Diel and Seasonal Cycles of Activity and Behavioral Thermoregulation in the Salamander Necturus maculosus

Abstract

When acclimatized to 15 ? 1 C and a photoperiod of LD 12:12 mudpuppies exhibited significant diel cycles of behavioral temperature selection and locomotor activity throughout the year when tested in horizontal thermal gradients over 2 d periods. Activity and mean preferred temperatures were highest during scotophase and demonstrate the high degree of nocturnality of this species. The marked diel and seasonal cycles in thermal selection in many ectotherms suggest that the concept of a final thermal preferendum is not a particularly useful paradigm for descriptions of thermal behavior.