An experimental test of the ideal despotic distribution

Summary

• 1
   Ideal despotic distribution theory predicts that the quality of habitat controlled by territorial animals should vary depending on their competitive ability and the availability of resources.
• 2
   In environments where resources have a patchy distribution, males that monopolize high quality territories may require less territory area than males in low quality areas. This has been a difficult premise to test in the wild owing to logistical constraints regarding manipulation of relevant resources and accurate measures of territory distributions.
• 3
   We present results from an experimental test of ideal despotic distribution theory in a wild population of side-blotched lizards, Uta stansburiana (Baird and Girard).
• 4
   We manipulated thermal resources on territories by shuttling rocks between dyads of neighbouring male territories. Manipulations created high quality territories by significantly increasing the variance in temperatures available for thermoregulation.
• 5
   Experimentally improved quality territories (rock addition) became smaller after treatment, while reduced quality territories (rock removal) became larger.
• 6
   Males on improved and reduced quality territories had equal numbers of females, resulting in higher densities of females on the smaller high quality territories.
• 7
   Densities of the snake Masticophis flagellum, the dominant predator of Uta stansburiana, were higher on reduced quality territories.
• 8
   Progeny released to experimental plots had significantly higher growth-rates and survival on experimentally improved sites relative to their neighbours on low quality territories.
• 9
   Our results demonstrate both the ecological factors that drive the ideal despotic distribution, and the fitness consequences of high and low quality territories to lizards.