Diet of a Piedmont population of Ctenomys mendocinus (Rodentia, Ctenomyidae): seasonal patterns and variations according sex and relative age

SILVIA PUIG; MARIA ROSI; MONICA CONA; VIRGILIO ROIG

ACTA THERIOLOGICA

POLISH ACAD SCIENCES

Lugar: Bialowieza; Año: 1999

0001-7051

Dietary composition was determined seasonally in males and females of Ctenomysmendocinus Philippi, 1869 from the Andean Piedmont (Mendoza, Argentina) duringthe reproductive and non-reproductive period. Reproductive condition and relative ageof each animal was determined. Stomach contents were individually analyzed withthe microhistological technique. Dietary generalism is supported by the high propor-tion of available genera eaten, but the intensity and continuity of use suggestedspecialization on grasses. Predation risk induces minimization of the exposure timeout of the burrow, and could justify the specialization in grasses, considering thatother rodents showed lower harvest and handling times for grasses than for shrubs.Males had a more varied diet than females in winter, and the opposite occurred inspring. Since males have been found to dig longer burrow systems than females inwinter, searching for mates might cause males to intersect a higher number of fooditems during that season. Higher energetic and nutritional requirements associatedwith pregnancy and nursing may lead to the inclusion of more food items in the springdiet of females, and their higher specialization on grasses. Dietary similarities betweenimmature and mature individuals suggested that age did not affect selection of dietitems. Seasonal variation in dietary diversity suggested a foraging strategy adaptiveto environmental seasonal variations and to the subterranean life style.