plant-herbivore interactions; plant volatiles; insect invasions; Brassica rapa; BVOCs; natural enemies; parasitoids
Desurmont Gaylord A., Xu Hao, Turlings Ted C. J. (2016), Powdery mildew suppresses herbivore-induced plant volatiles and interferes with parasitoid attraction in Brassica rapaA plant pathogen affects infochemical networks, in Plant, Cell & Environment
, 39(9), 1920-1927.
Desurmont Gaylord A., Zemanova Miriam A., Turlings Ted C. J. (2016), The Gastropod Menace: Slugs on Brassica Plants Affect Caterpillar Survival through Consumption and Interference with Parasitoid Attraction, in Journal of Chemical Ecology
, 42(3), 183-192.
Chabaane Yosra, Laplanche Diane, Turlings Ted C. J., Desurmont Gaylord A. (2015), Impact of exotic insect herbivores on native tritrophic interactions: a case study of the African cotton leafworm, Spodoptera littoralis and insects associated with the field mustard Brassica rapa, in Journal of Ecology
, 103(1), 109-117.
Desurmont G. A., Harvey J., van Dam N. M., Cristescu S., Schiestl F. P., Cozzolino S., Anderson P., Larsson M. C., Kindlmann P., Danner H., Turlings T. C. J. (2014), Alien interference: Disruption of infochemical networks by invasive insect herbivores., in Plant, Cell & the Environment
, 37(8), 1854-1865.
Desurmont Gaylord A., Pearse Ian S. (2014), Alien plants versus alien herbivores: does it matter who is non-native in a novel trophic interaction?, in Current Opinion in Insect Science
, 2, 20-25.
Schiestl F., Kirk H., Bigler L., Cozzolino S., Desurmont G. A. (2014), Herbivory and floral signalling: phenotypic plasticity and trade-offs between reproduction and indirect defence., in New Phytologist
, 203(1), 257-266.
Desurmont Gaylord A., Laplanche Diane, Schiestl Florian P., Turlings Ted C. J., Floral volatiles interfere with plant attraction of parasitoids: ontogeny-dependent infochemicals dynamics in Brassica rapa, in BMC Ecology
In the proposed project we join forces to determine how invading insects affect and disrupt the evolved communicative infochemical networks in native plant-insect communities. We will test our hypothesis with the use of two extremely polyphagous herbivores that have high potential to invade European natural and agro-ecosystems: the Egyptian cotton leafworm Spodoptera littoralis (Lepidoptera: Noctuidae) and the banded cucumber beetle Diabrotica balteata (Coleoptera: Chrysomelidae). The larvae of the former feed on the leaves and reproductive tissues of plants of at least 40 families, whereas the larvae of the latter are root feeders and have also been recorded on numerous different plant species, such as maize, beans, cotton and various cabbage species. These two major pests of crops in more tropical regions of the world have a high probability to be introduced into Europe as a result of human activity. The only current obstacle is the colder European climate, which does not yet allow them to survive the winters. This could rapidly change if the increase in average annual temperature continues.As plant model systems, we will largely focus on Brassica rapa and Silene latifolia. These plants are known to emit a range of different BVOCs, both from leaves and flowers. Among the BVOCs emitted by Brassica sp. flowers are the aromatics phenylacetaldehyde, 2-phenylethanol, benzaldehyde, a range of monoterpenes and sesquiterpenes as well as isothiocyanate28. Silene is characterized by the aromatics veratrole, phenylacetaldehyde, as well as the lilac aldehydes (monoterpenes)29. Brassica plants emit over one hundred volatiles after damage by Pieris caterpillars. These included green leaf volatiles, alcohols, and esters, as well as glucosinolate breakdown products such as isothiocyanates and nitriles30,31. In preliminary experiments we have found also considerable increase in the quantity and quantity of the BVOCs emitted by S. latifolia after caterpillar attack.We will study how the larval stages of both herbivores affect the volatile emissions of the native plants and how possible changes in the emissions affect attraction of local parasitoids and pollinators. We will also specifically study the responses of natural enemies that may follow the invading herbivores into the new habitats in order to determine how readily these “followers” adapt to novel odor cues. For S. littoralis we will also study the role of VOCs in neuro-physiological and genetic aspects of the host selection process and, using European wild and cultivated plants, we will determine how readily they will adopt novel host plants. Finally, we aim to assess the ecological and evolutionary consequences of the changes in BVOCs and insect behavior in field studies. The results of our studies will be used to provide parameter values for dynamic models that predict the ecological impact of the interference of invading insects in the native infochemical networks. Hence, the project will optimally exploit the expertise of the consortium to eventually make predictions about the indirect effects of invading insects on native plant-insect interactions. With the studies we aim to answer the following questions:1)What BVOVs are emitted by native plants in response to herbivory by invading insects and how different are these emissions from those induced by native shoot and root herbivores?2)How do native parasitoids and pollinators respond to novel volatile emissions and do the emissions interfere with the successful location of respectively, suitable hosts and flowers?3)How readily can parasitoids and pollinators adapt their responses at the individual level (associative learning) and over evolutionary time (local adaptation)?4)What are the ecological and evolutionary consequences of these changes in the infochemical web for plant gene flow, and the multitrophic foodweb associated with plants?The results of our studies will be used to provide parameter values for dynamic models that predict the consequences of interference of invading insects in the native infochemical networks. Hence, the project will optimally exploit the expertise at hand to eventually make predictions about the indirect effects of invading insects on native plant-insect interactions.