Natural Enemies Simulation

This page contains a computer simulation model for insect population studies. In the form below you can enter sets of data that are used in the simulation. Initially the form will show default values, which can be replaced by your own values.

For most parameters you can enter a low and a high value (see notes below).

Click the ‘Start Simulation’ button to see the results of the simulation: a graph and summary of the number of females in each generation, and a detailed list of simulation results.

Read the introduction page to learn more about this insect simulation program.

Simulation settings

Population development
Low High
Eggs per female Eggs (>0)
Sex ratio % females (0-100)
Eggs days to hatch Days
Larva days to pupa Days
Pupa days to adult Days
Adult days to egg Days
Egg mortality factors
Low High
Egg parasitoids %
Egg predators %
Egg other (weather, diseases) %
Larva mortality factors
Low High
Larva parasitoids %
Larva predators %
Larva other (weather, diseases) %
Pupa mortality factors
Low High
Pupa parasitoids %
Pupa predators %
Pupa other (weather, diseases) %
Adult mortality factors (before egg laying)
Low High
Adult predators %
Adult other (weather, diseases) %
Other settings
Start population size (eggs) Number of eggs (2 or more)
Number of generations Generations to simulate (max 40)
Maximum population size (larvae) Simulation stops (max 10,000,000)
Variability Variability factor (0-100)




For most parameters you have entered a "low" and a "high" value.

  • For density dependent factors (e.g. mortality caused by parasitoids or predators) the program will use an algorithm to select a value which is near the "low" when the population density is low, and near the "high" when population density is high.
  • For factors that are not density dependent (e.g. other mortality factors such as bad weather conditions) the program will in each cycle (generation) at random select a value between the "low" and the "high".

This variability factor (0-100%) makes the simulation more unpredictable by introducing at random some variation on top of the data that you entered. It varies the "low" and "high" values of density dependent factors, simulating an additional effect of good or bad weather conditions. A higher value will create more variation of the numbers that you entered (different values in each cycle). 0% means no variability, so the program will exactly use the low and high values that you entered. 100% means maximum variability.

The program will first verify the data you entered and if necessary make some corrections. For example, if you set a "low" value higher than the "high" value, the program swap them.

Read the introduction page to learn more about this insect simulation program. And please send me your comments.

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