Plant-mediated 'apparent effects' between mycorrhiza and insect herbivores

Plants mediate indirect ‘apparent’ effects between aboveground
herbivores and below-ground mutualistic mycorrhizal
fungi. The herbivore–plant–mycorrhiza continuum is further
complicated because signals produced by plants in response
to herbivores can be transmitted to other plants via shared
fungal networks below ground. Insect herbivores, such as
aphids, probably affect the functioning of mycorrhizal fungi by
changing the supply of recent photosynthate from plants to
mycorrhizas, whereas there is evidence that mycorrhizas affect
aphid fitness by changing plant signalling pathways, rather than
only through improved nutrition. New knowledge of the transfer
of signals through fungal networks between plant species
means we now need a better understanding of how this
process occurs in relation to the feeding preferences of
herbivores to shape plant community composition and
herbivore behaviour in nature.