Herbivore-induced plant volatiles accurately predict history of coexistence, diet breadth, and feeding mode of herbivores

Authors: DANNER, HOLGER - Radboud University; DESURMONT, GAYLORD - European Biological Control Laboratory (EBCL); CRISTESCU, SIMONA - Radboud University; VAN DAM, NICOLE - Radboud University

Submitted to: New Phytologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/4/2016
Publication Date: 1/20/2017
Citation: Danner, H., Desurmont, G.A., Cristescu, S.M., Van Dam, N.M. 2017. Herbivore-induced plant volatiles accurately predict history of coexistence, diet breadth, and feeding mode of herbivores. New Phytologist. 220(3):726-738. 10.1111/nph.14428.
DOI: https://doi.org/10.1111/nph.14428

Interpretive Summary: Natural enemies (insect parasites and predators) can provide sustainable, cost-effective control of important plant pests without the use of pesticides. When attacked by insect pests, plants release a variety of odors in the atmosphere, which often are used by natural enemies to help them find and attack the insect pests. However, little is known about what happens when a plant is attacked by multiple species of insect pests. We wanted to know if there were different odor patterns based on whether the insects were native vs. alien, leaf-chewing vs. sap-sucking, or host plant generalist vs. specialist. We analyzed the odors emitted by mustard plants (Brassica rapa) that were exposed to 10 different species of insect pests, including caterpillars, bugs, wasps and slugs. The results showed that different patterns of odors were released by mustard plants depending on 1) host specificity of the insects, 2) their method of feeding, and 3) whether they are native or exotic. This discovery could be applied to pest management in many ways, for example to help reconstruct the history of coexistence between plants and certain invasive species of insects.

Technical Abstract: Herbivore induced plant volatiles (HIPVs) serve as specific cues to higher trophic levels. Novel, exotic herbivores entering foodwebs with a common co-existence history may disrupt the native infochemical network due to changes in HIPV profiles. Here we analyzed HIPV blends of native Brassica rapa plants infested with either one of 10 herbivore species with different co-existence histories, diet breadths and feeding modes. Partial least squares (PLS) models were fitted to assess whether HIPV blends emitted by Dutch Brassica rapa differ between native and exotic herbivores, specialists and generalists, and between herbivores with different feeding modes. These models were used to predict the status of two additional herbivores. We found that HIPV blends predict the evolutionary history, diet breadth and feeding mode of the herbivore with an accuracy of 80 percent or higher. Based on the HIPVs, the PLS models reliably predicted that Trichoplusia ni and Spodoptera exigua are perceived as exotic, leaf chewing generalists by Dutch B. rapa plants. These results indicate that there are consistent and predictable differences in HIPV blends depending on global herbivore characteristics, including co-existence history.