A male-produced aggregation-sex pheromone of the beetle Arhopalus rusticus (Coleoptera: Cerambycidae, Spondylinae) may be useful in managing this invasive species

Alenka Žunič-Kosi,Jocelyn G Millar,Yunfan Zou,J Steven Mcelfresh,Nataša Stritih-Peljhan

doi:10.1038/s41598-019-56094-7

Alenka Žunič-Kosi, Jocelyn G Millar + Show 3 more

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https://doi.org/10.1038/s41598-019-56094-7

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Abstract

The longhorned beetle Arhopalus rusticus (Coleoptera: Cerambycidae, Spondylinae) is a common species in conifer forests of the Northern Hemisphere, but with global trade, it has invaded and become established in New Zealand, Australia, and South America. Arhopalus rusticus is a suspected vector of the phytopathogenic nematode, Bursaphelenchus xylophilus, the causative agent of pine wilt disease, which is a major threat to pine forests worldwide. Here, we report the identification of a volatile, male-produced aggregation-sex pheromone for this species. Headspace odours from males contained a major male-specific compound, identified as (2 S, 5E)-6,10-dimethyl-5,9-undecadien-2-ol (common name (S)-fuscumol), and a minor component (E)-6,10-dimethyl-5,9-undecadien-2-one (geranylacetone). Both compounds are known pheromone components for species in the same subfamily. In field trials in its native range in Slovenia, (S)-fuscumol was significantly more attractive to beetles of both sexes, than racemic fuscumol and a blend of host plant volatiles commonly used as an attractant for this species. Fuscumol-baited traps also caught significant numbers of another spondylidine species, Spondylis buprestoides (L.), and a rare click beetle, Stenagostus rufus (De Geer). The pheromone can be exploited as a cost-effective and environmentally safe tool for detection and monitoring of this invasive species at ports of entry, and for monitoring the beetle’s distribution and population trends in both endemic and invasive populations.

Highlights

The longhorned beetle Arhopalus rusticus (Coleoptera: Cerambycidae, Spondylinae) is a common species in conifer forests of the Northern Hemisphere, but with global trade, it has invaded and become established in New Zealand, Australia, and South America
While field testing a series of known cerambycid pheromones (AZK, unpub. data), we noticed that A. rusticus beetles were being caught in traps baited with racemic fuscumol and its acetate, which was the first indication that the alcohol and/or its acetate might be pheromone compounds of this species
The fact that only two compounds were consistently present in significant quantities in extracts of males suggested that these two components might be potential pheromone candidates

Summary

Introduction

The longhorned beetle Arhopalus rusticus (Coleoptera: Cerambycidae, Spondylinae) is a common species in conifer forests of the Northern Hemisphere, but with global trade, it has invaded and become established in New Zealand, Australia, and South America. Several wood-boring longhorned beetles (Cerambycidae) have successfully invaded new countries and new continents[8,9] As such, they are receiving increasing regulatory and public attention (e.g.10–12), with intensifying efforts to detect, monitor, and eradicate invasive species. Mate finding and recognition are mediated by emission of pheromones[24,25], and understanding this process is crucial for developing risk analyses, and for monitoring and management of invasive pest species[26] In this context, the use of attractant pheromones and host plant volatiles have been shown to be among the most efficient means of detection, sampling, monitoring movement, and/or management of forest and timber exotic pests. Recent rapid progress in the chemical ecology of wood-boring cerambycids[8] has demonstrated the potential for exploiting their pheromones for both surveillance and trapping of invasive pest species[27,28]

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