scholarly journals Cooperators trade off ecological resilience and evolutionary stability in public goods games

2017 ◽  
Vol 14 (127) ◽  
pp. 20160967 ◽  
Author(s):  
Joseph Rauch ◽  
Jane Kondev ◽  
Alvaro Sanchez
Keyword(s):  
Public Goods ◽  
Ecological Resilience ◽  
Trade Off ◽  
Public Goods Games ◽  
Regulatory Strategies ◽  
Cooperative Production ◽  
Key Factor ◽  
Viable Population ◽  
Population Sizes

Microbial populations often rely on the cooperative production of extracellular ‘public goods’ molecules. The cooperative nature of public good production may lead to minimum viable population sizes, below which populations collapse. In addition, ‘cooperator’ public goods producing individuals face evolutionary competition from non-producing mutants, or ‘freeloaders’. Thus, public goods cooperators should be resilient not only to the invasion of freeloaders, but also to ecological perturbations that may push their populations below a sustainable threshold. Through a mathematical analysis of the Ecological Public Goods Game, we show that game parameters that improve the cooperating population's stability to freeloader invasion also lead to a low ecological resilience. Complex regulatory strategies mimicking those used by microbes in nature may allow cooperators to beat this trade-off and become evolutionarily stable to invading freeloaders while at the same time maximizing their ecological resilience. Our results thus identify the coupling between resilience to evolutionary and ecological challenges as a key factor for the long-term viability of public goods cooperators.

scholarly journals A tradeoff between the ecological and evolutionary stabilities of public goods genes in microbial populations

2016 ◽  
Author(s):  
Joseph Rauch ◽  
Jané Kondev ◽  
Alvaro Sanchez
Keyword(s):  
Public Goods ◽  
Evolutionary Stability ◽  
Microbial Populations ◽  
Ecological Stability ◽  
Experimental Conditions ◽  
Regulatory Strategies ◽  
Cooperative Production ◽  
Viable Population ◽  
Population Sizes

Microbial populations often rely on the cooperative production of extracellular public goods molecules. The cooperative nature of public good production may lead to minimum viable population sizes, below which populations collapse. In addition, cooperator public goods producing cells face evolutionary competition from non-producing mutants, or freeloaders. Thus, public goods cooperators have to be stable not only to the invasion of freeloaders, but also to ecological perturbations that may push their numbers too small to be sustainable. Through a combination of experiments with microbial populations and mathematical analysis of the Ecological Public Goods Game, we show that game parameters and experimental conditions that improve the evolutionary stability of cooperators also lead to a low ecological stability of the cooperator population. Complex regulatory strategies mimicking those used by microbes in nature may allow cooperators to beat this eco-evolutionary stability tradeoff and become resistant to freeloaders while at the same time maximizing their ecological stability. Our results thus identify the coupled eco-evolutionary stability as being key for the long-term viability of microbial public goods cooperators.

scholarly journals Genetic signature of immigrants and their effect on genetic diversity in the recently established Scandinavian wolf population

2021 ◽  
Author(s):  
Mikael Åkesson ◽  
Øystein Flagstad ◽  
Jouni Aspi ◽  
Ilpo Kojola ◽  
Olof Liberg ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Canis Lupus ◽  
Animal Species ◽  
Allelic Richness ◽  
A Priori ◽  
Management Actions ◽  
Viable Population ◽  
Population Sizes ◽  
Source Populations

AbstractTransboundary connectivity is a key component when conserving and managing animal species that require large areas to maintain viable population sizes. Wolves Canis lupus recolonized the Scandinavian Peninsula in the early 1980s. The population is geographically isolated and relies on immigration to not lose genetic diversity and to maintain long term viability. In this study we address (1) to what extent the genetic diversity among Scandinavian wolves has recovered during 30 years since its foundation in relation to the source populations in Finland and Russia, (2) if immigration has occurred from both Finland and Russia, two countries with very different wolf management and legislative obligations to ensure long term viability of wolves, and (3) if immigrants can be assumed to be unrelated. Using 26 microsatellite loci we found that although the genetic diversity increased among Scandinavian wolves (n = 143), it has not reached the same levels found in Finland (n = 25) or in Russia (n = 19). Low genetic differentiation between Finnish and Russian wolves, complicated our ability to determine the origin of immigrant wolves (n = 20) with respect to nationality. Nevertheless, based on differences in allelic richness and private allelic richness between the two countries, results supported the occurrence of immigration from both countries. A priori assumptions that immigrants are unrelated is non-advisable, since 5.8% of the pair-wise analyzed immigrants were closely related. To maintain long term viability of wolves in Northern Europe, this study highlights the potential and need for management actions that facilitate transboundary dispersal.

Distribution and abundance of spectacled hare-wallabies and euros on Barrow Island, Western Australia

1991 ◽  
Vol 18 (4) ◽  
pp. 421 ◽  
Author(s):  
J Short ◽  
B Turner
Keyword(s):  
Population Size ◽  
Total Population ◽  
Empirical Measure ◽  
Habitat Types ◽  
Term Survival ◽  
Significant Difference ◽  
Viable Population ◽  
Population Sizes ◽  
Minimum Viable Population Size

Spectacled hare-wallabies (Lagorchestes conspicillatus) and euros (Macropus robustus isabellinus) occur on Barrow I. at densities of 42 and 8 km-2, respectively, which result in estimates of total population sizes of c. 10000 and 1800, respectively. Spectacled hare-wallabies occur throughout the island in all habitat types; euros tend to be concentrated in the deeply dissected country in the central-west of the island. Limited areas of floodout flats are important feeding areas for euros, being the only major habitat on the island dominated by grasses other than Triodia. There was no significant difference between density of either species on the two halves of the island (one half is dominated by a commercial oilfield; the other is relatively undisturbed). Barrow I. is the smallest island off the Australian coast to have successfully supported a population of large macropods for the 8000-10000 years since separation from the mainland by rising sea-level. Hence, the population estimate of euros on Barrow I. provides an empirical measure of the viable population size necessary for the long-term survival of large macropods. This estimate is nearly two orders of magnitude less than that estimated from a theoretical model of minimum viable population size (Belovsky 1987).

Attachment of oral bacteria to titanium surfaces: An SEM study

1994 ◽  
Vol 52 ◽  
pp. 468-469
Author(s):  
J. E. Laffoon ◽  
R. L. Anderson ◽  
J. C. Keller ◽  
C. D. Wu-Yuan
Keyword(s):  
Technical Problem ◽  
Titanium Implant ◽  
Oral Bacteria ◽  
Bacterial Cells ◽  
Thin Sections ◽  
Surface Ultrastructure ◽  
Sem Study ◽  
Key Factor ◽  
Titanium Surfaces

Titanium (Ti) dental implants have been used widely for many years. Long term implant failures are related, in part, to the development of peri-implantitis frequently associated with bacteria. Bacterial adherence and colonization have been considered a key factor in the pathogenesis of many biomaterial based infections. Without the initial attachment of oral bacteria to Ti-implant surfaces, subsequent polymicrobial accumulation and colonization leading to peri-implant disease cannot occur. The overall goal of this study is to examine the implant-oral bacterial interfaces and gain a greater understanding of their attachment characteristics and mechanisms. Since the detailed cell surface ultrastructure involved in attachment is only discernible at the electron microscopy level, the study is complicated by the technical problem of obtaining titanium implant and attached bacterial cells in the same ultra-thin sections. In this study, a technique was developed to facilitate the study of Ti implant-bacteria interface.Discs of polymerized Spurr’s resin (12 mm x 5 mm) were formed to a thickness of approximately 3 mm using an EM block holder (Fig. 1). Titanium was then deposited by vacuum deposition to a film thickness of 300Å (Fig. 2).

Experimente und forstökonomische Fragen

2012 ◽  
Vol 163 (10) ◽  
pp. 417-421
Author(s):  
Urs Fischbacher
Keyword(s):  
Public Goods ◽  
Experimental Method ◽  
Forest Product ◽  
Time Preferences ◽  
Economic Research ◽  
Timber Production ◽  
Markets And Institutions ◽  
Experimental Findings ◽  
Forest Economic

Experiments and forest economic questions During the last decades experiments have gained great importance in economics. These experiments deal with questions that are of significance for forest economic research, too. Timber production, for example, is characterised by long-term decisions and, in addition, forestry produces important public goods. In this article the experimental method is introduced. Furthermore, experimental findings are presented, e.g., concerning time preferences and externalities, and possible applications for the study of forest product markets and institutions are outlined.

Designing a CRM Framework for online & offline sports footwear retailers

2015 ◽  
Vol 3 (1) ◽  
Author(s):  
Rodrigo Cueva ◽  
Guillem Rufian ◽  
Maria Gabriela Valdes
Keyword(s):  
Environmental Changes ◽  
Customer Relationship ◽  
Business Strategies ◽  
Economic Sectors ◽  
Running Shoes ◽  
Brick And Mortar ◽  
Key Factor ◽  
On Line ◽  
The Impact

The use of Customer Relationship Managers to foster customers loyalty has become one of the most common business strategies in the past years.  However, CRM solutions do not fill the abundance of happily ever-after relationships that business needs, and each client’s perception is different in the buying process.  Therefore, the experience must be precise, in order to extend the loyalty period of a customer as much as possible. One of the economic sectors in which CRM’s have improved this experience is retailing, where the personalized attention to the customer is a key factor.  However, brick and mortar experiences are not enough to be aware in how environmental changes could affect the industry trends in the long term.  A base unified theoretical framework must be taken into consideration, in order to develop an adaptable model for constructing or implementing CRMs into companies. Thanks to this approximation, the information is complemented, and the outcome will increment the quality in any Marketing/Sales initiative. The goal of this article is to explore the different factors grouped by three main domains within the impact of service quality, from a consumer’s perspective, in both on-line and off-line retailing sector.  Secondly, we plan to go a step further and extract base guidelines about previous analysis for designing CRM’s solutions focused on the loyalty of the customers for a specific retailing sector and its product: Sports Running Shoes.

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