Seasonal patterns and influence of temperature on the daily activity of the diurnal neotropical rodent Necromys lasiurus

• Published in: Canadian journal of zoology Vol. 88; no. 3; pp. 259 - 265
• Main Authors: Vieira, E. M, Baumgarten, L. C, Paise, G, Becker, R. G
• Format: Journal Article
• Language: English
• Published: Ottawa National Research Council of Canada 01.03.2010; NRC Research Press; Canadian Science Publishing NRC Research Press
• Subjects: Ambient temperature; Animal and plant ecology; Animal ecology; Animal, plant and microbial ecology; Animals; Autoecology; Behavior; Biological and medical sciences; Dry season; Fundamental and applied biological sciences. Psychology; Gender differences; Grasslands; High temperature; Lasiurus; Mammalia; Rainy season; Relative humidity; Rodents; Seasons; Temperature; Vegetation; Vertebrata; South America; Brazil; America; Canada; Vertebrata; Diurnal animal; Temperature; Mammalia; Animal activity; Seasonal variation; Rodentia; Environmental factor; Neotropical Region
• ISSN: 0008-4301; 1480-3283; 1480-3283; 0008-4301
• DOI: 10.1139/Z09-142

We investigated the relation between temperature and diel activity patterns of Necromys lasiurus (Lund, 1841) in 10 sites of open vegetation (grassland fields) in the Cerrado (savanna-like vegetation) of central Brazil. We used live traps equipped with timing devices during two trapping sessions: in the end of the dry season (session 1, October 2001) and in the wet season (session 2, January-February 2002). Necromys lasiurus is basically a diurnal rodent with more pronounced crepuscular and nocturnal activity in the dry season than in the wet season. Only in the wet season did we detect significant between-gender differences, with males being less active than females in the first hours after sunrise but more active between 0900 and 1200. There was no significant activity-temperature relation in the dry season, but in the wet season, both genders showed a positive relation between ambient temperature and activity. Individuals might be avoiding hot midday hours in the end of the dry season to minimize time exposure to a physiologically stressful condition caused by the joint action of high temperatures and extremely low relative humidity (<15%). In the rainy season, the high relative humidity (80%-90%) might allow the animals to show a positive relation between activity and ambient temperature.