Carbon disulfide: a semiochemical mediating socially-induced diet choice in rats.

Gas chromatography/mass spectrometry revealed the presence of both carbon disulfide (CS2) and carbonyl sulfide (COS) on rat breath. Behavioral experiments indicated that rats exposed to an unfamiliar diet moistened with CS2, like rats exposed to an unfamiliar diet placed on the fur of an anesthetized rat, subsequently exhibited enhanced preference for the unfamiliar diet. Rats in experimental groups: (a) interacted for 30 min with a wad of cotton batting powdered with one of two unfamiliar foods (either Diet A or Diet B) and moistened with a dilute, aqueous CS2 solution, (b) ate Diets A and B in succession and finally, (c) were injected with LiCl. In a subsequent choice between Diets A and B, these rats exhibited a preference for whichever of the foods had been present on the cotton batting during (a). Rats in control groups were treated identically to those in experimental groups, except that the diet-coated cotton batting to which they were exposed was moistened with distilled water rather then CS2 solution. Rats in control groups were not affected in their later diet choice by the food present on the cotton batting during (a). These data are consistent with the hypothesis that CS2 is a semiochemical that mediates social influence on diet selection in rats.