| the combined influence of trematode parasites and predatory salamanders on wood frog (rana sylvatica) tadpoles. | predators can have important impacts on host-parasite dynamics. for many directly transmitted parasites, predators can reduce transmission by removing the most heavily infected individuals from the population. less is known about how predators might influence parasite dynamics in systems where the parasite relies on vectors or multiple host species to complete their life cycles. digenetic trematodes are parasitic flatworms with complex life cycles typically involving three host species. they are ... | 2011 | 21384178 |
| specific dynamic action of ambystomatid salamanders and the effects of meal size, meal type, and body temperature. | the past decade has witnessed a dramatic increase in studies of amphibian and reptile specific dynamic action (sda). these studies have demonstrated that sda, the summed energy expended on meal digestion and assimilation, is affected significantly by meal size, meal type, and body size and to some extent by body temperature. while much of this attention has been directed at anuran and reptile sda, we investigated the effects of meal size, meal type, and body temperature on the postprandial metab ... | 2006 | 16826498 |
| an examination of multiple factors affecting community structure in an aquatic amphibian community. | the potential effects of multiple factors structuring certain larval amphibian communities were studied using a pen experiment in a natural pond. potential factors (predation and competition from other species) were allowed to act in a stepwise fashion such that their relative importance could be evaluated. based on a previous study, it was hypothesized that predation by ambystoma salamander larvae on other larval amphibian species would be the most important factor. survival of ambystoma jeffer ... | 1990 | 28313252 |
| effects of boron and nitrate on hatching success of amphibian eggs. | as part of a land-application wastewater disposal system in central pennsylvania, vernal ponds are commonly exposed to wastewater effluent containing high levels of boron and nitrate. we examined the individual effects of these compounds on the eggs of amphibians breeding in these ponds. wood frog (rana sylvatica), jefferson salamander (ambystoma jeffersonianum), spotted salamander (a. maculatum), and american toad (bufo americanus) eggs were exposed to boron (0, 50, and 100 mg l-1) and nitrate ... | 1998 | 9776779 |
| caudal vertebral development and morphology in three salamanders with complex life cycles (ambystoma jeffersonianum, hemidactylium scutatum, and desmognathus ocoee). | we describe caudosacral and caudal vertebral morphology across life history stages in three caudate amphibians: ambystoma jeffersonianum (ambystomatidae), desmognathus ocoee (plethodontidae: desmognathinae), and hemidactylium scutatum (plethodontidae: plethodontinae). all three species have aquatic larvae, but adults differ in habitat and predator defense strategy. predator defense includes tail autotomy in d. ocoee and h. scutatum but not a. jeffersonianum. of the species that autotomize, h. sc ... | 2001 | 11223925 |
| embryo development inside female salamander (ambystoma jeffersonianum-laterale) prior to egg laying. | the length of embryo retention prior to oviposition is a critical evolutionary trait. in all oviparous salamanders, which include the vast majority of species in the order, fertilization is thought to occur at the time of egg laying. embryos then enter the first cleavage stage several hours after being deposited. this pattern holds for previously studied individuals in the ambystoma jeffersonianum-laterale complex. here, we document an instance in which a female ambystoma jeffersonianum-laterale ... | 2014 | 24651275 |
| pond acidification may explain differences in corticosterone among salamander populations. | physiological tolerances play a key role in determining species distributions and abundance across a landscape, and understanding these tolerances can therefore be useful in predicting future changes in species distributions that might occur. vertebrates possess several highly conserved physiological mechanisms for coping with environmental stressors, including the hormonal stress response that involves an endocrine cascade resulting in the increased production of glucocorticoids. we examined th ... | 2013 | 23434782 |
| variation in the hormonal stress response among larvae of three amphibian species. | in a series of studies, we examined how larval corticosterone treatment for several species of amphibians can impact fitness parameters both during exposure and after metamorphosis. we completed confinement stress series on larvae of three species in natural/semi-natural conditions: wood frogs (rana sylvatica), jefferson salamanders (ambystoma jeffersonianum), and eastern spadefoot toads (scaphiopus holbrooki). two of the species had a typical vertebrate response of increasing corticosterone wit ... | 2010 | 20878751 |
| effects of spray-irrigated wastewater effluent on temporary pond-breeding amphibians. | comparison was made of abiotic conditions, amphibian reproductive outputs, and the survival of embryonic and larval amphibians in wastewater effluent-irrigated and natural temporary ponds in an area in centre county, pennsylvania that has been spray-irrigated with secondarily treated, chlorinated wastewater effluent from the pennsylvania state university for approximately 14 years. three species of temporary pond-breeding amphibians were studied: wood frogs (rana sylvatica leconte), jefferson sa ... | 2000 | 10831333 |
| impacts of hydroperiod on growth and survival of larval amphibians in temporary ponds of central pennsylvania, usa. | the effects of variable hydroperiod (three levels) and initial density of amphibians (two levels) on survival, growth rate, and time to and mass at metamorphosis were studied for wood frogs (rana sylvatica), jefferson salamanders (ambystoma jeffersonianum), and spotted salamanders (a. maculatum). experiments were carried out in 260-1 mesocosms set up outdoors in a forest. these pond simulations were designed to mimic conditions that occur in palustrine temporary wetlands in central pennsylvania. ... | 1995 | 28306882 |
| the interactive effects of low ph, toxic metals, and doc on a simulated temporary pond community. | the effects of ph, potentially toxic metals, and dissolved organic carbon (doc) on a freshwater, palustrine wetland assemblage (three amphibian species, one mosquito genus, and 18 genera of algae) were examined in 500 liter outdoor mesocosms. the design was fully factorial and exposure levels were set to represent concentrations that occur naturally in temporary ponds in central pennsylvania, an acid-impacted region of the usa. water chemistry was precisely regulated by use of an artificial pond ... | 1995 | 15091528 |
| morphology and infectivity of cultivated trypanosoma ambystomae. | cultures of trypanosoma ambystomae were initiated and maintained in hypo-osmotic biphasic blood-agar medium. epimastigotes and trypomastigotes occurred in culture and although they were similar in size, epimastigotes predominated with about 70% of all stages. epimastigotes divided by equal binary fission and occasionally formed rosettes. cultured trypomastigotes did not divide. cultures isolated 118 days earlier were infective to all 3 laboratory-reared ambystoma jeffersonianum and to 2 of 3 amb ... | 1994 | 8064518 |
| behavioral and physiological responses of the terrestrial life stages of the jefferson salamander, ambystoma jeffersonianum, to low soil ph. | terrestrial metamorphs of the salamander, ambystoma jeffersonianum, were exposed to four levels of ph on artificial substrates in the laboratory. short-term exposure (7 d) to ph levels between 3.5 and 5.0 had no effect on total body mass, na+, k+, ca2+, and mg2+ concentrations. however, at 14 d in both laboratory experiments and in field microcosms, whole body water and na+ concentrations were significantly lower at the lower ph level. terrestrial metamorphs and adults of the jefferson salamande ... | 1994 | 8060167 |
| effects of acute and chronic acidification on three larval amphibians that breed in temporary ponds. | this study explored the effects of acute (7 days) and chronic (4 months) exposure to ph 4.2 on three species of larval amphibians, ambystoma jeffersonianum, ambystoma maculatum, and rana sylvatica. acute tests were conducted in 24 impermeable enclosures in three temporary ponds. total dissolved aluminum was higher in acidified enclosures in comparison with controls (ph 4.2, [al] approximately 10-30 microm and ph greater than 4.7, [al] approximately 5-15 microm, respectively). greater mortality o ... | 1992 | 1456779 |
| mitochondrial genotype of a unisexual salamander of hybrid origin is unrelated to either of its nuclear haplotypes. | we examined mitochondrial dna (mtdna), enzyme, and morphological variation among 17 unisexual ambystoma of hybrid origin. electrophoretic comparison of diagnostic enzymes indicates that these unisexuals are triploid with two nuclear genomes from the bisexual species ambystoma laterale and one from ambystoma jeffersonianum; however, according to restriction analysis, the mtdnas of these specimens derive from a third species, ambystoma texanum. this unusual situation is apparently due to a partial ... | 1990 | 2315316 |
| prey size-distributions and size-specific foraging success of ambystoma larvae. | we examined how prey size-distributions influence size-specific foraing rate and food gain, i.e., food intake scaled to metabolic demands, in jefferson's and small-mouth salamander larvae. ambystoma jeffersonianum larvae sampled on 17 dates from a farm pond whose fauna was dominated by macrozooplankton and chironomid larvae were rarely gape-limited, and total volume of food in the stomach (vs) showed only a slight tendency to increase with larval size. although 15 of 17 correlation coefficients ... | 1987 | 28312251 |
| serum proteins of salamanders of the ambystoma jeffersonianum complex, and the origin of the triploid species of this group. | | 1967 | 28556137 |
| gynogenesis in salamanders related to ambystoma jeffersonianum. | the oocytes of naturally occurring triploid females of the ambystoma jeffersonianum complex each contain 84 lampbrush chromosomes. this constitutes hexaploidy (n = 14). the chromosomes are joined into pairs by chiasmata and form 42 bivalents. it is suggested that meiosis in triploid females is preceded by an endomitosis and the resulting sister chromosomes synapse to form pseudo-bivalents. sperm from diploid males stimulate development of the triploid eggs but do not contribute chromosomes to th ... | 1964 | 14112709 |
| natural triploidy in salamanders related to ambystoma jeffersonianum. | female salamanders with large erythrocytes and erythrocyte nuclei produced triploid larvae; females with small erythrocytes and erythrocyte nuclei produced diploid larvae. larval chromosome counts, dimorphism in cell size, and sex inheritance indicate distinct, persisting populations of triploid females in parts of the range of the ambystoma jeffersonianum complex. | 1963 | 13995620 |
| 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 ... | 2020 | 32336925 |
| characterization of dermotheca sp. infection in a midwestern state-endangered salamander (ambystoma platineum) and a co-occurring common species (ambystoma texanum). | ichthyosporean parasites (order dermocystida) can cause morbidity and mortality in amphibians, but their ecology and epidemiology remain understudied. we investigated the prevalence, gross and histologic appearance, and molecular phylogeny of a novel dermocystid in the state-endangered silvery salamander (ambystoma platineum) and the co-occurring, non-threatened small-mouthed salamander (ambystoma texanum) from illinois. silvery salamanders (n = 610) were sampled at six ephemeral wetlands from 2 ... | 2020 | 31840622 |