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.

This dataset comprises the binary data that was obtained from odor-based choice experiments done with 5 semi-tame adult African elephants.

The first experiment's set of choices consisted of a bucket containing a food reward with no odour (i.e., dipropylene glycol) and a bucket containing a food reward with the odour of a monoterpene mixture. The second experiment's set of choices consisted of a bucket containing the odour of a monoterpene mixture and a bucket containing the odour of an individual monoterpene.

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