Mathematical modeling on obligate mutualism: Interactions between leaf-cutter ants and their fungus garden

Yun Kang, Rebecca Clark, Michael Makiyama, Jennifer Fewell

Research output: Contribution to journalArticlepeer-review

26 Scopus citations


We propose a simple mathematical model by applying Michaelis-Menton equations of enzyme kinetics to study the mutualistic interaction between the leaf cutter ant and its fungus garden at the early stage of colony expansion. We derive sufficient conditions on the extinction and coexistence of these two species. In addition, we give a region of initial condition that leads to the extinction of two species when the model has an interior attractor. Our global analysis indicates that the division of labor by worker ants and initial conditions are two important factors that determine whether leaf cutter ants' colonies and their fungus garden can survive and grow or not. We validate the model by comparing model simulations and data on fungal and ant colony growth rates under laboratory conditions. We perform sensitive analysis of the model based on the experimental data to gain more biological insights on ecological interactions between leaf-cutter ants and their fungus garden. Finally, we give conclusions and discuss potential future work.

Original languageEnglish (US)
Pages (from-to)116-127
Number of pages12
JournalJournal of Theoretical Biology
Issue number1
StatePublished - Nov 21 2011


  • Coexistence
  • Extinction
  • Functional/numerical response
  • Multiple attractors
  • Population dynamics

ASJC Scopus subject areas

  • Statistics and Probability
  • Modeling and Simulation
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)
  • Agricultural and Biological Sciences(all)
  • Applied Mathematics


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