Effect of Nutrient Restriction on Social Transmission of Food Preferences Depends on Nutrient and Species

Abstract

For omnivores to determine whether an unfamiliar item is an appropriate food, they could rely on personal information from sampling it themselves or rely on less risky observation of whether other individuals eat the item. Availability of information about food from social companions in group-living species is one of the benefits of group life. Adults of solitary-living species, however, seem typically less likely to rely on social information about food choice. If an individual faced a nutritional deficit, it would seem to increase the value of public information. This study addresses whether dietary restriction from certain nutrients (sodium, potassium, protein, carbohydrates) affects reliance on information about food from conspecifics. Without nutrient restriction, group-living Norway rats ( Rattus norvegicus ) preferred the diet that they smelled on the breath of a conspecific demonstrator, but solitary-living Syrian hamsters ( Mesocricetus auratus ) avoided it. Protein restriction yielded similar results as measured one hour into a diet choice test. Potassium restriction, however, reversed the pattern: rats avoided the demonstrator’s diet but hamsters preferred it. Clearly, the valence of social information depended on the nutrient from which individuals were restricted and the species under study. This could be related to the contrasting social organization that members of each species generate. Neither species relied on social information about the availability of a nutrient from which they were restricted if they could taste that nutrient for themselves (sodium, carbohydrates).