The effects of population density on time budgets of the Iberian wall lizard (Podarcis hispanica)

Individual time budgets under natural conditions and under increased popula tion density conditions were studied in a population of Podarcis hispanica in Western Spain. We examined the effects of sex, time of day, and density on daily time budgets. Artificially increasing density indicated that demog raphic changes do affect time budgets, and that the animals initially respo nd with short-term compensatory behavior. We found that: (1) basking was the predominant behavior in time budgets of all lizards; (2) thermoregulatory patterns are affected by high population density; (3) our results confirm the hypothesis that density of population, and not sex, is a primary factor affecting basking behavior, i.e., high po pulation density leads to increased basking; (4) social interaction frequen cy increased and percentage of time resting decreased at high population de nsity.