Temperature preference in geckos: Diel variation in juveniles and adults

Field studies of nocturnal geckos have revealed that many species actively thermoregulate during both the day and the night. Data from laboratory studies indicate that geckos prefer body temperatures greater than those experienced during activity in the field, but data on diel patterns of temperature preference are inconsistent. We measured preferred body temperature (T(p)) of five species of geckos (Coleonyx mitratus, Eublepharis macularius, Hemidactylus turcicus, Oedura marmorata, and O. reticulata) to determine the extent of within-day and between-day variation. Additionally, we compared T(p)s of juveniles and adults of O. marmorata and E. macularius. Preferred body temperature increased from morning to evening hours within days but did not differ between days. Juveniles and adults had similar T(p)s at all time periods. We hypothesize that a preference for higher T(b)s toward the end of photophase initiates the thermoregulatory behavior observed in field-active geckos, and facilitates higher body temperatures during activity in early scotophase.