| spermiophagy by the spermathecal epithelium of the salamander eurycea cirrigera. | the spermathecae of eurycea cirrigera are exocrine glands in the cloaca that secrete a substance that bathes sperm stored in the lumen after mating and prior to oviposition. many sperm remain in the spermathecae after oviposition, and the spermathecal epithelium becomes spermiophagic. pseudopodia enclose sperm into endocytic vacuoles. the vacuoles become associated with primary lysosomes in the cytoplasm. following formation of secondary lysosomes and resulting condensation of the sperm fragment ... | 1992 | 1507241 |
| bioaccumulation and maternal transfer of mercury and selenium in amphibians. | amphibian population declines have been documented worldwide and environmental contaminants are believed to contribute to some declines. maternal transfer of bioaccumulated contaminants to offspring may be an important and overlooked mechanism of impaired reproductive success that affects amphibian populations. mercury (hg) is of particular concern due to its ubiquity in the environment, known toxicity to other wildlife, and complex relationships with other elements, such as selenium (se). the o ... | 2010 | 20821530 |
| acute toxicity of acidity in larvae and adults of four stream salamander species (plethodontidae). | high levels of acid deposition have severely affected streamwater chemistry in the southern appalachians. plethodontid stream salamanders living in and around headwater streams rely on cutaneous respiration and are highly susceptible to changes in water quality. we examined the sensitivity to low ph conditions in four stream salamanders by monitoring the response to six ph treatments ranging from ph 2.75 to 6.5. to quantify acid tolerance, we determined median lethal concentrations (lc50) in 96- ... | 2008 | 18522477 |
| patterns of trombiculid mite (hannemania dunni) parasitism among plethodontid salamanders in the western piedmont of north carolina. | trombiculid mites are known to parasitize a variety of amphibian species, yet few comparisons of mite parasitism among amphibian species have been made. in this study, we investigated patterns of trombiculid mite parasitism among 3 plethodontid salamanders (desmognathus fuscus, eurycea cirrigera, and plethodon cylindraceus) in the western piedmont of north carolina. all 3 salamander species were parasitized by a single species, hannemania dunni. desmognathus fuscus harbored mites more frequently ... | 2008 | 18605777 |
| effects of urbanization on occupancy of stream salamanders. | urban development is the most common form of land conversion in the united states. using a before-after control-impact study design, we investigated the effects of urbanization on larval and adult stages of southern two-lined salamanders (eurycea cirrigera) and northern dusky salamanders (desmognathus fuscus). over 5 years, we estimated changes in occupancy and probabilities of colonization and survival in 13 stream catchments after urbanization and in 17 catchments that were not urbanized. we a ... | 2011 | 21175842 |
| stoichiometry of a semi-aquatic plethodontid salamander: intraspecific variation due to location, size and diet. | ecological stoichiometry provides a framework to investigate an organism's relationship to nutrient cycles. an organism's stoichiometry is thought to constrain its contribution to nutrient cycles (recycling or storage), and to limit its growth and reproduction. factors that influence the stoichiometry of a consumer are largely unstudied, but what is known is that consumer stoichiometry is influenced by the elemental requirements of the consumer (e.g. for growth, reproduction and cell maintenance ... | 2014 | 25236804 |
| variation in mating systems of salamanders: mate guarding or territoriality? | two of the most common mating tactics in vertebrates are mate guarding and territoriality, yet much of the research on these strategies has focused on mating systems in birds, despite novel insights gained from studying less traditional systems. north american stream salamanders that comprise the eurycea bislineata complex represent an excellent nontraditional system for comparing mating strategies because these species exhibit a continuum of male morphologies, diverse habitat associations, and ... | 2014 | 24802291 |
| leaf litterbag sampling for larval plethodontid salamander populations in georgia. | survey techniques for larval salamanders vary in their effectiveness and efficiencies. in this study, the leaf litterbag sampling technique was employed to gather data on larval salamander populations in perennial streams of southern georgia. salamanders were collected monthly for 12 months to analyze capture counts and population size-class structure. simultaneous dipnet sweep data were used to examine potential count data biases of the leaf litterbag sampling technique. in both leaf litterbag ... | 2007 | 17180410 |
| impact of cannibalism on predator-prey dynamics: size-structured interactions and apparent mutualism. | direct and indirect interactions between two prey species can strongly alter the dynamics of predator-prey systems. most predators are cannibalistic, and as a consequence, even systems with only one predator and one prey include two prey types: conspecifics and heterospecifics. the effects of the complex direct and indirect interactions that emerge in such cannibalistic systems are still poorly understood. this study examined how the indirect interaction between conspecific and heterospecific pr ... | 2008 | 18589529 |
| the influence of size-specific indirect interactions in predator-prey systems. | nonlethal indirect interactions between predators often lead to nonadditive effects of predator number on prey survival and growth. previous studies have focused on systems with at least two different predator species and one prey species. however, most predators undergo extreme ontological changes in phenotype such that interactions between different-sized cohorts of a predator and its prey could lead to nonadditive effects in systems with only two species. this may be important since different ... | 2006 | 16637362 |
| intraguild predation among larval plethodontid salamanders: a field experiment in artificial stream pools. | intraguild predation can be important in determining community structure and dynamics. artificial stream pools were used to test for the impacts of intraguild predation among three species of larval plethodontid salamanders. intraguild predators (large gyrinophilus porphyriticus and pseudotriton ruber) significantly decreased the survival of small pseudotriton ruber. there was a trend toward reduced growth of pseudotriton and eurycea cirrigera in the presence of intraguild predators. the presenc ... | 1993 | 28313424 |
| phylogeography of the brownback salamander reveals patterns of local endemism in southern appalachian springs. | the appalachian mountains of eastern north america are characterized by high faunal diversity and many endemic species, especially in the unglaciated southern latitudes where lineages have been accumulating for tens of millions of years. the brownback salamander, eurycea aquatica, is an enigmatic species that dwells in isolated springs in southeastern north america. eurycea aquatica have often been dismissed as simply robust spring-adapted ecomorphs of the widespread and more gracile species eur ... | 2009 | 19345271 |
| posterior tail development in the salamander eurycea cirrigera: exploring cellular dynamics across life stages. | during embryogenesis, the body axis elongates and specializes. in vertebrate groups such as salamanders and lizards, elongation of the posterior body axis (tail) continues throughout life. this phenomenon of post-embryonic tail elongation via addition of vertebrae has remained largely unexplored, and little is known about the underlying developmental mechanisms that promote vertebral addition. our research investigated tail elongation across life stages in a non-model salamander species, eurycea ... | 2017 | 28101674 |
| ultrastructure of the annual cycle of female sperm storage in spermathecae of the torrent salamander, rhyacotriton variegatus (amphibia: rhyacotritonidae). | this study is the first report on the ultrastructure of the sperm storage glands (spermathecae) in the salamander rhyacotriton variegatus. the population studied is associated with cold-water, rocky streams of the redwood (sequoia) zone in northern california. males possess sperm in their vasa deferentia and undergo spermiation throughout the year, but mating is seasonal. most females with large, vitellogenic follicles (2.0-3.9 mm mean dia.) collected from february-june contain sperm in their sp ... | 2004 | 15164363 |
| regionalization of eccrine and spermiophagic activity in spermathecae of the salamander eurycea cirrigera (amphibia: plethodontidae). | the spermathecae of female eurycea cirrigera are compound alveolar glands; narrow neck tubules connect the distal bulbs to a common tube that opens onto the roof of the cloaca. the common tube and neck tubules produce apical secretory vacuoles that contain a periodic acid-schiff (pas)+ substance for merocrine export into the lumen. this substance is produced throughout the year, although secretory vacuoles are less numerous during the period of reproductive inactivity in the summer. when sperm a ... | 1993 | 29865466 |
| sperm storage and degradation in the spermathecae of the salamander eurycea cirrigera. | spermathecae are exocrine glands in the roof of the female cloaca that store sperm. cytological and histochemical data indicate that the one type of secretion into the lumen is a glycoprotein. after a period of stasis in the summer, production of the secretion is initiated in the fall, coincident with an increase in ovarian follicular size. by the time of maximal follicular development and most intense mating activity in march and april, the spermathecal epithelium is filled with secretory granu ... | 1991 | 29865544 |