Ant predation on herbivores through a multitrophic lens: how effects of ants on plant herbivore defense and natural enemies vary along temperature gradients

•Ants are one of the most effective defenses of plants against herbivores.•As elevation increases and ants become rare, what happens to plants?.•Four hypotheses of how plants adapt to ants being rare are proposed.•New and traditional methods should be used to study multitrophic interactions across elevation.•Distribution models must include effects of species interactions at a landscape level.

Ants are keystone predators in terrestrial trophic cascades. Addressing ants’ roles in multitrophic interactions across regional gradients is important for understanding mechanisms behind range limits of species. We present four hypotheses of trophic dynamics occurring when ants are rare: first, there is a shift in predator communities; second, plants decrease investments in ant attraction and increase production of secondary metabolites; third, lower herbivory at high elevations allows plants to tolerate herbivory; and fourth, distribution of ant–plants can be limited based on ant abundance. Conducting experiments on multitrophic effects of ants across elevational gradients, and incorporating these results to ecological niche modeling (ENM) will improve our knowledge of the impacts of global change on ants, trophic interactions, and biodiversity.