isolation of ice-nucleating active bacteria from the freeze-tolerant frog, rana active (ina) bacteria were isolated from the gut of field-collected freeze-tolerant wood frogs (rana sylvatica) collected in winter. thirteen strains of pseudomonas fluorescens, four strains of pseudomonas putida, and two strains of enterobacter agglomerans had ice-nucleating activity. each of the ina pseudomonad strains was psychrophilic. p. putida strains were differentiated from p. fluorescens strains by gelatinase, lecithinase, and lipase production. the maximum nucleation tem ...19957656570
forest mediated light regime linked to amphibian distribution and performance.the vegetation in and around the basins of ephemeral wetlands can greatly affect light environments for aquatic species such as amphibians. we used hemispherical photographs to quantify the light environment in terms of the global site factor (gsf), the proportion of available solar radiation that actually strikes the wetland. we compared gsf to the distribution and performance of two amphibian species (pseudacris crucifer and rana sylvatica) within 17 ephemeral wetlands in northeastern connecti ...200312647143
discordant temporal and geographic patterns in maternal lineages of eastern north american frogs, rana catesbeiana (ranidae) and pseudacris crucifer (hylidae).whether the pleistocene has had a disproportionate impact on the recent diversification of temperate species, or played a lesser role in a more protracted process, has been a prominent evolutionary debate for the past decade. we used cytochrome b sequences to reconstruct the evolutionary histories of two widely co-distributed, and ecologically divergent frogs (rana catesbeiana and pseudacris crucifer) to examine the role of the pleistocene in structuring these species. results for r. catesbeiana ...200415288057
preliminary amphibian health survey in the delaware water gap national recreation detect aquatic animal diseases of national concern, 111 individual amphibians, including wood frogs rana sylvatica (28), spring peepers pseudacris crucifer (35), red-spotted newts notophthalmus viridescens (41), and gray tree frogs hyla versicolor (7), were sampled at seven different sites in the delaware water gap national recreation area (dgnra), pennsylvania, from june 14 to july 19, 2007. these samples were screened for batrachochytrium dendrobatidis and viral pathogens at the u.s. fish a ...201020848885
varying responses of northeastern north american amphibians to the chytrid pathogen batrachochytrium dendrobatidis.chytridiomycosis, caused by batrachochytrium dendrobatidis (bd), is widespread among amphibians in northeastern north america. it is unknown, however, whether bd has the potential to cause extensive amphibian mortalities in northeastern north america as have occurred elsewhere. in the laboratory, we exposed seven common northeastern north american amphibian species to bd to assess the likelihood of population-level effects from the disease. we exposed larval wood frogs (lithobates sylvaticus) an ...201122181933
blood feeding patterns of potential arbovirus vectors of the genus culex targeting ectothermic hosts.reptiles and amphibians constitute a significant portion of vertebrate biomass in terrestrial ecosystems and may be important arbovirus reservoirs. to investigate mosquito preference for ectothermic hosts, feeding indices were calculated from data collected in tuskegee national forest, alabama, usa. four mosquito species fed upon ectothermic hosts, with culex peccator and cx. territans feeding primarily upon ectotherms. these two species appeared to target distinct species with little overlap in ...018981528
effect of simultaneous amphibian exposure to pesticides and an emerging fungal pathogen, batrachochytrium dendrobatidis.amphibian declines have been linked to numerous factors, including pesticide use and the fungal pathogen batrachochytrium dendrobatidis (bd). moreover, research has suggested a link between amphibian sensitivity to bd and pesticide exposure. we simultaneously exposed postmetamorphic american toads (anaxyrus americanus), western toads (a. boreas), spring peepers (pseudacris crucifer), pacific treefrogs (p. regilla), leopard frogs (lithobates pipiens), and cascades frogs (rana cascadae) to a facto ...201728001054
effects of pesticide mixtures on host-pathogen dynamics of the amphibian chytrid fungus.anthropogenic and natural stressors often interact to affect organisms. amphibian populations are undergoing unprecedented declines and extinctions with pesticides and emerging infectious diseases implicated as causal factors. although these factors often co-occur, their effects on amphibians are usually examined in isolation. we hypothesized that exposure of larval and metamorphic amphibians to ecologically relevant concentrations of pesticide mixtures would increase their post-metamorphic susc ...201526181492
most of the dominant members of amphibian skin bacterial communities can be readily cultured.currently, it is estimated that only 0.001% to 15% of bacteria in any given system can be cultured by use of commonly used techniques and media, yet culturing is critically important for investigations of bacterial function. despite this situation, few studies have attempted to link culture-dependent and culture-independent data for a single system to better understand which members of the microbial community are readily cultured. in amphibians, some cutaneous bacterial symbionts can inhibit est ...201526162880
the benefits of coinfection: trematodes alter disease outcomes associated with virus infection.1.coinfections are increasingly recognized as important drivers of disease dynamics. consequently, greater emphasis has been placed on integrating principles from community ecology with disease ecology to understand within-host interactions among parasites. using larval amphibians and two amphibian parasites (ranaviruses and the trematode echinoparyphium sp.), we examined the influence of coinfection on disease outcomes. 2.our first objective was to examine how priority effects (the timing and s ...201728317105
novel features of an inducible defense system in larval tree frogs (hyla chrysoscelis).organisms in aquatic ecosystems must often tolerate variable environmental conditions, including an uncertain risk of predation. individuals that can maintain plastic defenses against predation will increase their survival when predators are present, but will not incur the costs of these defenses when the risk of predation is low and the defense is not induced. larvae of the pond-breeding anuran hyla chrysoscelis develop a conspicuous phenotype in the presence of predators consisting of a bright ...200616602306
effects of tannin source and concentration from tree leaves on two species of tadpoles.vegetation in and around freshwater ecosystems can affect aquatic organisms through the production of secondary compounds, which are retained in leaves after senescence and are biologically active. tannins can be toxic to tadpoles, but the plant source of tannins and tannin concentration have been confounded in experimental designs in previous studies. to examine the effects of the concentration and source of tannins (tree species), we examined the effects of 4 factors on tadpole survival, growt ...201525319714
effects of leachate from tree leaves and grass litter on tadpoles.tree species composition can change as a result of succession, climate change, fire suppression, and invasive species. these changes clearly affect forests, but they can also affect aquatic ecosystems based on differences in the input quality of leaf litter, such as plant secondary compounds. these compounds vary in type and concentration depending on species and can be toxic to aquatic organisms. to examine toxic effects on pseudacris maculata and pseudacris crucifer tadpoles, we conducted 60-d ...201222488805
the toxicity of roundup original max to 13 species of larval amphibians.with the increased use of glyphosate-based herbicides (marketed under several names, including roundup and vision), there has been a concomitant increased concern about the unintended impacts that particular formulations containing the popular surfactant polyethoxylated tallowamine (poea) might have on amphibians. published studies have examined a relatively small number of anuran species (primarily from australia and eastern north america) and, surprisingly, no species of salamanders. using a p ...200919405783
very highly toxic effects of endosulfan across nine species of tadpoles: lag effects and family-level sensitivity.pesticides are commonly used for health and economic benefits worldwide, but increased use has led to increased contamination of aquatic habitats. to understand potential impacts on nontarget organisms in these habitats, toxicologists generally use short-term (4-d) toxicity tests on model organisms. for most pesticides, few amphibian tests have been conducted, but there is growing concern about the potential impact of pesticides to amphibian populations. for the insecticide endosulfan, previous ...200919358624
toxicity of road salt to nova scotia amphibians.the deposition of chemical pollutants into roadside wetlands from runoff is a current environmental concern. in northern latitudes, a major pollutant in runoff water is salt (nacl), used as de-icing agents. in this study, 26 roadside ponds were surveyed for amphibian species richness and chloride concentration. acute toxicity tests (lc(50)) were performed on five locally common amphibian species using a range of environmentally significant nacl concentrations. field surveys indicated that spotte ...200918684543
helminth communities in five species of sympatric amphibians from three adjacent ephemeral ponds in southeastern wisconsin.representatives of 5 amphibian species (313 individuals), including eastern american toads (bufo americanus), wood frogs (rana sylvatica), spring peepers (pseudacris crucifer), blue-spotted salamanders (ambystoma laterale), and central newts (notophthalmus viridescens louisianensis), were collected from 3 ephemeral ponds during spring 1994, and they were inspected for helminth parasites. the component communities of anurans were more diverse than those of caudates. infracommunities of all host s ...200717918353
survivorship patterns of larval amphibians exposed to low concentrations of atrazine.amphibians can be exposed to contaminants in nature by many routes, but perhaps the most likely route is agricultural runoff in amphibian breeding sites. this runoff results in high-level pulses of pesticides. for example, atrazine, the most widely used pesticide in the united states, can be present at several parts per million in agricultural runoff. however, pesticide levels are likely to remain in the environment at low levels for longer periods. nevertheless, most studies designed to examine ...200415238276
white-throated sparrows alter songs differentially in response to chorusing anurans and other background noise.animals can use acoustic signals to attract mates and defend territories. as a consequence, background noise that interferes with signal transmission has the potential to reduce fitness, especially in birds that rely on song. while much research on bird song has investigated vocal flexibility in response to urban noise, weather and other birds, the possibility of inter-class acoustic competition from anurans has not been previously studied. using sound recordings from central ontario wetlands, w ...201424607392
dominance-function relationships in the amphibian skin microbiome.some amphibian skin bacteria inhibit growth of a fungal amphibian pathogen, batrachochytrium dendrobatidis (bd), but it is unclear how dominant these anti-bd bacteria are in skin communities. using in vitro co-culture challenge assays, we quantified bd inhibition by bacterial isolates collected from the skin of four amphibian species: bullfrogs, eastern newts, spring peepers and american toads. the 16s rrna sequences for each isolate were matched to culture-independent amplicon sequences from th ...201728677171
carry-over effects of the larval environment on post-metamorphic performance in two hylid history theory and empirical studies suggest that large size or earlier metamorphosis are suitable proxies for increased lifetime fitness. thus, across a gradient of larval habitat quality, individuals with similar phenotypes for these traits should exhibit similar post-metamorphic performance. here we examine this paradigm by testing for differences in post-metamorphic growth and survival independent of metamorphic size in a temperate (spring peeper, pseudacris crucifer) and tropical (red- ...201020658150
environmental factors influencing calling in sympatric anurans.anuran reproduction is influenced by various biotic and abiotic factors, of which temperature and rainfall are the best studied. here we examine the relationship between multiple abiotic environmental variables - specifically, air and water temperature, rainfall, barometric pressure, relative humidity and wind velocity - and the calling activity of five species (rana sylvatica, pseudacris crucifer, bufo americanus, rana clamitans, and rana catesbeiana) in an anuran community in new brunswick, ca ...200228466161
ultrastructural design of anuran muscles used for call production in relation to the thermal environment of a species.i examined the aerobic trunk muscles, which are used for call production, of male frogs from species that breed in different thermal environments to test the hypothesis that cold-adapted frogs should have fewer capillaries per unit mitochondrial volume in oxidative muscles than warm-adapted frogs because of reduced mitochondrial function at low temperatures. the species of interest were the cold-temperate pseudacris crucifer and the warm-tropical hyla microcephala in the family hylidae, and the ...200111273806
freeze-induced expression of a novel gene, fr47, in the liver of the freeze-tolerant wood frog, rana sylvatica.the ability to endure the freezing of body fluids is well developed as an adaptation for winter survival in several species of woodland frogs. recently, the mechanisms supporting natural freeze tolerance have been shown to include the expression of novel genes. one such novel gene, fr47, codes for a 390-amino acid protein present in the livers of freeze-tolerant anurans (rana sylvatica, pseudacris crucifer, hyla versicolor) but not in freeze-intolerant species (rana pipiens, scaphiopus couchii). ...200312531477
ichthyophonus-like infection in wild amphibians from québec, canada.myositis associated with infection by ichthyophonus-like organisms was diagnosed in 35 of 260 (13%) wild amphibians collected in quebec, canada, from 1959 to 1964 (n = 30), and 1992 to 1999 (n = 230). infection was diagnosed in 17 green frogs rana clamitans, 9 wood frogs r. sylvatica, 4 red-spotted newts notophthalmus viridescens, 3 bullfrogs r. catesbeiana, 1 spring peeper pseudacris crucifer, and 1 pickerel frog r. palustris. the spring peeper and one of the bullfrogs were collected in 1964 fr ...200010843557
can alternative mating tactics facilitate introgression across a hybrid zone by circumventing female choice?reproductive barriers and divergence in species' mate recognition systems underlie major models of speciation. however, hybridization between divergent species is common, and classic mechanisms to explain permeable reproductive barriers rarely consider how an individual may attain reproductive success. alternative mating tactics (amts) exist in various forms across animal taxa. such tactics may allow poorer quality individuals to gain mating opportunities and facilitate introgression either thro ...201727862550
short-term exposure to coal combustion waste has little impact on the skin microbiome of adult spring peepers (pseudacris crucifer).disruptions to the microbiome can impact host health as can exposure to environmental contaminants. however, few studies have addressed how environmental contaminants impact the microbiome. we explored this question for frogs that breed in wetlands contaminated with fly ash, a by-product of coal combustion that is enriched in trace elements. we found differences in the bacterial communities among a fly ash-contaminated site and several reference wetlands. we then experimentally assessed the impa ...201627037118
extensive variation in sperm morphology in a frog with no sperm competition.recent comparative studies of several taxa have found that within-species variation in sperm size decreases with increasing levels of sperm competition, suggesting that male-male gamete competition selects for an optimal sperm phenotype. previous studies of intraspecific sperm length variation have all involved internal fertilizers where some other factors-e.g., sperm storage and sperm movement along the walls of the female's reproductive tract-probably also influence and reduce sperm size varia ...201626832366
contact zone dynamics during early stages of speciation in a chorus frog (pseudacris crucifer).characterizing the genetic and behavioural consequences of contact between previously geographically isolated lineages provides insights into the mechanisms underlying diversification and ultimately speciation. the spring peeper (pseudacris crucifer) is a widespread nearctic chorus frog with six divergent mitochondrial dna (mtdna) lineages, many of which came into secondary contact during the holocene. we examined genetics, morphology, advertisement calls and female preference for two lineages t ...201626626576
testing for intraspecific postzygotic isolation between cryptic lineages of pseudacris crucifer.phenotypically cryptic lineages appear common in nature, yet little is known about the mechanisms that initiate and/or maintain barriers to gene flow, or how secondary contact between them might influence evolutionary trajectories. the consequences of such contact between diverging lineages depend on hybrid fitness, highlighting the potential for postzygotic isolating barriers to play a role in the origins of biological species. previous research shows that two cryptic, deeply diverged intraspec ...201324363891
weather variability permitted within amphibian monitoring protocol and affects on calling hylidae.anuran populations are sensitive to changing environmental conditions and act as useful indicators. presently, much information collected concerning frog populations comes from volunteers following the north american amphibian monitoring protocol. does weather variability allowed within protocol affect the abundance of calling frogs? for 10 years, credit valley conservation (ontario, canada) has been collecting anuran data concerning nine frog species employing three frog monitoring runs. record ...201323625355
pre-existing sensory biases in the spectral domain in frogs: empirical results and methodological many species of anurans, advertisement calls excite only one of the two inner-ear organs. one prediction of the pre-existing bias hypothesis is that signal innovations that additionally excite the "untapped" organ will be more behaviorally effective than normal calls. however, recent studies have shown that females of three species with single-peaked calls that stimulate only the basilar papilla (bp) preferred single-peaked synthetic calls with a frequency typical of conspecific calls to two- ...201323160797
water molds of the genera saprolegnia and leptolegnia are pathogenic to the north american frogs rana catesbeiana and pseudacris crucifer, respectively.water molds are commonly associated with amphibian mortality. since water molds often act as saprophytes, it is important to test their effects on amphibians to determine whether they can also act as pathogens. in controlled experiments, the eggs of 2 amphibian species, the american bullfrog rana catesbeiana and the spring peeper pseudacris crucifer, suffered higher mortality when they were exposed to zoospores of water molds of the genera saprolegnia and leptolegnia, respectively. water molds a ...200919565694
leaf litter input mediates tadpole performance across forest canopy treatments.understanding the mechanisms limiting the distributions of organisms is necessary for predicting changes in community composition along habitat gradients. in many areas of the usa, land originally cleared for agriculture has been undergoing a process of reforestation, creating a gradient of canopy cover. for small temporary wetlands, this gradient can alter abiotic conditions and influence the resource base of wetland food webs by affecting litter inputs. as distributions of amphibians and many ...200818049825
inclusion body myositis in spring peepers (pseudacris crucifer).in 2000, 2 adult captive spring peepers (pseudacris crucifer) from the same zoological park were humanely euthanized. histologically, both frogs had degeneration, atrophy, and necrosis of striated myofibers of the tongue admixed with chronic lymphohistiocytic inflammation. one frog had similar lesions in the skeletal muscles of the body wall. several degenerate and necrotic myofibers contained single, eosinophilic, intranuclear inclusion bodies. ultrastructural examination of the inclusions reve ...200212423034
cryptic lineages in a small frog: the post-glacial history of the spring peeper, pseudacris crucifer (anura: hylidae).the spring peeper (pseudacris crucifer) is believed to have been a primary herpetological invader of eastern north america following the most recent period of glacial retreat. we examined the phylogeographic pattern and population structure of p. crucifer to determine whether the distribution of haplotypic variants reflect post-pleistocene recolonization dynamics. a number of geographically isolated evolutionary lineages were supported by both maximum parsimony and neighbor-joining analyses, and ...200212414313
individual variation in morphological, physiological, and biochemical features associated with calling in spring peepers (pseudacris crucifer).in an eastern north american tree frog, the spring peeper (pseudacris crucifer), calling rate has been correlated with reproductive success in the field. to determine the sources of individual variation in calling rate in this species, i analyzed males calling at rates greater than and less than the chorus average throughout one breeding season. compared to low-rate callers, high-rate callers were relatively larger, heavier, older, and in better body condition, and their muscles used in calling ...201310603330
the neuroethology of frequency preferences in the spring peeper.we studied the relationship between auditory activity in the midbrain and selective phonotaxis in females of the treefrog, pseudacris crucifer. gravid females were tested in two-stimulus playback tests using synthetic advertisement calls of different frequencies (2600 versus 2875 hz; 2800 versus 3500 hz; 2600 versus 3500 hz). tests were conducted with and without a background of synthesized noise, which was filtered to resemble the spectrum of a chorus of spring peepers. there were no significan ...19989710462
intrahepatic larval nematode infection in the northern spring peeper, pseudacris crucifer crucifer (anura: hylidae), in west virginia.larval stages of an unknown nematode were observed encapsulated in the livers of spring peepers, pseudacris crucifer crucifer (weid-neuweid), collected from a marsh in western west virginia (usa) during the spring breeding seasons of 1993 and 1994. prevalence and mean intensity of infection were 37% (30 of 82 animals) and 2.03 parasites per infected host, respectively. capsules with white or darkly pigmented walls were observed in infected livers; the former containing viable larvae, and the lat ...19968722275
competition and the distribution of spring peeper larvae.studies of tadpole distributions have shown that despite overlapping affinities for semipermanent and permanent ponds, distributions of the spring peeper (pseudacris crucifer) and the green frog (rana clamitans) tend to be nonoverlapping. because spring peepers are believed to be poor competitors, i hypothesized that competition from green frog larvae limits the distribution of spring peeper larvae. i stocked field enclosures with a constant density of spring peeper larvae, and one of four densi ...199528306774
effects of dehydration on organ metabolism in the frog pseudacris crucifer: hyperglycemic responses to dehydration mimic freezing-induced cryoprotectant production.the metabolic effects of evaporative water loss at 5 degrees c were assessed for both fall- and spring-collected spring peepers pseudacris crucifer. frogs readily endured the loss of 50% of total body water. during dehydration organ water content was defined with no change in water content in skeletal muscle, gut, and kidney of 50% dehydrated frogs and reduced water content in liver, brain and heart. dehydration stimulated a rapid and massive increase in liver glucose production. in fall-collect ...19947860806
midbrain auditory sensitivity in the spring peeper (pseudacris crucifer): correlations with behavioral studies.1. we derived audiograms from recordings of multiunit activity in the torus semicircularis of 10 males and 6 females of the spring peeper from central missouri, usa. we used free-field stimulation with tone bursts that had temporal properties similar to typical advertisement calls and that ranged in frequency from 500-6000 hz. 2. audiograms from different electrode positions in the same animal had the same general shape. there was no evidence of tonotopy. 3. audiograms showed two regions of maxi ...19921432858
evaluating a hypothesis about heterochrony: larval life-history traits and juvenile hind-limb morphology in hyla crucifer.this paper reports the results of an investigation into whether selection on genetically based differences in the timing or rate of development (heterochrony) can give rise to nonadaptive morphological differences among individual frogs. we used a quantitative-genetics approach to examine the relationships among the life-history characters time to metamorphosis and larval-growth rate and a functionally significant morphological features, relative hind-limb length, in the spring peeper, hyla cruc ...198828563845
sexual differences in neural tuning and their effect on active space.sexual differences in receptor tuning are found in the auditory system in at least two species of anuran amphibians and are common in electric fish. since the boundary of a communication signal's active space is defined in terms of the sensitivity of the receptors to that signal, such sexual differences might result in active-space differences between males and females. in spring peepers, the sexual difference in the auditory system clearly results in a significantly larger active space in femal ...19863567543
using bloodmeal analysis to assess disease risk to wildlife at the new northern limit of a mosquito species.the historically southeastern mosquito species culex erraticus has over the last 30 years undergone a marked expansion north. we evaluated this species' potential to participate in local disease cycles in the northeastern usa by identifying the vertebrate sources of blood in cx. erraticus specimens from new jersey. we found that the majority of bloodmeals (92.6%) were derived from birds, followed by 6.8% from mammals (of which half were human), and a single amphibian bloodmeal from a spring peep ...201830242538
parasite-induced vulnerability to predation in larval anurans.within communities, pathogens and parasites have the potential to indirectly influence predator-prey interactions. for instance, prey that exhibit pathology or altered traits (e.g. behavioral shifts) following infection could be more prone to predation, which is known as parasite-induced vulnerability to predation (pivp). pivp has been frequently documented for pathogens with trophic transmission, because predators are often critical in the pathogen's life cycle. however, for pathogens without t ...201931535619
vernal pool amphibian breeding ecology monitoring from 1931 to present: a harmonised historical and ongoing observational ecology dataset.for 88 years (1931-present), the mohonk preserve's daniel smiley research center has been collecting data on occupancy and reproductive success of amphibian species, as well as associated water quality of 11 vernal pools each spring (february to may). though sampling effort has varied over the dataset range, the size of the dataset is unprecedented within the field of amphibian ecology. with more than 2,480 individual species sampling dates and more than 151,701 recorded individual occurrences o ...202032336925
ecological correlates of large-scale turnover in the dominant members of pseudacris crucifer skin bacterial communities.animals host a wide diversity of symbiotic microorganisms that contribute important functions to host health, and our knowledge of what drives variation in the composition of these complex communities continues to grow. microbiome studies at larger spatial scales present opportunities to evaluate the contribution of large-scale factors to variation in the microbiome. we conducted a large-scale field study to assess variation in the bacterial symbiont communities on adult frog skin (pseudacris cr ...201930949751
multi-year data from satellite- and ground-based sensors show details and scale matter in assessing climate's effects on wetland surface water, amphibians, and landscape conditions.long-term, interdisciplinary studies of relations between climate and ecological conditions on wetland-upland landscapes have been lacking, especially studies integrated across scales meaningful for adaptive resource management. we collected data in situ at individual wetlands, and via satellite for surrounding 4-km2 landscape blocks, to assess relations between annual weather dynamics, snow duration, phenology, wetland surface-water availability, amphibian presence and calling activity, greenne ...201830192764
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