EvoLudoLab: Spatial Ecological PGG - Diffusion induced instability in 1D

Cooperator density:	Low High

Payoff code:	Low High

Diffusion induced instability in 1D

Pattern formation process in ecological public goods games through diffusion-induced instability in 1-dimensional spatial systems. Initially the strategy distribution is homogeneous with densities near the stable coexistence equilibrium $\mathbf {Q}$ and a perturbation in the center (increase of the densities by 10%, fixed (reflecting) boundary conditions). The figure on the left shows a space–time plot of the pattern formation process where the abscissa denotes space, and the ordinate the time (from top to bottom).

The game parameters are $N=8$ , $b=1$ , $d=1.2$ , $r=2.5$ , which yield equilibrium densities of cooperators ${\hat {u}}=0.078$ and defectors ${\hat {v}}=0.11$ . Diffusion coefﬁcients are $D_{C}=1$ and $D_{D}=10$ , spatial extension is $L=100$ and numerical integration uses $dx=0.5$ and time increments of $dt=0.1$ .

Data views

Strategies - Structure	Snapshot of the spatial arrangement of strategies.
Strategies - Structure 3D	3D view of snapshot of the spatial arrangement of strategies.
Strategies - Mean	Time evolution of the strategy frequencies.
Simplex $S_3$	Strategy frequencies plotted in the simplex $S_3$. If no calculation is running, mouse clicks set the initial frequencies of strategies and stops the calculations otherwise (for the ODE solver it switches to backwards integration).
Phase plane 2D	Frequencies plotted in the phase plane spanned by the population density ($u + v = 1 - w$) and the relative frequency of cooperators ($f = u / (u + v)$). Again, mouse clicks set the initial frequencies of strategies, stop the simulations or switch to backward integration
Fitness - Structure	Snapshot of the spatial distribution of payoffs.
Fitness - Structure 3D	3D view of snapshot of the spatial distribution of payoffs.
Fitness - Mean	Time evolution of average population payoff bounded by the minimum and maximum individual payoff.
Fitness - Histogram	Snapshot of payoff distribution in population.
Structure - Degree	Degree distribution in structured populations.

Game parameters

The list below describes only the parameters related to the public goods game and the population dynamics. Follow the link for a complete list and descriptions of all other parameters such as spatial arrangements or update rules on the player and population level.

--interest <r>

multiplication factor $r$ of public good.

--cost <c>

cost of cooperation $c$ (investment into common pool).

--lonecooperator <l>

payoff for a cooperator if no one else joins the public goods interaction.

--lonedefector <l>

payoff for a defector if no one else joins the public goods interaction.

--basefit <b>

baseline reproductive rate of all individuals. The effective birthrate is affected by the individual's performance in the public goods game and additionally depends on the availability of empty space.

--deathrate <d>

constant death rate of all individuals.

--init <d,c,e>

initial frequencies of defectors d, cooperators c and vacant space e. Frequencies that do not add up to 100% are scaled accordingly.

--inittype <type>

type of initial configuration:

frequency <f0>,<f1>...: random distribution with given trait frequencies, f0, f1,.... Note, only available for frequency based modules and models.
density <d0>,<d1>...: initial trait densities <d1,...,dn>. Note, only available for density based modules and models.
uniform: uniform random distribution, equal frequencies of all traits.
monomorphic <t>[,<v>]: monomorphic initialization with trait t. Note, for modules with variable population densities, the optional parameter v indicates the initial frequency of vacant sites. If omitted the monomorphic trait is initialized at its (estimated) carrying capacity.
mutant <m>,<r>[,<v>]: single mutant with trait m in homogeneous resident population of type r. The mutant is placed in a location selected uniformly at random (mutants arising through cosmic rays). Note, for modules with variable population densities, the optional parameter v indicates the initial frequency of vacant sites. If omitted the resident trait is initialized at its (estimated) carrying capacity.
temperature <m>,<r>[,<v>]: single mutant with trait m in homogeneous resident population of type r. The mutant is placed in a location selected proportional to the in-degree of nodes (temperature initialization, mutants arising through errors in reproduction). Note, for modules with variable population densities, the optional parameter v indicates the initial frequency of vacant sites. If omitted the resident trait is initialized at its (estimated) carrying capacity.
stripes: stripes of traits. Note, only available for 2D lattices.
kaleidoscopes: configurations that produce evolutionary kaleidoscopes for deterministic updates (players and population). Note, only available for some modules.

Note, for modules that admit multiple species, the initialization types for each species can be specified as an array separated by ;. With more species than initialization types, they are assigned in a cyclical manner.