Plant-Insect Interactions in a Changing World

Global change is resetting the spatial and ecological equilibrium of complex coevolutionary
relationships between plants and their insect herbivores. We review the
mechanisms at play in the responses of planteinsect interactions to global changes,
including increased temperature and atmospheric CO2 concentrations, modification
of land use and pollution. We distinguish between the direct effects of global changes
on each partner from the indirect impacts on insects via the responses of plants. The
indirect effects include a change in the nutritional quality of the plant tissues for
herbivore insects, as well as a change in the microclimatic conditions at the leaf surface.
Pollinators are involved in a close symbiotic relationship with their favourite plants, and
any depression caused by climate stress can lead to pollination deficit. Pollinators are,
indeed, quite sensitive to global changes. Furthermore, although species are connected
by trophic links, all species respond differently to global changes. We highlight that
more research is needed to elucidate the plant-mediated indirect effects of climate
change on insects. Then, other human activities, such as land transformations and
release of pollutants, are likely to modulate these links between climate and plante
insect relationships. We argue that predicting the net effect of global change on
planteinsect relationships requires a comprehensive understanding of the
mechanisms that modulate the interaction strength between the plants and the
insects, rather than on focusing on each partner individually.
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