scholarly journals Senescence of song revealed by a long-term study of the Seychelles warbler (Acrocephalus sechellensis)

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mathew L. Berg ◽  
Sarah C. Beebe ◽  
Jan Komdeur ◽  
Adam P. A. Cardilini ◽  
Raoul F. H. Ribot ◽  
...  
Keyword(s):  
Empirical Work ◽  
Bird Species ◽  
Peak Frequency ◽  
Territory Quality ◽  
Long Term Study ◽  
Age Related ◽  
Age Dependent ◽  
Seychelles Warbler ◽  
Sexual Traits

AbstractSenescence is widespread in nature, often resulting in diminishing survival or reproduction with age, but its role in age-dependent variation in sexual traits is often poorly understood. One reason is that few studies of sexual traits consider non-linear relationships with age, or only consider a narrow range of years relative to the life span of the species. Birdsong has evolved to allow assessment of conspecific quality in numerous bird species. Whilst theory and empirical work suggests that song may become more elaborate with age, there are a paucity of long-term studies testing whether song is associated with age or longevity. In particular, the occurrence of song senescence has rarely been demonstrated. Using an exceptional long-term dataset for the Seychelles warbler (Acrocephalus sechellensis), we analysed relationships between male song, age, survival, and longevity. This species is a long-lived songbird with early life increases, followed by senescent declines, in survival and reproduction. The study population (Cousin Island, Seychelles) is a closed population, with no depredation of adults, providing an excellent opportunity to study senescence in free-living animals. We tested whether song traits were related to age at recording, future survival, longevity, and territory quality. We found age-dependent changes in five song traits (duration, maximum frequency, peak frequency of songs, and duration and frequency bandwidth of trills). Relationships with age were quadratic, indicating reversal in the expression of song coinciding with the onset of senescence in reproduction and survival in this species. One song trait (trill bandwidth) had a quadratic relationship with future survival, but no song traits were related to longevity, suggesting age-related patterns were not the result of selective disappearance. Our study provides one of the first examples of functional senescence in song, offering new insights into avian senescence. Late-life declines in avian song, and possibly other sexual traits, may be more common than currently known, and may play a fundamental role in age-dependent changes in reproductive success.

Nest cameras do not affect nest survival in a meadow-nesting shorebird

2020 ◽  
pp. 1-10
Author(s):  
VOLKER SALEWSKI ◽  
LUIS SCHMIDT
Keyword(s):  
Nest Survival ◽  
Bird Species ◽  
Conservation Strategies ◽  
Survival Models ◽  
Northern Germany ◽  
Term Study ◽  
Long Term Study ◽  
Limosa Limosa ◽  
Study Sites

Summary Identifying the fate of birds’ nests and the causes of breeding failure is often crucial for the development of conservation strategies for threatened species. However, collecting these data by repeatedly visiting nests might itself contribute to nest failure or bias. To solve this dilemma, automatic cameras have increasingly been used as a time-efficient means for nest monitoring. Here, we consider whether the use of cameras itself may influence hatching success of nests of the Black-tailed Godwit Limosa limosa at two long-term study sites in northern Germany. Annually between 2013 and 2019, cameras were used to monitor godwit nests. In 2014 and 2019, nests were randomly equipped with cameras or not, and nest survival checked independently of the cameras. Nest-survival models indicated that survival probabilities varied between years, sites and with time of the season, but were unaffected by the presence of cameras. Even though predation is the main cause of hatching failure in our study system, we conclude that predators did not learn to associate cameras with food either when the cameras were initially installed or after they had been used for several years. Cameras were thus an effective and non-deleterious tool to collect data for conservation in this case. As other bird species may react differently to cameras at their nests, and as other sets of predators may differ in their ability to associate cameras with food, the effect of cameras on breeding success should be carefully monitored when they are used in a new study system.

scholarly journals A Multivariate Assessment of Age-Related Cognitive Impairment in Octodon degus

2021 ◽  
Vol 15 ◽  
Author(s):  
Daniela S. Rivera ◽  
Carolina B. Lindsay ◽  
Carolina A. Oliva ◽  
Francisco Bozinovic ◽  
Nibaldo C. Inestrosa
Keyword(s):  
Recognition Memory ◽  
Cognitive Performance ◽  
Natural Aging ◽  
Long Term Memory ◽  
Barnes Maze ◽  
Short Term ◽  
Term Memory ◽  
Age Related ◽  
Age Dependent

Aging is a progressive functional decline characterized by a gradual deterioration in physiological function and behavior. The most important age-related change in cognitive function is decline in cognitive performance (i.e., the processing or transformation of information to make decisions that includes speed of processing, working memory, and learning). The purpose of this study is to outline the changes in age-related cognitive performance (i.e., short-term recognition memory and long-term learning and memory) in long-lived Octodon degus. The strong similarity between degus and humans in social, metabolic, biochemical, and cognitive aspects makes it a unique animal model for exploring the mechanisms underlying the behavioral and cognitive deficits related to natural aging. In this study, we examined young adult female degus (12- and 24-months-old) and aged female degus (38-, 56-, and 75-months-old) that were exposed to a battery of cognitive-behavioral tests. Multivariate analyses of data from the Social Interaction test or Novel Object/Local Recognition (to measure short-term recognition memory), and the Barnes maze test (to measure long-term learning and memory) revealed a consistent pattern. Young animals formed a separate group of aged degus for both short- and long-term memories. The association between the first component of the principal component analysis (PCA) from short-term memory with the first component of the PCA from long-term memory showed a significant negative correlation. This suggests age-dependent differences in both memories, with the aged degus having higher values of long-term memory ability but poor short-term recognition memory, whereas in the young degus an opposite pattern was found. Approximately 5% of the young and 80% of the aged degus showed an impaired short-term recognition memory; whereas for long-term memory about 32% of the young degus and 57% of the aged degus showed decreased performance on the Barnes maze test. Throughout this study, we outlined age-dependent cognitive performance decline during natural aging in degus. Moreover, we also demonstrated that the use of a multivariate approach let us explore and visualize complex behavioral variables, and identified specific behavioral patterns that allowed us to make powerful conclusions that will facilitate further the study on the biology of aging. In addition, this study could help predict the onset of the aging process based on behavioral performance.

scholarly journals miR-155 Predicts Long-Term Mortality in Critically Ill Patients Younger than 65 Years

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Frank Tacke ◽  
Martina E. Spehlmann ◽  
Mihael Vucur ◽  
Fabian Benz ◽  
Mark Luedde ◽  
...  
Keyword(s):  
Critical Illness ◽  
Critically Ill ◽  
Critically Ill Patients ◽  
Prognostic Biomarker ◽  
Serum Levels ◽  
Disease Etiology ◽  
Age Related ◽  
Age Dependent ◽  
Similar Accuracy

Introduction. Alterations in miR-155 serum levels have been described in inflammatory and infectious diseases. Moreover, a role for miR-155 in aging and age-related diseases was recently suggested. We therefore analyzed a potential age-dependent prognostic value of circulating miR-155 as a serum-based marker in critical illness. Methods. Concentrations of circulating miR-155 were determined in 218 critically ill patients and 76 healthy controls. Results. By using qPCR, we demonstrate that miR-155 serum levels are elevated in patients with critical illness when compared to controls. Notably, levels of circulating miR-155 were independent on the severity of disease, the disease etiology, or the presence of sepsis. In the total cohort, miR-155 was not an indicator for patient survival. Intriguingly, when patients were subdivided according to their age upon admission to the ICU into those younger than 65 years, lower levels of miR-155 turned out as a strong marker, indicating patient mortality with a similar accuracy than other markers frequently used to evaluate critically ill patients on a medical ICU. Conclusion. In summary, the data provided within this study suggest an age-specific role of miR-155 as a prognostic biomarker in patients younger than 65 years. Our study is the first to describe an age-dependent miRNA-based prognostic biomarker in human diseases.

scholarly journals Occupational Exposure to Noise and Age-related Hearing Loss in an Elderly Population of Southern Italy

2020 ◽  
Vol 13 (1) ◽  
pp. 69-74 ◽  
Author(s):  
Luigi De Maria ◽  
Antonio Caputi ◽  
Rodolfo Sardone ◽  
Enza Sabrina Silvana Cannone ◽  
Francesca Mansi ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Occupational Exposure ◽  
Elderly Population ◽  
Noise Exposure ◽  
Exposed Population ◽  
Age Related ◽  
Age Dependent ◽  
Occupationally Exposed ◽  
Age Related Hearing Loss

Background: Age-Related Hearing Loss (ARHL) is a gradual and irreversible age-dependent decline in auditory function. There is still no consensus on the long-term functional effects of noise exposure on ARHL. Objective: This study aimed to compare the prevalence of ARHL in an elderly population occupationally exposed to noise in a non-exposed population. Methods: The population was divided into two groups: a group of 482 subjects professionally exposed to noise for over 10 years and a group of 1129 non-exposed subjects. Among the exposed subjects, a subgroup of 298 who worked for over 10 years in the glassware industry was selected. All the participants underwent a thorough otorhinolaryngological examination. Results: The presence of ARHL was found in 81% of exposed subjects and in 4% of non-exposed subjects. In the sub-group of glassware workers, the prevalence was 88%. The statistical analysis showed a significant association between previous occupational exposure to noise and ARHL (OR = 1.09; 95% CI = 1.067-1.124; p = 0.0012) and between exposure to the glassware industry and ARHL (OR = 1.89; 95% CI = 1.78-1.96; p = 0.006). Conclusion: Consistent with recent studies, we found a significantly higher prevalence of ARHL among workers exposed to noise; however, further studies are needed to support these findings.

scholarly journals Spermidine protects from age-related synaptic alterations at hippocampal mossy fiber-CA3 synapses

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Marta Maglione ◽  
Gaga Kochlamazashvili ◽  
Tobias Eisenberg ◽  
Bence Rácz ◽  
Eva Michael ◽  
...  
Keyword(s):  
Molecular Basis ◽  
Memory Impairment ◽  
Mossy Fiber ◽  
Long Term Potentiation ◽  
Age Related ◽  
Term Potentiation ◽  
Hippocampal Synapses ◽  
Age Dependent ◽  
Age Related Changes

AbstractAging is associated with functional alterations of synapses thought to contribute to age-dependent memory impairment (AMI). While therapeutic avenues to protect from AMI are largely elusive, supplementation of spermidine, a polyamine normally declining with age, has been shown to restore defective proteostasis and to protect from AMI in Drosophila. Here we demonstrate that dietary spermidine protects from age-related synaptic alterations at hippocampal mossy fiber (MF)-CA3 synapses and prevents the aging-induced loss of neuronal mitochondria. Dietary spermidine rescued age-dependent decreases in synaptic vesicle density and largely restored defective presynaptic MF-CA3 long-term potentiation (LTP) at MF-CA3 synapses (MF-CA3) in aged animals. In contrast, spermidine failed to protect CA3-CA1 hippocampal synapses characterized by postsynaptic LTP from age-related changes in function and morphology. Our data demonstrate that dietary spermidine attenuates age-associated deterioration of MF-CA3 synaptic transmission and plasticity. These findings provide a physiological and molecular basis for the future therapeutic usage of spermidine.

Opposing population trajectories in two Bustard species: A long-term study in a protected area in Central Spain

2018 ◽  
Vol 29 (2) ◽  
pp. 308-320 ◽  
Author(s):  
FABIÁN CASAS ◽  
FRANÇOIS MOUGEOT ◽  
BEATRIZ ARROYO ◽  
MANUEL B. MORALES ◽  
ISRAEL HERVÁS ◽  
...  
Keyword(s):  
Protected Area ◽  
Bird Species ◽  
Population Monitoring ◽  
Population Trends ◽  
Central Spain ◽  
Great Bustard ◽  
Long Term Study ◽  
Tetrax Tetrax ◽  
Steppe Birds

SummaryIn conservation biology, population monitoring is a critical step, particularly for endangered groups, such as steppe birds in European agro-ecosystems. Long-term population monitoring allows for determination of species population trends and also provides insights into the relative roles that environmental variability and human activities have on priority species. Here, we compare the population trends of two sympatric, closely related farmland bird species, the Little Bustard Tetrax tetrax and Great Bustard Otis tarda, in a protected area of Central Spain, which is their main stronghold in Europe. Over 12 years of monitoring, the abundance of Little and Great Bustards shifted in opposite directions in our study area. Little Bustard abundance decreased significantly (both males [-56%], and harder-to-detect females [-55%]), while Great Bustard abundance increased significantly (1,800%). Future surveys should be more precise and frequent for Little Bustards to facilitate evaluation of their population status and trends. We recommend annual surveys in 2–3 important locations by region throughout the breeding range for Little Bustards, while for Great Bustard the current regional monitoring programmes would be sufficient.

scholarly journals Checklist of bird species in dharmadam estuary in kannur district of kerala

2021 ◽  
Vol 8 (1) ◽  
pp. 5-7
Author(s):  
Santhwana A ◽  
Venkitachalam R ◽  
Sridhu Prakash
Keyword(s):  
Seasonal Variation ◽  
Bird Species ◽  
Migratory Bird ◽  
Term Study ◽  
Long Term Study ◽  
Short Period ◽  
Near Threatened

A total of 20 bird species belongs to 7 orders and 11 families were recorded in Dharmadam estuary in Kannur district. The record of migratory bird Eurasian Curlew and two species near threatened birds within a short period of study and this record indicate that Dharmadam estuary may be attracting more number of migratory bird species. A long-term study is needed to understand the seasonal variation of the bird species in Dharmadam estuary in Kannur district.

scholarly journals Understanding the Potential Role of Sirtuin 2 on Aging: Consequences of SIRT2.3 Overexpression in Senescence

2021 ◽  
Vol 22 (6) ◽  
pp. 3107
Author(s):  
Noemi Sola-Sevilla ◽  
Ana Ricobaraza ◽  
Ruben Hernandez-Alcoceba ◽  
Maria S. Aymerich ◽  
Rosa M. Tordera ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Potential Role ◽  
Adeno Associated Virus ◽  
Age Related ◽  
Age Dependent ◽  
Molecular Effects ◽  
Samp8 Mice ◽  
The Brain

Sirtuin 2 (SIRT2) has been associated to aging and age-related pathologies. Specifically, an age-dependent accumulation of isoform 3 of SIRT2 in the CNS has been demonstrated; however, no study has addressed the behavioral or molecular consequences that this could have on aging. In the present study, we have designed an adeno-associated virus vector (AAV-CAG-Sirt2.3-eGFP) for the overexpression of SIRT2.3 in the hippocampus of 2 month-old SAMR1 and SAMP8 mice. Our results show that the specific overexpression of this isoform does not induce significant behavioral or molecular effects at short or long term in the control strain. Only a tendency towards a worsening in the performance in acquisition phase of the Morris Water Maze was found in SAMP8 mice, together with a significant increase in the pro-inflammatory cytokine Il-1β. These results suggest that the age-related increase of SIRT2.3 found in the brain is not responsible for induction or prevention of senescence. Nevertheless, in combination with other risk factors, it could contribute to the progression of age-related processes. Understanding the specific role of SIRT2 on aging and the underlying molecular mechanisms is essential to design new and more successful therapies for the treatment of age-related diseases.

scholarly journals Inter-island transfers and population dynamics of Seychelles Warblers Acrocephalus sechellensis

1997 ◽  
Vol 7 (1) ◽  
pp. 7-26 ◽  
Author(s):  
Jan Komdeur
Keyword(s):  
Population Dynamics ◽  
First Year ◽  
Territory Quality ◽  
Island Endemic ◽  
Breeding Populations ◽  
Suitable Space ◽  
Seychelles Warbler ◽  
Successful Establishment ◽  
Term Management

SummaryIn the 1950s the Seychelles Warbler Acrocephalus sechellensis was a highly threatened single-island endemic species with a population of 26 individuals confined to Cousin Island in the inner Seychelles. Following long-term management of Cousin, the population steadily recovered to around 300–360 birds. In order to give the species the security of additional breeding populations, some warblers were successfully transferred to the islands of Aride and Cousine in September 1988 and June 1990 respectively. During the three years after the transfer to Aride and the first year after the transfer to Cousine, mean territory quality (measured as insect prey available) on these islands was significantly higher than that on Cousin, leading to higher reproductive success per territory and survival of juveniles and adult birds. In November 1991, all transferred birds were still alive, and 205 young had fledged successfully, bringing the total warbler population to c.585 birds. By then there was enough suitable space still remaining on Aride and Cousine for young birds to establish territories and the rise in warbler numbers is expected to continue. The successful establishment of three self-sustaining and viable breeding populations has ensured that the Seychelles Warbler is no longer a globally threatened species.

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