scholarly journals Effects of Road De-Icing Salts on Two Amphibian Species, Rana Sylvatica and Rana Pipiens, and Their Trematode Parasites

2021 ◽  
Author(s):  
Dino Milotic
Keyword(s):  
Rana Sylvatica ◽  
Amphibian Declines ◽  
High Salt ◽  
Amphibian Species ◽  
Wood Frogs ◽  
Leopard Frogs ◽  
Larval Amphibians ◽  
Potential Contaminant ◽  
Northern Leopard Frogs ◽  
Host Parasite

With ongoing amphibian declines, it is essential to determine possible contributors such as diseases and environmental contaminants that may increase susceptibility. A potential contaminant is road salt (mainly NaCl), which leaches into aquatic environments. I examined whether road salts make larval amphibians (tadpoles) more susceptible to trematode parasite infection, and also how these affect free-living trematode infectious stages (cercariae). I exposed Rana sylvatica (wood frogs) and R. pipiens (northern leopard frogs) to control, medium (400 mg/L), and high salt (800 mg/L) treatments, and then to trematodes. High salt tended to reduce wood frog anti-parasite behaviour and resistance to infection but the opposite was seen for R. pipiens, although these tadpoles had elevated lymphocyte counts in high salinity. Trematodes were differentially affected by increased salinities. The results suggest that host-parasite-environment interactions are complex, with species differentially affected by contaminants, which may lead to community shifts in predominant hosts and parasite species.

scholarly journals Effects of Road De-Icing Salts on Two Amphibian Species, Rana Sylvatica and Rana Pipiens, and Their Trematode Parasites

2021 ◽  
Author(s):  
Dino Milotic
Keyword(s):  
Rana Sylvatica ◽  
Amphibian Declines ◽  
High Salt ◽  
Amphibian Species ◽  
Wood Frogs ◽  
Leopard Frogs ◽  
Larval Amphibians ◽  
Potential Contaminant ◽  
Northern Leopard Frogs ◽  
Host Parasite

With ongoing amphibian declines, it is essential to determine possible contributors such as diseases and environmental contaminants that may increase susceptibility. A potential contaminant is road salt (mainly NaCl), which leaches into aquatic environments. I examined whether road salts make larval amphibians (tadpoles) more susceptible to trematode parasite infection, and also how these affect free-living trematode infectious stages (cercariae). I exposed Rana sylvatica (wood frogs) and R. pipiens (northern leopard frogs) to control, medium (400 mg/L), and high salt (800 mg/L) treatments, and then to trematodes. High salt tended to reduce wood frog anti-parasite behaviour and resistance to infection but the opposite was seen for R. pipiens, although these tadpoles had elevated lymphocyte counts in high salinity. Trematodes were differentially affected by increased salinities. The results suggest that host-parasite-environment interactions are complex, with species differentially affected by contaminants, which may lead to community shifts in predominant hosts and parasite species.

Immediate and lag effects of pesticide exposure on parasite resistance in larval amphibians

Parasitology ◽  
2017 ◽  
Vol 144 (6) ◽  
pp. 817-822 ◽  
Author(s):  
KATHERINE M. POCHINI ◽  
JASON T. HOVERMAN
Keyword(s):  
Species Interactions ◽  
Pesticide Exposure ◽  
Parasite Clearance ◽  
Ecological Communities ◽  
Lag Effects ◽  
Leopard Frogs ◽  
Larval Amphibians ◽  
Parasite Infections ◽  
Northern Leopard Frogs ◽  
Host Parasite

SUMMARYAcross host–parasite systems, there is evidence that pesticide exposure increases parasite loads and mortality following infection. However, whether these effects are driven by reductions in host resistance to infection or slower rates of parasite clearance is often unclear. Using controlled laboratory experiments, we examined the ability of larval northern leopard frogs (Lithobates pipiens) and American toads (Anaxyrus americanus) to resist and clear trematode (Echinoparyphium sp.) infections following exposure to the insecticide carbaryl. Northern leopard frogs exposed to 1 mg L−1 of carbaryl had 61% higher parasite loads compared with unexposed individuals, while there was no immediate effect of carbaryl on parasite encystment in American toads. However, when tadpoles were exposed to carbaryl and moved to freshwater for 14 days before the parasite challenge, we recovered 37 and 63% more parasites from carbaryl-exposed northern leopard frogs and American toads, respectively, compared with the control. No effects on clearance were found for either species. Collectively, our results suggest that pesticide exposure can reduce the ability of amphibians to resist parasite infections and that these effects can persist weeks following exposure. It is critical for researchers to incorporate species interactions into toxicity studies to improve our understanding of how contaminants affect ecological communities.

Variation in amount of surrounding forest habitat influences the initial orientation of juvenile amphibians emigrating from breeding ponds

2008 ◽  
Vol 86 (2) ◽  
pp. 141-146 ◽  
Author(s):  
Leroy J. Walston ◽  
Stephen J. Mullin
Keyword(s):  
Positive Relationship ◽  
Rana Sylvatica ◽  
Environmental Cues ◽  
Bufo Americanus ◽  
Forest Habitat ◽  
Amphibian Species ◽  
Wood Frogs ◽  
Juvenile Dispersal ◽  
Woodland Ponds ◽  
Emigration Behavior

Juvenile dispersal is important for the persistence of ​amphibian populations. Previous studies have observed nonrandom orientation in juvenile amphibians emigrating from breeding ponds; however, the environmental cues associated with these movements are not well understood. We examined the emigration behavior of recently metamorphosed juveniles of three pond-breeding amphibian species from three woodland ponds. We found that juvenile small-mouthed salamanders ( Ambystoma texanum (Matthes, 1855)), American toads ( Bufo americanus Holbrook, 1836), and wood frogs ( Rana sylvatica LeConte, 1825) exhibited nonrandom orientation upon exiting the breeding ponds. Furthermore, we found a positive relationship between captures of juvenile small-mouthed salamanders and wood frogs and width of the surrounding forest habitat, indicating that these species are selecting areas with broader forested habitat upon exiting the breeding ponds. Our results indicate that migrating juvenile amphibians may rely on direct environmental cues because the orientation of small-mouthed salamanders and wood frogs was influenced by width of the surrounding forested habitat. These observations support previous studies suggesting that maintaining forest habitat, along at least a portion of breeding ponds, is important for the persistence of amphibian populations.

Nematode parasites and leukocyte profiles of Northern Leopard Frogs, Rana pipiens: location, location, location

2015 ◽  
Vol 93 (1) ◽  
pp. 41-49 ◽  
Author(s):  
Dave Shutler ◽  
Andrée D. Gendron ◽  
Myriam Rondeau ◽  
David J. Marcogliese
Keyword(s):  
Spatial Organization ◽  
Rana Pipiens ◽  
Pesticide Exposure ◽  
Nematode Species ◽  
Agricultural Pesticides ◽  
Leopard Frogs ◽  
Nematode Parasites ◽  
Northern Leopard Frogs ◽  
Host Parasite ◽  
Leukocyte Profiles

Globally, amphibians face a variety of anthropogenic stresses that include exposure to contaminants such as agricultural pesticides. Pesticides may negatively affect amphibian immune systems, concomitantly increasing susceptibility to parasitism. We quantified nematodes and evaluated leukocyte profiles of Northern Leopard Frogs (Rana pipiens Schreber, 1782) collected from five wetlands in southwestern Quebec, Canada, that spanned a gradient of pesticide exposure. Three taxa of nematode parasites (Rhabdias ranae Walton, 1929, genus Oswaldocruzia Travassos, 1917, and genus Strongyloides Grassi, 1879) were sufficiently numerous for detailed evaluation. When all frogs were pooled, frog size was negatively correlated with nematode species richness, abundances of each of the three nematode species, and densities of three different leukocytes. When all frogs were pooled, there was strong evidence of both negative and positive associations between pairs of parasite species. However, none of the previous relationships was significant within wetlands. Our results reveal strong spatial organization of amphibian–parasite communities and illustrate the importance of controlling for sampling locale in evaluating host–parasite associations. Finally, although several response variables varied significantly among wetlands, causes of this variation did not appear to be related to variation in nematode parasitism or pesticide exposure.

Carryover effects of phenotypic plasticity: embryonic environment and larval response to predation risk in Wood Frogs (Lithobates sylvaticus) and Northern Leopard Frogs (Lithobates pipiens)

2015 ◽  
Vol 93 (11) ◽  
pp. 867-877 ◽  
Author(s):  
A.M. Bennett ◽  
D.L. Murray
Keyword(s):  
Predation Risk ◽  
Wood Frog ◽  
Leopard Frog ◽  
Carryover Effects ◽  
Wood Frogs ◽  
Lithobates Sylvaticus ◽  
Northern Leopard Frog ◽  
Leopard Frogs ◽  
Frog Tadpoles ◽  
Northern Leopard Frogs

Limitations of phenotypic plasticity affect the success of individuals and populations in changing environments. We assessed the plasticity-history limitation on predator-induced defenses in anurans (Wood Frogs, Lithobates sylvaticus (LeConte, 1825), and Northern Leopard Frogs, Lithobates pipiens (Schreber, 1782)), predicting that plastic responses to predation risk by dragonfly larvae (family Aeshnidae) in the embryonic environment would limit the defensive response to predators in the larval environment. Predator-conditioned Wood Frog embryos increased relative tail depth in response to those same cues as larvae, whereas predator-naive tadpoles did not. However, no carryover effect was noted in the behavioural response of Wood Frog tadpoles to predation risk. Predator-naive Northern Leopard Frog tadpoles increased relative tail depth in response to predation risk in the larval environment. Predator-conditioned Northern Leopard Frog embryos hatched with, and maintained, a marginal increase in tail depth as larvae in the absence of predation risk. Predator-conditioned Northern Leopard Frog embryos exposed to predation risk as larvae showed no morphological response. While we find no strong support for the plasticity-history limitation per se, carryover effects across embryonic and larval life-history stages were noted in both Wood Frog and Northern Leopard Frog, suggesting that predation risk early in ontogeny can influence the outcome of future interactions with predators.

Patterns of trematode and nematode lungworm infections in northern leopard frogs and wood frogs from Ontario, Canada

2009 ◽  
Vol 83 (4) ◽  
pp. 339-343 ◽  
Author(s):  
O.K. Dare ◽  
M.R. Forbes
Keyword(s):  
Host Species ◽  
Spatial Segregation ◽  
Negative Association ◽  
Competitive Interactions ◽  
Future Research ◽  
Wood Frogs ◽  
Leopard Frogs ◽  
Strong Negative Association ◽  
Northern Leopard Frogs ◽  
Dual Infections

AbstractIn this study we examined trematode and nematode lung helminths commonly found in two species of host ranid frogs for competitive interactions. We examined 147 adult (breeding and non-breeding) and juvenile northern leopard frogs, and 84 breeding male wood frogs in Bishops Mills, Ontario for Haematoloechus spp. (Trematoda) and Rhabdias sp. (Nematoda) infections. A strong negative association between phyla of helminth was observed in breeding and juvenile northern leopard frogs, and also in breeding wood frogs, but not in non-breeding adult northern leopard frogs. Few hosts carried both types of worm concurrently. Thirteen northern leopard frogs carried dual infections, while 77 carried only one phylum of helminth. Twenty-seven wood frogs carried dual infections, while 54 carried only one phylum of helminth. We also observed spatial segregation of the two phyla in host lungs. Our study informs future research on the dynamics of interactions among lung helminths in these two host species.

Impact of eutrophication on wood frog, Rana sylvatica, tadpoles infected with Echinostoma trivolvis cercariae

2006 ◽  
Vol 84 (9) ◽  
pp. 1315-1321 ◽  
Author(s):  
L.K. Belden
Keyword(s):  
Environmental Changes ◽  
Rana Sylvatica ◽  
Infection Level ◽  
Wood Frogs ◽  
Host Parasite Interactions ◽  
Infection Treatment ◽  
Second Intermediate Host ◽  
Host Parasite ◽  
The Impact ◽  
Echinostoma Trivolvis

In freshwater systems, environmental changes, such as eutrophication, are occurring that could impact the outcome of host–parasite interactions. Using tadpole infection with trematode cercariae as a host–parasite system, this study examined (i) growth, development, and maintenance of trematode ( Echinostoma trivolvis (Cort, 1914)) infection levels in second intermediate host larval wood frogs ( Rana sylvatica LeConte, 1825) and (ii) post-infection impacts of eutrophication on R. sylvatica tadpoles infected to varying degrees with E. trivolvis cercariae. Results from the first experiment suggest no impact of infection with 50 cercariae on R. sylvatica growth and development compared with uninfected controls. Results from the second experiment, investigating the impact of eutrophication on infected tadpoles, showed that survival to metamorphosis of the individuals in the highest infection treatment (80 cercariae) was reduced regardless of eutrophication treatment. However, for individuals surviving infection with 80 cercariae and for individuals infected with only 20 cercariae, no impact of infection on mass at metamorphosis was documented, although individuals were larger at metamorphosis in the eutrophic tanks. These data demonstrate that infection with E. trivolvis can impact R. sylvatica survivorship, at least above some threshold infection level, and that eutrophication may have minimal impacts on tadpole hosts once infection has occurred.

scholarly journals Mitochondria and the Frozen Frog

Antioxidants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 543
Author(s):  
Janet M. Storey ◽  
Shaobo Wu ◽  
Kenneth B. Storey
Keyword(s):  
Cell Volume ◽  
Ischemia Reperfusion ◽  
Enzyme Regulation ◽  
Rana Sylvatica ◽  
Volume Reduction ◽  
Whole Body ◽  
Amphibian Species ◽  
Wood Frogs ◽  
16S Rna ◽  
Total Body

The wood frog, Rana sylvatica, is the best-studied of a small group of amphibian species that survive whole body freezing during the winter months. These frogs endure the freezing of 65–70% of their total body water in extracellular ice masses. They have implemented multiple adaptations that manage ice formation, deal with freeze-induced ischemia/reperfusion stress, limit cell volume reduction with the production of small molecule cryoprotectants (glucose, urea) and adjust a wide variety of metabolic pathways for prolonged life in a frozen state. All organs, tissues, cells and intracellular organelles are affected by freeze/thaw and its consequences. This article explores mitochondria in the frozen frog with a focus on both the consequences of freezing (e.g., anoxia/ischemia, cell volume reduction) and mitigating defenses (e.g., antioxidants, chaperone proteins, upregulation of mitochondria-encoded genes, enzyme regulation, etc.) in order to identify adaptive strategies that defend and adapt mitochondria in animals that can be frozen for six months or more every year. A particular focus is placed on freeze-responsive genes in wood frogs that are encoded on the mitochondrial genome including ATP6/8, ND4 and 16S RNA. These were strongly up-regulated during whole body freezing (24 h at −2.5 °C) in the liver and brain but showed opposing responses to two component stresses: strong upregulation in response to anoxia but no response to dehydration stress. This indicates that freeze-responsive upregulation of mitochondria-encoded genes is triggered by declining oxygen and likely has an adaptive function in supporting cellular energetics under indeterminate lengths of whole body freezing.

Patterns of larval amphibian distribution along a wetland hydroperiod gradient

2003 ◽  
Vol 81 (9) ◽  
pp. 1539-1552 ◽  
Author(s):  
Kimberly J Babbitt ◽  
Matthew J Baber ◽  
Tracy L Tarr
Keyword(s):  
Species Richness ◽  
Rana Catesbeiana ◽  
Rana Sylvatica ◽  
Predatory Fish ◽  
Bufo Americanus ◽  
Amphibian Species ◽  
Larval Amphibians ◽  
Pseudacris Crucifer ◽  
Wetland Hydroperiod ◽  
Species Richness And Abundance

We investigated the response of pond-breeding amphibian assemblages to wetland hydroperiod and associated predator changes (invertebrates (abundance and richness) and fish (presence/absence)) in relatively undisturbed landscapes in southern New Hampshire, U.S.A. We sampled 42 wetlands for larval amphibians in 14 spatial blocks (each with a short-, intermediate-, and permanent-hydroperiod wetland) in 1998 and 1999. Assemblages in short-hydroperiod wetlands (<4 months) were depauperate (4 species only) compared with intermediate-hydroperiod (non-permanent but >4 months) and permanent wetlands, which included 7 and 9 species, respectively. Total amphibian abundance did not vary among hydroperiod categories. Species distributions along the hydrological gradient also differed. Rana sylvatica dominated wetlands with short and intermediate hydroperiods, whereas Rana catesbeiana, Bufo americanus, Rana clamitans, and Pseudacris crucifer dominated in those with a longer hydroperiod. Among permanent wetlands, amphibian species richness and abundance did not differ with respect to the presence of predatory fish, although there were species-compositional differences. Amphibian species richness and abundance were positively correlated with the abundance and richness of predatory invertebrates, suggesting that both amphibian and macroinvertebrate predator assemblages may be responding similarly to differences in wetland characteristics (e.g., dissolved oxygen concentration). Overall, our results indicate that wetland hydroperiod has an important influence on amphibian distribution and should be incorporated into regulations and legislation designed to protect biologically diverse isolated wetlands.

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