Oak bodyguards

Scientific context

Oaks are among the European tree species associated with the greatest diversity of insects herbivores. Consequences of defoliation can simply consist in growth loss, but massive and repeated defoliations can result in tree mortality.

Oaks are not defenceless: they produce repulsive or toxic molecules in their leaves. They also receive help from firends. Herbivorous insects are on the menu of many predators: birds, carnivorous insects, spiders and mammals. Oaks are therefore protected by the enemies of their enemies, it is what we call a trophic cascade.

Scientists have recently shown that herbivores cause less damage to oaks as one moves from southern to northern Europe. By studying the chemical composition of the oak leaves, they found that this could be explained by oaks being more defended in colder regions. But what about herbivores' enemies? Are they less effective in warmer regions or do they compensate for oaks lower investment into defenses? This is what we want to test in this project.

Experimental protocols

Further information