Temporal Dissociation Between Activity and Body Temperature Rhythms of a Subterranean Rodent (Ctenomys famosus) in Field Enclosures

Author(s)

Jannetti, Milene G. ; Tachinardi, Patricia ; Valentinuzzi, Veronica S. ; Oda, Gisele A.

• Document type: Journal article
• Source: JOURNAL OF BIOLOGICAL RHYTHMS; v. 38, n. 3, p. 12-pg., 2023-03-16.

Abstract

Several wild rodents, such as the subterranean tuco-tucos (Ctenomys famosus), switch their time of activity from diurnal to nocturnal when they are transferred from field to the laboratory. Nevertheless, in most studies, different methods to measure activity in each of these conditions were used, which raised the question of whether the detected change in activity timing could be an artifact. Because locomotor activity and body temperature (Tb) rhythms in rodents are tightly synchronized and because abdominal Tb loggers can provide continuous measurements across field and laboratory, we monitored Tb as a proxy of activity in tuco-tucos transferred from a semi-field enclosure to constant lab conditions. In the first stage of this study ("Tb-only group," 2012-2016), we verified high incidence (55%, n = 20) of arrhythmicity, with no consistent diurnal Tb rhythms in tuco-tucos maintained under semi-field conditions. Because these results were discrepant from subsequent findings using miniature accelerometers (portable activity loggers), which showed diurnal activity patterns in natural conditions (n = 10, "Activity-only group," 2016-2017), we also investigated, in the present study, whether the tight association between activity and Tb would be sustained outside the lab. To verify this, we measured activity and Tb simultaneously across laboratory and semi-field deploying both accelerometers and Tb loggers to each animal. These measurements (n = 11, "Tb + activity group," 2019-2022) confirmed diurnality of locomotor activity and revealed an unexpected loosening of the temporal association between Tb and activity rhythms in the field enclosures, which is otherwise robustly tight in the laboratory. (AU)

• FAPESP's process: 14/20671-0 - Chronobiology of South American subterranean rodents, in laboratory and field
• Grantee: Gisele Akemi Oda
• Support Opportunities: Regular Research Grants
• FAPESP's process: 16/25058-0 - Seasonality of daily surface activity patterns on a subterranean rodent, the tuco-tuco
• Grantee: Milene Gomes Jannetti
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 17/22973-1 - Investigation of seasonality and plasticity of daily activity patterns in a subterranean rodent (Ctenomys aff. knighti) using noninvasive methods of endocrine monitoring
• Grantee: Patricia Tachinardi Andrade Silva
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 12/23393-5 - Daily patterns of energy expenditure in the subterranean rodent Ctenomys aff. knighti, the tuco-tuco
• Grantee: Patricia Tachinardi Andrade Silva
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 14/09324-6 - Field and computer simulation studies on the chronobiology of subterranean rodents (Ctenomys aff knighti)
• Grantee: Milene Gomes Jannetti
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 17/19680-2 - Photoperiodism in South American subterranean rodents under field and laboratory conditions
• Grantee: Gisele Akemi Oda
• Support Opportunities: Regular Research Grants
• FAPESP's process: 19/26752-5 - Seasonality and photoperiodism in South American subterranean rodents under field and laboratory conditions
• Grantee: Gisele Akemi Oda
• Support Opportunities: Regular Research Grants