About the Model
This model was inspired by the Red Queen Card
Game
as described in Gibson, Drown, anc
Lively (2015)
The model aims to demonstrate the Red Queen Hypothesis by simulating paired populations
of hosts and their parasites.
Each individual host and parasite in the simulation has a 'genotype' consisting of one allele.
In each round, a host is randomly paired with a parasite.
If the parasite genotype matches that of the host, the parasite wins and the host has a certain
probability of dying.
If the host and parasite genotypes are mismatched, the host wins and the parasite dies.
After winners are chosen, all surviving hosts reproduce.
Only the winning parasites reproduce.
Offspring of hosts and parasites have the same genotypes as their parents.
The population sizes of hosts and parasites are kept constant throughout the simulation.
If after the reproduction step, the number of hosts or parasites exceeds the population size, randomly
chosen individuals are removed.
If there are too few hosts or parasites, individuals with randomly chosen genotyeps are added.
You can explore the companion workshop with suggested questions and activities.
Model Parameters
The user can set the values of the following parameters:
- Number of Alleles: This is the number of distinct genotypes that the hosts and
parasites can have.
- Population: This parameter controls the popultion sizes of hosts and parasites.
- Host Fertility: This is the number of offspring that each surviving host
produces at the end of the turn.
- Parasite Fertility: This is the number of offspring that each winning
parasite produces at the end of the turn.
- Infection Mortality Rate: This is the probability that an infected host will die.
- Generations per Step: This is the number of generations that will be simulated when you hit the Play button
Model Interface
- The simulation loads with default settings.
- To run the simulation with different settings, the user can change the parameters to the desired
settings
and click the Reset button.
- To run the simulation(s), press the Play button. You can adjust the number of steps per turn using the Generations per Step paremeter.
The plot will update with the new genotype counts for the hosts and parasites.
- The plots show the number of individual hosts and parasites with each genotype for each generation.
The user can save a PNG image of the current plot by clicking on the camera icon.
- To start over and run a new simulation, simply press the Reset button.
© Michael France Nelson