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

Abstract

Body temperatures and thermoregulatory behavior of field-active 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.