| comparative contractile dynamics of calling and locomotor muscles in three hylid frogs. | isometric twitch and tetanus parameters, force-velocity curves, maximum shortening velocity (vmax) and percentage relaxation between stimuli (%r) across a range of stimulus frequencies were determined for a muscle used during call production (the tensor chordarum) and a locomotor muscle (the sartorius) for three species of hylid frogs, hyla chrysoscelis, h. versicolor and h. cinerea. the call of h. chrysoscelis has a note repetition rate (nrr) approximately twice as fast as the call of h. versic ... | 1995 | 7658189 |
| brain regions and encephalization in anurans: adaptation or stability? | relative brain size and the relative size of six brain regions (main olfactory bulbs, accessory olfactory bulbs, telencephalon, optic tectum, cerebellum and brain stem) in ten species of anurans from five habitats were examined to determine whether there was any evidence of adaptation in brain structure. a previously published data set was also reanalysed. arboreal frogs have larger body-size corrected brains than frogs from other habitats. arboreal ranid (platymantis vitiensis) and hylid (hyla ... | 1995 | 7749729 |
| spontaneous otoacoustic emissions in seven frog species. | spontaneous otoacoustic emissions were screened for in five advanced frog species (hyla cinerea, n = 10 ears; hyla chrysoscelis, n = 10; hyla versicolor, n = 7; leptodactylus albilabris, n = 2; rana pipiens pipiens, n = 8), and two primitive frog species (xenopus laevis, n = 9; bombina orientalis, n = 12). emissions were found in 90% of the advanced species' ears, whereas none of the primitive species' ears had emissions. emission frequencies ranged from 645 hz to 1680 hz. the absence of emissio ... | 1996 | 8951437 |
| immunocytochemical evidence for the involvement of an fmrfamide-related peptide in egg production in the flatworm parasite polystoma nearcticum. | the monogenean flatworm polystoma nearcticum exhibits reproductive synchrony with its treefrog host, hyla versicolor, and becomes reproductively active only during the short period of host sexual activity at spawning. in this way, it provides a useful model system for exploring factors that may influence egg production in flatworm parasites. one such factor is the peptidergic innervation of the egg chamber or ootype. by using immunocytochemical techniques, the occurrence and distribution of gyir ... | 1997 | 8986871 |
| dorsal striatopallidal system in anurans. | the dorsal striatopallidal system of tetrapods consists of the dorsal striatum (caudate-putamen in mammals) and the dorsal pallidum. although the existence of striatal and pallidal structures has been well documented in anuran amphibians, the exact boundaries of these structures have so far been a matter of debate. to delineate precisely the dorsal striatopallidal system of anurans, we used quantitative analysis of leucine-enkephalin immunohistochemistry (in bombina orientalis, discoglossus pict ... | 2004 | 14648686 |
| synergistic impacts of malathion and predatory stress on six species of north american tadpoles. | the decline of many amphibian populations is associated with pesticides, but for most pesticides we know little about their toxicity to amphibians. malathion is a classic example; it is sprayed over aquatic habitats to control mosquitoes that carry malaria and the west nile virus, yet we know little about its effect on amphibians. i examined the survival of six species of tadpoles (wood frogs, rana sylvatica; leopard frogs, r. pipiens; green frogs, r. clamitans; bullfrogs, r. catesbeiana; americ ... | 2004 | 15095908 |
| 6-hydroxydopamine lesions in anuran amphibians: a new model system for parkinson's disease? | we investigated the effects of dopamine depletion on acoustically guided behavior of anurans by conducting phonotaxis experiments with female gray treefrogs (hyla versicolor) before and 90 min after bilateral injections of 3, 6, or 12 microg 6-hydroxydopamine (6-ohda) into the telencephalic ventricles. in experiments with one loudspeaker playing back a standard artificial mating call, we analyzed the effects of 6-ohda on phonotactic response time. in choice tests we measured the degree of distra ... | 2004 | 15307145 |
| differential metamorphosis alters the endocrine response in anuran larvae exposed to t3 and atrazine. | pesticide chemical contamination is one of the suspected contributors of the amphibian population decline. the herbicide atrazine is one of the major surface water contaminants in the u.s. a previous study has shown that atrazine at concentrations as low as 100 parts per billion (ppb) increased the time to metamorphosis in xenopus laevis tadpoles. however, questions remain as to the applicability of a study of a non-native species to a native organism. the possible effects of atrazine on develop ... | 2005 | 16213604 |
| frog virus 3-like infections in aquatic amphibian communities. | frog virus 3 (fv3) and fv3-like viruses, are members of the genus ranavirus (family iridoviridae), and they have been associated with infectious diseases that may be contributing to amphibian population declines. we examined the mode of transmission of an fv3-like virus, and potential hosts and reservoirs of the virus in a local amphibian community. using the polymerase chain reaction to detect infected animals, we found an fv3-like virus in south-central ontario, canada, amphibian communities, ... | 2008 | 18263826 |
| all hosts are not equal: explaining differential patterns of malformations in an amphibian community. | 1. within a community, different host species often exhibit broad variation in sensitivity to infection and disease. because such differences can influence the strength and outcome of community interactions, it is essential to understand differential disease patterns and identify the mechanisms responsible. 2. in north american wetlands, amphibian species often exhibit extraordinary differences in the frequency of limb malformations induced by the digenetic trematode, ribeiroia ondatrae. by coup ... | 2009 | 18671806 |
| echinostome-induced mortality varies across amphibian species in the field. | echinostomes are receiving increased attention because of their emerging parasite status in landscapes associated with human development and their ability to infect and kill many north american larval amphibians. while laboratory experiments have shown that echinostomes can cause extensive mortality in their amphibian hosts, their effect on tadpoles in the field is less clear. i conducted a controlled-infection field-enclosure experiment in 4 ponds to compare the effects of echinostomes on green ... | 2010 | 20469948 |
| preliminary amphibian health survey in the delaware water gap national recreation area. | to 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 ... | 2010 | 20848885 |
| can differences in host behavior drive patterns of disease prevalence in tadpoles? | differences in host behavior and resistance to disease can influence the outcome of host-pathogen interactions. we capitalized on the variation in aggregation behavior of fowler's toads (anaxyrus [ = bufo] fowleri) and grey treefrogs (hyla versicolor) tadpoles and tested for differences in transmission of batrachochytrium dendrobatidis (bd) and host-specific fitness consequences (i.e., life history traits that imply fitness) of infection in single-species amphibian mesocosms. on average, a. fowl ... | 2011 | 21949824 |
| carotenoids and amphibians: effects on life history and susceptibility to the infectious pathogen, batrachochytrium dendrobatidis. | carotenoids are considered beneficial nutrients because they provide increased immune capacity. although carotenoid research has been conducted in many vertebrates, little research has been done in amphibians, a group that is experiencing global population declines from numerous causes, including disease. we raised two amphibian species through metamorphosis on three carotenoid diets to quantify the effects on life-history traits and post-metamorphic susceptibility to a fungal pathogen (batracho ... | 2015 | 27293690 |
| the interactive effects of chytrid fungus, pesticides, and exposure timing on gray treefrog (hyla versicolor) larvae. | aquatic organisms are often exposed to a wide variety of perturbations in nature, including pathogens and chemical contaminants. despite the co-occurrence of these 2 stressors, few studies have examined the effects of chemical contaminants on host-pathogen dynamics. the authors tested the individual and combined effects on gray treefrog (hyla versicolor) tadpoles of 2 commonly used pesticides (roundup® and sevin®) and the pathogenic fungus batrachochytrium dendrobatidis (bd). a fully factorial d ... | 2014 | 24259231 |
| efficacy of treatment and long-term follow-up of batrachochytrium dendrobatidis pcr-positive anurans following itraconazole bath treatment. | all anuran specimens in the wildlife conservation society's collections testing positive for batrachochytrium dendrobatidis (bd) were treated with itraconazole and then studied after treatment to assess the long-term effects of itraconazole and the drug's effectiveness in eliminating bd carriers. twenty-four individuals and eight colonies of 11 different species (75 total specimens) tested positive for bd via polymerase chain reaction (pcr) on multicollection survey. all positive individuals and ... | 2013 | 23805558 |
| 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 ... | 2017 | 28317105 |
| experimental infection dynamics: using immunosuppression and in vivo parasite tracking to understand host resistance in an amphibian-trematode system. | although naturally occurring hosts often exhibit pronounced differences in infection and pathology, the relative importance of factors associated with host life history and immunity in explaining such patterns often remains speculative. research in eco-immunology highlights the trade-offs between host physiology and immunity, for which natural variations in disease susceptibility offer a valuable platform to test predictions within this framework. here, we combined use of a novel, in vivo assay ... | 2013 | 23821713 |
| bottom-up meets top-down: leaf litter inputs influence predator-prey interactions in wetlands. | while the common conceptual role of resource subsidies is one of bottom-up nutrient and energy supply, inputs can also alter the structural complexity of environments. this can further impact resource flow by providing refuge for prey and decreasing predation rates. however, the direct influence of different organic subsidies on predator-prey dynamics is rarely examined. in forested wetlands, leaf litter inputs are a dominant energy and nutrient resource and they can also increase benthic surfac ... | 2013 | 23386045 |
| biomarker analysis of american toad (anaxyrus americanus) and grey tree frog (hyla versicolor) tadpoles following exposure to atrazine. | the objective of the current study was to use a biomarker-based approach to investigate the influence of atrazine exposure on american toad (anaxyrus americanus) and grey tree frog (hyla versicolor) tadpoles. atrazine is one of the most frequently detected herbicides in environmental matrices throughout the united states. in surface waters, it has been found at concentrations from 0.04-2859μg/l and thus presents a likely exposure scenario for non-target species such as amphibians. studies have e ... | 2017 | 27912165 |
| variation in anti-parasite behaviour and infection among larval amphibian species. | along with immune defences, many animals exhibit effective anti-parasite behaviours such as parasite avoidance and removal that influence their susceptibility to infection. host ecology and life history influence investment into comparatively fixed defences such as innate immunity but may affect the strength of anti-parasite behaviours as well. we investigated activity levels in five different species of larval amphibian with varying life histories and ecology in control, novel food stimulus, an ... | 2014 | 24337712 |
| 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 ... | 2012 | 22488805 |
| intersex gonads in frogs: understanding the time course of natural development and role of endocrine disruptors. | the paucity of data on sexual development of anuran amphibians has played an important role in the recent controversy over atrazine exposure. although some studies have demonstrated the presence of abnormal gonads in control treatments, others have not, leading to varying interpretations of the effects of atrazine exposure on sexual development. however, the timing of development varies among anuran amphibians such that, at any snapshot in time, different species may exhibit different stages of ... | 2010 | 19588491 |
| 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 ... | 2009 | 19405783 |
| 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 ... | 2009 | 19358624 |
| variation in somatic and ovarian development: predicting susceptibility of amphibians to estrogenic contaminants. | although amphibian sex determination is genetic, it can be manipulated by exogenous hormone exposure during sexual differentiation. the timing of sexual differentiation varies among anuran amphibians such that species may or may not be a tadpole during this period, and therefore, may or may not be exposed to aquatic contaminants. estrogenic contamination is present in amphibian habitats worldwide. we examined three species with varying somatic and ovarian developmental rates to assess their susc ... | 2008 | 18420201 |
| the lethal impacts of roundup and predatory stress on six species of north american tadpoles. | the decline in amphibians across the globe has sparked a search for the causes, and recent evidence suggests a connection with pesticides. however, for most pesticides, tests on amphibians are rare and conducted only for short durations (1 to 4 days) and without natural stressors. recent studies have discovered that the stress of predator cues in the water can make insecticides much more lethal to larval amphibians, but it is unknown whether this phenomenon can be generalized to other types of p ... | 2005 | 15886853 |
| growth and survival of five amphibian species exposed to combinations of pesticides. | the global decline of amphibians has sparked interest in the role that pesticides may play. pesticides in nature typically exist in combinations, but given the vast number of chemicals used, most toxicological experiments necessarily have examined one pesticide at a time. i examined how four commercial formulations of pesticides (diazinon, carbaryl, malathion, and glyphosate) affected the survival and growth of five larval amphibian species (rana pipiens, r. clamitans, r. catesbeiana, bufo ameri ... | 2004 | 15230326 |
| infectivity of cultured trypanosoma fallisi (kinetoplastida) to various anuran species and its evolutionary implications. | trypanosoma fallisi, a hemoflagellate infecting bufo americanus from ontario, was grown in vitro, and metatrypanosomes from the primary culture were inoculated into 4 uninfected test groups from 3 anuran families: bufonidae, hylidae, and ranidae. in vitro-cultured t. fallisi was found to infect b. americanus and to induce transient infections in bufo valliceps and hyla versicolor. the flagellate was not infective to rana clamitans. trypanosoma ranarum was uninfective to the bufonids and hylids t ... | 1991 | 2040964 |
| freeze tolerance and intolerance as strategies of winter survival in terrestrially-hibernating amphibians. | the ability to tolerate extracellular freezing as an adaptation for winter survival was tested in seven species of terrestrially-hibernating amphibians found in eastern canada. all species had only moderate supercooling abilities, with whole animal supercooling points of -1.5 to -3 degrees c. two salamander species, plethodon cinereus and ambystoma laterale, and the toad, bufo americanus, were freezing intolerant and were killed when frozen for 24 hr at temperatures just below their supercooling ... | 1986 | 2870854 |
| ribosomal rna structure in the diploid and phylogenetically polyploid amphibian species hyla and odontophrynus. | ribosomal rna of the diploid amphibian species hyla chrysoscelis and odontophrynus americanus is structurally modified by hidden breaks. phylogenetically polyploid related species like the tetraploid hyla versicolor, the tetraploid odontophrynus americanus and the octoploid ceratophrys ornata do not show hidden breaks in ribosomal rna. structural modifications of rrna molecules in diploid amphibians has no detectable effect on the ribosomal activity in vitro. | 1984 | 6509913 |
| agricultural effects on amphibian parasitism: importance of general habitat perturbations and parasite life cycles. | agricultural activity can alter host-parasite interactions through associated contaminants and habitat perturbations. it is critical to determine whether agricultural effects are widespread or limited to specific types of agriculture. we examined influences of soybean agriculture on trematode parasitism of larval amphibians (grey tree frogs; hyla versicolor) to assess the potential effects of a commonly applied pesticide (glyphosate) and landscape factors relative to previous field studies focus ... | 2012 | 23060494 |
| glucocorticosteroid hormone treatment of larval treefrogs increases infection by alaria sp. trematode cercariae. | in many amphibian species, an apparent increase has occurred in the prevalence of limb deformities caused by parasitic trematodes. we are interested in the role of environmental stressors in increasing these infections in amphibians. one mechanism by which environmental stressors could act to increase disease prevalence is to increase circulating levels of glucocorticosteroid hormones, which are released in response to stressors and can be immunosuppressive. in the present study, we treated gray ... | 2005 | 16108567 |
| non-parallel coevolution of sender and receiver in the acoustic communication system of treefrogs. | advertisement calls of closely related species often differ in quantitative features such as the repetition rate of signal units. these differences are important in species recognition. current models of signal-receiver coevolution predict two possible patterns in the evolution of the mechanism used by receivers to recognize the call: (i) classical sexual selection models (fisher process, good genes/indirect benefits, direct benefits models) predict that close relatives use qualitatively similar ... | 2002 | 12350274 |
| a cocktail of contaminants: how mixtures of pesticides at low concentrations affect aquatic communities. | the ubiquity of anthropogenic chemicals in nature poses a challenge to understanding how ecological communities are impacted by them. while we are rapidly gaining an understanding of how individual contaminants affect communities, communities are exposed to suites of contaminants yet investigations of the effects of diverse contaminant mixtures in aquatic communities are rare. i examined how a single application of five insecticides (malathion, carbaryl, chlorpyrifos, diazinon, and endosulfan) a ... | 2009 | 19002502 |
| previous exposure of predatory fish to a pesticide alters palatability of larval amphibian prey. | habitat preferences of organisms are reliant on a variety of factors. for amphibians specifically, preferences can depend on factors such as food availability, water quality, and the presence of potential predators. because some amphibians breed in permanent bodies of water (e.g., ponds), the threat of predation (e.g., from fish) is constant. thus, some amphibians are unpalatable to many predators, allowing them to coexist in the same habitats. however, the addition of anthropogenic stressors (i ... | 2013 | 24383102 |
| female túngara frogs do not experience the continuity illusion. | in humans and some nonhuman vertebrates, a sound containing brief silent gaps can be rendered perceptually continuous by inserting noise into the gaps. this so-called "continuity illusion" arises from a phenomenon known as "auditory induction" and results in the perception of complete auditory objects despite fragmentary or incomplete acoustic information. previous studies of auditory induction in gray treefrogs (hyla versicolor and h. chrysoscelis) have demonstrated an absence of this phenomeno ... | 2016 | 26692450 |
| female preferences for spectral call properties in the western genetic lineage of cope's gray treefrog (hyla chrysoscelis). | female frogs discriminate among potential mates based on individual variation in male advertisement calls. while considerable data have accumulated allowing comparisons of female preference functions among species, we still lack fundamental knowledge about how and why the shapes of preference functions for particular call properties vary among populations within all but a few species. here, we report results from a study aimed at describing female preference functions for spectral call propertie ... | 2012 | 24496093 |
| parallel changes in mate-attracting calls and female preferences in autotriploid tree frogs. | for polyploid species to persist, they must be reproductively isolated from their diploid parental species, which coexist at the same time and place at least initially. in a complex of biparentally reproducing tetraploid and diploid tree frogs in north america, selective phonotaxis--mediated by differences in the pulse-repetition (pulse rate) of their mate-attracting vocalizations--ensures assortative mating. we show that artificially produced autotriploid females of the diploid species (hyla ch ... | 2012 | 22113033 |
| temporal order and the evolution of complex acoustic signals. | the evolution of complex signals may be favoured by hidden preferences or pre-existing sensory biases. females of two species of grey treefrogs (hyla chrysoscelis and hyla versicolor) were tested with combinations of a conspecific advertisement call and acoustic appendages. appendages consisted of aggressive calls and segments of advertisement calls from conspecific males and males of three other species and bursts of filtered noise. when a wide variety of these acoustic appendages followed the ... | 2007 | 17507330 |
| advertisement-call preferences in diploid-tetraploid treefrogs (hyla chrysoscelis and hyla versicolor): implications for mate choice and the evolution of communication systems. | signals used for mate choice and receiver preferences are often assumed to coevolve in a lock-step fashion. however, sender-receiver coevolution can also be nonparallel: even if species differences in signals are mainly quantitative, females of some closely related species have qualitatively different preferences and underlying mechanisms. two-alternative playback experiments using synthetic calls that differed in fine-scale temporal properties identified the receiver criteria in females of the ... | 2005 | 15807424 |
| replication banding patterns of the diploid-tetraploid treefrogs hyla chrysoscelis and h. versicolor. | populations of the diploid-tetraploid treefrogs hyla chrysoscelis and h. versicolor can be defined by the polymorphic positions of the nucleolar organizing regions (nors) on their chromosomes. evidence from nor positions and interstitial telomere sequence data shows that gene flow between h. chrysoscelis populations appears to be restricted, with contact occurring only in narrow "hybrid" zones. hyla versicolor appears to have had multiple origins from h. chrysoscelis populations, and this, too, ... | 2000 | 10773656 |
| power output of sound-producing muscles in the tree frogs hyla versicolor and hyla chrysoscelis. | sound-producing muscles provide the opportunity of studying the limits of power production at high contractile frequencies. we used the work loop technique to determine the power available from the external oblique muscles in two related species of north american gray tree frog, hyla chrysoscelis and hyla versicolor. these trunk muscles contract cyclically, powering high-intensity sound production in anuran amphibians. the external oblique muscles in h. chrysoscelis have an in vivo operating fre ... | 1999 | 10539971 |
| contractile properties of muscles used in sound production and locomotion in two species of gray tree frog. | the sound-producing muscles of frogs and toads are interesting because they have been selected to produce high-power outputs at high frequencies. the two north american species of gray tree frog, hyla chrysoscelis and hyla versicolor, are a diploid-tetraploid species pair. they are morphologically identical, but differ in the structure of their advertisement calls. h. chrysoscelis produces very loud pulsed calls by contracting its calling muscles at approximately 40 hz at 20 degrees c, whereas, ... | 1999 | 10539970 |
| in vivo performance of trunk muscles in tree frogs during calling. | we used high-speed video and electromyography (emg) to measure in vivo performance of the trunk muscles (external obliques) in two related species of north american gray tree frogs, hyla versicolor and hyla chrysoscelis. both species produce trilled calls with high sound intensity, but the sound pulse frequency within calls in h. chrysoscelis is twice that in h. versicolor. in both species, sound pulse frequency is directly correlated with the active contractions of the trunk muscles. the length ... | 1997 | 9364018 |
| speciation by polyploidy in treefrogs: multiple origins of the tetraploid, hyla versicolor. | speciation by polyploidy is rare in animals, yet, in vertebrates, there is a disproportionate concentration of polyploid species in anuran amphibians. sequences from the cytochrome b gene of the mitochondrial dna (mtdna) were used to determine phylogenetic relationships among 37 populations of the diploid-tetraploid species pair of gray treefrogs, hyla chrysoscelis and hyla versicolor. the diploid species, h. chrysoscelis, consists of an eastern and a western lineage that have 2.3% sequence dive ... | 1994 | 28568266 |
| restriction endonuclease mapping of ribosomal rna genes: sequence divergence and the origin of the tetraploid treefrog hyla versicolor. | hyla chrysoscelis (2n = 24) and h. versicolor (2n = 48) are a diploid-tetraploid species pair of treefrogs. restriction endonuclease mapping of ribosomal rna (rrna) gene repeat units of diploids collected from eastern and western populations reveals no differences within rrna gene coding regions but distinctive differences within the nontranscribed spacers. a minimum of two physical maps is required to construct an rrna gene map for the tetraploid, whose repeat units appear to be a composite, wi ... | 1986 | 3017294 |
| species specificity and temperature dependency of temporal processing by the auditory midbrain of two species of treefrogs. | the mating (advertisement) calls of two sibling species of gray treefrogs, hyla versicolor and hyla chrysoscelis, are spectrally identical but differ in trill rate; being higher for h. chrysoscelis. single-unit recordings were made from the torus semicircularis of both species to investigate the neural mechanisms by which this species-specific temporal feature is analyzed. using sinusoidally amplitude-modulated (am) white noise as a stimulus, the temporal selectivity of these midbrain auditory n ... | 1985 | 3837112 |
| diploid and tetraploid grey treefrogs (hyla chrysoscelis and hyla versicolor) have similar metabolic rates. | we measured oxygen consumption of the diploid frog hyla chrysoscelis and its recently evolved tetraploid cryptic species hyla versicolor at rest and during forced locomotory exercise. we also measured whole-body lactic acid concentrations of individuals of the two species at rest and following 4 min of exercise. contrary to predictions based on tissue-culture experiments, rates of organismal metabolism are not different in this diploid/tetraploid species pair: the diploid and tetraploid species ... | 1985 | 2864204 |
| further evidence for a polymorphism in gametic segregation in the tetraploid treefrog hyla versicolor using a glutamate oxaloacetic transaminase locus. | intra- and interspecific cross combinations between the tetraploid treefrog hyla versicolor, and between h. versicolor and the diploid treefrog hyla chrysoscelis were performed. progeny phenotypes resulting from these crosses were examined electrophoretically using a polymorphic glutamate oxaloacetic transaminase (got-1) locus, to determine the mechanism of chromosome segregation in h. versicolor, and to test theoretical expectations for isozyme expression in interspecific (2n x 4n or 4n x 2n) h ... | 1983 | 6852524 |
| gene dosage effects on mdh isozyme expression in diploid, triploid, and tetraploid treefrogs of the genus hyla. | electrophoretic staining intensities at a polymorphic malate dehydrogenase locus (mdh-1) in the tetraploid treefrog hyla versicolor and diploid hyla chrysoscelis were compared using intraspecific and interspecific crosses. gene dosage levels within the three ploidies were additive for the expression of isozymes encoded by this locus. using densitometry, phenotypes from intraspecific tetraploid progeny conformed to a tetraploid gene dosage model, while phenotypes from interspecific hybrids confor ... | 2006 | 7108184 |
| immunological resolution of a diploid-tetraploid species complex of tree frogs. | micro-complement fixation studies of eastern and western populations of the north american tree frog hyla chrysoscelis reveal they have been genetically isolated for about 4 million years. immunological comparisons of populations of the cryptic tetraploid hyla versicolor indicate a recent origin, from hybridization between eastern and western h. chrysoscelis. | 1977 | 17784138 |
| comparative cytochemical measurements in the diploid-tetraploid species pair of hylid frogs hyla chrysoscelis and h. versicolor. | hyla versicolor (2n = 48) is a tetraploid counterpart to h. chrysoscelis (2n = 24). cytochemical measurements revealed that no cytological parameter of the two species conformed to the expected 2:1 ratio. every cytological factor of the tetraploid appeared to have been regulated toward the diploid level. h. veriscolor-to-h. chrysoscelis mean ratios and their standard errors were: dna 1.90 +/- 0.03; nuclear histone, 1.70 +/- 0.18; nuclear rna, 1.63 +/- 0.19; total nuclear protein, 1.46 +/- 0.05; ... | 1975 | 1192844 |
| arboreal camera trapping expands hyla versicolor complex (hylidae) canopy use to new heights. | | 2017 | 28505383 |
| effects of a common insecticide on wetland communities with varying quality of leaf litter inputs. | chemical contamination of aquatic systems often co-occurs with dramatic changes in surrounding terrestrial vegetation. plant leaf litter serves as a crucial resource input to many freshwater systems, and changes in litter species composition can alter the attributes of freshwater communities. however, little is known how variation in litter inputs interacts with chemical contaminants. we investigated the ecological effects resulting from changes in tree leaf litter inputs to freshwater communiti ... | 2017 | 28431762 |
| frequency channel-dependent selectivity for temporal call characteristics in gray treefrogs, hyla versicolor. | sensory receptors transmit information on multiple stimulus dimensions. much remains to be understood about how the processing of different signal characteristics is partitioned and integrated in different areas of the nervous system. amphibian hearing involves two morphologically distinct inner-ear organs that process different components of the frequency spectrum. many anuran signals contain two frequency peaks, each one matching the sensitivity of one of these two organs. we hypothesized that ... | 2017 | 28104800 |
| larger females are choosier in the gray treefrog (hyla versicolor). | individual variation in female mate choice has important implications for sexual trait evolution and the maintenance of phenotypic diversity. in this study we examined several potential drivers of individual variation in female choosiness for the well-studied, energetically expensive courtship signal of male gray treefrogs, hyla versicolor. specifically, we investigated the relationship between female choosiness and other female traits (female body size, physical condition, and age) using a cost ... | 2017 | 27913165 |
| context and condition dependent plasticity in sexual signaling in gray treefrogs. | for many species sexual signaling is a very costly activity, both in terms of energetic expenditure and increased conspicuousness to predators. one potential strategy to limit the costs of signaling is to only signal at maximum effort in contexts when signaling is expected to be most effective. multiple studies have documented extensive plasticity in sexual signaling within a variety of contexts, however fewer experiments have examined individual-level variation in the extent of signaling plasti ... | 2016 | 26706029 |
| dissecting the smell of fear from conspecific and heterospecific prey: investigating the processes that induce anti-predator defenses. | prey use chemical cues from predation events to obtain information about predation risk to alter their phenotypes. though we know how many prey respond to predators, we still have a poor understanding of the processes and chemical cues involved during a predation event. we examined how gray treefrog tadpoles (hyla versicolor) altered their behavior and morphology when raised with cues from different stages of predator attack, predators fed different amounts of prey, and predators consuming diffe ... | 2016 | 26363906 |
| modality interactions alter the shape of acoustic mate preference functions in gray treefrogs. | sexual selection takes place in complex environments where females evaluating male mating signals are confronted with stimuli from multiple sources and modalities. the pattern of expression of female preferences may be influenced by interactions between modalities, changing the shape of female preference functions, and thus ultimately altering the selective landscape acting on male signal evolution. we tested the hypothesis that the responses of female gray treefrogs, hyla versicolor, to acousti ... | 2015 | 26282702 |
| chemosensory perception of predators by larval amphibians depends on water quality. | the acquisition of sensory information by animals is central to species interactions. in aquatic environments, most taxa use chemical cues to assess predation risk and other key ecological factors. a number of laboratory studies suggest that anthropogenic pollutants can disrupt chemoreception, even when at low, non-toxic concentrations, but there are few tests of whether real-world variation in water quality affects chemoreception. here we investigate whether chemosensory perception of predators ... | 2015 | 26114749 |
| here today, gone tomorrow: short-term retention of pesticide-induced tolerance in amphibians. | pesticide use has led to the ubiquitous contamination of natural habitats, which has inadvertently increased pesticide tolerance in target and nontarget species. historically, increased pesticide tolerance has been attributed to natural selection for tolerance among individuals of affected populations. recent research, however, has discovered that pesticide tolerance can be increased through phenotypic plasticity. although induced pesticide tolerance may benefit organisms experiencing contaminat ... | 2015 | 25940070 |
| female gray treefrogs, hyla versicolor, are responsive to visual stimuli but unselective of stimulus characteristics. | the visual ecology of nocturnal anurans is poorly understood, but there is growing evidence that vision plays a role in important behaviors such as mate choice. while several recent studies have demonstrated that females are responsive to visual cues when selecting mates, the forces responsible for these preferences are unknown. we investigated the responsiveness of female gray treefrogs, hyla versicolor, to video playbacks of calling conspecific males in which we varied attributes of the vocal ... | 2014 | 25013111 |
| swimming with predators and pesticides: how environmental stressors affect the thermal physiology of tadpoles. | to forecast biological responses to changing environments, we need to understand how a species's physiology varies through space and time and assess how changes in physiological function due to environmental changes may interact with phenotypic changes caused by other types of environmental variation. amphibian larvae are well known for expressing environmentally induced phenotypes, but relatively little is known about how these responses might interact with changing temperatures and their therm ... | 2014 | 24869960 |
| a multivariate analysis of genetic variation in the advertisement call of the gray treefrog, hyla versicolor. | genetic variation in sexual displays is crucial for an evolutionary response to sexual selection, but can be eroded by strong selection. identifying the magnitude and sources of additive genetic variance underlying sexually selected traits is thus an important issue in evolutionary biology. we conducted a quantitative genetics experiment with gray treefrogs (hyla versicolor) to investigate genetic variances and covariances among features of the male advertisement call. two energetically expensiv ... | 2014 | 24621402 |
| road salts as environmental constraints in urban pond food webs. | freshwater salinization is an emerging environmental filter in urban aquatic ecosystems that receive chloride road salt runoff from vast expanses of impervious surface cover. our study was designed to evaluate the effects of chloride contamination on urban stormwater pond food webs through changes in zooplankton community composition as well as density and biomass of primary producers and consumers. from may - july 2009, we employed a 2×2×2 full-factorial design to manipulate chloride concentrat ... | 2014 | 24587259 |
| effects of subsidy quality on reciprocal subsidies: how leaf litter species changes frog biomass export. | spatial subsidies are resources transferred from one ecosystem to another and which can greatly affect recipient systems. increased subsidy quantity is known to increase these effects, but subsidy quality is likely also important. we examined the effects of leaf litter quality (varying in nutrient and tannin content) in pond mesocosms on gray treefrog (hyla versicolor) biomass export, as well as water quality and ecosystem processes. we used litter from three different tree species native to mis ... | 2014 | 24399483 |
| predator-induced defenses in tadpoles confound body stoichiometry predictions of the general stress paradigm. | predation is known to have both direct and indirect effects on nutrient cycling in terrestrial and aquatic ecosystems, and the general stress paradigm (gsp) has been promoted as a theory for describing predator-mediated indirect effects on nutrient cycling. the gsp predicts that prey exposed to predators will produce glucocorticosteroids, which have a host of physiological effects including gluconeogenesis, increased respiration, excretion of n and p, and increases in body c:n. we tested the nut ... | 2013 | 24358709 |
| trade-offs and upper limits to signal performance during close-range vocal competition in gray tree frogs hyla versicolor. | performance limitations on signal production constrain signal evolution. variation in signaling performance may be related to signaler quality and therefore is likely to be a salient aspect of communication systems. when multiple signal components are involved in communication, there may be trade-offs between components, and performance can be measured as the degree to which signalers approach the upper limits of the trade-off function. we examined vocal performance in the gray tree frog hyla ve ... | 2012 | 22976007 |
| effects of road deicer (nacl) and amphibian grazers on detritus processing in pond mesocosms. | road deicers have been identified as potential stressors in aquatic habitats throughout the united states, but we know little regarding associated impacts to ecosystem function. a critical component of ecosystem function that has not previously been evaluated with respect to freshwater salinization is the impact on organic matter breakdown. the purpose of this study was to evaluate cumulative effects of road deicers and tadpole grazers on leaf litter breakdown rate (g d(-1) ) and microbial respi ... | 2012 | 22821388 |
| competitive stress can make the herbicide roundup® more deadly to larval amphibians. | toxicity assessments on nontarget organisms have largely been addressed using short-term, single-species laboratory experiments. although extremely helpful, these experiments inherently lack many pervasive ecological stressors found in nature. though a substantial challenge, incorporating these ecological stressors in contaminant studies would shed light on potential synergistic effects. for the world's leading herbicide, glyphosate, we know little about how natural stressors affect the toxicity ... | 2011 | 21038363 |
| differential patterns of accumulation and depuration of dietary selenium and vanadium during metamorphosis in the gray treefrog (hyla versicolor). | selenium (se) and vanadium (v) are contaminants commonly found in aquatic systems affected by wastes derived from fossil fuels. to examine their effects on a widely distributed species of amphibian, we exposed gray tree frogs (hyla versicolor) to se (as seo₂) or v (as navo₃) in their diet from the early larval period to metamorphosis. concentrations of se in se-enriched food were 1.0 (se control), 7.5 (se low), and 32.7 (se high) μg/g dw. concentrations of v in v-enriched food were 3.0 (v contro ... | 2011 | 20878520 |
| a precedence effect underlies preferences for calls with leading pulses in the grey treefrog, hyla versicolor. | the temporal relationship between signals often has strong and repeatable influences on receiver behaviour. while several studies have shown that receivers prefer temporally leading signals, we show that the relative timing of signal elements within overlapping signals can also have repeatable influences on receiver responses. female grey treefrogs, hyla versicolor, preferred overlapping conspecific advertisement call alternatives in which pulses were in the leading position relative to pulses i ... | 2010 | 20625471 |
| phonotaxis to male's calls embedded within a chorus by female gray treefrogs, hyla versicolor. | during the reproductive season, male hyla versicolor produce advertisement calls to attract females. females exhibit phonotaxis and approach the individual callers, resulting in amplexus. for frogs that call from dense choruses, the extent to which and the range from which a male's advertisement call within a chorus can be heard by a receptive female leading to phonotaxis is unclear. we investigated females' responses to natural choruses in the field and found that they were attracted and showed ... | 2010 | 20577882 |
| effect of anomalous pulse timing on call discrimination by females of the gray treefrog (hyla versicolor): behavioral correlates of neurobiology. | research has demonstrated that certain midbrain neurons of anurans 'count' interpulse intervals (ipis). some neurons fire after exposure to fewer intervals than do others. counting can be reset to zero if an ipi falls outside the cell's tolerance range. we tested female gray treefrogs for behavioral correlates of these neural response patterns using phonotaxis tests in order to gain a better understanding of the mechanistic bases of female responses to calls. for example, previous work demonstra ... | 2010 | 20511520 |
| lethal and sublethal effects of embryonic and larval exposure of hyla versicolor to stormwater pond sediments. | stormwater ponds are common features of modern stormwater management practices. stormwater ponds often retain standing water for extended periods of time, develop vegetative characteristics similar to natural wetlands, and attract wildlife. however, because stormwater ponds are designed to capture pollutants, wildlife that utilize ponds might be exposed to pollutants and suffer toxicological effects. to investigate the toxicity of stormwater pond sediments to hyla versicolor, an anuran commonly ... | 2010 | 19685097 |
| experimental analysis of multivariate female choice in gray treefrogs (hyla versicolor): evidence for directional and stabilizing selection. | even simple biological signals vary in several measurable dimensions. understanding their evolution requires, therefore, a multivariate understanding of selection, including how different properties interact to determine the effectiveness of the signal. we combined experimental manipulation with multivariate selection analysis to assess female mate choice on the simple trilled calls of male gray treefrogs. we independently and randomly varied five behaviorally relevant acoustic properties in 154 ... | 2009 | 19500145 |
| hormonal modulation of phonotaxis and advertisement-call preferences in the gray treefrog (hyla versicolor). | hormonal levels fluctuate during the breeding season in many anurans, but the identity of the hormones that modulate breeding behavior and their effects remain unclear. we tested the influence of a combined treatment of progesterone and prostaglandin on phonotaxis, the key proceptive reproductive behavior of female anurans. first, we found that female gray treefrogs (hyla versicolor) treated with progesterone and prostaglandin exhibited phonotaxis to synthetic male advertisement signals signific ... | 2009 | 18926827 |
| annual variation in glycerol mobilization and effect of freeze rigor on post-thaw locomotion in the freeze-tolerant frog hyla versicolor. | this study documents post-thaw recovery of jump distance and cryoprotectant mobilization in the freeze-tolerant frog hyla versicolor over two successive years. cold acclimated frogs had plasma glycerol levels near 1.0 mm in 2004 but it was nearly 70x higher during 2005. freezing of frogs induced nearly identical levels of plasma glycerol (ca. 177 mm) during 2004 and 2005. plasma glucose was only mobilized upon somatic freezing, with averages ranging between 21 and 36 mm. control jump distance sh ... | 2009 | 18797878 |
| interference risk and the function of dynamic shifts in calling in the gray treefrog (hyla versicolor). | male gray treefrogs call to attract females under challenging acoustic conditions. at higher chorus densities, there is considerable background noise and a good chance that a male's calls will often be overlapped by calls of other individuals. call overlap may reduce the probability of mating because females prefer calls with internal pulse structure that is not obscured. with increases in acoustic stimulation, males lengthen call duration while simultaneously reducing call rate such that "pulse ... | 2008 | 18729656 |
| effects of atrazine on anuran development are altered by the presence of a nonlethal predator. | although predator-induced stress is a common biotic factor in aquatic communities that can strongly influence anuran development, there have been no studies to date that examined the interaction between this factor and atrazine, the most widely used pesticide in the united states. the potential synergistic effects of atrazine (0, 20, or 200 microg/l) and predatory stress on the survival, growth, development, and reproductive development of hyla versicolor (gray treefrog) tadpoles were investigat ... | 2008 | 18338285 |
| examining multiple sublethal contaminants on the gray treefrog (hyla versicolor): effects of an insecticide, herbicide, and fertilizer. | we examined the single and interactive effects of an insecticide, an herbicide, and a fertilizer on gray treefrog (hyla versicolor) tadpoles. tadpoles were reared in mesocosms from hatching through metamorphosis and were exposed to the presence or absence of as many as three contaminants. tadpoles did not appear to be more susceptible to single versus multiple contaminants, which may result from positive changes in food resources that compensate for the effects of other contaminants. | 2006 | 17220097 |
| environmental factors influencing trematode prevalence in grey tree frog (hyla versicolor) tadpoles in southern ontario. | the emergence or increased prevalence of various parasites may be linked to alterations in host-parasite interactions caused by environmental changes. we investigated prevalence of trematode infections in grey tree frog (hyla versicolor) tadpoles from ponds in nonagricultural settings versus ponds adjacent to cornfields in southern ontario. we found that agricultural activity was a significant factor in determining the percentage of tadpoles infected by 1 or more trematodes from 1 or more specie ... | 2006 | 17152940 |
| polyploid hybrids: multiple origins of a treefrog species. | hyla versicolor, a tetraploid treefrog, is reported to have originated via multiple hybridization events involving three diploid ancestors. its complex reticulate history provides insights into the roles that polyploidy and hybridization can play in the origin of species. | 2006 | 16581499 |
| success of intracoelomic radiotransmitter implantation in the treefrog (hyla versicolor). | concern about the effects of habitat modification on the natural movements and behavior of amphibians has led researchers to devise several methods to follow individual animals as they migrate among seasonal resources; one such method is the surgical insertion of radiotransmitters. intracoelomic implantation has come into general use despite the relative lack of specific procedural guidelines and information about the effects of transmitter insertion and removal. the author outlines the surgical ... | 2006 | 16446735 |
| damage, digestion, and defence: the roles of alarm cues and kairomones for inducing prey defences. | inducible defences are widely used for studying phenotypic plasticity, yet frequently we know little about the cues that induce these defences. for aquatic prey, defences are induced by chemical cues from predators (kairomones) and injured prey (alarm cues). rarely has anyone determined the separate and combined effects of these cues, particularly across phylogenetically diverse prey types. we examined how tadpoles (hyla versicolor) altered their defences when 10 different prey were either crush ... | 2005 | 21352454 |
| hodological characterization of the septum in anuran amphibians: ii. efferent connections. | the efferent connections of the septum of the gray treefrog hyla versicolor were studied by combining anterograde and retrograde tracing with biotin ethylendiamine (neurobiotin). the lateral septal complex projects mainly to the medial pallium, limbic regions (e.g., amygdala and nucleus accumbens), and hypothalamic areas but also to sensory nuclei in the diencephalon and midbrain. the central septal complex strongly innervates the medial pallium, limbic, and hypothalamic areas but also specific ... | 2005 | 15700277 |
| hodological characterization of the septum in anuran amphibians: i. afferent connections. | on the basis of nissl-stained sections, we subdivided the septum of the gray treefrog hyla versicolor in the lateral, central, and medial septal complex. the afferent projections of the different septal nuclei were studied by combined retrograde and anterograde tracing with biotin ethylendiamine (neurobiotin). the central and medial septal complex receives direct input from regions of the olfactory bulb and from all other limbic structures of the telencephalon (e.g., amygdalar regions, nucleus a ... | 2005 | 15700270 |
| phonotaxis in hyla versicolor (anura, hylidae): the effect of absolute call amplitude. | the influence of call amplitude on phonotaxis in female hyla versicolor was studied using a no-choice paradigm. one set of experiments estimated effects of stimulus amplitude on phonotaxis toward a synthetic model of a conspecific call. the response strength increased with amplitude from the behavioral threshold (37-43 db spl) up to 79 db spl and then decreased at higher amplitudes. females approached the loudspeaker with short walking bouts (approximately 1 s duration) occurring immediately aft ... | 2004 | 15316730 |
| roles of the auditory midbrain and thalamus in selective phonotaxis in female gray treefrogs (hyla versicolor). | diencephalic and midbrain auditory nuclei are involved in the processing of auditory communication signals in anurans [comparative hearing: fish and amphibians, springer-verlag, new york, 1999, p. 218], but their exact roles in acoustically guided behavior, such as female phonotaxis, are unclear. to address this question, behavioral experiments were combined with lesions of dorsal thalamic nuclei and the midbrain torus semicircularis. females were tested in two-alternative-forced-choice phonotac ... | 2003 | 14529806 |
| defining core habitat of local populations of the gray treefrog (hyla versicolor) based on choice of oviposition site. | concern over amphibian population declines and loss of terrestrial and aquatic habitat have emphasized the need to define habitat requirements for each stage in a species' life history. the realization that pond-breeding amphibians spend most of their lives in the terrestrial environment suggests the need to protect terrestrial as well as aquatic habitat. many studies on amphibian populations have focused on emigration from breeding sites to define habitat use; however these studies do not typic ... | 2003 | 12883991 |
| geographic variation in energy storage and physiological responses to freezing in the gray treefrogs hyla versicolor and h. chrysoscelis. | the physiological responses supporting freeze tolerance in anurans are well known, but the evolution of this trait remains little studied. this is the first common-garden study of geographic variation in cryoprotective responses to freezing and the degree of freeze tolerance. we studied the gray treefrogs (hyla versicolor and h. chrysoscelis) from sympatric sites in minnesota, indiana and missouri. patterns in the literature suggest that northern frogs produce more cryoprotectants upon freezing, ... | 2003 | 12847129 |
| arginine vasotocin interacts with the social environment to regulate advertisement calling in the gray treefrog (hyla versicolor). | arginine vasotocin (avt) has different effects on social behaviors across species with different social systems. however, less attention has been directed towards the way environmental stimuli interact with avt to affect social behaviors. previous work found that avt affects the production of advertisement calls and the outcome of competitive interactions between male gray treefrogs (hula versicolor). we conducted a field study to investigate how the presence of other males in a chorus influence ... | 2003 | 12784054 |
| genetic benefits of a female mating preference in gray tree frogs are context-dependent. | "good genes" models of sexual selection predict that male courtship displays can advertise genetic quality and that, by mating with males with extreme displays, females can obtain genetic benefits for their offspring. however, because the relative performance of different genotypes can vary across environments, these genetic benefits may depend on the environmental context; in which case, static mating preferences may not be adaptive. to better understand how selection acts on the preference tha ... | 2003 | 12778557 |
| 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). ... | 2003 | 12531477 |
| population genetics of a polyploid: is there hybridization between lineages of hyla versicolor? | several studies have demonstrated that polyploid species can form recurrently from their progenitors, but few studies have evaluated gene flow between the resultant polyploid lineages. here we examine the possibility of hybridization between lineages of the tetraploid common gray treefrog (hyla versicolor). we utilize a polymerase chain reaction (pcr) cloning approach to estimate the genotypes of tetraploid individuals and measure genetic differentiation between (1) sympatric populations of two ... | 2007 | 12140266 |
| freeze tolerance in the gray treefrog: cryoprotectant mobilization and organ dehydration. | freeze tolerance in the frog rana sylvatica is supported by nonanticipatory mobilization of cryoprotectant (glucose) and redistribution of organ water. other freeze-tolerant frogs may manifest these responses but differences exist. for example, the gray treefrog (hyla versicolor) accumulates mostly glycerol as opposed to glucose. the current study reports additional novel features about cryoprotection in h. versicolor. frogs were acclimated to low temperature for 12 weeks and frozen for 3 days a ... | 2001 | 11429758 |
| predator-induced stress makes the pesticide carbaryl more deadly to gray treefrog tadpoles (hyla versicolor). | global declines in amphibians likely have multiple causes, including widespread pesticide use. our knowledge of pesticide effects on amphibians is largely limited to short-term (4-d) toxicity tests conducted under highly artificial conditions to determine lethal concentrations (lc50). we found that if we used slightly longer exposure times (10-16 d), low concentrations of the pesticide carbaryl (3-4% of lc50(4-d)) killed 10-60% of gray treefrog (hyla versicolor) tadpoles. if predatory cues also ... | 2001 | 11226266 |
| physical factors affecting the cost and efficiency of sound production in the treefrog hyla versicolor. | the metabolic cost, energy output and efficiency (i.e. the ratio of energy output to metabolic cost) of sound production were compared among male grey treefrogs (hyla versicolor) as a function of body size and temperature. the effects of call length (in notes per call) and dominant frequency (in khz) were also considered. cost, determined from the amount of oxygen consumed, averaged 12.1 mj per note and was dependent only upon body mass. acoustic energy per note, determined from oscillograms of ... | 2001 | 11104712 |
| genetic variation and a fitness tradeoff in the tolerance of gray treefrog (hyla versicolor) tadpoles to the insecticide carbaryl. | one of the major unanswered questions in the study of global amphibian declines is why only some species or populations suffer declines. a possible explanation is that species and populations vary in the genetic basis of their tolerance to environmental stress such as chemical contamination. the presence of genetic variation in tolerance to chemicals and in fitness traits of amphibians is essential for persistence of species populations through survival and successful reproduction in contaminate ... | 2000 | 24595829 |