot-legged turtle Rhinoclemmys punctularia (Daudin, 1801) was infected with two species of Neopolystoma Price, 1939, one in the conjunctival sacs and the oth...
Contaminants found in watercourses are not only the result of anthropogenic activities but also d... more Contaminants found in watercourses are not only the result of anthropogenic activities but also depend on river's seasonal hydrodynamics. This is particularly true in Mediterranean climate regions where long dry periods are interrupted by strong rainfalls. Storm events remobilize particles from soils and sediments and, as a consequence, the load of particulate matter in rivers can be quite considerable, severely affecting water quality. Nevertheless, an absence of fieldwork studies exists concerning the simultaneous dynamics of mixtures of pollutants in river waters, particularly during strong rainfalls and floods. Our study assessed the concentrations of six families of pollutants, including pesticides, at these events, and compared them to those observed at drought sampling periods. We have used as model a typical Mediterranean coastal river from Southeast France, the Têt River, whose hydrodynamics and major elements fluxes have been fairly investigated. As expected, our resul...
Apres avoir effectue l'historique des connaissances concernant les relations evolutives hotes... more Apres avoir effectue l'historique des connaissances concernant les relations evolutives hotes-parasites, nous avons entrepris l'analyse des processus evolutifs (coevolution, cospeciation, captures et rythmes d'evolution) regissant les interactions durables a travers le modele biologique poissons (teleosteens) helminthes (cestodes). Nos resultats, qui reposent sur l'examen des phylogenies de sept especes hotes et de leurs parasites, etablies par trois approches moleculaires (electrophorese des isoenzymes, hybridations adn/adn et sequencage partiel du gene ribosomique 18s et de l'its1), montrent que: les phylogenies hotes et parasites ne sont pas congruentes et nous amenent a rejeter l'hypothese de coevolution au sein de cette association heterospecifique ; les taux d'evolution moleculaire intra-lignee ne sont pas similaires. Cependant, les taux d'evolution compares du gene 18s entre la lignee poissons et la lignee bothriocephales semblent globalement du meme ordre de grandeur ; la divergence nucleotidique entre paires d'hotes est superieure a celle estimee entre parasites. De plus, les hotes les plus apparentes sont plus divergents que les parasites les moins apparentes. Le groupe parasite semble donc plus jeune. Ces resultats doivent etre interpretes comme la resultante de deux processus: une colonisation sequentielle des hotes, suivie de speciation ; l'explosion massive d'un parasite ubiquiste en un complexe d'especes. Cette radiation doit trouver son origine lors d'evenements paleoclimatiques
Novel fossil discoveries have contributed to our understanding of the evolutionary appearance of ... more Novel fossil discoveries have contributed to our understanding of the evolutionary appearance of parasitism in flatworms. Furthermore, genetic analyses with greater coverage have shifted our views on the coevolution of parasitic flatworms and their hosts. The putative record of parasitic flatworms is consistent with extant host associations and so can be used to put constraints on the evolutionary origin of the parasites themselves. The future lies in new molecular clock analyses combined with additional discoveries of exceptionally preserved flatworms associated with hosts and coprolites. Besides direct evidence, the host fossil record and biogeography have the potential to constrain their evolutionary history, albeit with caution needed to avoid circularity, and a need for calibrations to be implemented in the most conservative way. This might result in imprecise, but accurate divergence estimates for the evolution of parasitic flatworms.
Six M. leprosa turtles were collected in the south of France. • Infected with Polystomoides sp. a... more Six M. leprosa turtles were collected in the south of France. • Infected with Polystomoides sp. and Neopolystoma sp. in the bladder. • Housed individually in plastic boxes containing water to the depth of about 20 mm. • Containers were placed outside to expose them to environmental temperatures. • Parasite egg production was monitored daily over a period of 26 days. • Local climatological data was obtained from the University of Perpignan weather station.
Parasite host-switching from the invasive American red-eared slider, Trachemys scripta elegans, t... more Parasite host-switching from the invasive American red-eared slider, Trachemys scripta elegans, to the native Mediterranean pond turtle, Mauremys leprosa, in natural environments
Du, Louis H., Verneau, Olivier, Gross, Timothy S. (2007): Polystoma floridana n. sp. (Monogenea: ... more Du, Louis H., Verneau, Olivier, Gross, Timothy S. (2007): Polystoma floridana n. sp. (Monogenea: Polystomatidae) a parasite in the green tree frog, Hyla cinerea (Schneider), of North America. Zootaxa 1663: 33-45, DOI: 10.5281/zenodo.179988
We reviewed several published and ongoing studies concerning monogenean communities. Patterns of ... more We reviewed several published and ongoing studies concerning monogenean communities. Patterns of species richness, host specificity, community structure and host-parasite coevolutionary interaction were carefully analysed, and hypotheses of evolutionary processes are proposed. The structuring of monogenean communities seems to be related to both ecological and historical constraints. The database supports an absence of intra- and interspecific competition in monogeneans. Species richness seems to be more due to host characteristics than to parasite interactions. Monogeneans seem to specialise on large hosts, leading to greater species richness on those hosts. The morphometric evolution of attachment and copulatory organs support the hypothesis of a reproductive segregation among conspecifics parasitising the same host(s). It also suggests the existence of concurrent adaptive and non-adaptive processes. The general absence of a coevolutionary pattern between host and parasites also s...
Rivers are representative of the overall contamination found in their catchment area. Contaminant... more Rivers are representative of the overall contamination found in their catchment area. Contaminant concentrations in watercourses depend on numerous factors including land use and rainfall events. Globally, in Mediterranean regions, rainstorms are at the origin of fluvial multipollution phenomena as a result of Combined Sewer Overflows (CSOs) and floods. Large loads of urban-associated microorganisms, including faecal bacteria, are released from CSOs which place public health - as well as ecosystems - at risk. The impacts of freshwater contamination on river ecosystems have not yet been adequately addressed, as is the case for the release of pollutant mixtures linked to extreme weather events. In this context, microbial communities provide critical ecosystem services as they are the only biological compartment capable of degrading or transforming pollutants. Through the use of 16S rRNA gene metabarcoding of environmental DNA at different seasons and during a flood event in a typical Mediterranean coastal river, we show that the impacts of multipollution phenomena on structural shifts in the particle-attached riverine bacteriome were greater than those of seasonality. Key players were identified via multivariate statistical modelling combined with network module eigengene analysis. These included species highly resistant to pollutants as well as pathogens. Their rapid response to contaminant mixtures makes them ideal candidates as potential early biosignatures of multipollution stress. Multiple resistance gene transfer is likely enhanced with drastic consequences for the environment and human-health, particularly in a scenario of intensification of extreme hydrological events.
Madapolystoma n. g. (Monogenea, Polystomatidae), is proposed for a new genus of polystomatid from... more Madapolystoma n. g. (Monogenea, Polystomatidae), is proposed for a new genus of polystomatid from the urinary bladder of the Malagasy poison frogs of the genus Mantella (family Mantellidae), with the description of one new species. This is the second anuran polystome to be described from Madagascar. The parasites are small with a maximum body length of less than 3 mm. The two gut caeca have a few diverticulae but no prehaptoral anastomoses and are confluent posteriorly. The haptor bears six well-developed suckers and one pair of hamuli. A single small ovary lies in mid-body while the single follicular testis lies posteriorly in the body. Vaginae are present. The new genus is unique among all known polystomes in that it apparently has no free-swimming ciliated larvae but instead is characterized by advanced intra-uterine development with larvae developing hamuli and even suckers while still in utero. Based on molecular phylogenetic data, the closest relative of Madapolystoma is the g...
Increasing anthropogenic activities, like agricultural practices, constitute the main causes of t... more Increasing anthropogenic activities, like agricultural practices, constitute the main causes of the loss of water quality and disruption of freshwater ecosystems. High concentrations of pesticides, as shown under experimental conditions, can indeed impact freshwater animals. In Southern France, especially in the Pyrénées-Orientales department, because agricultural activities are mainly based on fruit crops and vineyards, glyphosate and AMPA were detected in some watercourses. Thereby we investigated the effects of degraded waters on the physiology of the endemic endangered freshwater species, namely the Mediterranean pond turtle Mauremys leprosa, in contrasted environments along the same rivers on the one hand and between different rivers on the other. We measured the activity and gene expression of two enzymes involved in the oxidative detoxification processes, namely the Catalase and the Superoxide dismutase. We showed significant variations in the Catalase gene expression and activity within turtles of the Fosseille River depending of their location, i.e. upstream or downstream of the wastewater treatment plants (WTP). Because agricultural environments are similar all along this river, they can no be longer considered as the unique source of turtle stress. The processed waters discharged by the WTP, which contribute to watercourses degradation, could therefore considerably impact the biodiversity of the freshwater environments.
SUMMARY In an interconnected world, the international pet trade on wild animals is becoming incre... more SUMMARY In an interconnected world, the international pet trade on wild animals is becoming increasingly important. As a consequence, non-native parasite species are introduced, which affect the health of wildlife and contribute to the loss of biodiversity. Because the investigation of parasite diversity within vulnerable host species implies the molecular identification of large samples of parasite eggs, the sequencing of DNA barcodes is time-consuming and costly. Thereby, the objectives of our study were to apply the high resolution melting (HRM) approach for species determination from pools of parasite eggs. Molecular assays were validated on flatworm parasites (polystomes) infecting the Mediterranean pond turtle Mauremys leprosa and the invasive red-eared slider Trachemys scripta elegans in French natural environments. HRM analysis results indicated that double or multiple parasitic infections could be detected from wild animal populations. They also showed that the cycle of par...
The North American red-eared slider Trachemys scripta elegans, which is nowadays considered among... more The North American red-eared slider Trachemys scripta elegans, which is nowadays considered among the world’s worst invasive species, could constitute a real threat to native freshwater turtles. Because this species shares the same habitats of the European pond turtle Emys orbicularis since its introduction in the European wetlands, we surveyed populations of both alien and indigenous species in France and Spain in order to determine the diversity of platyhelminth parasites (Monogenea, Polystomatidae) in natural environments and to evaluate the levels of risks associated with parasitism. DNA barcoding procedure based on partial cytochrome c oxydase I sequences revealed ten monogenean parasite species within E. orbicularis populations and/or captive animals among which at least eight could be considered as introduced parasites from American freshwater turtles. Results indicated that host switching could have occurred either in natural environments or in captivity, when indigenous turtles were kept with exotic species, demonstrating that captive turtles could act as reservoirs of parasites. The presence of non-native parasite species within wild populations of E. orbicularis in the European freshwater ecosystems also highlighted the risks that these parasites may pose on the survival of natural turtle’s populations and on the dynamics of native parasites.
Polystomatid flatworms in chelonians are divided into three genera, i.e. Polystomoides Ward, 1917... more Polystomatid flatworms in chelonians are divided into three genera, i.e. Polystomoides Ward, 1917, Polystomoidella Price, 1939 and Neopolystoma Price, 1939, according to the number of haptoral hooks. Among the about 55 polystome species that are known to date from the 327 modern living chelonians, only four species of Polystomoides are currently recognised within the 45 South American freshwater turtles. During 2012, several sites in the vicinity of the cities Cayenne and Kaw in French Guiana were investigated for freshwater turtles. Turtles were collected at six sites and the presence of polystomatid flatworms was assessed from the presence of polystome eggs released by infected specimens. Among the three turtle species that were collected, no polystomes were found in the gibba turtle Mesoclemmys gibba (Schweigger, 1812). The spot-legged turtle Rhinoclemmys punctularia (Daudin, 1801) was infected with two species of Neopolystoma Price, 1939, one in the conjunctival sacs and the oth...
Contaminants found in watercourses are not only the result of anthropogenic activities but also d... more Contaminants found in watercourses are not only the result of anthropogenic activities but also depend on river's seasonal hydrodynamics. This is particularly true in Mediterranean climate regions where long dry periods are interrupted by strong rainfalls. Storm events remobilize particles from soils and sediments and, as a consequence, the load of particulate matter in rivers can be quite considerable, severely affecting water quality. Nevertheless, an absence of fieldwork studies exists concerning the simultaneous dynamics of mixtures of pollutants in river waters, particularly during strong rainfalls and floods. Our study assessed the concentrations of six families of pollutants, including pesticides, at these events, and compared them to those observed at drought sampling periods. We have used as model a typical Mediterranean coastal river from Southeast France, the Têt River, whose hydrodynamics and major elements fluxes have been fairly investigated. As expected, our resul...
Apres avoir effectue l'historique des connaissances concernant les relations evolutives hotes... more Apres avoir effectue l'historique des connaissances concernant les relations evolutives hotes-parasites, nous avons entrepris l'analyse des processus evolutifs (coevolution, cospeciation, captures et rythmes d'evolution) regissant les interactions durables a travers le modele biologique poissons (teleosteens) helminthes (cestodes). Nos resultats, qui reposent sur l'examen des phylogenies de sept especes hotes et de leurs parasites, etablies par trois approches moleculaires (electrophorese des isoenzymes, hybridations adn/adn et sequencage partiel du gene ribosomique 18s et de l'its1), montrent que: les phylogenies hotes et parasites ne sont pas congruentes et nous amenent a rejeter l'hypothese de coevolution au sein de cette association heterospecifique ; les taux d'evolution moleculaire intra-lignee ne sont pas similaires. Cependant, les taux d'evolution compares du gene 18s entre la lignee poissons et la lignee bothriocephales semblent globalement du meme ordre de grandeur ; la divergence nucleotidique entre paires d'hotes est superieure a celle estimee entre parasites. De plus, les hotes les plus apparentes sont plus divergents que les parasites les moins apparentes. Le groupe parasite semble donc plus jeune. Ces resultats doivent etre interpretes comme la resultante de deux processus: une colonisation sequentielle des hotes, suivie de speciation ; l'explosion massive d'un parasite ubiquiste en un complexe d'especes. Cette radiation doit trouver son origine lors d'evenements paleoclimatiques
Novel fossil discoveries have contributed to our understanding of the evolutionary appearance of ... more Novel fossil discoveries have contributed to our understanding of the evolutionary appearance of parasitism in flatworms. Furthermore, genetic analyses with greater coverage have shifted our views on the coevolution of parasitic flatworms and their hosts. The putative record of parasitic flatworms is consistent with extant host associations and so can be used to put constraints on the evolutionary origin of the parasites themselves. The future lies in new molecular clock analyses combined with additional discoveries of exceptionally preserved flatworms associated with hosts and coprolites. Besides direct evidence, the host fossil record and biogeography have the potential to constrain their evolutionary history, albeit with caution needed to avoid circularity, and a need for calibrations to be implemented in the most conservative way. This might result in imprecise, but accurate divergence estimates for the evolution of parasitic flatworms.
Six M. leprosa turtles were collected in the south of France. • Infected with Polystomoides sp. a... more Six M. leprosa turtles were collected in the south of France. • Infected with Polystomoides sp. and Neopolystoma sp. in the bladder. • Housed individually in plastic boxes containing water to the depth of about 20 mm. • Containers were placed outside to expose them to environmental temperatures. • Parasite egg production was monitored daily over a period of 26 days. • Local climatological data was obtained from the University of Perpignan weather station.
Parasite host-switching from the invasive American red-eared slider, Trachemys scripta elegans, t... more Parasite host-switching from the invasive American red-eared slider, Trachemys scripta elegans, to the native Mediterranean pond turtle, Mauremys leprosa, in natural environments
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Papers by Olivier Verneau