scholarly journals Kin competition, natal dispersal and the moulding of senescence by natural selection

2010 ◽  
Vol 277 (1700) ◽  
pp. 3659-3667 ◽  
Author(s):  
Ophélie Ronce ◽  
Daniel Promislow
Keyword(s):  
Social Interactions ◽  
Life History Traits ◽  
Theoretical Models ◽  
Antagonistic Pleiotropy ◽  
Vital Rates ◽  
Slowing Down ◽  
Kin Competition ◽  
Limited Dispersal ◽  
Patchy Population ◽  
Age Population Structure

Most theoretical models for the evolution of senescence have assumed a very large, well mixed population. Here, we investigate how limited dispersal and kin competition might influence the evolution of ageing by deriving indicators of the force of selection, similar to Hamilton (Hamilton 1966 J. Theor. Biol. 12 , 12–45). Our analytical model describes how the strength of selection on survival and fecundity changes with age in a patchy population, where adults are territorial and a fraction of juveniles disperse between territories. Both parent–offspring competition and sib competition then affect selection on age-specific life-history traits. Kin competition reduces the strength of selection on survival. Mutations increasing mortality in some age classes can even be favoured by selection, but only when fecundity deteriorates rapidly with age. Population structure arising from limited dispersal however selects for a broader distribution of reproduction over the lifetime, potentially slowing down reproductive senescence. The antagonistic effects of limited dispersal on age schedules of fecundity and mortality cast doubts on the generality of conditions allowing the evolution of ‘suicide genes’ that increase mortality rates without other direct pleiotropic effects. More generally, our model illustrates how limited dispersal and social interactions can indirectly produce patterns of antagonistic pleiotropy affecting vital rates at different ages.

scholarly journals First determination of the $${\rho }$$ parameter at $${\sqrt{s} = 13}$$ TeV: probing the existence of a colourless C-odd three-gluon compound state

2019 ◽  
Vol 79 (9) ◽  
Author(s):  
G. Antchev ◽  
P. Aspell ◽  
I. Atanassov ◽  
V. Avati ◽  
J. Baechler ◽  
...  
Keyword(s):  
Elastic Scattering ◽  
Total Cross Section ◽  
Cross Section ◽  
Scattering Amplitude ◽  
Theoretical Models ◽  
Proton Proton ◽  
Slowing Down ◽  
Proton Elastic Scattering ◽  
Compound State ◽  
Elastic Scattering Amplitude

Abstract The TOTEM experiment at the LHC has performed the first measurement at $$\sqrt{s} = 13\,\mathrm{TeV}$$s=13TeV of the $$\rho $$ρ parameter, the real to imaginary ratio of the nuclear elastic scattering amplitude at $$t=0$$t=0, obtaining the following results: $$\rho = 0.09 \pm 0.01$$ρ=0.09±0.01 and $$\rho = 0.10 \pm 0.01$$ρ=0.10±0.01, depending on different physics assumptions and mathematical modelling. The unprecedented precision of the $$\rho $$ρ measurement, combined with the TOTEM total cross-section measurements in an energy range larger than $$10\,\mathrm{TeV}$$10TeV (from 2.76 to $$13\,\mathrm{TeV}$$13TeV), has implied the exclusion of all the models classified and published by COMPETE. The $$\rho $$ρ results obtained by TOTEM are compatible with the predictions, from other theoretical models both in the Regge-like framework and in the QCD framework, of a crossing-odd colourless 3-gluon compound state exchange in the t-channel of the proton–proton elastic scattering. On the contrary, if shown that the crossing-odd 3-gluon compound state t-channel exchange is not of importance for the description of elastic scattering, the $$\rho $$ρ value determined by TOTEM would represent a first evidence of a slowing down of the total cross-section growth at higher energies. The very low-|t| reach allowed also to determine the absolute normalisation using the Coulomb amplitude for the first time at the LHC and obtain a new total proton–proton cross-section measurement $$\sigma _{\mathrm{tot}} = (110.3 \pm 3.5)\,\mathrm{mb}$$σtot=(110.3±3.5)mb, completely independent from the previous TOTEM determination. Combining the two TOTEM results yields $$\sigma _{\mathrm{tot}} = (110.5 \pm 2.4)\,\mathrm{mb}$$σtot=(110.5±2.4)mb.

scholarly journals Kinship and the evolution of social behaviours in the sea

2013 ◽  
Vol 9 (6) ◽  
pp. 20130454 ◽  
Author(s):  
Stephanie J. Kamel ◽  
Richard K. Grosberg
Keyword(s):  
Social Interactions ◽  
Kin Selection ◽  
Life Histories ◽  
Social Evolution ◽  
Family Members ◽  
Marine Organisms ◽  
Limited Dispersal ◽  
Kin Structure ◽  
Social Behaviours

Until recently, little attention has been paid to the existence of kin structure in the sea, despite the fact that many marine organisms are sessile or sedentary. This lack of attention to kin structure, and its impacts on social evolution, historically stems from the pervasive assumption that the dispersal of gametes and larvae is almost always sufficient to prevent any persistent associations of closely related offspring or adults. However, growing evidence, both theoretical and empirical, casts doubt on the generality of this assumption, not only in species with limited dispersal, but also in species with long dispersive phases. Moreover, many marine organisms either internally brood their progeny or package them in nurseries, both of which provide ample opportunities for kinship to influence the nature and outcomes of social interactions among family members. As the evidence for kin structure within marine populations mounts, it follows that kin selection may play a far greater role in the evolution of both behaviours and life histories of marine organisms than is presently appreciated.

The outcome of online social interactions on Facebook pages

2019 ◽  
Vol 29 (1) ◽  
pp. 2-23 ◽  
Author(s):  
Hamid Khobzi ◽  
Raymond Y.K. Lau ◽  
Terence C.H. Cheung
Keyword(s):  
Social Interactions ◽  
Panel Data Analysis ◽  
Message Framing ◽  
Theoretical Models ◽  
Ordinary Least Squares ◽  
Omitted Variables ◽  
Content Type ◽  
Engagement Behavior ◽  
Facebook Pages ◽  
The Impact

Purpose The purpose of this paper is to investigate the impact of different ways of message framing on users’ engagement behavior regarding the brand posts on Facebook and to determine whether users’ thumbs-up and reply moderate this impact. Design/methodology/approach A panel data analysis was conducted on a panel with 11,894 observations on 850 unique brand posts from the Facebook pages of the world’s most valuable brands over a seven days window with two observations each day. A system of equations was estimated using ordinary least squares, Hausman–Taylor IV and seemingly unrelated regressions to test study’s hypotheses. Findings The empirical findings confirm that more positively and negatively framed comments result in increased users’ engagement. Also, an increase in thumbs-up ratio for neutrally and negatively framed comments results in less engagement. The reply ratio might also have a positive and negative moderation effect on the influence of neutrally and positively framed comments on engagement behavior, respectively. Practical implications This study provides an in-depth understanding of online social interactions on Facebook pages for firms’ managers and marketers. Online social interactions might be either harmful or fruitful for firms depending on the type of interaction and engagement behavior. Findings can help managers and marketer to improve their strategies for leveraging Facebook for electronic marketing. Originality/value This is likely to be the first study that examines the moderating effect of users’ thumbs-up and reply on the relationship between message framing and users’ engagement behavior. By providing robust findings by addressing issues like omitted variables and endogeneity, the findings of this study are promising for developing new hypotheses and theoretical models in the context of online social interactions.

scholarly journals Kin competition promotes dispersal in a male pollinating fig wasp

2005 ◽  
Vol 2 (1) ◽  
pp. 17-19 ◽  
Author(s):  
Jamie C Moore ◽  
Antoinette Loggenberg ◽  
Jaco M Greeff
Keyword(s):  
Social Interactions ◽  
Fig Wasp ◽  
Fig Wasps ◽  
Local Conditions ◽  
Kin Competition ◽  
Similar Work ◽  
Theoretical Predictions ◽  
Competition Avoidance ◽  
Selective Forces ◽  
Fighting Behaviour

Despite theoretical predictions, there is little empirical evidence that kin competition avoidance promotes dispersal. We show that dispersal by male Platyscapa awekei pollinating fig wasps is promoted by both low returns in the natal fig and kin competition avoidance, with strategies depending on the interaction between phenotype (body size) and local conditions. We discuss the paucity of similar work, how males might assess conditions, and then contrast male dispersal and fighting behaviour. This indicates that differences in the scale at which behaviours affect competition can mean that they are the product of dissimilar selective forces even when they have the same recipients. More generally, this could explain why other social interactions are often mixtures of cooperation and conflict.

Strain-specific vital rates in four Acartia tonsa cultures II: Life history traits and biochemical contents of eggs and adults

Aquaculture ◽  
2008 ◽  
Vol 279 (1-4) ◽  
pp. 47-54 ◽  
Author(s):  
Guillaume Drillet ◽  
Per M. Jepsen ◽  
Jonas K. Højgaard ◽  
Niels O.G. Jørgensen ◽  
Benni W. Hansen
Keyword(s):  
Life History ◽  
Life History Traits ◽  
Acartia Tonsa ◽  
Vital Rates

scholarly journals Brainless but not clueless: earthworms boost their ejaculates when they detect fecund non-virgin partners

2008 ◽  
Vol 275 (1638) ◽  
pp. 1067-1072 ◽  
Author(s):  
Alberto Velando ◽  
Julio Eiroa ◽  
Jorge Domínguez
Keyword(s):  
Sperm Competition ◽  
Life History Traits ◽  
Empirical Support ◽  
Theoretical Models ◽  
Mating Status ◽  
Mating Experiment ◽  
Ejaculate Size ◽  
Double Mating ◽  
Fine Tune ◽  
Simultaneous Hermaphrodites

In many animals in which females store sperm, males may detect female mating status and, in order to outcompete rival sperm, increase ejaculate size when copulating with non-virgin females. Although most studies have been restricted to organisms with separate sexes, theoretical models suggest that sperm competition should also be an important selective agent shaping life-history traits in simultaneous hermaphrodites. Nevertheless, the empirical support for ejaculate adjustment in a mating opportunity is scarce in hermaphrodites. In the present study, we performed a double-mating experiment to determine whether earthworms ( Eisenia andrei ) detect the mating status of their partners and whether they respond by adjusting their ejaculate. We found that earthworms triplicated the donated sperm when mating with a non-virgin mate. Moreover, such increases were greater when the worms were mated with larger (more fecund) partners, indicating that earthworms perform a fine-tune control of ejaculate volume. The results of the present study suggest that, under high intensity of sperm competition, partner evaluation is subject to intense selection in hermaphrodite animals, and donors are selective about to whom they donate how much sperm.

scholarly journals Evolution of reduced dormancy during range expansions

2021 ◽  
Author(s):  
Justin M. J. Travis ◽  
Poppy Mynard ◽  
Greta Bocedi
Keyword(s):  
Seed Dormancy ◽  
Range Expansion ◽  
Life History Traits ◽  
Empirical Work ◽  
Spatial Equilibrium ◽  
Kin Competition ◽  
Population Spread ◽  
Dynamics Of Population ◽  
Selection For ◽  
Dispersal Evolution

AbstractThere is increasing evidence that life-history traits can evolve rapidly during range expansion and that this evolution can impact the ecological dynamics of population spread. While dispersal evolution during range expansion has received substantial attention, dormancy (dispersal in time) has not. Here, we use an individual-based model to investigate the evolution of seed dormancy during range expansion. When a population is at spatial equilibrium our model produces results that are consistent with previous theoretical studies: seed dormancy evolves due to kin competition and the degree of dormancy increases as temporal environmental variation increases. During range expansions we consistently observe evolution towards reduced rates of dormancy at the front. Behind the front there is selection for higher rates of dormancy. Notably, the decreased dormancy towards the expanding margin reduces the regional resilience of recently expanded populations to a series of harsh years. We discuss how dormancy evolution during range expansion, and its consequences for spatial population dynamics, may impact other evolutionary responses to environmental change. We end with suggestions for future theoretical and empirical work.

scholarly journals Sensorimotor, Cognitive and Affective Barriers to Social Relations in Aging: A Dynamical Framework

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. 926-927
Author(s):  
Emmanuelle Tognoli ◽  
Alice Wead ◽  
Joseph McKinley ◽  
Christopher Beetle ◽  
Christine Williams
Keyword(s):  
Social Interactions ◽  
Social Relations ◽  
Social Engagement ◽  
Healthy Aging ◽  
Theoretical Models ◽  
Social Contexts ◽  
Mitigation Strategies ◽  
Wide Range ◽  
Diverse Groups

Abstract Social interactions of all sorts (e.g. conversing, playing tennis, singing, strolling, etc.) rely on information flows between participants. The process of aging, however, can alter individuals’ sensorial, motor, cognitive and affective functioning in ways that may compromise their affinity for social interactions. For instance, hearing deficits or cognitive difficulties associated with word retrieval may contribute to disengagement from conversation and other forms of social interaction, which can lead to social retreat of the affected individuals. Strategies for mitigating such effects must take into account not only individuals’ own functional capacities, but also those of their partners in varying social contexts. Indeed, varied social contexts and diversity in partners can offer a beneficial balance of relational effort and comfort. For example, instead of comfortably strolling exclusively with partners of comparable cognitive and motor capabilities, strolling with faster partners can improve social engagement and long-term prospects for a wider range of social interactions. This work reviews an array of possible changes in individual abilities arising from both normal healthy aging and complications due to medical conditions, with an emphasis on their impact on interactions in varying social contexts and diverse groups of social partners. We incorporate theoretical models to explore a wide range of potential mitigation strategies, both for affected individuals and for other members of the social groups surrounding them. Our work focuses on healthy social aging over the long term, which is known to protect physical wellbeing, cognition and brain function.

scholarly journals Dispersal alters the nature and scope of sexually antagonistic variation

2020 ◽  
Author(s):  
Ewan O Flintham ◽  
Vincent Savolainen ◽  
Charles Mullon
Keyword(s):  
Genetic Variation ◽  
Balancing Selection ◽  
Sexual Antagonism ◽  
Previous Theory ◽  
Fitness Effects ◽  
Kin Competition ◽  
Spatial Subdivision ◽  
Subdivided Populations ◽  
Limited Dispersal ◽  
Intralocus Conflict

AbstractIntra-locus sexual conflict, or sexual antagonism, occurs when alleles have opposing fitness effects in the two sexes. Previous theory suggests that sexual antagonism is a driver of genetic variation by generating balancing selection. However, these studies assume that populations are well-mixed, neglecting the effects of spatial subdivision. Here we use mathematical modelling to show that limited dispersal can fundamentally change evolution at sexually antagonistic autosomal and X-linked loci due to inbreeding and sex-specific kin competition. We find that if the sexes disperse at different rates, kin competition within the philopatric sex biases intralocus conflict in favour of the more dispersive sex. Furthermore, kin competition diminishes the strength of balancing selection relative to genetic drift, reducing genetic variation in small subdivided populations. Meanwhile, by decreasing heterozygosity, inbreeding reduces the scope for sexually antagonistic polymorphism due to non-additive allelic effects, and this occurs to a greater extent on the X-chromosome than autosomes. Overall, our results demonstrate that spatial structure is an important factor in predicting where to expect sexually antagonistic alleles. We suggest that observed interspecific and intragenomic variation in sexual antagonism may be explained by sex-specific dispersal ecology and demography.

scholarly journals Human pressures filter out the less resilient demographic strategies in natural populations of plants and animals worldwide

2021 ◽  
Author(s):  
Thomas Merrien ◽  
Katrina Joan Davis ◽  
Pol Capdevila ◽  
Moreno Di Marco ◽  
Roberto Salguero-Gomez
Keyword(s):  
Life History ◽  
Human Activities ◽  
Land Surface ◽  
Urban Areas ◽  
Life History Traits ◽  
Natural Populations ◽  
Life History Strategies ◽  
Vital Rates ◽  
Long Distance ◽  
Animal Populations

The exponential growth that has characterised human societies since the industrial revolution has fundamentally modified our surroundings. Examples include rapid increases in agricultural fields, now accounting for 37% of the land surface, as well as increases in urban areas, projected to triple worldwide by 2030. As such, understanding how species have adapted to and will respond to increasing human pressures is of key importance. Resilience, the ability of an ecological system to resist, recover, and even benefit from disturbances, is a key concept in this regard. Here, using a recently develop comparative demographic framework, we examine how the inherent ability of 921 natural populations of 279 plants and 45 animal species worldwide to respond to disturbances correlates with human settlement size and human activities. We develop a spatially and phylogenetically explicit model parameterised with life history traits and metrics of demographic resilience using the open-access COMPADRE and COMADRE databases, coupled with high-resolution human impact information via the Human Footprint database. We expected: (H1) populations located nearer urban areas to have a greater ability to resist, recover, or benefit from human-related disturbances compared to pristine habitats; (H2) human effects on the responses of animal populations to disturbances to depend on the ability for long-distance mobility; and (H3): human pressures to constrain the repertoire of life history strategies of animal and plant species via their effects on underlying vital rates and life history traits. We find that: (1) urban areas host a limited diversity of strategies that achieve demographic resilience with, on average, more resistant and faster-recovery populations located near human activities than in pristine habitats; (2) species with limited mobility tend to be more strongly affected by human activities than those with long-distance mobility; and (3) human pressures correlate with a limited set of vital rates and life history traits, including the ability to shrink, and reproduce earlier. Our results provide a tangible picture of how, having drastically transformed terrestrial landscapes, humans have shaped the ways animals and plants respond to disturbances.

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