Native plant diversity increases herbivory to non-natives

Area of Science:

• Ecology
• Plant-insect interactions
• Invasive species biology

Background:

• Plant community diversity often inversely correlates with susceptibility to invasive species.
• Native herbivores may influence this diversity-invasibility relationship by impacting non-native plants.

Purpose of the Study:

• To investigate the role of native herbivores in the diversity-invasibility relationship of non-native oak trees.
• To determine if native herbivores preferentially attack non-native plants based on relatedness to native species.

Main Methods:

• Assessed leaf damage on non-native oak collections across the USA.
• Correlated leaf damage with local native oak species richness.
• Examined the phylogenetic relatedness between non-native and native oak species.

Main Results:

• Non-native oaks in areas with higher native oak diversity experienced greater leaf damage.
• Herbivore damage was higher when non-native oaks were more closely related to native host plants.
• Native herbivores successfully colonized and damaged non-native plants phylogenetically similar to native hosts.

Conclusions:

• Native insect herbivores contribute to limiting non-native plant success in diverse communities.
• Phylogenetic relatedness between native and non-native plants is a key factor in herbivore colonization.
• Increased native plant diversity can enhance herbivory on related non-native species.