Comparing Foraging Success in Submissive Malaria-Infected and Territorial Noninfected Fence Lizards (Sceloporus occidentalis)

Defending a territory must have significant costs, such as expenditure of energy by the territorial animal, loss of time that could be devoted to other activities, and increased danger from predation or injury during defensive activities. A fundamental assumption of studies of animal territorial behavior is that there must be some profit from the behavior that more than offsets the obvious costs; this could include protecting valuable resources, such as food or retreat site, or access to mates (reviews in Morse, 1980; Krebs and Davies, 1981). Testing this assumption is notoriously difficult because territories may have multiple functions, and the importance of these functions may differ over time for individuals (Hinde, 1956; Stamps, 1994).