Journal of Chemical Ecology (2007) 33, 997-1012

Casey M. Delphia, Mark C. Mescher and Consuelo M. De Moraes (2007)
Induction of plant volatiles by herbivores with different feeding habits and the effects of induced defenses on host-plant selection by thrips
Journal of Chemical Ecology 33 (5), 997-1012
Abstract: Induced plant responses to attack by chewing insects have been intensively studied, but little is known about plant responses to nonchewing insects or to attack by multiple herbivores with different feeding habits. We examined volatile emissions by tobacco, Nicotiana tabacum, in response to feeding by the piercing-sucking insect western flower thrips (WFT), Frankliniella occidentalis, the chewing herbivore Heliothis virescens, and both herbivores simultaneously. In addition, we examined the effects of herbivore-induced plant defenses on host-plant selection by WFT. Plants responded to thrips feeding by consistently releasing five compounds. Simultaneous feeding by WFT and H. virescens elicited the same 11 compounds emitted in response to caterpillar feeding alone; however, two compounds, alpha-humulene and caryophyllene oxide, were produced in greater amounts in response to simultaneous herbivory. In choice tests, thrips consistently preferred uninduced plants over all other treatments and preferred plants damaged by caterpillars and those treated with caterpillar saliva over those treated with caterpillar regurgitant. The results are consistent with a previous finding that caterpillar regurgitant induces the release of significantly more volatile nicotine than plants damaged by caterpillars or plants treated with caterpillar saliva. A repellent effect of nicotine on WFT was confirmed by encircling unwounded plants with septa releasing volatile nicotine. Our results provide the first direct evidence that thrips feeding induces volatile responses and indicates that simultaneous herbivory by insects with different feeding habits can alter volatile emissions. In addition, the findings demonstrate that induced plant responses influence host-plant selection by WFT and suggest that the induction of volatile nicotine may play a role in this process.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Consuelo M. De Moraes, Mark C. Mescher

Research topic(s) for pests/diseases/weeds:
environment - cropping system/rotation
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Heliothis virescens	Tobacco (Nicotiana tabacum)
	Frankliniella occidentalis	Tobacco (Nicotiana tabacum)