Host functional and phylogenetic composition rather than host diversity structure plant-herbivore networks

Area of Science:

• Ecology
• Evolutionary Biology
• Conservation Biology

Background:

• Declining plant diversity disrupts ecological networks, particularly plant-herbivore interactions.
• Mechanisms linking plant species loss to altered network structure require further investigation.

Purpose of the Study:

• To investigate how tree species richness, functional diversity, phylogenetic diversity, and composition influence herbivore communities and plant-herbivore interaction networks.
• To determine the relative importance of different plant diversity facets in shaping herbivore communities.

Main Methods:

• Utilized DNA barcoding to identify herbivore-host plant associations in a subtropical biodiversity experiment with varying tree diversity.
• Assessed effects of tree species richness, host functional traits (leaf traits), and phylogenetic composition on herbivore species, phylogenetic, and network composition.

Main Results:

• Phylogenetic host composition and associated palatability/defense traits significantly influenced herbivore communities and interaction network complexity.
• Tree species richness alone did not significantly affect herbivore communities or network structure.
• Effects were observed at both species and community levels of herbivore organization.

Conclusions:

• Evolutionary dependencies and functional traits of host plants are critical drivers of higher trophic level composition and interaction networks in diverse ecosystems.
• The characteristics of lost plant species, beyond mere species number, are crucial for predicting ecosystem structure and function across trophic levels.