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Most organisms synchronize to an approximately 24-hour (circadian) rhythm. This study introduces a novel deep learning-powered video tracking method to assess the stability, fragmentation, robustness and synchronization of activity rhythms in Xyrichtys novacula. Experimental X. novacula were distributed into three groups and monitored for synchronization to a 14/10 hours of light/dark to assess acclimation to laboratory conditions. Group GP7 acclimated for 1 week and was tested from days 7 to 14, GP14 acclimated for 14 days and was tested from days 14 to 21 and GP21 acclimated for 21 days and was tested from days 21 to 28. Telemetry data from individuals in the wild depicted their natural behavior. Wild fish displayed a robust and minimally fragmented rhythm, entrained to the natural photoperiod. Under laboratory conditions, differences in activity levels were observed between light and dark phases. However, no differences were observed in activity rhythm metrics among laboratory groups related to acclimation period. Notably, longer acclimation (GP14 and GP21) led to a larger proportion of individuals displaying rhythm synchronization with the imposed photoperiod. Our work introduces a novel approach for monitoring biological rhythms in laboratory conditions, employing a specifically engineered video tracking system based on deep learning, adaptable for other species. [ABSTRACT FROM AUTHOR]

The adaptive value of sleep remains unknown in spite of the intense research performed throughout the last decades. However, few sleep researchers are aware of the difficulties posed by the blind acceptance of an extreme adaptationist viewpoint. Under this philosophy, every anatomical and functional detail present in a living being should have a positive adaptive value, a position that has been considered as rather doubtful. In this report, it is proposed that most of the physiological changes used for mammalian sleep definition could be mere by-products of other true adaptations, such as the ontogenetic and phylogenetic development of the nervous system. As a result, complex mammalian sleep could have no adaptive value over that of the simplest forms of rest-activity cycles present in all living forms. In addition, it is proposed that the absence of adaptive value should, by default, be the first option regarding the function of sleep. Besides, the burden of the proof should be always charged over the proponents of every particular adaptive function. As this proof has not been reached, it is the absence of function for sleep which should be taken for granted. [Copyright &y& Elsevier]