Photoperiodism in tuco-tuco (Ctenomys aff. knighti), a subterranean rodent

• Grant number: 16/25968-6
• Support type: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): July 01, 2017
• Effective date (End): December 31, 2017
• Field of knowledge: Biological Sciences - Physiology
• Principal Investigator: Gisele Akemi Oda
• Grantee: Giovane Carreira Improta
• Home Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Biological rhythms displaying periods of 24h and 365 days are synchronized by the Earth´s environmental cycles such as the daily light/dark and the annual photoperiodic (ratio between day and night lengths) cycles, respectively. Little is known about annual rhythmicity and photoperiodism in organisms that live in extreme photic environments such as caves, underground tunnels and abyssal regions. Our group has developed chronobiological studies in an endemic subterranean rodent species from South America (Ctenomys aff. knighti) known as tuco-tuco. They display daily rhythms of locomotor activity and body temperature, which are synchronized by daily light/dark cycles, both in field and laboratory conditions. Seasonal variation of the temporal patterns of daily activity rhythms have been indicated by preliminary works from our group, in tuco-tucos released in semi-natural enclosures. The objective of this project is to verify temporal patterns of daily synchronization of activity in tuco-tucos under different artificial photoperiods, as well as to characterize the after-effects of natural entrainment in individuals captured under summer and winter photoperiod conditions. (AU)