Washington, Apr 24 : Insects that survive on leaves use the plants they occupy as 'green telephone lines' for communicating with other insects, says a Dutch ecologist
Roxina Soler and her colleagues have found that subterranean and aboveground herbivorous insects are able to communicate with each other by releasing chemical warning signals via the leaves of the plant, which in turn alerts aboveground insects that the plant is already 'occupied'.
Usually, aboveground, leaf-eating insects go for 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 allows spatially-separated insects to avoid each other, so that they do not unintentionally compete for the same plant.
It has recently been discovered that different types of aboveground insects tend to develop slowly if they feed on plants that also have subterranean residents and vice versa.
This indicates that a mechanism has developed through natural selection, which makes this detection between the subterranean and aboveground insects possible. This avoids unnecessary competition.
Using these 'green telephone lines', subterranean insects can also communicate with a third party, namely the natural enemy of caterpillars.
It is known that parasitic wasps lay their eggs inside aboveground insects. Even these wasps get benefited from the volatile signals emitted by the leaves, as these help them to know where to find a good host for their eggs.
As this communication between subterranean and aboveground insects has only been studied in a few systems, it's still unclear how widespread this phenomenon is.