Identification and Field Assay of Two Aggregation Pheromone Components Emitted by Males of the Bark Beetle Polygraphus punctifrons (Coleoptera: Curculionidae)

Abstract

The bark beetle Polygraphus punctifrons (Coleoptera: Curculionidae) is a species that feeds on Norway spruce ( Picea abies ) and is found in the Northern parts of Europe and Russia. The release of volatile organic compounds (VOCs) produced by males and females of P. punctifrons when the beetles bore into spruce stem sections in a laboratory environment was studied using solid phase microextraction (SPME). The sampled VOCs emitted by boring beetles were analysed by gas chromatography and mass spectrometry (GCMS). (+)-2-[(1 R ,2 S )-1-Methyl-2-(prop-1-en-2-yl)cyclobutyl]ethanol [(+)-(1 R ,2 S )-grandisol] and (−)-( R )-1-isopropyl-4-methyl-3-cyclohexen-1-ol [(−)-( R )-terpinen-4-ol] were identified to be male specific volatiles. The identity of the compounds was confirmed by comparison with synthetic samples. Field trials with synthetic compounds in Sweden showed that racemic grandisol per se was strongly attractive for both males and females, while (−)-( R )-terpinen-4-ol was not. Further, when adding (−)-( R )-terpinen-4-ol to rac -grandisol, a synergistic effect was observed as the trap catch of P. punctifrons was fourfold. (−)-( R )-Terpinen-4-ol by its own did not attract P. punctifrons but Polygraphus poligraphus, and the latter was also attracted to traps baited with a 10:90 mixture of the two compounds. Thus, we have identified (+)-(1 R ,2 S )-grandisol as a main component and (−)-( R )-terpinen-4-ol as a minor component of the aggregation pheromone of P. punctifrons. This opens future possibilities to monitor and, if necessary, manage populations of P. punctifrons . Electronic supplementary material The online version of this article (10.1007/s10886-019-01056-6) contains supplementary material, which is available to authorized users.

Profile of Terpenoid Compounds Mediating a Plant‐Herbivore Interaction: Screening by Static Headspace Solid‐Phase Microextraction‐Gas Chromatography/Q‐ToF Mass Spectrometry

“…The current study indicates that both sexes of C. dimidiatus release the same detected volatiles. This is new in relation to reports of other weevils, in that the aggregation pheromone has only been found in males, [10,32–34] but it is also not an uncommon since something similar occurred in another subfamily (Coleoptera: Curculionidae: Scolytinae) where the same volatiles ( trans‐ verbenol, verbone, brevicomin) were in the hindgut of females and males of D. armandi , and the pheromone biosynthesis did not seem to be specific to the insect sex [35] …”

Identification of male produced compounds in the bark beetle Polygraphus subopacus and establishment of (Z)-2-(3,3-dimethylcyclohexylidene)-ethanol as an aggregation pheromone component

“…Both isomers of DMCHE (trade names Grandlure II and (E)-isomer of Grandlure II) were purchased from Bedoukian Research (Danbury, CT, USA), as was racemic grandisol, (Grandlure I) and a 1:1 mixture of (Z)-and (E)-2-(3,3-dimethylcyclohexylidene)-acetaldehyde (Grandlure III and IV). Racemic fragranol was synthesized previously at our laboratory (Rahmani et al 2019). Citral was bought from Acros Organics (Geel, Belgium).…”

“…Polygraphus use aggregation pheromones to coordinate mass attacks on trees, and male-produced pheromone compounds have been identified for P. rufipennis (3-methyl-3-buten-1-ol, Bowers et al 1991), P. poligraphus [( −)-(R)-terpinen-4-ol, Schurig et al 1985, ( −)-(R)-and ( +)-(S)-terpinen-4-ol, Rahmani et al 2015] and for P. punctifrons [( +)-(1R,2S)-grandisol and ( −)-(R)-terpinen-4-ol, Rahmani et al 2019]. No pheromone has yet been identified for P. subopacus and little has been published about the species.…”

Bark beetles locate fungal symbionts by detecting volatile fungal metabolites of host tree resin monoterpenes

“…Among microbial sources of oxygenated monoterpenes are several yeast species including Hansenula holstii, H. capsulata and Candida nitratophila , which were isolated from I. typographus , and produce terpinen-4-ol, α-terpineol, borneol and trans -pinocarveol when grown in phloem medium or in α-pinene-supplemented medium [67]. In addition, another bark beetle species, Polygraphus poligraphus , which is sometimes found together with I. typographus , was shown to emit large amounts of terpinene-4-ol [91,92]. Intermediate amounts of α-terpineol, cis- and trans- 4-thujanol were also identified from the hindgut as well as the entrance holes of this beetle’s gallery and could be formed by this beetle or its associated microorganisms from host tree monoterpenes.…”