"Dutch ecologist Roxina Soler and her colleagues from the Netherlands Institute for Ecology have discovered that subterranean and aboveground herbivorous insects can communicate with each other by using plants as telephones.
'Subterranean insects issue chemical warning signals via the leaves of the plant. This way, aboveground insects are alerted that the plant is already 'occupied’.
Aboveground, leaf-eating insects prefer plants that have not yet been occupied by subterranean root-eating insects. Subterranean insects emit chemical signals via the leaves of the plant, which warn the aboveground insects about their presence. This messaging enables spatially-separated insects to avoid each other, so that they do not unintentionally compete for the same plant.
... The communication between subterranean and aboveground insects has only been studied in a few systems. It is still not clear how widespread this phenomenon is.'"