scholarly journals Extraordinary Self-Sacrifice

2017 ◽  
Author(s):  
D.B. Krupp
Keyword(s):  
Inclusive Fitness ◽  
Simple Rule ◽  
Fitness Effects ◽  
Structured Population ◽  
Spatially Structured Population

AbstractTheories of self-sacrifice ordinarily assume that actors will have larger fitness effects on recipients than on themselves. There are, however, conditions in which actors can pay costs that exceed the altruistic benefits they provide or the spiteful costs they impose. In a spatially structured population, I show that such “extraordinary” self-sacrifice evolves when actors use information about kinship and dispersal to maximize inclusive fitness. The result can be described by a simple rule: extraordinary self-sacrifice evolves when the actor’s neighbors are kin and the recipient’s neighbors are not.

scholarly journals An inclusive fitness analysis of synergistic interactions in structured populations

2012 ◽  
Vol 279 (1747) ◽  
pp. 4596-4603 ◽  
Author(s):  
Peter Taylor ◽  
Wes Maciejewski
Keyword(s):  
Frequency Dependence ◽  
Allele Frequency ◽  
Inclusive Fitness ◽  
Selective Advantage ◽  
Structured Populations ◽  
Weak Selection ◽  
Synergistic Interactions ◽  
Fitness Effects ◽  
Structured Population

We study the evolution of a pair of competing behavioural alleles in a structured population when there are non-additive or ‘synergistic’ fitness effects. Under a form of weak selection and with a simple symmetry condition between a pair of competing alleles, Tarnita et al. provide a surprisingly simple condition for one allele to dominate the other. Their condition can be obtained from an analysis of a corresponding simpler model in which fitness effects are additive. Their result uses an average measure of selective advantage where the average is taken over the long-term—that is, over all possible allele frequencies—and this precludes consideration of any frequency dependence the allelic fitness might exhibit. However, in a considerable body of work with non-additive fitness effects—for example, hawk–dove and prisoner's dilemma games—frequency dependence plays an essential role in the establishment of conditions for a stable allele-frequency equilibrium. Here, we present a frequency-dependent generalization of their result that provides an expression for allelic fitness at any given allele frequency p . We use an inclusive fitness approach and provide two examples for an infinite structured population. We illustrate our results with an analysis of the hawk–dove game.

scholarly journals Evolutionary dynamics of n -player games played by relatives

2014 ◽  
Vol 369 (1642) ◽  
pp. 20130359 ◽  
Author(s):  
Hisashi Ohtsuki
Keyword(s):  
Social Interactions ◽  
Genetic Association ◽  
Kin Selection ◽  
Social Evolution ◽  
Evolutionary Dynamics ◽  
Inclusive Fitness ◽  
Theoretical Frameworks ◽  
Fitness Effects ◽  
Structured Population ◽  
Core Concepts

One of the core concepts in social evolution theory is kin selection. Kin selection provides a perspective to understand how natural selection operates when genetically similar individuals are likely to interact. A family-structured population is an excellent example of this, where relatives are engaged in social interactions. Consequences of such social interactions are often described in game-theoretical frameworks, but there is a growing consensus that a naive inclusive fitness accounting with dyadic relatedness coefficients are of limited use when non-additive fitness effects are essential in those situations. Here, I provide a general framework to analyse multiplayer interactions among relatives. Two important results follow from my analysis. First, it is generally necessary to know the n -tuple genetic association of family members when n individuals are engaged in social interactions. However, as a second result, I found that, for a special class of games, we need only measures of lower-order genetic association to fully describe its evolutionary dynamics. I introduce the concept of degree of the game and show how this degree is related to the degree of genetic association.

scholarly journals Male relatedness and familiarity are required to modulate male-induced harm to females in Drosophila

2017 ◽  
Vol 284 (1860) ◽  
pp. 20170441 ◽  
Author(s):  
Sally Le Page ◽  
Irem Sepil ◽  
Ewan Flintham ◽  
Tommaso Pizzari ◽  
Pau Carazo ◽  
...  
Keyword(s):  
Potential Role ◽  
Genetic Relatedness ◽  
Inclusive Fitness ◽  
Kin Recognition ◽  
Female Reproduction ◽  
Fitness Effects ◽  
Inclusive Fitness Theory ◽  
Indirect Fitness ◽  
Female Lifespan

Males compete over mating and fertilization, and often harm females in the process. Inclusive fitness theory predicts that increasing relatedness within groups of males may relax competition and discourage male harm of females as males gain indirect benefits. Recent studies in Drosophila melanogaster are consistent with these predictions, and have found that within-group male relatedness increases female fitness, though others have found no effects. Importantly, these studies did not fully disentangle male genetic relatedness from larval familiarity, so the extent to which modulation of harm to females is explained by male familiarity remains unclear. Here we performed a fully factorial design, isolating the effects of male relatedness and larval familiarity on female harm. While we found no differences in male courtship or aggression, there was a significant interaction between male genetic relatedness and familiarity on female reproduction and survival. Relatedness among males increased female lifespan, reproductive lifespan and overall reproductive success, but only when males were familiar. By showing that both male relatedness and larval familiarity are required to modulate female harm, these findings reconcile previous studies, shedding light on the potential role of indirect fitness effects on sexual conflict and the mechanisms underpinning kin recognition in fly populations.

scholarly journals A general modeling framework for describing spatially structured population dynamics

2017 ◽  
Vol 8 (1) ◽  
pp. 493-508 ◽  
Author(s):  
Christine Sample ◽  
John M. Fryxell ◽  
Joanna A. Bieri ◽  
Paula Federico ◽  
Julia E. Earl ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Modeling Framework ◽  
Structured Population ◽  
Structured Population Dynamics ◽  
Spatially Structured Population

Evolution in a spatially structured population subject to rare epidemics

2001 ◽  
Vol 63 (4) ◽  
Author(s):  
Joshua E. S. Socolar ◽  
Shane Richards ◽  
William G. Wilson
Keyword(s):  
Structured Population ◽  
Spatially Structured Population

scholarly journals Fitness benefits of low infectivity in a spatially structured population of bacteriophages

2014 ◽  
Vol 281 (1774) ◽  
pp. 20132563 ◽  
Author(s):  
Pavitra Roychoudhury ◽  
Neelima Shrestha ◽  
Valorie R. Wiss ◽  
Stephen M. Krone
Keyword(s):  
Transmission Rate ◽  
Burst Size ◽  
Structured Populations ◽  
Host Cells ◽  
Structured Population ◽  
Spatially Structured Populations ◽  
Lysis Time ◽  
Evolution Experiment ◽  
Spatially Structured Population ◽  
And Diffusion

For a parasite evolving in a spatially structured environment, an evolutionarily advantageous strategy may be to reduce its transmission rate or infectivity. We demonstrate this empirically using bacteriophage (phage) from an evolution experiment where spatial structure was maintained over 550 phage generations on agar plates. We found that a single substitution in the major capsid protein led to slower adsorption of phage to host cells with no change in lysis time or burst size. Plaques formed by phage isolates containing this mutation were not only larger but also contained more phage per unit area. Using a spatially explicit, individual-based model, we showed that when there is a trade-off between adsorption and diffusion (i.e. less ‘sticky’ phage diffuse further), slow adsorption can maximize plaque size, plaque density and overall productivity. These findings suggest that less infective pathogens may have an advantage in spatially structured populations, even when well-mixed models predict that they will not.

scholarly journals Slightly beneficial genes are retained by evolving Horizontal Gene Transfer despite selfish elements

2020 ◽  
Author(s):  
B. van Dijk ◽  
P. Hogeweg ◽  
H.M. Doekes ◽  
N. Takeuchi
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Growth Rates ◽  
Selfish Genetic Elements ◽  
Structured Population ◽  
Rapid Changes ◽  
Spatially Structured Population ◽  
Fitness Benefits ◽  
Bacterial Growth Rates ◽  
Gene Sharing

AbstractHorizontal gene transfer (HGT) is a key component of bacterial evolution, which in concert with gene loss can result in rapid changes in gene content. While HGT can evidently aid bacteria to adapt to new environments, it also carries risks since bacteria may pick up selfish genetic elements (SGEs). Here, we use modeling to study how bacterial growth rates are affected by HGT of slightly beneficial genes, if bacteria can evolve HGT to improve their growth rates, and when HGT is evolutionarily maintained in light of harmful SGEs. We find that we can distinguish between four classes of slightly beneficial genes: indispensable, enrichable, rescuable, and unrescuable genes. Rescuable genes – genes that confer small fitness benefits and are lost from the population in the absence of HGT — can be collectively retained by a bacterial community that engages in HGT. While this ‘gene-sharing’ cannot evolve in well-mixed cultures, it does evolve in a spatially structured population such as a biofilm. Although HGT does indeed enable infection by harmful SGEs, HGT is nevertheless evolutionarily maintained by the hosts, explaining the stable coexistence and co-evolution of bacteria and SGEs.

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