Approaching photoperiodism in subterranean rodents (Ctenomys aff. knighti)

IMPROTA CG; VALENTINUZZI VS; ODA GA

Sao Paulo

Workshop; International Workshop on Organism-environment interactions: timing, plasticity and metabolic adjustments; 2018

Biological rhythms displaying periods of 24h and 365 days are synchronized by the Earth?s environmental cycles such as the 24h light/dark (LD) and the annual photoperiod (ratio between day and night lengths) cycles, respectively. We test the hypothesis that these animals, even living in the underground and exposing themselves daily to light at irregular times in nature, have the capacity to process the photoperiodic information that marks the different seasons. For this, we verified the difference in synchronization patterns between animals exposed to different natural and artificial summer and winter photoperiods. Freshly caught animals from Monte Desert, Argentina (28°48'S, 66°56'W; altitude: 1,350 m) had their wheel activity recorded (ArChron Data Acquisition System) for at least 10 days under constant darkness (DD), to measure the aftereffects of natural photoperiods. This was followed by recording under one of the experimental artificial photoperiods (light-dark (LD) 6:18, LD 9:15 and LD 15:9) or long-lasting DD for at least 21 days, under constant temperature. Given the seasonal aspect of the study, the protocol was applied in summer and winter. Preliminary results indicate that animals from different natural photoperiodic regimens present a difference in the duration of their phase of wheel activity (α). When subjected to light/dark cycles more discordant to their capture season, animals generally take a greater number of transients for their resynchronization. Young animals (determined by capture mass and general morphology) demonstrate shorter transients and greater lability when induced to experimental entrainments.