The Evolution of Gut Modulation and Diet Specialization as a Consumer-Resource Game

  • Christopher J. Whelan
  • Joel S. Brown
  • Jason Moll
Part of the Annals of the International Society of Dynamic Games book series (AISDG, volume 9)


Diet provides an important source of niche partitioning that promotes species coexistence and biodiversity. Often, one species selects for a scarcer but more nutritious food (Thomson gazelle) while another opportunistically consumes low-and high-quality foods indiscriminately (African buffalo). In addition to choosing a diet (selective versus opportunistic), organisms have co-adapted digestion physiologies that vary in size and the throughput rate at which food passes through the gut. We combine these elements into a game of resource competition. We consider a vector-valued strategy with elements of gut size and throughput rate. To the forager, food items now have three properties relating to the value of a particular strategy: profitability (energy gained per unit handling time), richness (energy gained per unit bulk), and ease of digestion (energy gain per unit of passage time). When foraging on foods that differ in profitability, richness, and ease of digestion, adjustment or modulation of gut size and throughput rate leads to digestive-system specialization. Modulation of digestive physiology to a particular food type causes different food types to become antagonistic resources. Adjustment of gut volume and processing thus selects for different degrees of diet specialization or opportunism, and thus may promote niche diversification. This in turn sets the stage for disruptive or divergent selection and may promote sympatric speciation.


Food Type Sympatric Speciation Handling Time Evolutionarily Stable Strategy Throughput Rate 
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Copyright information

© Birkhäuser Boston 2007

Authors and Affiliations

  • Christopher J. Whelan
    • 1
  • Joel S. Brown
    • 2
  • Jason Moll
    • 2
  1. 1.Illinois Natural History SurveyMidewin National Tallgrass PrairieWilmingtonUSA
  2. 2.Department of Biological SciencesUniversity of Illinois at ChicagoChicagoUSA

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