A Perspective on the Consequences for Insect Herbivores and Their Natural Enemies When They Share Plant Resources

Abstract EN

Thousands of insect species consume both animal and plant-derived food resources.

However, little recognition is given to the fact that omnivory is a general feeding strategy common to all higher trophic levels.

Species in multitrophic interactions can all directly rely on the same plant resources.

Nonetheless, little is known about the effect of a change in the relative abundance of a shared plant resource on trophic dynamics.

Here we describe how a relative change of resource availability can affect multitrophic interactions and we emphasise its importance.

Changes in multitrophic interactions can be induced by unequal alterations of individual fitness across trophic levels, possibly leading to changes in population structure of interacting species.

At least ten ecological mechanisms can be involved and these are explored here.

It is concluded that shared plant resources that are differentially used over several trophic levels have the potential to modify community structure and energy flow within food webs and ecosystems in more complex ways than previously recognised.

The synthesis presented here provides an understanding of this complexity and can lead to improved deployment of biodiversity when manipulating food webs to protect ecological communities or to enhance ecosystem services such as biological control of agricultural pests.