Seasonal changes in daily activity patterns in a free-living subterranean rodent (Ctenomys aff. knightii)

SILVÉRIO JT; TACHINARDI P; VALENTINUZZI VS; ODA GA

Simposio; XVI Latin American Symposium on Chronobiology-LASC; 2021

The Anillaco tuco-tuco (Ctenomys aff. knighti) is a subterranean rodent which inhabitsthe Monte desert in Northwest Argentina. They exhibit highly different daily activity patterns between laboratory and natural conditions, switching from diurnal to nocturnal when transferred from the field to the laboratory. This suggests that environmental and social factors might interact with the circadian system and play a role in the modulation of their activity patterns. Since these factors undergo seasonal changes, our goal was to investigate possible seasonal changes in the daily activity patterns of free-living tuco-tucos. We trapped animals and deployed collars containing movement and light sensors, which recorded continuous body movement and light exposure. All captured animals showed diurnal activity, with individual and seasonal changes in daily pattern and overall level of activity. To further analyze their activity, we used Hidden Markov Models to classify their activity in three distinct behavioral states. We also observed seasonal changes in the time spent in each state, especially for the state with higher levels of activity. Moreover, circadian rhythmicity is more pronounced in the state associated with higher levels of activity while moderate activity is spread throughout the day. Our results suggest that seasonally changing environmental, physiological or social factors are playing a role in the timing of activity and behavioral states in free-living tuco-tucos.