The Model

Bugs move around randomly in a 2 dimensional and toroidal grid space. They feed and grow. Food is represented as a grid cell property. When a bug arrives on a new cell, it eats the available food. Bugs also reproduce and cannibalize each other.

The model was inspired by the paper of Railsback et al.: Agent-based Simulation Platforms: Review and Development Recommendations.

Just download the model archive and import it through Fables by right-clicking on the Project Explorer and select Import... from the popup menu.

Tutorial 

An extensive tutorial is also available for the model.

Both the model and the source code was contributed by This e-mail address is being protected from spambots. You need JavaScript enabled to view it at August 17, 2011.

How does it work?

Bugs move around randomly in a 2 dimensional and toroidal grid space. They feed and grow. Food is represented as a grid cell property. When a bug arrives on a new cell, it eats the available food. Bugs also reproduce and cannibalize each other, implemented in the following way:

• When two bugs of the same gender meet in one cell the older bug eats the younger one and increases his weight about the weight value of the younger bug.
• When a bug male and female meet each other in a cell they reproduce if both of them are older than the maturity level (= 20 Days), otherwise the older bug eats the younger one.
• The pregnant female bug will give birth to a new bug after some time interval: the pregnancy interval (= 3 Days).
  
• If a bug found a cell with food he eats 20% of the avaiable food and increases his weight about the eaten foodvalue.
• A bug looses one weight point per simulation step and if his weight reached zero then he will die because of starvation.

Modifying the model

If you want to practice a little bit then it could be a good exercise to extend the bugs scenario. For example you could add one (or more) of the following improvements:

• Only one food per cell
  
• Food can grow continuosly
  
• Bugs move in a more natural way (bugs move currently and do not jump)
  
• Bugs get some kind of "battle skill" which is in influenced by the age and some kind of "battle experience"
  
• Pregnant bugs lose some weight for giving birth 

Related Models

• StupidModel A Template and Teaching Tool for Agent-based Modeling Platforms, as described in Railsback, S., Lytinen, S., Grimm, V. (2005). StupidModel and Extensions.
• Randomwalk Fleas jumping on the flat.

References

• Steven F. Railsback, Steven L. Lytinen, Stephen K. Jackson, Agent-based Simulation Platforms: Review and Development Recommendations