Variation In Plant Volatiles and Attraction Of The ParasitoidDiadegma semiclausum(Hellén)

Abstract

Abstract-Differences in allelochemistry of plants may influence their ability to attract parasitoids. We studied responses of Diadegma semiclausum (Hellén), a parasitoid of the diamondback moth (Plutella xylostella L.), to inter-and intraspecific variation in odor blends of crucifers and a non-crucifer species. Uninfested Brussels sprout (Brassica oleracea L. gemmifera), white mustard (Sinapis alba L.), a feral Brassica oleracea, and malting barley (Hordeum vulgare L.) were compared for their attractivity to D. semiclausum in a Y-tube bioassay. Odors from all plants were more attractive to the parasitoid than clean air. However, tested against each other, parasitoids preferred the volatile blend from the three cruciferous species over that of malting barley. Wasps also discriminated between uninfested crucifers: mustard was as attractive as feral B. oleracea, and both were more attractive than Brussels sprout. Attractivity of uninfested plants was compared with that of plants infested by larvae of the host P. xylostella. Host-infested mustard and Brussels sprout were more attractive than uninfested conspecifics. Interestingly, the volatile blends of uninfested white mustard and infested Brussels sprout were equally attractive. We also compared the volatile composition of different plant sources by collecting headspace samples and analysing them with GC-MS. Similarities of volatile profiles were determined by hierarchic clustering and non-metric scaling based on the Horn-index. Due to the absence of several compounds in its blend, the volatile profile of barley showed dissimilarities from blends of crucifers. The odor profile of white mustard was distinctly different from the two Brassicaceae. * To whom correspondence should be addressed. E-mail: tibor.bukovinszky@wur.nl Feral Brassica oleracea odor profile was different from infested Brussels sprout, but showed overlap with uninfested Brussels sprout. Odor blends from infested and uninfested Brussels sprout were similar, and mainly quantitative differences were found. D. semiclausum appears to discriminate based on subtle differences in volatile composition of odor blends from infested and uninfested plants.

Three-step pathway engineering results in more incidence rate and higher emission of nerolidol and improved attraction of Diadegma semiclausum

“…The effect of the volatile blend of transgenic lines on parasitoid behaviour was compared with that of wild type plants using a closed-system Y-tube olfactometer as described before (Bukovinszky et al, 2005). In short, filtered air was led through activated charcoal and split into two air streams (4 L.min -1 )…”

Identification of a Widespread Monomolecular Odor Differentially Attractive to Several Delia Radicum Ground-dwelling Predators in the Field

“…For example, sprouts infested by Plutella xylostella emit 10 additional VOCs compared to uninfested sprouts that emit 49 compounds. These qualitative differences are perceived by the parasitoid wasp Diadegma semiclausum that prefer the odor of infested plants (Bukovinszky et al 2005). Among the myriad of VOCs identified, some are common and emitted in many plant arthropod interactions, whereas others are highly specific to a particular interaction.…”

Differences in Induced Volatile Emissions among Rice Varieties Result in Differential Attraction and Parasitism of Nilaparvata lugens Eggs by the Parasitoid Anagrus nilaparvatae in the Field

“…The release of these attractants can also be achieved by wounding the plants and applying herbivore regurgitant or elicitors such as jasmonates (JA) to the damaged sites (Turlings et al, 1993a;Hopke et al, 1994;Halitschke et al, 2001). Induced volatile blends vary considerably in quantity and quality with plant species or variety (Takabayashi and Dicke, 1996;Krips et al, 2001;Fritzsche-Hoballah et al, 2002;Degen et al, 2004;Van Den Boom et al, 2004;Bukovinszky et al, 2005), which may reflect in differences in attractiveness to the natural enemies of herbivores (Krips et al, 2001;Fritzsche-Hoballah et al, 2002;Bukovinszky et al, 2005). However, little to nothing is known about the consequences of these differences among plant genotypes for the effectiveness of the natural enemies in the field.…”