Context Dependent Territory Defense: The Importance of Habitat Structure in Anolis sagrei

Authors

  • Ryan Calsbeek,

    1.  Center for Tropical Research, Institute of the Environment, University of California, Los Angeles, CA, USA
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  • Erin Marnocha

    1.  Center for Tropical Research, Institute of the Environment, University of California, Los Angeles, CA, USA
    2.  Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA
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Ryan Calsbeek, Center for Tropical Research, Institute of the Environment, University of California, Los Angeles, CA, USA.
E-mail: calsbeek@ucla.edu

Abstract

Territoriality is a potentially costly endeavor, and several mechanisms for mitigating the costs of territoriality have been investigated in the wild. For example, territory owners can reduce the costs of defending territory boundaries by prioritizing defense of the most valuable areas within territories, investing less energy in low quality areas. We staged pairwise encounters between adult male lizards on natural territories in the wild, to test whether male brown anoles, Anolis sagrei, would differentially defend certain regions of their territories over others. Based on our observations that male A. sagrei spend most of their time on elevated perches on tree trunks or branches compared with sites on the ground, we predicted that territory residents would respond more aggressively to territory invasions that took place on elevated perches than to invasions on the ground. We measured significant differences in the behavior of residents following invasion on the ground vs. on the elevated perches, and results partially supported our hypothesis. Males performed more displays and approached intruders more often when territory invasion took place on the ground, but were quicker to attack intruders that entered territories on elevated perches. Our hypothesis was only partially supported, potentially indicating that elevated perches are preferred as outposts to monitor valuable sites on the ground. Our study provides evidence that territory defense varies not just among individuals, but also within individuals at different locations in a territory.

Ancillary