INTRASPECIFIC VARIATION IN BEHAVIOR - COMPARISONS BETWEEN POPULATIONSAT DIFFERENT ALTITUDES OF THE LIZARD SCELOPORUS-JARROVI

We observed the social behavior of a high-elevation population of the lizard Sceloporus jarrovi on Mt. Graham in southeastern Arizona during August 1985, the month prior to the fall breeding season when territo riality should be intense. This population displayed lower levels of f emale territoriality than reported elsewhere for this species. Aggress ive levels of resident females as measured in staged encounters were s ignificantly lower than male aggressive levels. Display and feeding ra tes showed significant between-sex variation, also. Home ranges of adu lt males and females did not differ in size but were significantly lar ger than home ranges of juveniles. Home range sizes in adult females a t high elevation were significantly larger than those at low elevation . Overlap between female home ranges was much higher than overlap betw een male home ranges. The large number of overlapping females per male (xBAR = 3.75 +/- 2.4) made determination of potential mating opportun ities difficult. Some variation in behavioral patterns may result from the different demography of high elevation populations (delayed matur ity, smaller effective population size) relative to low elevation popu lations. Intraspecific variation may strongly affect the selective pre ssures on social structures and reproductive success patterns.