title: Modeling natural photic entrainment in a subterranean rodent (Ctenomys aff. knighti), the Tuco-Tuco.
abstract: Subterranean rodents spend most of the day inside underground tunnels, where there is little daily change in environmental variables. Our observations of tuco-tucos (Ctenomys aff. knighti) in a field enclosure indicated that these animals perceive the aboveground light-dark cycle by several bouts of light-exposure at irregular times during the light hours of the day. To assess whether such light-dark pattern acts as an entraining agent of the circadian clock, we first constructed in laboratory the Phase Response Curve for 1 h light-pulses (1000lux). Its shape is qualitatively similar to other curves reported in the literature and to our knowledge it is the first Phase Response Curve of a subterranean rodent. Computer simulations were performed with a non-linear limit-cycle oscillator subjected to a simple model of the light regimen experienced by tuco-tucos. Results showed that synchronization is achieved even by a simple regimen of a single daily light pulse scattered uniformly along the light hours of the day. Natural entrainment studies benefit from integrated laboratory, field and computational approaches.
authors.affiliation: Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil.
authors.forename: Danilo E F L
authors.initials: DE
authors.lastname: Flôres
authors.forename: Barbara M
authors.initials: BM
authors.lastname: Tomotani
authors.forename: Patricia
authors.initials: P
authors.lastname: Tachinardi
authors.forename: Gisele A
authors.initials: GA
authors.lastname: Oda
authors.forename: Veronica S
authors.initials: VS
authors.lastname: Valentinuzzi
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology; D003198:Computer Simulation; D017753:Ecosystem; D006799:Housing, Animal; D008027:Light; D008954:Models, Biological; D009425:Nesting Behavior / Q000502:physiology; D017440:Photoperiod; D012377:Rodentia / Q000502:physiology*