Comparison of antennal responses of Ovalisia festiva and Phloeosinus aubei to volatile compounds of their common host, Thuja occidentalis

Abstract

The cypress jewel beetle, Ovalisia festiva L. (Coleoptera: Buprestidae, Chrysochroinae), and the cypress bark beetle, Phloeosinus aubei Perris (Coleoptera: Curculionidae, Scolytinae), are invasive wood‐boring pests of scale‐leafed conifers (Cupressaceae), threatening tree nurseries and urban green areas. In order to reveal which volatile compounds of their common host, the American arborvitae, Thuja occidentalis L. cultivar ‘Smaragd’, they can perceive, we collected headspace volatiles from live attached twigs and screened them for bioactivity by gas chromatography coupled to an electroantennographic detector (GC‐EAD). Compounds eliciting antennal responses were identified by gas chromatography coupled to mass spectroscopy (GC‐MS). Synthetic samples of bioactive compounds were then screened by electroantennography. GC‐EAD analyses of volatile collections revealed that E–β–caryophyllene elicited antennal responses only from O. festiva (from both sexes), whereas borneol only from P. aubei. Electroantennography screening of synthetic compounds showed further differences between the two species. Even many of those compounds, which elicited responses from both species, differed in the relative intensities of responses they evoked. This indicates that O. festiva and P. aubei probably use different key compounds in the Thuja volatile blend for host recognition.

Changing volatile profile of arborvitae, Thuja occidentalis, by drying up and infestation: selective olfactory cues for the cypress bark beetle, Phloeosinus aubei

“…For the development of kairomone-based monitoring, we revealed how P. aubei adapted to the temperate climate (Bozsik and Szőcs 2017) and began to study host plant kairomones intensively (Bozsik et al 2016;Bozsik et al 2022). Our present study ts to the latter line of research, by reporting on the effects of stress on the composition of volatiles emitted by declining trees, suffering from either draught, or infestation of P. aubei.…”

“…Injection of synthetic samples (source: camphene and fenchene are supplied from Thermo Fisher Scienti c Inc., Waltham, MA USA; the others are supplied from Sigma Aldrich, Merck KGaA, Darmstadt, Germany) and comparison of retention times with the EAD active compounds in the GC-EAD setup, were performed to verify the results. Methodology and instrumentation were based on our related, previous MS identi cations (Bozsik et al 2016;Bozsik et al 2022). Brie y, an Agilent 6890 GC (Agilent Technologies Inc.) coupled to an Agilent 5973 mass selective detector was used for GC-MS.…”

“…In that study, however, the freshly cut twigs originated from otherwise healthy tree, therefore represented rather an immediate response to an acute physical stress factor, than that of an altered volatile pro le of a declining tree, suffering from chronic stresses. In a more recent study, sixteen components were found in the VOC pro le of healthy T. occidentalis 'Smaragd', which elicited antennal response from either males, or females of CBB, and of the cypress jewel beetle, Ovalisia (Lamprodila/Palmar) festiva L. (Coleoptera: Buprestidae, Chrysochroinae), respectively (Bozsik et al 2022). The cypress jewel beetle is another upcoming, invasive wood-boring pest of Cupressaceae, which attacks both healthy and declining trees.…”

Identification of two aggregation pheromone components from female cypress bark beetles and evaluation of their activity in the laboratory and the field

“…Alternative inspection techniques, e. g. recordings of newly built breeding galleries are neither feasible nor effective for plant protection purpose, as entering openings of galleries can hardly be noticed in time. There has been progress in identifying host plant volatiles that are attractive for the beetles (Bozsik et al 2016(Bozsik et al , 2022, however, the development of respective kairomone-baited traps is still awaited. Therefore, we attempted to identify key components in the aggregation pheromone system of the cypress bark beetle, to provide a starting point for the development of pheromone-based monitoring traps.…”

Identification of two female cypress bark beetle pheromone components and evaluation of their activity in the laboratory and the field

“…There is a progress in revealing host plant volatiles attractive for the beetles (Bozsik et al 2016(Bozsik et al , 2022, however, the development of kairomonal-baited traps is still awaited. Therefore, we attempted to identify key components in the sex pheromone system of the cypress bark beetle, to provide a starting point for the development of pheromone-based monitoring traps.…”