Eco-evolutionary Factors Driving Plant-Mediated Above–Belowground Invertebrate Interactions along Elevation Gradients

Plant-mediated aboveground (AG)–belowground (BG) interactions have received increasing interest over the past two decades. Despite several conceptual models to unravel AG–BG outcomes on plant-associated invertebrate communities, further efforts are required to apprehend eco-evolutionary factors driving such interactions. We here conducted an extensive literature review of the current knowledge about AG–BG interactions at the community level. We particularly highlighted the current shifts in AG–BG research towards a multi-trophic context, and we stressed the importance to consider these interactions under fluctuating environments. After presenting the main mechanisms involved in AG–BG plant-mediated effects on insect and nematode herbivore communities, we model how AG–BG interactions could be affected by environmental variations. We next develop a conceptual framework for predicting how the strength of AG–BG interactions could vary along steep elevation gradients. We suggest that the strengths of these interactions should be strongest at mid-range, where both the simultaneous AG–BG herbivore pressures and systemic defence induction should be strongest. Future tests of such model will allow disentangling the interactive effects of biotic and abiotic factors driving the ecology and evolution of AG–BG interactions.