Data from: African elephant dietary responses to odors of monoterpene mixtures and individual monoterpenes

The detoxification limitation hypothesis posits that, unless plant defense
compounds interact synergistically or additively to increase their harmful
effects, generalist herbivores will prefer consuming combinations of these
compounds over singular compounds. Monoterpenes are odoriferous defense
compounds that may be toxic to mammalian herbivores when ingested in
sufficient quantities. Previous research has shown that the addition of
individual monoterpenes to food sources reduces consumption by generalist
mammalian herbivores. By using African elephants as a case study, we aimed
to determine whether odors from monoterpene combinations (i.e., two or
more monoterpenes) also deter generalist mammalian herbivory, and whether
generalist herbivores prefer the odors of monoterpene combinations over
individual monoterpenes. First, we tested whether the odor of monoterpene
combinations that resemble the monoterpene profiles of a
high-acceptability, intermediate-acceptability, and low-acceptability
plant deter herbivory. We found that elephants preferred plants without
the added odors of the monoterpene combinations. Second, we explored how
elephants responded to individual monoterpenes found within the
combinations compared to the combinations at the same set concentration,
and found that the elephants did not always prefer the combinations over
the individual monoterpenes. Moreover, the more diverse the combination,
the less frequently it was preferred when compared to the individual
monoterpene odors. Our results imply that generalist herbivores do not
necessarily prefer combinations of plant chemical defenses at
comparatively lower concentrations and that, consequently, the composition
and diversity of monoterpene profiles in plants likely determine the
efficacy of these compounds as an olfactory defense against mammalian
herbivory.