Identification of the aggregation-sex pheromone of Plagionotus arcuatus ssp. arcuatus (Coleoptera: Cerambycidae) from two geographically separated European populations

Abstract

Plagionotus arcuatus ssp. arcuatus (L.) is a common saproxylic cerambycid beetle in most parts of Europe, and is designated as an occasional pest of oak wood that is stored outside during the summer months. In an effort to identify attractants that can be used for monitoring this species, we collected headspace samples from adult beetles and conducted field bioassays with the resulting compounds as potential aggregation-sex pheromone components for this species. Three compounds, (R)-3hydroxyhexan-2-one, (R)-3-hydroxyoctan-2-one, and (R)-3-hydroxydecan-2-one, were consistently present in relatively large quantities in headspace extracts from male P. arcuatus populations in both Hungary and Sweden, regardless of the adsorbent media (activated charcoal or Porapak™ Q) used to sample beetle odors, or the type of solvent (hexane, diethyl ether, or dichloromethane) used to elute trapped volatiles from the collectors. None of the hydroxyketone and related compounds were detected in corresponding extracts from females. In field bioassays in both countries, the blend of the C 6 and C 10 compounds, and the ternary blend both attracted significantly more beetles than the control, while other combinations or single compounds were not significantly attractive. Males and females showed similar patterns of responses to treatments. Our results demonstrate that (R)-3-hydroxyhexan-2-one and (R)-3-hydroxydecan-2-one constitute a male-produced aggregation-sex pheromone of P. arcuatus, whereas the role of (R)-3-hydroxyoctan-2-one remains unclear. Lures with the pheromone could be developed for monitoring of P. arcuatus populations as an indicator of fresh oak wood resources.

Identification of Pheromone Components of Plagionotus detritus (Coleoptera: Cerambycidae), and Attraction of Conspecifics, Competitors, and Natural Enemies to the Pheromone Blend

“…As suggested by previous studies with other cerambycids in the subfamily Cerambycinae [15,28], the presence of sex-specific pores on the prothoraces of male P. detritus (Figure 1) indicated that these are likely to be where the male-specific pheromone components are produced and released. Analogous pores had been previously noted in the congener P. arcuatus [15,21], for which male-produced aggregation-sex pheromones have been recently identified [21].…”

“…Plagionotus arcuatus occasionally is considered a pest because it can damage fresh oak wood stored outdoors [14,38]. However, P. arcuatus catches showed no clear tendencies (Figure 4B), although racemic 3-C6 was tested, which includes (R)-3-hydroxyhexan-2-one, the major pheromone component of P. arcuatus [21]. Our results are congruent with Swedish and Hungarian field tests [21], which showed that the 3-C6 component alone was insufficient to attract this species and that blends of this compound with the minor components 3-hydroxyoctan-2-one and 3hydroxydecan-2-one are required in order to achieve attraction.…”

“…Field tests were carried out with funnel traps (Figure S1) consisting of a funnel trap body emptying into a collection bucket and surmounted with a transparent upper funnel, a vertical plastic sheet that enlarges the trap funnel to intercept flying insects. The version with a light green funnel sheet has been shown to be highly effective in catching Plagionotus floralis (Pallas), a congener of P. detritus [18,19] and with a transparent funnel sheet in catching Molorchus umbellatarum Schreb [20] and Plagionotus arcuatus L. (Coleoptera: Cerambycidae) [21]. To reduce the potentially confounding effects of the light green visual stimulus, a transparent funnel was used in the test of the pheromone compounds.…”

Longhorn beetles and predatory clerid beetles attracted to a blend of longhorn beetle pheromone compounds in a Central European oak forest (Coleoptera: Cerambycidae, Cleridae)

“…Further experiments would be required to test these variables and determine which are most important for trap captures. However, this funnel trap, fitted with a light green funnel, was used to catch the cerambycid Plagionotus floralis (Pallas) (Imrei et al, 2014; Toshova et al, 2010) and with a transparent funnel to catch the cerambycids Molorchus umbellatarum (Schreber) (Imrei et al, 2012) and Plagionotus arcuatus arcuatus (L.) (Imrei et al, 2019), and the congener P. detritus (L.) (Imrei et al, 2021).…”