title: The effect of photoperiod on temperature selection in the European green lizard, Lacerta viridis.
abstract: Voluntary body temperature selection of unrestrained Lacerta viridis revealed consistant photoperiod entrained diel patterns. Each daily cycle was characterized by an elevation in body temperature (Tb) to a high level plateau which declined at the onset of scotophase to a low level; both of which were maintained within narrow ranges.Under natural photoperiod in fall, lizards responded to shorter days by sinking low level Tb's and expanding the duration of these low levels until no rhythmicity was shown. Subsequent exposure to long day, LD 16:8, induced self-arousal and a slightly altered diel Tbselection with significantly higher Tb's being chosen at both the elevated and lower daily levels. Changes in the relations of diel Tbselection due to shift in photoperiod, suggest that photoperiod acts as a seasonal indicator for thermal adaptation.
authors.affiliation: Department of Biology, Philipps-University, D-3550, Marburg, Germany.
authors.forename: Peggy D
authors.initials: PD
authors.lastname: Rismiller
authors.affiliation: Department of Biology, Philipps-University, D-3550, Marburg, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Heldmaier