Department of Physiology, Faculty of Biology, Regional Campus of International Excellence “Campus Mare Nostrum”, University of Murcia, 30100 Murcia, Spain; Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy
Elena Frigato
Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy
Pietro Negrini
Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy
Walter Cristiano
Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy; Ecosystems and Health Unit, Environment and Health Department, Italian National Institute of Health, 00161 Rome, Italy
Jose Fernando López-Olmeda
Department of Physiology, Faculty of Biology, Regional Campus of International Excellence “Campus Mare Nostrum”, University of Murcia, 30100 Murcia, Spain
Sylvie Rétaux
Paris-Saclay Institute of Neuroscience, CNRS and University Paris-Saclay, 91400 Saclay, France
Francisco Javier Sánchez-Vázquez
Department of Physiology, Faculty of Biology, Regional Campus of International Excellence “Campus Mare Nostrum”, University of Murcia, 30100 Murcia, Spain
Nicholas S. Foulkes
Institute of Biological and Chemical Systems, Biological Information Processing (IBCS-BIP), Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany; Corresponding author
Cristiano Bertolucci
Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy; Corresponding author
Summary: The circadian clock represents a key timing system entrained by various periodic signals that ensure synchronization with the environment. Many investigations have pointed to the existence of two distinct circadian oscillators: one regulated by the light-dark cycle and the other set by feeding time. Blind cavefish have evolved under extreme conditions where they completely lack light exposure and experience food deprivation. Here, we have investigated feeding regulated clocks in two cavefish species, the Somalian cavefish Phreatichthys andruzzii and the Mexican cavefish Astyanax mexicanus, in comparison with the surface-dwelling zebrafish Danio rerio. Our results reveal that feeding represents an extremely strong synchronizer for circadian locomotor rhythmicity in subterranean cavefish. Indeed, we showed that consuming just one meal every 4 days is sufficient to entrain circadian rhythmicity in both cavefish species, but not in zebrafish. These profound adaptations to an extreme environment provide insight into the connections between feeding and circadian clocks.
