Water balance of Graomys griseoflavus (2n=37)

POL R; POL R., RODRÍGUEZ N., ALMEIDA C. CAVIDES VIDAL, CAVIEDES CODELIA; ALMEIDA C; CAVIDES VIDAL; CAVIEDES CODELIA

Mendoza, Argentina

Congreso; XVII Reunión Científica Anual; 1999

Sociedad de Biología de Cuyo

G. griseoflavus is a rodent with a wide geographical distribution in Argentina, including areas with extreme climatic condition (i.e. annual rainfall < 300 mm, seasonal temperature range >40ºC). Water balance is a challenger for survival in these harsh environments. Water intake and balance was assessed in G. griseoflavus(2n=37). Six adult individuals with a body mass of 62.08 ± 4.33 g captured in the Desierto del Monte (32º 43´S, 66º 45´ W, San Luis, Argentina) were used. They were kept at 21 ± 2ºC, a photoperiod of 12:12 and ad libitum food consumption (Fi), water intake (Wi), urine production (OR), Feces production (Mf), and body mass changes during the trial period (∆BM) were mesured. Means ± sem were: Fi 0.10 ± 0.003 g food g-1 day-1, Wi 0.068 ± 0.004 g water g-1 day-1, Mf 0.019 ± 0.001 g feces g-1 day-1, OR 0.027 ± 0.010 g urine g-1 day-1, ∆BM  -1.62 ± 1.08 %. The apparent coefficient of mass assimilation (AMC*) was 0.85 ± 0.01. Thus, G. griseoflavus (2n=37) Wi was al least 25.8 % lower than that of other desertdwelling sigmodontine rodents, and supports the hypotheses of a water economical adaption to xeric environments.