Untitled

Abstract

Coupled gas chromatography with electroantennographic detection (GC-EAD) using antennae of adult female Manduca sexta was employed to screen for olfactory stimulants present in headspace collections from four species of larval host plants belonging to two families: Solanaceae--Lycopersicon esculentum (tomato), Capiscum annuum (bell pepper), and Datura wrightii; and Martyniaceae--Pronboscideaparviflora. Headspace volatiles were collected from undamaged foliage of potted, living plants. GC-EAD revealed 23 EAD-active compounds, of which 15 were identified by GC-mass spectrometry. Identified compounds included aliphatic, aromatic, and terpenoid compounds bearing a range of functional groups. Nine EAD-active compounds were common to all four host plant species: (Z)-3-hexenyl acetate, nonanal, decanal, phenylacetaldehyde, methyl salicylate, benzyl alcohol, geranyl acetone, (E)-nerolidol, and one unidentified compound. Behavioral responses of female moths to an eight-component synthetic blend of selected tomato headspace volatiles were tested in a laboratory wind tunnel. Females were attracted to the blend. A comparison of responses from antennae of males and females to bell pepper headspace volatiles revealed that males responded to the same suite of volatiles as females, except for (Z)-3-hexenyl benzoate. EAD responses of males also were lower for (Z)-and (E)-nerolidol and one unidentified compound. Electroantennogram EAG dose-response curves for the 15 identified EAD-active volatiles were recorded. At the higher test doses (10-100 microg), female antennae yielded larger EAG responses to terpenoids and to aliphatic and aromatic esters. Male antennae did respond to the higher doses of (Z)-3-hexenyl benzoate, indicating that they can detect this compound. On the basis of ubiquity of the EAD-active volatiles identified to date in host plant headspace collections, we suggest that M. sexta uses a suite of volatiles to locate and identify appropriate host plants.

Herbivory-induced volatiles function as defenses increasing fitness of the native plant Nicotiana attenuata in nature

“…oviposition (De Moraes et al, 2001; Kessler and Baldwin, 2001; Fraser et al, 2003), and the timing and extent of Manduca spp. oviposition varies from year to year, we created even, synchronous oviposition events by infesting plants with Manduca spp.…”

“…Furthermore, GLVs prime or directly regulate responses in neighboring plants (Kessler et al, 2006; Paschold et al, 2006), attract herbivores as well as predators (Halitschke et al, 2008), and are important cues for pollinating and ovipositing moths (Kessler and Baldwin, 2001, 2006; De Moraes et al, 2001; Fraser et al, 2003), thus performing several roles which may harm or benefit plant fitness in addition to their role in attracting predators. Perhaps most significantly, GLVs also stimulate Manduca spp.…”

Neuronal Processing of Complex Mixtures Establishes a Unique Odor Representation in the Moth Antennal Lobe

“…All odors were acquired from Sigma at highest purity available. Odors were selected because of their ecological and physiological relevance as shown in previous studies of M. sexta (King et al, 2000; Shields and Hildebrand, 2001; Fraser et al, 2003; Hansson et al, 2003; Reisenman et al, 2004; Hoballah and Turlings, 2005). New odor dilutions were prepared approximately once per month and unused vials were kept at 4°C.…”

Enzymatic, expression and structural divergences among carboxyl O-methyltransferases after gene duplication and speciation in Nicotiana

“…MeSA has also been shown to be emitted from herbivore-damaged leaf tissues (van Poecke et al 2001; Van den Boom et al 2004). MeSA and MeBA are often found in floral scents likely playing roles in pollinator attraction because insects can detect the molecules and show behavioural responses to them (Raguso et al 1996;Fraser et al 2003;Hoballah et al 2005;Knudsen et al 2006).…”