| pathogenicity of aeromonas hydrophila, klebsiella pneumoniae, and proteus mirabilis to brown tree frogs (litoria ewingii). | bacterial dermatosepticemia, a systemic infectious bacterial disease of frogs, can be caused by several opportunistic gram-negative bacterial species including aeromonas hydrophila, chryseobacterium indologenes, chryseobacterium meningosepticum, citrobacter freundii, klebsiella pneumoniae, proteus mirabilis, pseudomonas aeruginosa, and serratia liquifaciens. here we determined the pathogenicity of 3 bacterial species (aeromonas hydrophila, klebsiella pneumoniae, and proteus mirabilis) associated ... | 2010 | 20412685 |
| a new species of frog in the litoria ewingii species group (anura: pelodryadidae) from south-eastern australia. | population declines and range contractions among australian frogs that commenced in the early 1980s continue in some species that were once widespread. the generality of this pattern has been difficult to discern, especially for those species that are encountered rarely because they have restricted periods of calling activity with poorly defined habitat preferences, and are not common. several lines of evidence indicate that litoria littlejohni is such a species. this frog was once known from mi ... | 2020 | 33056230 |
| inheritance of transferrins in progeny of in vitro crosses involving the tree frog litoria ewingi (anura: hylidae). | | 1976 | 1261230 |
| effect of acute captivity stress on plasma concentrations of corticosterone and sex steroids in female whistling frogs, litoria ewingi. | plasma concentrations of corticosterone and sex steroids were examined in vitellogenic frogs (litoria ewingi) at 0, 0.5, 3, and 24 hr after capture from the wild. plasma corticosterone concentrations were undetectable (< 1.8 ng/ml) in all frogs at capture and rose significantly as time in captivity increased (p < 0.05). plasma concentrations of estradiol (1001 +/- 13 pg/ml) and testosterone (4.0 +/- 0.7 ng/ml) did not change after capture (p > 0.05). plasma progesterone concentration varied slig ... | 1995 | 8575656 |
| cold tolerance and overwintering of an introduced new zealand frog, the brown tree frog (litoria ewingii). | the overwintering strategy of litoria ewingii in otago, new zealand, was studied under laboratory and field conditions. microhabitat temperature measurements showed that the frogs were often exposed to subzero temperatures. in the laboratory, litoria ewingii tolerated freezing for up to 6 hrs at -1 degrees c, and after the completion of the freezing event (about 1 hr) at -2 degrees c. frogs frozen with insulation survived freezing for 12 hrs at -1 degrees c. frogs supercooled to -1.2 +/- 0.1 deg ... | 2008 | 18075704 |
| skin ice nucleators and glycerol in the freezing-tolerant frog litoria ewingii. | the brown tree frog (litoria ewingii) is the only known southern hemisphere vertebrate that can survive full-body freezing. freezing challenges living organisms in many ways, with ice formation in the body producing a suite of physical and metabolic stresses which can damage cells and tissues. the present study looked at two mechanisms that address some of these stresses: cryoprotectants and ice nucleating agents (inas). skin secretions from l. ewingii were sampled along with microhabitat substr ... | 2011 | 21373937 |
| molecular patterns of introgression in a classic hybrid zone between the australian tree frogs, litoria ewingii and l. paraewingi: evidence of a tension zone. | hybrid zones provide a rare opportunity to explore the processes involved in reproductive isolation and speciation. the southern hybrid zone between the southeastern australian tree frogs litoria ewingii and l. paraewingi has been comprehensively studied over the last 40 years, primarily using reproductive compatibility experiments and male advertisement calls. we used mitochondrial dna (mtdna) and eight nuclear microsatellite markers to characterize this hybrid zone along a historically studied ... | 2013 | 23294099 |
| anesthesia of tadpoles of the southern brown tree frog (litoria ewingii) with isoeugenol (aqui-s). | because anesthesia of amphibian larvae is currently problematic, the aim of this study was to test if a fish anesthetic containing approximately 500 g/l isoeugenol (aqui-s) could anesthetize tadpoles. three concentrations of aqui-s were tested (of commercial solution 10, 20, and 50 microl/l) with 10 tadpoles of the southern brown tree frog (litoria ewingii) per concentration. tadpoles were anesthetized for 15 min in water at 18-20 degrees c. anesthetic criteria included four time points and two ... | 2014 | 25314815 |
| anuran larval developmental plasticity and survival in response to variable salinity of ecologically relevant timing and magnitude. | salinity in affected freshwater ecosystems fluctuates with seasonal rainfall, tidal flux, rates of evaporation, chemical runoff and the influence of secondary salinization. environmental stressors such as salinity can have lasting effects on anuran development, yet little is known about the effects of fluctuating salinity on tadpole ontogeny or the effects of differing magnitudes of salinity exposure, as would occur in natural wetland systems. we examined how salinity fluctuations affected survi ... | 2014 | 25366570 |
| identifying hybridization and admixture using snps: application of the dartseq platform in phylogeographic research on vertebrates. | next-generation sequencing (ngs) approaches are increasingly being used to generate multi-locus data for phylogeographic and evolutionary genetics research. we detail the applicability of a restriction enzyme-mediated genome complexity reduction approach with subsequent ngs (dartseq) in vertebrate study systems at different evolutionary and geographical scales. we present two case studies using snp data from the dartseq molecular marker platform. first, we used dartseq in a large phylogeographic ... | 2017 | 28791133 |
| spatio-temporal changes in the structure of an australian frog hybrid zone: a 40-year perspective. | spatio-temporal studies of hybrid zones provide an opportunity to test evolutionary hypotheses of hybrid zone maintenance and movement. we conducted a landscape genetics study on a classic hybrid zone of the south-eastern australian frogs, litoria ewingii and litoria paraewingi. this hybrid zone has been comprehensively studied since the 1960s, providing the unique opportunity to directly assess changes in hybrid zone structure across time. we compared both mtdna and male advertisement call data ... | 2013 | 24299399 |
| short- and long-term consequences of developmental saline stress: impacts on anuran respiration and behaviour. | secondary salinization has been identified as a major stressor to amphibians. exposure to elevated salinity necessitates physiological adjustments and biochemical changes that may be energetically demanding. as such, exposure to non-lethal levels of salinity during development could potentially alter anuran metabolic rates and individual performance in both pre- and post-metamorphic life stages. we investigated the effects of non-lethal levels of salinity on metamorphic traits (time to reach met ... | 2016 | 26998337 |
| interspecific variation in the phenology of advertisement calling in a temperate australian frog community. | spatial and temporal partitioning of resources underlies the coexistence of species with similar niches. in communities of frogs and toads, the phenology of advertisement calling provides insights into temporal partitioning of reproductive effort and its implications for community dynamics. this study assessed the phenology of advertisement calling in an anuran community from melbourne, in southern australia. we collated data from 1432 surveys of 253 sites and used logistic regression to quantif ... | 2015 | 26442760 |
| experimental infection of self-cured leiopelma archeyi with the amphibian chytrid batrachochytrium dendrobatidis. | the susceptibility of archey's frog leiopelma archeyi to batrachochytrium dendrobatidis (bd) is unknown, although one large population is thought to have declined sharply due to chytridiomycosis. as primary infection experiments were not permitted in this endangered new zealand species, 6 wild-caught l. archeyi that naturally cleared infections with bd while in captivity were exposed again to bd to assess their immunity. these frogs were from an infected population at whareorino, which has no kn ... | 2010 | 21268977 |
| skin peptides of different life stages of ewing's tree frog. | in frogs, an important mechanism of skin innate immunity against invading microbial pathogens is secretion of antimicrobial peptides from the specialized granular glands. since these glands develop fully in skin dermis after completion of metamorphosis, they are small and immature in skin of larvae (tadpoles). skin secretions vary among different life stages. antimicrobial activity and peptide composition of natural mixture of skin peptides of three different life stages of new zealand ewing's t ... | 2010 | 20034019 |
| environmental deterioration increases tadpole vulnerability to predation. | human-induced environmental change is occurring at an unprecedented rate and scale. many freshwater habitats, in particular, have been degraded as a result of increased salinity. little is known about the effects of anthropogenic salinization on freshwater organisms, especially at sublethal concentrations, where subtle behavioural changes can have potentially drastic fitness consequences. using a species of australian frog (litoria ewingii), we experimentally examined the effects of salinization ... | 2008 | 18492650 |