2 resultados para toe

em Bucknell University Digital Commons - Pensilvania - USA


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Many global amphibian declines have been linked to the fungal pathogen Batrachochytrium dendrobatidis (Bd). The knowledge on Bd distribution provides a fundamental basis for amphibian conservation planning. Yet, such Bd distribution information is currently insufficient, in particular at a regional scale. The college classroom provides an excellent opportunity to expand the knowledge of Bd distribution. Here we provide an example of such research projects to detect Bd prevalence among local amphibians in a college course setting and present the results of work conducted in central Pennsylvania, USA. We collected toe clips and conducted PCR assays of six species, Plethodon cinereus, Desmognathus fuscus, Notophthalmus viridescens, Lithobates catesbeianus, L. clamitans, and L. sylvaticus (59 individuals). Four groups of students independently conducted entire projects, orally presented their findings, and submitted manuscripts to the professor at the end of the semester. This example demonstrates that it is feasible for an undergraduate class to complete a Bd-detection project within a single semester. Such a project not only contributes to Bd research but also promotes conservation education among students through hands-on research experiences. We found Bd infection in only one sample of N. viridescens, but no sign of infection in the rest of the samples. As a relatively high prevalence of Bd has been reported in surrounding areas, our results suggest spatial heterogeneity in Bd occurrence at a regional scale and thus, the need for continued efforts to monitor Bd prevalence.

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The examination of telomere dynamics is a recent technique in ecology for assessing physiological state and age-related traits from individuals of unknown age. Telomeres shorten with age in most species and are expected to reflect physiological state, reproductive investment, and chronological age. Loss of telomere length is used as an indicator of biological aging, as this detrimental deterioration is associated with lowered survival. Lifespan dimorphism and more rapid senescence in the larger, shorter-lived sex are predicted in species with sexual size dimorphism, however, little is known about the effects of behavioral dimorphism on senescence and life history traits in species with sexual monomorphism. Here we compare telomere dynamics of thick-billed murres (Uria lomvia), a species with male-biased parental care, in two ways: 1) cross-sectionally in birds of known-age (0-28 years) from one colony and 2) longitudinally in birds from four colonies. Telomere dynamics are compared using three measures: the telomere restriction fragment (TRF), a lower window of TRF (TOE), and qPCR. All showed age-related shortening of telomeres, but the TRF measure also indicated that adult female murres have shorter telomere length than adult males, consistent with sex-specific patterns of ageing. Adult males had longer telomeres than adult females on all colonies examined, but chick telomere length did not differ by sex. Additionally, inter-annual telomere changes may be related to environmental conditions; birds from a potentially low quality colony lost telomeres, while those at more hospitable colonies maintained telomere length. We conclude that sex-specific patterns of telomere loss exist in the sexually monomorphic thick-billed murre but are likely to occur between fledging and recruitment. Longer telomeres in males may be related to their homogamous sex chromosomes (ZZ) or to selection for longer life in the care-giving sex. Environmental conditions appeared to be the primary drivers of annual changes in adult birds.