scholarly journals Violent encounters between social units hinder the growth of a high-density mountain gorilla population

2020 ◽  
Vol 6 (45) ◽  
pp. eaba0724
Author(s):  
Damien Caillaud ◽  
Winnie Eckardt ◽  
Veronica Vecellio ◽  
Felix Ndagijimana ◽  
Jean-Pierre Mucyo ◽  
...  
Keyword(s):  
Natural Populations ◽  
Disease Outbreaks ◽  
Behavior Changes ◽  
Mountain Gorilla ◽  
Sudden Increase ◽  
Island Populations ◽  
Social Species ◽  
Solitary Males ◽  
Group Density ◽  
Social Units

Density-dependent processes such as competition for resources, migration, predation, and disease outbreaks limit the growth of natural populations. The analysis of 50 years of mountain gorilla data reveals that social behavior changes observed at high group density may also affect population growth in social species. A sudden increase in social group density observed in 2007 caused a threefold increase in the rate of violent encounters between social units (groups and solitary males). A fivefold increase in the rate of infanticide and seven cases of lethal fights among mature males were subsequently recorded, and the annual subpopulation growth rate declined by half between 2000 and 2017. The increase in infanticide alone explains 57% of this decline. These findings highlight the complex relationship between population density and growth in social species and hold important implications for the management of island populations.

Genetic structure and dispersal of red foxes (Vulpes vulpes) in urban Melbourne

2001 ◽  
Vol 49 (6) ◽  
pp. 589 ◽  
Author(s):  
Nicholas A. Robinson ◽  
Clive A. Marks
Keyword(s):  
Vulpes Vulpes ◽  
Dispersal Distance ◽  
Regression Equations ◽  
Ecological Data ◽  
Red Foxes ◽  
Island Populations ◽  
Straight Line ◽  
Straight Line Distance ◽  
Dispersal Distances ◽  
Group Density

This study sought to investigate the potential for gene flow and dispersal between three sampled populations of urban Melbourne foxes (Vulpes vulpes). Five highly polymorphic canine microsatellites were used to investigate the population structure of foxes. The dispersal of 14 foxes, captured and radio-collared as cubs, were monitored periodically over two years. Dispersal estimates for males and females were also calculated from published regression equations that related social group density to dispersal distance. Genetic differentiation between urban populations was greater than between more widely spaced rural populations and was also greater than that found between San Remo and Phillip Island populations, which are separated by a water barrier. A deficiency of heterozygotes was detected in the total Melbourne population, but not at any of the field sites. Mean dispersal distances after 24 months (male = 3.5 km, female = 2.0 km) compared well with published accounts of dispersal in British cities. Dispersal distance estimates for female foxes from all sites were lower than straight-line distance for all but one site. Both the genetic and ecological data suggest a restricted ability for foxes to disperse between sites within urban Melbourne.

The Dynamics of Cooperative Bacterial Virulence in the Field

Science ◽  
2012 ◽  
Vol 337 (6090) ◽  
pp. 85-88 ◽  
Author(s):  
Ben Raymond ◽  
Stuart A. West ◽  
Ashleigh S. Griffin ◽  
Michael B. Bonsall
Keyword(s):  
Social Interactions ◽  
Laboratory Experiments ◽  
Diamondback Moth ◽  
Natural Populations ◽  
Disease Outbreaks ◽  
Toxin Production ◽  
Microbial Life ◽  
The Face ◽  
Crystal Toxins ◽  
Density Dependent Selection

Laboratory experiments have shown that the fitness of microorganisms can depend on cooperation between cells. Although this insight has revolutionized our understanding of microbial life, results from artificial microcosms have not been validated in complex natural populations. We investigated the sociality of essential virulence factors (crystal toxins) in the pathogenBacillus thuringiensisusing diamondback moth larvae (Plutella xylostella) as hosts. We show that toxin production is cooperative, and in a manipulative field experiment, we observed persistent high relatedness and frequency- and density-dependent selection, which favor stable cooperation. Conditions favoring social virulence can therefore persist in the face of natural population processes, and social interactions (rapid cheat invasion) may account for the rarity of natural disease outbreaks caused byB. thuringiensis.

scholarly journals Does Eating Chicken Feet With Pickled Peppers Cause Avian Influenza? Observational Case Study on Chinese Social Media During the Avian Influenza A (H7N9) Outbreak (Preprint)

2017 ◽  
Author(s):  
Bin Chen ◽  
Jian Shao ◽  
Kui Liu ◽  
Gaofeng Cai ◽  
Zhenggang Jiang ◽  
...  
Keyword(s):  
Social Media ◽  
Avian Influenza ◽  
Influenza A ◽  
Personal Narratives ◽  
Disease Outbreaks ◽  
Sudden Increase ◽  
Equal Importance ◽  
Social Media Platforms ◽  
Avian Origin ◽  
High Level

BACKGROUND A hot topic on the relationship between a popular avian-origin food and avian influenza occurred on social media during the outbreak of the emerging avian influenza A (H7N9). The misinformation generated from this topic had caused great confusion and public concern. OBJECTIVE Our goals were to analyze the trend and contents of the relevant posts during the outbreak. We also aimed to understand the characteristics of the misinformation and to provide suggestions to reduce public misconception on social media during the emerging disease outbreak. METHODS The original microblog posts were collected from China’s Sina Weibo and Tencent Weibo using a combination of keywords between April 1, 2013 and June 2, 2013. We analyzed the weekly and daily trend of the relevant posts. Content analyses were applied to categorize the posts into 4 types with unified sorting criteria. The posts’ characteristics and geographic locations were also analyzed in each category. We conducted further analysis on the top 5 most popular misleading posts. RESULTS A total of 1680 original microblog posts on the topic were retrieved and 341 (20.30%) of these posts were categorized as misleading messages. The number of relevant posts had not increased much during the first 2 weeks but rose to a high level in the next 2 weeks after the sudden increase in number of reported cases at the beginning of week 3. The posts under “misleading messages” occurred and increased from the beginning of week 3, but their daily posting number decreased when the daily number of posts under “refuting messages” outnumbered them. The microbloggers of the misleading posts had the lowest mean rank of followers and previous posts, but their posts had a highest mean rank of posts. The proportion of “misleading messages” in places with no reported cases was significantly higher than that in the epidemic areas (23.6% vs 13.8%). The popular misleading posts appeared to be short and consisted of personal narratives, which were easily disseminated on social media. CONCLUSIONS Our findings suggested the importance of responding to common questions and misconceptions on social media platforms from the beginning of disease outbreaks. Authorities need to release clear and reliable information related to the popular topics early on. The microbloggers posting correct information should be empowered and their posts could be promoted to clarify false information. Equal importance should be attached to clarify misinformation in both the outbreak and nonoutbreak areas.

scholarly journals Poor maternal environment enhances offspring disease resistance in an invertebrate

2005 ◽  
Vol 272 (1581) ◽  
pp. 2601-2607 ◽  
Author(s):  
Suzanne E Mitchell ◽  
Andrew F Read
Keyword(s):  
Environmental Conditions ◽  
Natural Populations ◽  
Disease Outbreaks ◽  
Host Population ◽  
Optimal Resource Allocation ◽  
Host Genotype ◽  
Evolutionary Response ◽  
Optimal Resource ◽  
Maternal Responses ◽  
The Impact

Natural populations vary tremendously in their susceptibility to infectious disease agents. The factors (environmental or genetic) that underlie this variation determine the impact of disease on host population dynamics and evolution, and affect our capacity to contain disease outbreaks and to enhance resistance in agricultural animals and disease vectors. Here, we show that changes in the environmental conditions under which female Daphnia magna are kept can more than halve the susceptibility of their offspring to bacterial infection. Counter-intuitively, and unlike the effects typically observed in vertebrates for transfer of immunity, mothers producing offspring under poor conditions produced more resistant offspring than did mothers producing offspring in favourable conditions. This effect occurred when mothers who were well provisioned during their own development then found themselves reproducing in poor conditions. These effects likely reflect adaptive optimal resource allocation where better quality offspring are produced in poor environments to enhance survival. Maternal exposure to parasites also reduced offspring susceptibility, depending on host genotype and offspring food levels. These maternal responses to environmental conditions mean that studies focused on a single generation, and those in which environmental variation is experimentally minimized, may fail to describe the crucial parameters that influence the spread of disease. The large maternal effects we report here will, if they are widespread in nature, affect disease dynamics, the level of genetic polymorphism in populations, and likely weaken the evolutionary response to parasite-mediated selection.

The genetic structure and the conservation of the five natural populations of Pinusradiata

1988 ◽  
Vol 18 (5) ◽  
pp. 506-514 ◽  
Author(s):  
G. F. Moran ◽  
J. C. Bell ◽  
K.G. Eldridge
Keyword(s):  
Genetic Diversity ◽  
Natural Populations ◽  
Allozyme Variation ◽  
Conservation Strategies ◽  
Mainland Population ◽  
Island Populations ◽  
Expected Heterozygosity ◽  
Environmental Criteria ◽  
Total Genetic Diversity ◽  
Allozyme Loci

Pinusradiata is restricted to three mainland coastal populations in California and two island populations off Baja California, Mexico. In this study each population was divided into two geographic stands based on natural disjunctions within populations. In addition to the division mentioned above, each mainland population was also divided into a number of ecological stands based on ecological and environmental criteria. Genetic variation was measured by analysing 31 allozyme loci electrophoretically using germinated seed from 272 families across all stands and populations. Moderate levels of allozyme variation were found as shown by population averages for mean number of alleles per locus (1.79), percent polymorphic loci (46.4%, 0.99 criterion), and expected heterozygosity (0.098). In fact, the overall genetic diversity in P. radiata (HT = 0.117) is low compared with that of other conifers. In comparison with populations, the levels of allozyme variation in both ecological and geographic stands were slightly lower (means across ecological stands: A = 1.56, P = 39.3%, and He = 0.095). Of the total genetic diversity in P. radiata, 16.2% could be apportioned between populations, a high proportion for a conifer. In contrast, only 2.0 and 1.3% of the genetic diversity on average within mainland populations was between ecological and geographic stands, respectively. These results indicate a low level of genetic differentiation within populations, at least based on the ecological or geographic criteria used in this study. The implications and usefulness of these findings for the development of insitu conservation strategies are discussed.

scholarly journals Disease Outbreak Surge Response: How a Singapore Tertiary Hospital Converted a Multi-story Carpark Into a Flu Screening Area to Respond to the COVID-19 Pandemic

2020 ◽  
pp. 1-6 ◽  
Author(s):  
Jeevan Raaj Thangayah ◽  
Kenneth Boon Kiat Tan ◽  
Chin Siah Lim ◽  
Tzay-Ping Fua
Keyword(s):  
Public Health ◽  
Disease Outbreaks ◽  
Healthcare Services ◽  
Tertiary Hospital ◽  
Disease Outbreak ◽  
World Health ◽  
Medical Attention ◽  
Sudden Increase ◽  
Healthcare Facilities ◽  
Health Organization

Abstract Coronavirus disease 2019 (COVID-19), first documented in December 2019, was declared a public health emergency by the World Health Organization (WHO) on January 30, 2020 (https://www.who.int/westernpacific/emergencies/covid-19). The disease, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus, has affected more than 9 million people and contributed to at least 490,000 deaths globally as of June 2020, with numbers on the rise (https://www.worldometers.info/coronavirus/#countries). Increased numbers of patients seeking medical attention during disease outbreaks can overwhelm healthcare facilities, hence requiring an equivalent response from healthcare services. Surge capacity is a concept that has not only been defined as the “ability to respond to a sudden increase in patient care demands” (Hick et al., Disaster Med Public Health Prep. 2008;2:S51-S57) but also to “effectively and rapidly expand capacity” (Watson et al., Milbank Q. 2013;91(1):78-122). This narrative review discusses how Singapore’s largest tertiary hospital has encapsulated the elements of surge capability and transformed a peacetime multi-story carpark into a flu screening area in response to the COVID-19 disease outbreak.

scholarly journals Adaptation to enemy shifts: rapid resistance evolution to local Vibrio spp. in invasive Pacific oysters

2015 ◽  
Vol 282 (1804) ◽  
pp. 20142244 ◽  
Author(s):  
Carolin C. Wendling ◽  
K. Mathias Wegner
Keyword(s):  
Invasive Species ◽  
Elevated Temperatures ◽  
Genetic Resistance ◽  
Resistance Mechanism ◽  
Natural Populations ◽  
Disease Outbreaks ◽  
Resistance Evolution ◽  
The North ◽  
Evolutionary Response ◽  
Pure Lines

One hypothesis for the success of invasive species is reduced pathogen burden, resulting from a release from infections or high immunological fitness of invaders. Despite strong selection exerted on the host, the evolutionary response of invaders to newly acquired pathogens has rarely been considered. The two independent and genetically distinct invasions of the Pacific oyster Crassostrea gigas into the North Sea represent an ideal model system to study fast evolutionary responses of invasive populations. By exposing both invasion sources to ubiquitous and phylogenetically diverse pathogens ( Vibrio spp.), we demonstrate that within a few generations hosts adapted to newly encountered pathogen communities. However, local adaptation only became apparent in selective environments, i.e. at elevated temperatures reflecting patterns of disease outbreaks in natural populations. Resistance against sympatric and allopatric Vibrio spp. strains was dominantly inherited in crosses between both invasion sources, resulting in an overall higher resistance of admixed individuals than pure lines. Therefore, we suggest that a simple genetic resistance mechanism of the host is matched to a common virulence mechanism shared by local Vibrio strains. This combination might have facilitated a fast evolutionary response that can explain another dimension of why invasive species can be so successful in newly invaded ranges.

scholarly journals Temperature and pathogen exposure act independently to drive host phenotypic trajectories

2021 ◽  
Vol 17 (6) ◽  
pp. 20210072
Author(s):  
Tobias E. Hector ◽  
Carla M. Sgrò ◽  
Matthew D. Hall
Keyword(s):  
Thermal Stress ◽  
Life History Traits ◽  
Natural Populations ◽  
Reproductive Potential ◽  
Bacterial Pathogen ◽  
Disease Outbreaks ◽  
Population Growth Rates ◽  
Pasteuria Ramosa ◽  
The Impact ◽  
Pathogen Exposure

Natural populations are experiencing an increase in the occurrence of both thermal stress and disease outbreaks. How these two common stressors interact to determine host phenotypic shifts will be important for population persistence, yet a myriad of different traits and pathways are a target of both stressors, making generalizable predictions difficult to obtain. Here, using the host Daphnia magna and its bacterial pathogen Pasteuria ramosa , we tested how temperature and pathogen exposure interact to drive shifts in multivariate host phenotypes. We found that these two stressors acted mostly independently to shape host phenotypic trajectories, with temperature driving a faster pace of life by favouring early development and increased intrinsic population growth rates, while pathogen exposure impacted reproductive potential through reductions in lifetime fecundity. Studies focussed on extreme thermal stress are increasingly showing how pathogen exposure can severely hamper the thermal tolerance of a host. However, our results suggest that under milder thermal stress, and in terms of life-history traits, increases in temperature might not exacerbate the impact of pathogen exposure on host performance, and vice versa.

Population Dynamics of Social Species under Perturbations

2020 ◽  
pp. 44-67
Author(s):  
Daniel Oro
Keyword(s):  
Population Dynamics ◽  
Natural Populations ◽  
Population Data ◽  
Social Species ◽  
Theoretical Approaches ◽  
Abrupt Changes ◽  
Riverine Habitats ◽  
Original Habitat ◽  
The Stability

The detection of abrupt changes in natural populations of social and nonsocial animals as a result of perturbations is challenging. This chapter highlights some empirical examples from the literature and the author’s own studies, and the responses of populations of species with different degree of sociality are compared. To overcome the difficulties of obtaining field population data, theoretical approaches can be very useful for simulating these responses from social feedbacks. These models show the influence of social information and social copying to generate nonlinear population dynamics, such as bifurcations and cascades. The chapter’s final section explores the stability properties of populations subjected to perturbations and the role of social feedbacks for resilience. These properties depend on the time of occupation of the patch, its suitability compared to other patches, and the type of perturbation (e.g. pulsed, in regime, or in combination). This section ends by exploring how social copying influences collective cultural innovations of social populations under perturbations. For instance, the American Pueblo tribe colonized riverine habitats and changed their way of living following the collapse of their original habitat due to droughts and tribal fights.

scholarly journals Modeling the impact ofex-nidotransmitted parasites on ant colony dynamics

2018 ◽  
Author(s):  
Lauren E. Quevillon ◽  
David P. Hughes ◽  
Jessica M. Conway
Keyword(s):  
Natural Populations ◽  
Group Living ◽  
Disease Outbreaks ◽  
Realistic Model ◽  
Ant Colony ◽  
Ant Colonies ◽  
Diverse Range ◽  
Living Organisms ◽  
The Impact ◽  
Colony Dynamics

Infectious disease outbreaks are a common constraint of group living organisms. Ants (Hymenoptera: Formicidae) live in large, dense colonies and are host to a diverse range of parasites and pathogens, facilitating the possibility of epidemic-induced collapse. However, the majority of parasites infecting ants require a period of development outside of the nest before they can transmit to their next ant host (‘ex-nido’ transmission) and the impact of these parasites on colony dynamics is unknown. Here we develop a mathematical model to assess ant colony dynamics in the presence of such parasites. We find that under field-realistic model conditions, such parasites are unlikely to cause the epidemic collapse of mature ant colonies, unless colony birth rate drops below 0.2328 ants/day. The preponderance ofex-nidotransmitting parasites infecting ants and their limited epidemiological impact on colony dynamics may partly explain why collapsed ant colonies are rarely, if ever, observed in natural populations.

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