Herbivory induces massive metabolic reconfigurations in plants.
Such changes mediate tissue repair, resource allocation and
defence. Induced plant-defences constitute an array of changes
decreasing the plant's palatability i.e. directly via toxins and
accumulation of proteins that interfere with herbivore digestion
but also indirectly via volatile signals that attract the
herbivore's natural enemy. However, because these defences
decrease herbivore fecundity and survival they impose selection
pressure on herbivores which in turn are sometimes selected to
increase their resistance, something which can only happen when
there is sufficient genetic variation. Indeed herbivore
resistance to plant defences, as to pesticides, occurs
frequently. However, recently convincing data emerged that some
herbivores do not become resistant to plant defence products
directly but, like some virulent pathogens, suppress host plant
defences. Since the ability to sabotage host plant defences was
discovered for several arthropod sp