Abstract:
African savanna elephants use pre-ingestive olfactory cues when making dietary choices, and previous research has observed
that elephant diet choice is negatively correlated with vegetation species that contain high concentrations of monoterpenes.
However, the frequency and concentration of monoterpenes can vary dramatically across plant species. Thus, we aimed to
explore the efects that the odours of individual monoterpenes have on elephant diet choice and how these efects vary with
concentration. To do this, we conducted three odour-based choice experiments focusing on eight common monoterpenes
found in the woody plants in Southern African savannas. In the frst experiment, we tested whether elephant diet choice for
a frequently consumed plant (Euclea crispa) was infuenced by the addition of the odour of an individual monoterpene at a
set concentration. In the second experiment, we explored the relative deterrence of each monoterpene. Lastly, we tested how
elephant diet choice varied as a function of the addition of individual monoterpene odours at 5%, 10%, and 20% concentrations. We found that the elephants avoided most individual monoterpenes at high concentrations, with the exception being
α-pinene. Furthermore, we found that the odours of some individual monoterpenes were, in fact, more deterrent than others. In the third experiment, we found that the elephants avoided β-pinene, limonene, ocimene, γ-terpinene, and terpinolene
across all concentrations, but only avoided sabinene and linalool at high concentrations. Ultimately, our results show that
the odour of individual monoterpenes may deter elephant consumption, but that this deterrent efect depends on both the
monoterpene and its concentration.
