Geographic and seasonal variability in feeding behaviour of a small herbivorous rodent

Abstract

Foraging strategies have traditionally been modelled as a result of food selection in response to one factor, as for instance resource availability, deterrent compounds or nutrients. Thus, a trade-off is assumed between plasticity (generalist strategy) and efficiency (specialist strategy). Nevertheless, several studies have demonstrated that animals cope behaviourally with food supply variation. For instance, desertdwelling rodents partially compensate for nutritional bottlenecks through diet selection. The aim of our study was to test how foraging behaviour matches spatial and temporal variations in the trophic environment and how modelling hypotheses help us to understand the resultant foraging strategy. Our animal study model was the small cavy Microcavia australis, a widely distributed herbivorous rodent. Fieldwork was carried out in four places, in wet and dry seasons. We found significant differences in plant cover, plant diversity and niche breadth, and diet selection revealed a complex foraging strategy. M. australis shows a behavioural repertoire that exceeds single-criterion categories; therefore, we appeal to theoretical models that consider ecological and physiological perspectives. We classified the small cavy as a facultative specialist displaying a thoroughly opportunistic strategy based on the plasticity of the behavioural phenotype. We finally discuss the evolutionary relevance of our results and propose further investigation avenues.

Feeding strategies of a small mammal (Phyllotis xanthopygus, Rodentia Cricetidae) at diverse altitudes in the Central Andes, Argentina

“…Standardised means and standard errors for stomach, small intestine, caecum, colon and total gastrointestinal tract are detailed in Table 3. DISCUSSION In order to maintain their energy and nutritional balance, animals cope with variations in the trophic scenario through behavioural and physiological adjustments that translate into their dietary choices (Sherry 1990;Chambers et al 1995;Kyriazakis et al 1999;Sassi et al 2011). Furthermore, all this occurs under temperature and other climatic factors that impose diverse energy demands and restrictions to the foraging behaviour (Caraco et al 1990;Murray & Smith 2012).…”

Costs of exploratory behavior: the energy trade-off hypothesis and the allocation model tested under caloric restriction

“…In fact, many studies indicate that laboratory rodents (rats and mice) show an increase in their activity under food deprivation, which is proportional to the severity of food restriction 64 . Because animals often face nutritional bottlenecks 65,66 , it is not surprising that under these circumstances, the physiological and behavioral adjustments observed in the current study could occur in wild life.…”

High genetic differentiation among populations of the small cavy Microcavia australis occupying different habitats

“…Sassi et al (2007, 2010) demonstrated significant variations in morphological and physiological digestive traits, with large gastrointestinal chambers in cavies from El Leoncito and Matagusanos, which are exposed to comparatively low quality diets compared with animals from Villavicencio and Ñacuñán. Foraging behavior also changed thoroughly among the cited populations, and particular items were dominant in the different sites: mesquite forest in Matagusanos and Ñacuñan diets and creosotebush in El Leoncito and Villavicencio diets (Sassi et al, 2011). The latter result is especially interesting because it has been demonstrated that the phenolic resin of creosotebush affects negatively other rodent species (Dearing et al, 2001; Mangione et al, 2004).…”