ABSTRACT Quality and intensity of environmental light are stressors that affect animal function rate, thus limiting their distribution. Extreme values in photoperiod or light irradiance produce animal behavioral and metabolic changes as a strategy to adapt. In the present work we review some studies on metabolic and behavioral strategies shown by two species of crayfish, Procambarus clarkii, and Procambarus digueti when submitted to various conditions of photoperiod and light irradiance The review is focused on 1) the ecological and latitudinal differences of both species, and the behavioral and metabolic changes produced by 24 light-dark cycles of two different photoperiod lengths, 12 and 20 h, of low and high irradiance; 2) the differences in photo-oxidative stress produced by light in both species and the anti-oxidant endogenous rhythms that allow both species to adapt to the periodical oxidation of light-dark cycles. Results of the reviewed works demonstrate that oxidative stress produced by light parameters as well as the survival ability of the different crayfish species to cope with it seem to be related to the ecological and latitudinal background of both species.
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