title: Ozone degrades common herbivore-induced plant volatiles: does this affect herbivore prey location by predators and parasitoids?
abstract: Inducible terpenes and lipoxygenase pathway products, e.g., green-leaf volatiles (GLVs), are emitted by plants in response to herbivory. They are used by carnivorous arthropods to locate prey. These compounds are highly reactive with atmospheric pollutants. We hypothesized that elevated ozone (O(3)) may affect chemical communication between plants and natural enemies of herbivores by degrading signal compounds. In this study, we have used two tritrophic systems (Brassica oleracea-Plutella xylostella-Cotesia plutellae and Phaseolus lunatus-Tetranychus urticae-Phytoseiulus persimilis) to show that exposure of plants to moderately enhanced atmospheric O(3) levels (60 and 120 nl l(-1)) results in complete degradation of most herbivore-induced terpenes and GLVs, which is congruent with our hypothesis. However, orientation behavior of natural enemies was not disrupted by O(3) exposure in either tritrophic system. Other herbivore-induced volatiles, such as benzyl cyanide, a nitrile in cabbage, and methyl salicylate in lima bean, were not significantly reduced in reactions with O(3). We suggest that more atmospherically stable herbivore-induced volatile compounds can provide important long-distance plant-carnivore signals and may be used by natural enemies of herbivores to orientate in O(3)-polluted environments.
authors.affiliation: Department of Environmental Science, University of Kuopio, P.O. Box 1627, 70211, Kuopio, Finland. Delia.Pinto@uku.fi
authors.forename: Delia M
authors.initials: DM
authors.lastname: Pinto
authors.forename: James D
authors.initials: JD
authors.lastname: Blande
authors.forename: Riikka
authors.initials: R
authors.lastname: Nykänen
authors.forename: Wen-Xia
authors.initials: WX
authors.lastname: Dong
authors.forename: Anne-Marja
authors.initials: AM
authors.lastname: Nerg
authors.forename: Jarmo K
authors.initials: JK
authors.lastname: Holopainen
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D005260:Female; D007313:Insecta / Q000502:physiology; D010126:Ozone / Q000737:chemistry*; D010944:Plants / Q000737:chemistry / Q000378:metabolism*; D011235:Predatory Behavior; D014835:Volatilization
chemical_list: D010126:Ozone