VARIATION IN BODY TEMPERATURE AND THERMOREGULATORY BEHAVIOR BETWEEN TWO POPULATIONS OF THE LESSER EARLESS LIZARD, HOLBROOKIA MACULATA

Abstract

Body temperatures and thermoregulatory behavior of fieldactive Holbrookia maculata were evaluated for two sites at approximately equal elevation (approximately1200 m) in southern New Mexico: 1) a population at White Sands National Monument, and 2) a population at the Jornada Long-term Ecological Research site. H. maculata at WS had significantly lower body temperatures (mean = 36.3°C) than those measured at the Jornada Long-term Ecological Research site (mean = 39.5°C). The slope of a regression of body temperature on air temperature was significantly different between populations (White Sands National Monument; 0.65, the Jornada Long-term Ecological Research site; 0.36). The microhabitats in which individuals were first observed correlated with body temperatures at White Sands National Monument, but not at the Jornada Long-term Ecological Research site. These data suggest that environmental temperature differences between sites influenced body temperatures and thermoregulation in behavior H. maculata.