David Marcogliese - Academia.edu (original) (raw)

Papers by David Marcogliese

Detailed description of sampling methods and additional parasite observations. Supplementary resu... more Detailed description of sampling methods and additional parasite observations. Supplementary results Tables and Figures, and a comprehensive record of all parasite species observed to infect guppies across previously published studies

abstract: The separation of Clinostomum complanatum Rudolphi, 1814 and Clinostomum marginatum Ru... more abstract: The separation of Clinostomum complanatum Rudolphi, 1814 and Clinostomum marginatum Rudolphi, 1819 has long been unclear. Recent data confirm the validity of the junior species, C. marginatum, by ∼1% differences in its 18S rDNA sequences. We collected adults and metacercariae of C. complanatum and C. marginatum and found reliable morphological differences in the genital complex at both developmental stages. In addition, we identified basic morphometrics (distance between suckers, body width) in metacercariae that may be useful for discriminating the species. The morphological differences were supported by the comparison of sequences of internal transcribed spacers of ribosomal DNA and of the mitochondrial gene cytochrome c oxidase I (COI) from 39 specimens. In 36 specimens, the average divergence between the species was 7.3% in ITS and 19.4% in COI sequences. Two specimens from North America and 1 from Europe had sequences that did not allow them to be clearly allied with...

Archives of Environmental Contamination and Toxicology, 2011

Wild-caught European perch (Perca fluviatilis) were exposed in the laboratory to untreated bleach... more Wild-caught European perch (Perca fluviatilis) were exposed in the laboratory to untreated bleached pulp and paper mill effluent in two separate experiments. The first experiment was conducted at 7-8°C using effluent concentrations of 5 and 10%, and the second experiment was conducted at ambient river temperature of 4-20°C using an effluent concentration of 1%. Trichodinid ciliates were identified and enumerated at the end of the exposure using a mucus subsampling technique from gill and skin as well as a formalin immersion technique, which provided total counts on each fish. Four different trichodinid species were identified on the fish. Prevalence of infection, mean number, and mean density of Trichodina spp. decreased on fish exposed to effluents compared with controls. Prevalence of infection, mean number, and mean density of Trichodinella epizootica decreased on fish exposed to 5% and 10% effluents but increased on fish exposed to 1% effluents compared with controls. These results demonstrate that trichodinid ciliates vary in their susceptibility to at least certain types of contaminants and cautions against using trichodinids as environmental indicators without delineating species.

Archives of Environmental Contamination and Toxicology, 2001

burden of habitats result into a different survival of these free-living parasite stages.

Encyclopedia of Aquatic Ecotoxicology, 2013

International audienc

Supplementary Table S1; Individual infection infracommunity data for each male guppy. Supplementa... more Supplementary Table S1; Individual infection infracommunity data for each male guppy. Supplementary Table S2; Parasite prevalence and mean abundances in 18 populations of guppy.

Parasitology

Abstract Abstract Natural and anthropogenic stressors, including parasites and pesticides, may in... more Abstract Abstract Natural and anthropogenic stressors, including parasites and pesticides, may induce oxidative stress in animals. Measuring oxidative stress responses in sentinel species that are particularly responsive to environmental perturbations not only provides insight into host physiology but is also a useful readout of ecosystem health. Newly metamorphosed northern leopard frogs (Lithobates pipiens), a sentinel species, were collected from agricultural and non-agricultural wetlands exposed to varying concentrations of the herbicide atrazine. Significant effects of certain parasites' abundance and their interaction with atrazine exposure on frog oxidative stress were identified. Specifically, increased protein levels were detected in frogs infected with echinostome metacercariae. In addition, the nematode Oswaldocruzia sp. was significantly associated with increased thiol concentration and catalase activity. Significant parasite × atrazine interactions were observed for atrazine exposure and the abundance of Oswaldocruzia sp. on thiol, as thiol concentrations increased with parasite abundance at low atrazine localities and decreased in high atrazine wetlands. In addition, a significant interaction between the abundances of Oswaldocruzia sp. and gorgoderid trematodes on thiol concentrations was observed. These findings demonstrate that studies of oxidative stress on animals in natural ecosystems should account for the confounding effects of parasitism, particularly for amphibians in agricultural landscapes.

Interactions between parasite species may influence their distribution and abundance within commu... more Interactions between parasite species may influence their distribution and abundance within communities. Experimental single species infections of Diplostomum spp. in the gut of the definitive host, ringed-billed gulls (Larus delawarensis Ord, 1815), were compared to mixed species infections to explore interactions among parasites. Three species of Diplostomum (Digenea), designated as Diplostomum sp. 1, Diplostomum sp. 4 and Diplostomum baeri Dubois, 1937 were examined for intestinal distribution and fecundity in single and mixed infections. In single species infections, most specimens of Diplostomum sp. 1 and D. baeri were recovered from the mid-region of the intestine, whereas Diplostomum sp. 4 were mainly present in the anterior region. Significant spatial displacement Page 2 of 38 https://mc06.manuscriptcentral.com/cjz-pubs Canadian Journal of Zoology

Diplostomum spp. (Trematoda) are widespread parasites of freshwater and brackish water fishes (Ch... more Diplostomum spp. (Trematoda) are widespread parasites of freshwater and brackish water fishes (Chappell, 1995), and they infect different parts of the fish eyes such as lens, humour

Third-stage larvae of Hysterothylacium aduncum were found infecting the hermit crab Pagurus acadi... more Third-stage larvae of Hysterothylacium aduncum were found infecting the hermit crab Pagurus acadianus, the gammaridean amphipod Proboloides holmesi, and the caprellid amphipod Caprella linearis. Five nematodes were found in 3 infected hermit crabs (100%) collected from the brackish Bras d'Or Lakes, Cape Breton Island, Nova Scotia. One infected hermit crab (0.3%) and 2 specimens of P. holmesi (7.7%) on the Scotian Shelf (the continental shelf off Nova Scotia) near Sable Island were each infected with single worms. One specimen of C. linearis (0.06%) in the St. Croix River, close to where it enters Passamaquoddy Bay, New Brunswick, was infected with a single nematode. No larva of H. aduncum was found in 18,210 amphipods belonging to 32 species other than P. holmesi and C. linearis, 1,254 mud shrimp (Crangon septemspinosa), 1,147 cumaceans, 417 isopods, or 4,819 polychaetes collected near Sable Island nor in 780 other hermit crabs (P. arcuatus and P. pubescens) collected from vario...

Journal of Helminthology

The round goby (Neogobius melanostomus) is a successful invader of the Great Lakes–St Lawrence Ri... more The round goby (Neogobius melanostomus) is a successful invader of the Great Lakes–St Lawrence River basin that harbours a number of local parasites. The most common are metacercariae of the genus Diplostomum. Species of Diplostomum are morphologically difficult to distinguish but can be separated using molecular techniques. While a few species have been sequenced from invasive round gobies in this study system, their relative abundance has not been documented. The purpose of this study was to determine the species composition of Diplostomum spp. and their relative abundance in round gobies in the St Lawrence River by sequencing the barcode region of cytochrome c oxidase I. In 2007–2011, Diplostomum huronense (=Diplostomum sp. 1) was the most common, followed in order by Diplostomum indistinctum (=Diplostomum sp. 4) and Diplostomum indistinctum sensu Galazzo, Dayanandan, Marcogliese & McLaughlin (2002). In 2012, the most common species infecting the round goby in the St Lawrence Riv...

Royal Society Open Science

The guppy ( Poecilia reticulata ) is a model species in ecology and evolution. Many studies have ... more The guppy ( Poecilia reticulata ) is a model species in ecology and evolution. Many studies have examined effects of predators on guppy behaviour, reproduction, survival strategies, feeding and other life-history traits, but few have studied variation in their parasite diversity. We surveyed parasites of 18 Trinidadian populations of guppy, to provide insight on the geographical mosaic of parasite variability, which may act as a source of natural selection acting on guppies. We found 21 parasite species, including five new records for Trinidad. Spatial variation in parasite diversity was significantly higher than that of piscine predators, and significant variation in parasite richness among individuals and populations was correlated with: (i) host size, (ii) snail species richness, and (iii) the distance between populations. Differences in parasite species richness are likely to play an important, yet underestimated role in the biology of this model species of vertebrate ecology an...

Aquatic Invasions

Brown bullhead (Ameiurus nebulosus), pumpkinseed (Lepomis gibbosus) and bluegill (Lepomis macroch... more Brown bullhead (Ameiurus nebulosus), pumpkinseed (Lepomis gibbosus) and bluegill (Lepomis macrochirus) collected from the Paskamansett River, Massachusetts, were infected with larval Anguillicola crassus. These are new records of paratenic hosts of A. crassus in North America, although infected brown bullhead and pumpkinseed have been found in Europe. Prevalence was 64-100% and mean abundance 5.50-9.32. Morphological identification of L3 was confirmed by molecular sequence analysis of mitochondrial cytochrome c oxidase subunit I (COI, barcode) and the nuclear large subunit nLSU (28S) ribosomal RNA genes. Analysis of COI sequences from larval and adult worms from the Paskamansett River and nLSU (sequences from those L3 and adults from the Mira River, Cape Breton, Nova Scotia) showed that the COI gene better discriminated among species of Anguillicola than did the nLSU gene. At least 9% difference in sequence similarity was found between A. crassus and other species with COI, whereas there was overlap in the nLSU sequence similarity between A. crassus and other Anguillicola species. Comparative sequence analysis suggests that North American A. crassus originated from Japan, whereas European A. crassus originated from Taiwan, in agreement with previous studies. Two single nucleotide polymorphism (SNP) markers, SNP 390 and SNP 91 in COI and nLSU, respectively, are informative for differentiating between North American and European sources. Analyses with both genes also supports the monophyly of the Anguillicolidae.

Evolutionary applications, 2018

Both field and experimental evolution studies have demonstrated that organisms naturally or artif... more Both field and experimental evolution studies have demonstrated that organisms naturally or artificially exposed to environmental oncogenic factors can, sometimes rapidly, evolve specific adaptations to cope with pollutants and their adverse effects on fitness. Although numerous pollutants are mutagenic and carcinogenic, little attention has been given to exploring the extent to which adaptations displayed by organisms living in oncogenic environments could inspire novel cancer treatments, through mimicking the processes allowing these organisms to prevent or limit malignant progression. Building on a substantial knowledge base from the literature, we here present and discuss this progressive and promising research direction, advocating closer collaboration between the fields of medicine, ecology, and evolution in the war against cancer.

The Journal of parasitology, Jan 8, 2018

Species composition and diversity of dactylogyrids were compared on gills of wild and cultured go... more Species composition and diversity of dactylogyrids were compared on gills of wild and cultured goldfish Carassius auratus from 3 naturally populated lakes and 3 stocked aquaculture ponds in Hubei province of China to examine the differences in the gill parasite community between in natural and farmed waters. Of the 7 detected species of Dactylogyrus, all were found in lakes and 5 in ponds, Dactylogyrus inexpectatus and Dactylogyrus anchoratus being absent from ponds. No significant correlation was found between the species richness and habitat area or host size, nor was there a significant difference in mean species richness between lakes (0.41-0.65) and ponds (0.30-0.76). Brillouin's diversity in lakes (0.049-0.067) was higher than in ponds (0.024-0.046), but not significantly so. Although the diversity of parasite communities was higher in wild goldfish, higher mean abundance of some Dactylogyrus species was found in cultured goldfish. Based on Bray-Curtis similarity, it was d...

Aquatic Invasions

With economic globalization, a growing number of exotic species are integrating into food webs ou... more With economic globalization, a growing number of exotic species are integrating into food webs outside their historical range, giving rise to the development of novel associations between exotic hosts and local parasites. Depending on the parasite's ability to survive and undergo transmission, invasive exotic hosts can act as sinks or reservoirs for native parasites, thus either decreasing or increasing their overall abundance in indigenous hosts. Here we evaluate the relative host competence of the invasive round goby (Neogobius melanostomus) for a native acanthocephalan species, Neoechinorhynchus tenellus, in the Great Lakes-St. Lawrence River basin. The second most abundant helminth acquired by the round goby, N. tenellus was found to die prematurely in this novel paratenic (transport) host. On average, nearly half of the cysts found in gobies sampled at 14 localities contained dead and degenerated cystacanths. Parasite remnants in hepatic tissues were surrounded by mast cells indicative of an innate inflammatory host reaction. Conversely, cystacanths of N. tenellus were intact in johnny darters (Etheostoma nigrum) and logperch (Percina caprodes), two co-occurring native paratenic hosts. We conclude that the round goby is currently a poor host for N. tenellus relative to indigenous counterparts. As such, this abundant exotic fish could act as a sink and impair the transmission of N. tenellus, possibly resulting in parasite dilution in native fish competitors. The significantly higher intensity and prevalence of infection in johnny darters at a goby-free locality supports this hypothesis. However, this new host-parasite relationship might evolve with time toward an attenuation of the goby immune defense reaction. Indeed, we found a negative correlation between the frequency of cystacanth degradation and time since gobies established in a given locality, with the lowest degeneration rate in the St. Clair River area where the round goby was first recorded in the Great Lakes-St. Lawrence basin. The dilution effect, if it exists, could then be temporary.

International Journal for Parasitology: Parasites and Wildlife

As they integrate into recipient food webs, invasive exotic species may influence the population ... more As they integrate into recipient food webs, invasive exotic species may influence the population dynamics of native parasites. Here we assess the potential impact of the Eurasian round goby (Neogobius melanostomus) on the abundance of eyeflukes of the genus Diplostomum, which are common parasites in fishes of the St. Lawrence River (Canada). Analyses of data collected over nearly two decades revealed that the infection levels in three native fish [spottail shiner (Notropis hudsonius), golden shiner (Notemigonus crysoleucas) yellow perch (Perca flavescens)] declined sharply throughout the St. Lawrence River after the introduction of the goby. At two sites where data were collected at regular time intervals, declines of Diplostomum spp. in spottail shiners occurred within two years of the goby's first recorded appearance, with prevalence dropping as much as 77e80% between pre-invasion and post-invasion periods. Furthermore, in localities where gobies remained scarce, infection in native species did not change significantly over time. Altogether, these observations suggest that gobies play a role in the eyefluke collapse. The decline in populations of the main definitive host (ring-billed gulls, Larus delawarensis) and changes in hydrology during periods of parasite recruitment were not strongly supported as alternate explanations for this phenomenon. Since other snail-transmitted trematodes with similar life cycles to Diplostomum spp. did not show the same decreasing pattern, we conclude that eyeflukes did not decline as a result of snail depletion due to goby predation. Rather, we suggest that gobies acted as decoys, diluting the infection. As Diplostomum spp. occurred at lower abundance in gobies than in native fish hosts, the replacement of native fish with exotic gobies in the diet of gulls might have played a part in reducing parasite transmission. In contrast to the typically negative impact of invasions, the gobyinduced decline of this pathogen may have beneficial effects for native fishes.

Integrative and Comparative Biology

Evaluation of the potential response of parasites of aquatic organisms to climate change illustra... more Evaluation of the potential response of parasites of aquatic organisms to climate change illustrates the complexity of hostparasite relationships and the difficulty of making accurate predictions for these biological systems. In recent years, trematodes have proven to be a useful model to evaluate potential effects of climate change on host-parasite systems. In the first part of this article, I review and summarize results from the recent use of trematodes and specifically their early life cycle stages in testing effects of temperature and other climate-driven variables on life history traits and hostparasite interactions. However, metazoan parasites in aquatic systems respond directly to changes in temperature and also to changes in other climate-driven abiotic parameters that are mediated directly on the parasite or indirectly through changes in the distribution and abundance of their hosts. In addition, though most research to date has focused on the effects of temperature, it is imperative to explore effects of precipitation, eutrophication, acidification, water levels and flow rates, habitat loss and fragmentation, extreme weather, and other forms of anthropogenic interference on the distribution of both hosts and parasites, as these biotic and abiotic factors and stressors do not operate independently of climate. In the second part of this article, the effects of some of these factors derived from our own field studies, as well as other investigations both in the laboratory and the field, on the distribution, abundance, and community structure of parasites in aquatic ecosystems will be reviewed and discussed.

Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology

Daily energy expenditure (DEE) in animals is influenced by many factors although the impact of st... more Daily energy expenditure (DEE) in animals is influenced by many factors although the impact of stressors remains largely unknown. The objective of this study was to determine how multiple physiological stressors (parasite infection and contaminant exposure) and natural challenges (energy-demanding activities and weather conditions) may affect DEE in nesting ring-billed gulls (Larus delawarensis) exposed to high concentrations of persistent organic contaminants (POPs). Physical activity, temperature, gastrointestinal parasitic worm abundance, relative spleen mass, plasma thyroid hormone levels and liver concentrations of POPs were determined; field metabolic rate (FMR) was used as a measure of DEE. For females, FMR was best explained by the percent of time spent in nest-site attendance and exposure to temperatures below their lower critical limit (65% of variation); 32% was also explained by relative spleen mass. In males, FMR was best explained by the number of hours spent in nest site attendance and either relative spleen mass or liver concentrations of tetra-brominated diphenyl ethers (tetra-BDEs) (55% of variation). Relative spleen mass, as an important factor relating to FMR, was best explained by models with a combination of parasite abundance (Diplostomum for females and Eucoleus for males) in a negative relationship, and liver POP concentrations (p,p'-DDE for females and tetra-BDEs for males) in a positive relationship (34%, 55% of variation for females and males, respectively). This study demonstrates that immune activity may be an important factor affecting energy expenditure in ring-billed gulls, and that contaminants and parasite abundance may have both a direct and/or indirect influence on FMR.

Parasitology, Jan 15, 2017

Field surveys indicate that host population size, rather than density, is the most important dete... more Field surveys indicate that host population size, rather than density, is the most important determinant of monogenean infection dynamics. To verify this prediction, epidemic parameters were monitored for 70 days at five host population sizes held at constant density using a goldfish - Gyrodactylus kobayashii laboratory model. During the first 20 days, the rate of increase of prevalence and mean abundance was faster in small host populations. Total mean prevalence and total mean abundance throughout the experiment were not significantly affected by host population sizes. Higher transmission rates were detected in larger host populations. However, there were no significant differences in effective contact rates among the five host populations on each sampling day during the first 20 days, implying that contact rates may be saturated at a sufficiently high host density. These results demonstrate that the epidemic occurs more quickly in smaller host populations at the beginning of the ...

Detailed description of sampling methods and additional parasite observations. Supplementary resu... more Detailed description of sampling methods and additional parasite observations. Supplementary results Tables and Figures, and a comprehensive record of all parasite species observed to infect guppies across previously published studies

abstract: The separation of Clinostomum complanatum Rudolphi, 1814 and Clinostomum marginatum Ru... more abstract: The separation of Clinostomum complanatum Rudolphi, 1814 and Clinostomum marginatum Rudolphi, 1819 has long been unclear. Recent data confirm the validity of the junior species, C. marginatum, by ∼1% differences in its 18S rDNA sequences. We collected adults and metacercariae of C. complanatum and C. marginatum and found reliable morphological differences in the genital complex at both developmental stages. In addition, we identified basic morphometrics (distance between suckers, body width) in metacercariae that may be useful for discriminating the species. The morphological differences were supported by the comparison of sequences of internal transcribed spacers of ribosomal DNA and of the mitochondrial gene cytochrome c oxidase I (COI) from 39 specimens. In 36 specimens, the average divergence between the species was 7.3% in ITS and 19.4% in COI sequences. Two specimens from North America and 1 from Europe had sequences that did not allow them to be clearly allied with...

Archives of Environmental Contamination and Toxicology, 2011

Wild-caught European perch (Perca fluviatilis) were exposed in the laboratory to untreated bleach... more Wild-caught European perch (Perca fluviatilis) were exposed in the laboratory to untreated bleached pulp and paper mill effluent in two separate experiments. The first experiment was conducted at 7-8°C using effluent concentrations of 5 and 10%, and the second experiment was conducted at ambient river temperature of 4-20°C using an effluent concentration of 1%. Trichodinid ciliates were identified and enumerated at the end of the exposure using a mucus subsampling technique from gill and skin as well as a formalin immersion technique, which provided total counts on each fish. Four different trichodinid species were identified on the fish. Prevalence of infection, mean number, and mean density of Trichodina spp. decreased on fish exposed to effluents compared with controls. Prevalence of infection, mean number, and mean density of Trichodinella epizootica decreased on fish exposed to 5% and 10% effluents but increased on fish exposed to 1% effluents compared with controls. These results demonstrate that trichodinid ciliates vary in their susceptibility to at least certain types of contaminants and cautions against using trichodinids as environmental indicators without delineating species.

Archives of Environmental Contamination and Toxicology, 2001

burden of habitats result into a different survival of these free-living parasite stages.

Encyclopedia of Aquatic Ecotoxicology, 2013

International audienc

Supplementary Table S1; Individual infection infracommunity data for each male guppy. Supplementa... more Supplementary Table S1; Individual infection infracommunity data for each male guppy. Supplementary Table S2; Parasite prevalence and mean abundances in 18 populations of guppy.

Parasitology

Abstract Abstract Natural and anthropogenic stressors, including parasites and pesticides, may in... more Abstract Abstract Natural and anthropogenic stressors, including parasites and pesticides, may induce oxidative stress in animals. Measuring oxidative stress responses in sentinel species that are particularly responsive to environmental perturbations not only provides insight into host physiology but is also a useful readout of ecosystem health. Newly metamorphosed northern leopard frogs (Lithobates pipiens), a sentinel species, were collected from agricultural and non-agricultural wetlands exposed to varying concentrations of the herbicide atrazine. Significant effects of certain parasites' abundance and their interaction with atrazine exposure on frog oxidative stress were identified. Specifically, increased protein levels were detected in frogs infected with echinostome metacercariae. In addition, the nematode Oswaldocruzia sp. was significantly associated with increased thiol concentration and catalase activity. Significant parasite × atrazine interactions were observed for atrazine exposure and the abundance of Oswaldocruzia sp. on thiol, as thiol concentrations increased with parasite abundance at low atrazine localities and decreased in high atrazine wetlands. In addition, a significant interaction between the abundances of Oswaldocruzia sp. and gorgoderid trematodes on thiol concentrations was observed. These findings demonstrate that studies of oxidative stress on animals in natural ecosystems should account for the confounding effects of parasitism, particularly for amphibians in agricultural landscapes.

Interactions between parasite species may influence their distribution and abundance within commu... more Interactions between parasite species may influence their distribution and abundance within communities. Experimental single species infections of Diplostomum spp. in the gut of the definitive host, ringed-billed gulls (Larus delawarensis Ord, 1815), were compared to mixed species infections to explore interactions among parasites. Three species of Diplostomum (Digenea), designated as Diplostomum sp. 1, Diplostomum sp. 4 and Diplostomum baeri Dubois, 1937 were examined for intestinal distribution and fecundity in single and mixed infections. In single species infections, most specimens of Diplostomum sp. 1 and D. baeri were recovered from the mid-region of the intestine, whereas Diplostomum sp. 4 were mainly present in the anterior region. Significant spatial displacement Page 2 of 38 https://mc06.manuscriptcentral.com/cjz-pubs Canadian Journal of Zoology

Diplostomum spp. (Trematoda) are widespread parasites of freshwater and brackish water fishes (Ch... more Diplostomum spp. (Trematoda) are widespread parasites of freshwater and brackish water fishes (Chappell, 1995), and they infect different parts of the fish eyes such as lens, humour

Third-stage larvae of Hysterothylacium aduncum were found infecting the hermit crab Pagurus acadi... more Third-stage larvae of Hysterothylacium aduncum were found infecting the hermit crab Pagurus acadianus, the gammaridean amphipod Proboloides holmesi, and the caprellid amphipod Caprella linearis. Five nematodes were found in 3 infected hermit crabs (100%) collected from the brackish Bras d'Or Lakes, Cape Breton Island, Nova Scotia. One infected hermit crab (0.3%) and 2 specimens of P. holmesi (7.7%) on the Scotian Shelf (the continental shelf off Nova Scotia) near Sable Island were each infected with single worms. One specimen of C. linearis (0.06%) in the St. Croix River, close to where it enters Passamaquoddy Bay, New Brunswick, was infected with a single nematode. No larva of H. aduncum was found in 18,210 amphipods belonging to 32 species other than P. holmesi and C. linearis, 1,254 mud shrimp (Crangon septemspinosa), 1,147 cumaceans, 417 isopods, or 4,819 polychaetes collected near Sable Island nor in 780 other hermit crabs (P. arcuatus and P. pubescens) collected from vario...

Journal of Helminthology

The round goby (Neogobius melanostomus) is a successful invader of the Great Lakes–St Lawrence Ri... more The round goby (Neogobius melanostomus) is a successful invader of the Great Lakes–St Lawrence River basin that harbours a number of local parasites. The most common are metacercariae of the genus Diplostomum. Species of Diplostomum are morphologically difficult to distinguish but can be separated using molecular techniques. While a few species have been sequenced from invasive round gobies in this study system, their relative abundance has not been documented. The purpose of this study was to determine the species composition of Diplostomum spp. and their relative abundance in round gobies in the St Lawrence River by sequencing the barcode region of cytochrome c oxidase I. In 2007–2011, Diplostomum huronense (=Diplostomum sp. 1) was the most common, followed in order by Diplostomum indistinctum (=Diplostomum sp. 4) and Diplostomum indistinctum sensu Galazzo, Dayanandan, Marcogliese & McLaughlin (2002). In 2012, the most common species infecting the round goby in the St Lawrence Riv...

Royal Society Open Science

The guppy ( Poecilia reticulata ) is a model species in ecology and evolution. Many studies have ... more The guppy ( Poecilia reticulata ) is a model species in ecology and evolution. Many studies have examined effects of predators on guppy behaviour, reproduction, survival strategies, feeding and other life-history traits, but few have studied variation in their parasite diversity. We surveyed parasites of 18 Trinidadian populations of guppy, to provide insight on the geographical mosaic of parasite variability, which may act as a source of natural selection acting on guppies. We found 21 parasite species, including five new records for Trinidad. Spatial variation in parasite diversity was significantly higher than that of piscine predators, and significant variation in parasite richness among individuals and populations was correlated with: (i) host size, (ii) snail species richness, and (iii) the distance between populations. Differences in parasite species richness are likely to play an important, yet underestimated role in the biology of this model species of vertebrate ecology an...

Aquatic Invasions

Brown bullhead (Ameiurus nebulosus), pumpkinseed (Lepomis gibbosus) and bluegill (Lepomis macroch... more Brown bullhead (Ameiurus nebulosus), pumpkinseed (Lepomis gibbosus) and bluegill (Lepomis macrochirus) collected from the Paskamansett River, Massachusetts, were infected with larval Anguillicola crassus. These are new records of paratenic hosts of A. crassus in North America, although infected brown bullhead and pumpkinseed have been found in Europe. Prevalence was 64-100% and mean abundance 5.50-9.32. Morphological identification of L3 was confirmed by molecular sequence analysis of mitochondrial cytochrome c oxidase subunit I (COI, barcode) and the nuclear large subunit nLSU (28S) ribosomal RNA genes. Analysis of COI sequences from larval and adult worms from the Paskamansett River and nLSU (sequences from those L3 and adults from the Mira River, Cape Breton, Nova Scotia) showed that the COI gene better discriminated among species of Anguillicola than did the nLSU gene. At least 9% difference in sequence similarity was found between A. crassus and other species with COI, whereas there was overlap in the nLSU sequence similarity between A. crassus and other Anguillicola species. Comparative sequence analysis suggests that North American A. crassus originated from Japan, whereas European A. crassus originated from Taiwan, in agreement with previous studies. Two single nucleotide polymorphism (SNP) markers, SNP 390 and SNP 91 in COI and nLSU, respectively, are informative for differentiating between North American and European sources. Analyses with both genes also supports the monophyly of the Anguillicolidae.

Evolutionary applications, 2018

Both field and experimental evolution studies have demonstrated that organisms naturally or artif... more Both field and experimental evolution studies have demonstrated that organisms naturally or artificially exposed to environmental oncogenic factors can, sometimes rapidly, evolve specific adaptations to cope with pollutants and their adverse effects on fitness. Although numerous pollutants are mutagenic and carcinogenic, little attention has been given to exploring the extent to which adaptations displayed by organisms living in oncogenic environments could inspire novel cancer treatments, through mimicking the processes allowing these organisms to prevent or limit malignant progression. Building on a substantial knowledge base from the literature, we here present and discuss this progressive and promising research direction, advocating closer collaboration between the fields of medicine, ecology, and evolution in the war against cancer.

The Journal of parasitology, Jan 8, 2018

Species composition and diversity of dactylogyrids were compared on gills of wild and cultured go... more Species composition and diversity of dactylogyrids were compared on gills of wild and cultured goldfish Carassius auratus from 3 naturally populated lakes and 3 stocked aquaculture ponds in Hubei province of China to examine the differences in the gill parasite community between in natural and farmed waters. Of the 7 detected species of Dactylogyrus, all were found in lakes and 5 in ponds, Dactylogyrus inexpectatus and Dactylogyrus anchoratus being absent from ponds. No significant correlation was found between the species richness and habitat area or host size, nor was there a significant difference in mean species richness between lakes (0.41-0.65) and ponds (0.30-0.76). Brillouin's diversity in lakes (0.049-0.067) was higher than in ponds (0.024-0.046), but not significantly so. Although the diversity of parasite communities was higher in wild goldfish, higher mean abundance of some Dactylogyrus species was found in cultured goldfish. Based on Bray-Curtis similarity, it was d...

Aquatic Invasions

With economic globalization, a growing number of exotic species are integrating into food webs ou... more With economic globalization, a growing number of exotic species are integrating into food webs outside their historical range, giving rise to the development of novel associations between exotic hosts and local parasites. Depending on the parasite's ability to survive and undergo transmission, invasive exotic hosts can act as sinks or reservoirs for native parasites, thus either decreasing or increasing their overall abundance in indigenous hosts. Here we evaluate the relative host competence of the invasive round goby (Neogobius melanostomus) for a native acanthocephalan species, Neoechinorhynchus tenellus, in the Great Lakes-St. Lawrence River basin. The second most abundant helminth acquired by the round goby, N. tenellus was found to die prematurely in this novel paratenic (transport) host. On average, nearly half of the cysts found in gobies sampled at 14 localities contained dead and degenerated cystacanths. Parasite remnants in hepatic tissues were surrounded by mast cells indicative of an innate inflammatory host reaction. Conversely, cystacanths of N. tenellus were intact in johnny darters (Etheostoma nigrum) and logperch (Percina caprodes), two co-occurring native paratenic hosts. We conclude that the round goby is currently a poor host for N. tenellus relative to indigenous counterparts. As such, this abundant exotic fish could act as a sink and impair the transmission of N. tenellus, possibly resulting in parasite dilution in native fish competitors. The significantly higher intensity and prevalence of infection in johnny darters at a goby-free locality supports this hypothesis. However, this new host-parasite relationship might evolve with time toward an attenuation of the goby immune defense reaction. Indeed, we found a negative correlation between the frequency of cystacanth degradation and time since gobies established in a given locality, with the lowest degeneration rate in the St. Clair River area where the round goby was first recorded in the Great Lakes-St. Lawrence basin. The dilution effect, if it exists, could then be temporary.

International Journal for Parasitology: Parasites and Wildlife

As they integrate into recipient food webs, invasive exotic species may influence the population ... more As they integrate into recipient food webs, invasive exotic species may influence the population dynamics of native parasites. Here we assess the potential impact of the Eurasian round goby (Neogobius melanostomus) on the abundance of eyeflukes of the genus Diplostomum, which are common parasites in fishes of the St. Lawrence River (Canada). Analyses of data collected over nearly two decades revealed that the infection levels in three native fish [spottail shiner (Notropis hudsonius), golden shiner (Notemigonus crysoleucas) yellow perch (Perca flavescens)] declined sharply throughout the St. Lawrence River after the introduction of the goby. At two sites where data were collected at regular time intervals, declines of Diplostomum spp. in spottail shiners occurred within two years of the goby's first recorded appearance, with prevalence dropping as much as 77e80% between pre-invasion and post-invasion periods. Furthermore, in localities where gobies remained scarce, infection in native species did not change significantly over time. Altogether, these observations suggest that gobies play a role in the eyefluke collapse. The decline in populations of the main definitive host (ring-billed gulls, Larus delawarensis) and changes in hydrology during periods of parasite recruitment were not strongly supported as alternate explanations for this phenomenon. Since other snail-transmitted trematodes with similar life cycles to Diplostomum spp. did not show the same decreasing pattern, we conclude that eyeflukes did not decline as a result of snail depletion due to goby predation. Rather, we suggest that gobies acted as decoys, diluting the infection. As Diplostomum spp. occurred at lower abundance in gobies than in native fish hosts, the replacement of native fish with exotic gobies in the diet of gulls might have played a part in reducing parasite transmission. In contrast to the typically negative impact of invasions, the gobyinduced decline of this pathogen may have beneficial effects for native fishes.

Integrative and Comparative Biology

Evaluation of the potential response of parasites of aquatic organisms to climate change illustra... more Evaluation of the potential response of parasites of aquatic organisms to climate change illustrates the complexity of hostparasite relationships and the difficulty of making accurate predictions for these biological systems. In recent years, trematodes have proven to be a useful model to evaluate potential effects of climate change on host-parasite systems. In the first part of this article, I review and summarize results from the recent use of trematodes and specifically their early life cycle stages in testing effects of temperature and other climate-driven variables on life history traits and hostparasite interactions. However, metazoan parasites in aquatic systems respond directly to changes in temperature and also to changes in other climate-driven abiotic parameters that are mediated directly on the parasite or indirectly through changes in the distribution and abundance of their hosts. In addition, though most research to date has focused on the effects of temperature, it is imperative to explore effects of precipitation, eutrophication, acidification, water levels and flow rates, habitat loss and fragmentation, extreme weather, and other forms of anthropogenic interference on the distribution of both hosts and parasites, as these biotic and abiotic factors and stressors do not operate independently of climate. In the second part of this article, the effects of some of these factors derived from our own field studies, as well as other investigations both in the laboratory and the field, on the distribution, abundance, and community structure of parasites in aquatic ecosystems will be reviewed and discussed.

Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology

Daily energy expenditure (DEE) in animals is influenced by many factors although the impact of st... more Daily energy expenditure (DEE) in animals is influenced by many factors although the impact of stressors remains largely unknown. The objective of this study was to determine how multiple physiological stressors (parasite infection and contaminant exposure) and natural challenges (energy-demanding activities and weather conditions) may affect DEE in nesting ring-billed gulls (Larus delawarensis) exposed to high concentrations of persistent organic contaminants (POPs). Physical activity, temperature, gastrointestinal parasitic worm abundance, relative spleen mass, plasma thyroid hormone levels and liver concentrations of POPs were determined; field metabolic rate (FMR) was used as a measure of DEE. For females, FMR was best explained by the percent of time spent in nest-site attendance and exposure to temperatures below their lower critical limit (65% of variation); 32% was also explained by relative spleen mass. In males, FMR was best explained by the number of hours spent in nest site attendance and either relative spleen mass or liver concentrations of tetra-brominated diphenyl ethers (tetra-BDEs) (55% of variation). Relative spleen mass, as an important factor relating to FMR, was best explained by models with a combination of parasite abundance (Diplostomum for females and Eucoleus for males) in a negative relationship, and liver POP concentrations (p,p'-DDE for females and tetra-BDEs for males) in a positive relationship (34%, 55% of variation for females and males, respectively). This study demonstrates that immune activity may be an important factor affecting energy expenditure in ring-billed gulls, and that contaminants and parasite abundance may have both a direct and/or indirect influence on FMR.

Parasitology, Jan 15, 2017

Field surveys indicate that host population size, rather than density, is the most important dete... more Field surveys indicate that host population size, rather than density, is the most important determinant of monogenean infection dynamics. To verify this prediction, epidemic parameters were monitored for 70 days at five host population sizes held at constant density using a goldfish - Gyrodactylus kobayashii laboratory model. During the first 20 days, the rate of increase of prevalence and mean abundance was faster in small host populations. Total mean prevalence and total mean abundance throughout the experiment were not significantly affected by host population sizes. Higher transmission rates were detected in larger host populations. However, there were no significant differences in effective contact rates among the five host populations on each sampling day during the first 20 days, implying that contact rates may be saturated at a sufficiently high host density. These results demonstrate that the epidemic occurs more quickly in smaller host populations at the beginning of the ...