The role of volatile plant secondary metabolites as pre-ingestive cues and potential toxins dictating diet selection by African elephants

Understanding the factors driving diet selection represents one of the main thrusts of contemporary foraging ecology. Many studies have focussed on nutritional factors and anti-nutritional factors (such as tannins) that may describe diet selection of generalist mammalian herbivores, but these often do not explain the observed feeding patterns. Alternatively, generalist herbivores may be influenced by the presence, diversity, and/or concentration of toxins. Plant volatiles have been understudied, yet may play an important role in this context. We aimed to determine whether diet selection by African elephants is better correlated with the presence and concentration of toxic plant secondary metabolites (PSMs) than with nutritional or anti-nutritional factors. We also aimed to identify the specific aspects of the plant-odour profiles that were correlated with dietary selection, which could be used as a pre-ingestive cue for food selection. We found that elephant diet selection was not well ...