Life-history characteristics of the yakka skink, Egernia rugosa, indicate long-term social structure

2016 ◽  
Vol 64 (5) ◽  
pp. 335 ◽  
Author(s):  
Stephen Peck ◽  
Michael G. Gardner ◽  
Jennifer M. Seddon ◽  
Greg Baxter

One lineage of squamates, the Egernia group, has received particular study due to stable aggregations identified in many of the species. Egernia rugosa is a large, terrestrial, viviparous skink and has been reported living communally. To investigate whether this species lives in social aggregations, we examined life-history characteristics in one population within the Mulga Lands bioregion of south-west Queensland. We found this skink used both active and inactive rabbit burrows. Parturition occurred in January/February and took several days to complete, with a mean litter size of 2.4 and a mean snout–vent length (SVL) of 84.5 mm. Six subadult age cohorts were identified. Juveniles took at least five years to reach sexual maturity and lizards had a life expectancy of >12 years. Lizards were found clustered in aggregations of up to 21 individuals (mean = 7.21) of multiple ages. An average of 50% (range = 31–67%) of all individuals within each of the age cohorts were located at their original location for two or more seasons. Dispersal was recorded for older subadult lizards. These characteristics support the hypothesis that E. rugosa aggregations comprise long-term family units; however, genetic analysis would be needed to confirm kin-based associations.

2013 ◽  
Vol 280 (1750) ◽  
pp. 20122313 ◽  
Author(s):  
Aïda Nitsch ◽  
Charlotte Faurie ◽  
Virpi Lummaa

Determining the fitness consequences of sibling interactions is pivotal for understanding the evolution of family living, but studies investigating them across lifetime are lacking. We used a large demographic dataset on preindustrial humans from Finland to study the effect of elder siblings on key life-history traits. The presence of elder siblings improved the chances of younger siblings surviving to sexual maturity, suggesting that despite a competition for parental resources, they may help rearing their younger siblings. After reaching sexual maturity however, same-sex elder siblings' presence was associated with reduced reproductive success in the focal individual, indicating the existence of competition among same-sex siblings. Overall, lifetime fitness was reduced by same-sex elder siblings' presence and increased by opposite-sex elder siblings' presence. Our study shows opposite effects of sibling interactions depending on the life-history stage, and highlights the need for using long-term fitness measures to understand the selection pressures acting on sibling interactions.


2003 ◽  
Vol 24 (1) ◽  
pp. 65-74 ◽  
Author(s):  
Mariano Sironi ◽  
Margarita Chiaraviglio ◽  
Sergio Lucino ◽  
Miguel Bertona

AbstractWe provide data on intrapopulation variation of life history traits of Boa constrictor occidentalis in the District of Pocho, Córdoba, Argentina. A total of 153 individuals were captured. The distribution of individuals among four size classes differed significantly among the five years of study. The proportion of mature individuals did not differ between sexes but it showed variation among years. Females were longer and heavier than males. The mean litter size of the species was 24 and there was a linear relationship between litter size and maternal snout-vent length. Most boas were captured during the dry season. There were no significant sex differences in the time of capture and air temperature in either the wet or the dry seasons. However, we found significant differences in the time of capture and air temperature between the seasons. The long-term monitoring of wild populations should be a priority for the development of conservation and management plans for this boid.


1985 ◽  
Vol 63 (9) ◽  
pp. 2105-2109 ◽  
Author(s):  
F. Stephen Dobson ◽  
Julia D. Kjelgaard

Life history characteristics were studied experimentally in Columbian ground squirrels (Spermophilus columbianus) at two elevations in the Rocky Mountains of southwestern Alberta, Canada, from 1981 to 1984. In two populations with supplemented food resources, survival of young increased, age at maturity of females decreased, litter size increased, and spring body weight increased in comparison with an initial unmanipulated period and with two populations monitored for reference. For individual ground squirrels, litter size and spring body weight increased under supplementation. Thus, life history characteristics exhibited phenotypically plastic responses to experimental manipulation of food resources. Life history patterns changed among natural ground squirrel populations at different elevations and these changes were likely due to changes in food resources. A general prediction of life history theory that reproductive effort should be highest in years favorable for juvenile survivorship was supported by the experimental results. The results did not support predictions from interspecific studies of changes in life history characteristics that scale to body weight.


Author(s):  
Diana Hart

All countries are faced with the problem of the prevention and control of non-communicable diseases (NCD): implement prevention strategies eff ectively, keep up the momentum with long term benefi ts at the individual and the population level, at the same time tackling hea lth inequalities. Th e aff ordability of therapy and care including innovative therapies is going to be one of the key public health priorities in the years to come. Germany has taken in the prevention and control of NCDs. Germany’s health system has a long history of guaranteeing access to high-quality treatment through universal health care coverage. Th r ough their membership people are entitled to prevention and care services maintaining and restoring their health as well as long term follow-up. Like in many other countries general life expectancy has been increasing steadily in Germany. Currently, the average life expectancy is 83 and 79 years in women and men, respectively. Th e other side of the coin is that population aging is strongly associated with a growing burden of disease from NCDs. Already over 70 percent of all deaths in Germany are caused by four disease entities: cardiovascular disease, cancer, chronic respiratory disease and diabetes. Th ese diseases all share four common risk factors: smoking, alcohol abuse, lack of physical activity and overweight. At the same time, more and more people become long term survivors of disease due to improved therapy and care. Th e German Government and public health decision makers are aware of the need for action and have responded by initiating and implementing a wide spectrum of activities. One instrument by strengthening primary prevention is the Prevention Health Care Act. Its overarching aim is to prevent NCDs before they can manifest themselves by strengthening primary prevention and health promotion in diff erent sett ings. One of the main emphasis of the Prevention Health Care Act is the occupational health promotion at the workplace.


2018 ◽  
Vol 69 (3) ◽  
pp. 688-692
Author(s):  
Lucian Nita ◽  
Dorin Tarau ◽  
Gheorghe Rogobete ◽  
Simona Nita ◽  
Radu Bertici ◽  
...  

The issue addressed relates to an area of 1891694 ha of which 1183343 ha are agricultural land (62, 56) located in the south-west of Romania and refer to the use of soil chemical and physical properties as an acceptor for certain crop systems, with minimal undesirable effects both for plants to be grown, as well as soil characteristics and groundwater surface quality. It is therefore necessary on a case-by-case basis, measure stoc or rect the acidic reaction by periodic or alkaline calculations, the improvement of plant nutrition conditions through ameliorative fertilization and the application of measures to improve the physical state, sufficient justification for the need to develop short and long term strategies for the protection and conservation of edifying factors and the need to respect the frequency of field and laboratory investigations at all 8x8 km grids of the National Soil-Grounds Monitoring System (organized by I.C.P.A.) and completing it with the relevant pedological and agrochemical studies.


Biology ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 522
Author(s):  
Régis Santos ◽  
Wendell Medeiros-Leal ◽  
Osman Crespo ◽  
Ana Novoa-Pabon ◽  
Mário Pinho

With the commercial fishery expansion to deeper waters, some vulnerable deep-sea species have been increasingly captured. To reduce the fishing impacts on these species, exploitation and management must be based on detailed and precise information about their biology. The common mora Mora moro has become the main deep-sea species caught by longliners in the Northeast Atlantic at depths between 600 and 1200 m. In the Azores, landings have more than doubled from the early 2000s to recent years. Despite its growing importance, its life history and population structure are poorly understood, and the current stock status has not been assessed. To better determine its distribution, biology, and long-term changes in abundance and size composition, this study analyzed a fishery-dependent and survey time series from the Azores. M. moro was found on mud and rock bottoms at depths below 300 m. A larger–deeper trend was observed, and females were larger and more abundant than males. The reproductive season took place from August to February. Abundance indices and mean sizes in the catch were marked by changes in fishing fleet operational behavior. M. moro is considered vulnerable to overfishing because it exhibits a long life span, a large size, slow growth, and a low natural mortality.


Heart ◽  
2021 ◽  
Vol 107 (5) ◽  
pp. 389-395
Author(s):  
Jianhua Wu ◽  
Alistair S Hall ◽  
Chris P Gale

AimsACE inhibition reduces mortality and morbidity in patients with heart failure after acute myocardial infarction (AMI). However, there are limited randomised data about the long-term survival benefits of ACE inhibition in this population.MethodsIn 1993, the Acute Infarction Ramipril Efficacy (AIRE) study randomly allocated patients with AMI and clinical heart failure to ramipril or placebo. The duration of masked trial therapy in the UK cohort (603 patients, mean age=64.7 years, 455 male patients) was 12.4 and 13.4 months for ramipril (n=302) and placebo (n=301), respectively. We estimated life expectancy and extensions of life (difference in median survival times) according to duration of follow-up (range 0–29.6 years).ResultsBy 9 April 2019, death from all causes occurred in 266 (88.4%) patients in placebo arm and 275 (91.1%) patients in ramipril arm. The extension of life between ramipril and placebo groups was 14.5 months (95% CI 13.2 to 15.8). Ramipril increased life expectancy more for patients with than without diabetes (life expectancy difference 32.1 vs 5.0 months), previous AMI (20.1 vs 4.9 months), previous heart failure (19.5 vs 4.9 months), hypertension (16.6 vs 8.3 months), angina (16.2 vs 5.0 months) and age >65 years (11.3 vs 5.7 months). Given potential treatment switching, the true absolute treatment effect could be underestimated by 28%.ConclusionFor patients with clinically defined heart failure following AMI, ramipril results in a sustained survival benefit, and is associated with an extension of life of up to 14.5 months for, on average, 13 months treatment duration.


Sign in / Sign up

Export Citation Format

Share Document