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

Abstract

Puig S., Rosi M. I., Cona M. I., Roig V. G. and Monge S. A. 1999. Diet of a Piedmont population of Ctenomys mendocinus (Rodentia, Ctenomyidae): seasonal patterns and variations according sex and relative age. Acta Theriologica 44: 15-27.Dietary composition was determined seasonally in males and females of Ctenomys mendocinus Philippi, 1869 from the Andean Piedmont (Mendoza, Argentina) during the reproductive and non-reproductive period. Reproductive condition and relative age of each animal was determined. Stomach contents were individually analyzed with the microhistological technique. Dietary generalism is supported by the high proportion of available genera eaten, but the intensity and continuity of use suggested specialization on grasses. Predation risk induces minimization of the exposure time out of the burrow, and could justify the specialization in grasses, considering that other 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 in spring. Since males have been found to dig longer burrow systems than females in winter, searching for mates might cause males to intersect a higher number of food items during that season. Higher energetic and nutritional requirements associated with pregnancy and nursing may lead to the inclusion of more food items in the spring diet of females, and their higher specialization on grasses. Dietary similarities between immature and mature individuals suggested that age did not affect selection of diet items. Seasonal variation in dietary diversity suggested a foraging strategy adaptive to environmental seasonal variations and to the subterranean life style.

DNA metabarcoding diet analysis for species with parapatric vs sympatric distribution: a case study on subterranean rodents

“…C. mendocinus lives in Midwestern Argentina. Although this species has generalist habits, a preference for some food items was observed, mainly represented by above-ground parts of grasses, even in populations inhabiting environments with low food availability and harsh climatic conditions (Puig et al, 1999;Rosi et al, 2003). C. eremophilus has generalist behavior with a preference on aerial vegetative part of grasses, but in grazed paddocks their diet showed lower percentage of grasses and higher dietary diversities compared with ungrazed paddocks, which was associated with the competition for grasses with cattle (Rosi et al, 2009).…”

“…Distinct foraging strategies between males and females were described in rodents, and were mainly associated to differences in nutritional requirements during the growth and reproduction stages (Puig et al, 1999). The microhistological analysis of the diet of C. mendocinus demonstrated that males have a more varied diet in winter, attributed to changes in the behavior during the beginning of the reproductive season, while females showed a higher specialization on grasses in spring, probably associated to the high energetic costs of pregnancy and lactation occurring during this period of the year (Puig et al, 1999).…”

“…C. talarum and C. australis are also generalists but prefer the aerial vegetative part of grasses over forbs throughout the year (Comparatore et al, 1995). Selective behaviors observed in ctenomyids have also been associated with specific nutritional requirements during the reproductive season, the time spent harvesting and handling the plants and the balance between the quality of the food to supply the energy, protein and fiber requirements vs the quantity of secondary components and plant defenses, which can influence their palatability and digestibility (Comparatore et al, 1995;Puig et al, 1999;Martino et al, 2007).…”

“…However, to avoid competition in the sympatric distribution, it would not be surprising that C. minutus and/or C. flamarioni would present at least some degree of food specialization, or microhabitat differences, unless there is enough food and space in the overlapping area. Moreover, rodent males and females can show distinct foraging strategies associated with differences in nutritional requirements during the growth and reproduction stages (Puig et al, 1999). To better understand how C. minutus and C. flamarioni can co-occur in the same habitat, and the level of possible competition for Figure 1 Geographic distribution of C. minutus and C. flamarioni in the southern Brazilian coastal plain.…”

Architecture of Ctenomys mendocinus (Rodentia) burrows from two habitats differing in abundance and complexity of vegetation

“…A lower food availability for C. mendocinus would be expected in environments with lower plant abundance and complexity, taking into account that this rodent has been identified as a generalist herbivore in other environment of the Andean Piedmont (Madoery 1993, Puig et al 1999. These researches revealed that this rodent diet included most plant categories presented (grasses, forbs, succulents and shrubs).…”