Plasticity of daily rhythms and thermoregulation in a South American subterranean rodent

TACHINARDI P; JANNETTI MG; FLORES DEFL; BUCK LC; VALENTINUZZI VS; ODA GA

New Orleans

Congreso; Intersociety Meeting - Comparative Physiology: Complexity and Integration; 2018

American Physiological Society

Plasticity in the expression of 24h rhythms has been a subject of increasing interest. This plasticity can involve a change in the time of day a certain behavioral or physiological process occurs (such as a change from nocturnal to diurnal) or a change in the amplitude of rhythms, such as in the daily body temperature rhythm. The subterranean rodent tuco-tuco (Ctenomys aff. knighti) is among the species which display rhythmic plasticity. This animal is nocturnal under standard lab conditions but mostly diurnal in the field. It also shows drastic changes in amplitude of the body temperature rhythm when in the field, with changes in maximum, minimum and mean body temperature values. This plasticity was revealed by several years of data collection on body temperature rhythms of tuco-tucos in the laboratory and in outdoor enclosures. The differences between the rhythms observed in the laboratory and in the field suggest an interaction of the circadian system with a wide set of biotic and abiotic factors that differ between these two conditions. A lot of these variables are related to daily energetic challenges, which are much greater in the field than in the lab. This herbivorous rodent forage by intense digging, in a semi-arid habitat where vegetation is sparse and there are great daily changes in environmental temperature. Noteworthy, food availability and temperature have been changing in the last years, in their natural habitat in Argentina, especially with the increase in rainfall. Increase in the plasticity of rhythmic patterns have been registered along these years and investigation of this phenomenon may provide insights into the role of environmental changes on timing of activity and physiological functions.