Male-Produced Pheromone in the European Woodwasp, Sirex noctilio

Abstract

A male-produced pheromone that attracts both males and females was identified for the European woodwasp, Sirex noctilio, a serious pest of pine trees. Males displayed excitatory behaviors when placed in groups, and were attracted to the odors from males that were 2-5-d-old, but not to odors from males that were 0-1-d-old. An unsaturated short-chain alcohol, (Z)-3-decen-1-ol, was discovered in samples collected on SuperQ filters over groups of males and identified by using micro-derivatization reactions and gas chromatography coupled with mass spectrometry (GC-MS). The compound was not detected in volatile samples from females. Gas chromatography coupled electroantennographic detection (GC-EAD) of antennae from males exposed to male headspace odors produced strong antennal responses to the main peak of (Z)-3-decen-1-ol, as well as to an unknown minor component that had a similar retention time. Antennae from both males and females responded to synthetic (Z)-3-decen-1-ol. Several different synthetic candidates for the GC-EAD active minor components were selected based on GC-MS and GC-EAD responses to male headspace collections. These synthetic compounds were tested for antennal activity using GC-EAD, and those that produced strong responses were blended with the major component and tested for male attraction in the Y-tube olfactometer at different concentrations and ratios. Males tested in the Y-tube olfactometer were attracted to a synthetic blend of (Z)-3-decen-1-ol and (Z)-4-decen-1-ol at a ratio of 100:1. Whereas the addition of some suspected minor compounds reduced attraction, the addition of a third compound found in male emanations that produced strong male antennal responses, (E,E)-2,4-decadienal (at a ratio of 100:1:1), resulted in attraction of both males (Y-tube and wind tunnel) and females (wind tunnel).

The importance of olfactory and visual cues in developing better monitoring tools forSirex noctilio(Hymenoptera: Siricidae)

“…Because S. noctilio has become an important invasive pest in a number of countries, efforts to identify attractants have been made using electrophysiology, field studies and laboratory bioassays (Simpson, ; Simpson & McQuilkin, ; Cooperband et al , ; Crook et al , ). Bashford () conducted field studies in Tasmania aimed at developing a trap and lure for S. noctilio to detect new populations without the use of trap trees, ground surveys or aerial surveys.…”

Type of Intercept Trap Not Important for Capturing Female <I>Sirex noctilio</I> and <I>S. nigricornis</I> (Hymenoptera: Siricidae) in North America

“…Johnson et al (2013) found that intercept traps baited with semiochemicals (e.g., Sirex lure ϩ ipsenol ϩ ipsdienol) generally caught more S. nigricornis than trap trees. Semiochemicals are important for attracting S. noctilio as well (Bö rö czky et al 2009Cooperband et al 2012), but an effective combination and quantity of attractants has yet to be found. Future investigations should focus on developing and testing an effective attractant for S. noctilio.…”

“…Studies have tested and improved lures for woodwasps (Siricidae) , Cooperband et al 2012, Coyle et al 2012, Johnson et al 2013, Barnes et al 2014), but information on effective trap type is limited to studies of related species (McIntosh et al 2001, Costello et al 2008, Barnes et al 2014. This is probably not because efforts have been lacking, but more likely because of difÞculty in comparing low S. noctilio catch among different traps.…”

The influence of Canadian research on semiochemical-based management of forest insect pests in Canada

“…This approach has led to the identification of three contact sex pheromone components, (Z)-7-heptacosene, (Z)-7-nonacosene, and (Z)-9-nonacosene (Böröczky et al 2009). There is currently little evidence that the European woodwasp uses long-range sex pheromone communication, although Cooperband et al (2012) identified a potential male-produced pheromone candidate, but no field trapping data are available. This compound, (3Z)-decen-1-ol, may, in fact, be a volatile male-produced lek signalling pheromone (Thompson et al 2013).…”