Subfamily Cerambycinae Research Articles

Field Screening of Known Pheromone Components of Longhorned Beetles in the Subfamily Cerambycinae (Coleoptera: Cerambycidae) in Hungary

Field Screening of Known Pheromone Components of Longhorned Beetles in the Subfamily Cerambycinae (Coleoptera: Cerambycidae) in Hungary

Blends of (R)-3-hydroxyhexan-2-one and alkan-2-ones identified as potential pheromones produced by three species of cerambycid beetles

We present data indicating that three species of cerambycid beetles (subfamily Cerambycinae) produce the common cerambycine pheromone component (R)-3-hydroxyhexan-2-one as well as an alkan-2-one component, a possible new motif for cerambycid pheromone components. GC/MS analyses of headspace volatiles produced by male beetles indicated that Cyrtophorus verrucosus (Olivier) produced (R)-3-hydroxyhexan-2-one but also nonan-2-one at ~18 % of the hydroxyketone component, whereas Orwellion gibbulum arizonense (Casey) and Parelaphidion aspersum (Haldeman) produced decan-2-one at ~40 and 7 % of the amount of the hydroxyketone, respectively. In field bioassays, adult C. verrucosus were attracted by (R)-3-hydroxyhexan-2-one alone, but attraction was significantly enhanced by nonan-2-one. This effect was lost if the quantity of nonan-2-one exceeded 100 % of the hydroxyketone, suggesting that beetles could discern ratios of the two chemicals and were most strongly attracted to those approximating the blend produced by males. We suggest that nonan-2-one plays a role in the species specificity of the pheromone signal of C. verrucosus, and that decan-2-one plays a similar role in the semiochemical communication of O. g. arizonense and P. aspersum.

2,3-Hexanediols as Sex Attractants and a Female-produced Sex Pheromone for Cerambycid Beetles in the Prionine Genus Tragosoma

Recent work suggests that closely related cerambycid species often share pheromone components, or even produce pheromone blends of identical composition. However, little is known of the pheromones of species in the subfamily Prioninae. During field bioassays in California, males of three species in the prionine genus Tragosoma were attracted to 2,3-hexanediols, common components of male-produced aggregation pheromones of beetles in the subfamily Cerambycinae. We report here that the female-produced sex pheromone of Tragosoma depsarium "sp. nov. Laplante" is (2R,3R)-2,3-hexanediol, and provide evidence from field bioassays and electroantennography that the female-produced pheromone of both Tragosoma pilosicorne Casey and T. depsarium "harrisi" LeConte may be (2S,3R)-2,3-hexanediol. Sexual dimorphism in the sculpting of the prothorax suggests that the pheromone glands are located in the prothorax of females. This is the second sex attractant pheromone structure identified from the subfamily Prioninae, and our results provide further evidence of pheromonal parsimony within the Cerambycidae, in this case extending across both subfamily and gender lines.

Blending Synthetic Pheromones of Cerambycid Beetles to Develop Trap Lures That Simultaneously Attract Multiple Species

We evaluated attraction of cerambycid beetle species to blends of known cerambycid pheromones to determine whether such blends could be used as effective trap lures for detecting and monitoring multiple species simultaneously. Pheromone-baited traps captured 1,358 cerambycid beetles of which 1,101 (81.1%) belonged to three species in the subfamily Cerambycinae: Neoclytus acuminatus (F.), Neoclytus mucronatus (F.), and Xylotrechus colonus (F.). Beetles of these species were significantly attracted to synthetic blends that contained their pheromone components (isomers of 3-hydroxy-2-hexanone, 2,3-hexanediol, or both), despite the presence of pheromone components of different species, including other isomers of 2,3-hexanediol, (E/Z)-6,10-dimethyl-5,9-undecadien-2-yl acetate, and citral. In some cases, attraction was partially inhibited by the pheromone components of heterospecific species, whereas for N. acuminatus, attraction was completely inhibited when blends contained (2R*,3S*)-hexanediol, the racemic mixture of diastereomers of its pheromone, (2S,3S)-hexanediol. Among the remaining beetles captured were three species in the subfamily Lamiinae: Astyleiopus variegatus (Haldeman), Graphisurus fasciatus (Degeer), and Lepturges angulatus (LeConte). All three lamiine species were previously known to be attracted to (E/Z)-6,10-dimethyl-5,9-undecadien-2-yl acetate and were captured in significant numbers by blends containing that compound. Our results suggest that different types of cerambycid pheromones can be combined to create effective multispecies lures for use in surveillance programs that target exotic cerambycid species.

Using blends of cerambycid beetle pheromones and host plant volatiles to simultaneously attract a diversity of cerambycid species

We evaluated the attraction of native species of cerambycid beetles to blends of cerambycid pheromones and the host plant volatiles ethanol and α-pinene to determine whether such blends could be effective lures for detecting and monitoring multiple species. The complete six-component blend of pheromones included racemic 3-hydroxy-2-hexanone, 2,3-hexanediol isomers, (E)-6,10-dimethyl-5,9-undecadien-2-ol and the corresponding acetate, 2-(undecyloxy)-ethanol, and racemic 2-methyl-1-butanol. Bioassays in east-central Illinois captured 3070 cerambycid beetles of 10 species, including four species in the subfamily Cerambycinae ( Neoclytus acuminatus (Fabricius, 1775), Neoclytus mucronatus (Fabricius, 1775), Phymatodes lengi Joutel, 1911, and Xylotrechus colonus (Fabricius, 1775)) and six species in the subfamily Laminiae ( Aegomorphus modestus (Gyllenhal in Schoenherr, 1817), Astyleiopus variegatus (Haldeman, 1847), Astylidius parvus (LeConte, 1873), Graphisurus fasciatus (DeGeer, 1775), Lepturges angulatus (LeConte, 1852), and Monochamus carolinensis (Olivier, 1792)). Beetles were attracted to their pheromone components within the blend, with inhibition only evident in one species. Host plant volatiles synergized attraction for some species, and synergism usually was attributed to ethanol, with α-pinene enhancing attraction only for the pine specialist M. carolinensis. The optimal strategy for targeting a broad range of cerambycid species would be to bait traps with a blend of several pheromones plus ethanol and α-pinene because synergism by these plant volatiles is critical for some species, whereas strong inhibition is uncommon.

Fuscumol and fuscumol acetate are general attractants for many species of cerambycid beetles in the subfamily Lamiinae

(E)-6,10-dimethyl-5,9-undecadien-2-ol (fuscumol) is an important component of male-produced aggregation pheromones for several species of cerambycid beetles in the genus Tetropium (subfamily Aseminae ⁄ Spondylidinae). Here, we describe the experiments that tested the hypothesis that fuscumol and ⁄ or fuscumol acetate also are general attractants for species in the cerambycid subfamily Lamiinae. At field sites in northwestern Indiana and central Texas (USA), panel traps baited with fuscumol or its acetate captured 331 lamiine beetles, compared to 11 beetles captured in control traps. Three species were attracted to traps baited with fuscumol as a single component, whereas another four species were attracted to fuscumol acetate alone. Surprisingly, fuscumol acetate also attracted two species in the subfamily Cerambycinae: Xylotrechus colonus (Fabricius) (males of which produce a pheromone composed only of stereoisomers of 2,3-hexanediol and 3-hydroxyhexan-2-one), and Obrium maculatum (Olivier) (for which a pheromone has yet to be identified). In an independent field experiment in east-central Illinois (USA), traps baited with fuscumol and ⁄ or its acetate captured 136 beetles of eight lamiine species, all but one species of which were also captured in the other experiment. Blending fuscumol and its acetate did not inhibit responses of species to either of the individual compounds, but synergized their activity for one species. Our results support the hypothesis that fuscumol and fuscumol acetate are widespread pheromone components or attractants for a variety of cerambycid species, especially lamiines in the tribe Acanthocinini.

Two new synonymies and lectotype designation in Trachyderini (Insecta: Coleoptera: Cerambycidae)

The subfamily Cerambycinae includes, at present 716 genera and 3889 species in the Neotropical region (Monné & Bezark, 2009). Trachyderini Dupont, 1836, one of the largest tribes of Cerambycinae, is widely distributed in the Americas, especially in the Neotropics where 441 species belonging to 133 genera are recorded, about 11% of the diversity of the subfamily (Monné & Bezark, 2009; Eya, 2010).

Male-Produced Aggregation Pheromone of the Cerambycid Beetle Rosalia funebris

We report the identification, synthesis, and field bioassays of a volatile, male-produced aggregation pheromone of a long-horned beetle, the banded alder borer, Rosalia funebris Mots. Headspace collections from males contained a major male-specific compound, (Z)-3-decenyl (E)-2-hexenoate, and several minor components, identified as (Z)-3-decenol, (Z)-3-nonenyl (E)-2-hexenoate, and (Z)-3-decenyl (E)-3-hexenoate. The antennae of both males and females responded strongly to (Z)-3-decenyl (E)-2-hexenoate. We collected significant numbers of adult R. funebris in field bioassays using traps baited with this compound. This pheromone structure is unprecedented in the literature of cerambycid pheromones and distinct from the more common diol/hydroxyketone pheromone motif of many other species of the diverse subfamily Cerambycinae. This is the first pheromone identified for a species in the tribe Rosaliini.

A new genus and species of Cerambycidae from Utah (Coleoptera: Cerambycidae: Cerambycinae)

A new genus and species of Cerambycidae, Liberedaxia deslauriersi Alten, Alten and Ramey, is described, figured and provisionally assigned to the tribe Oemini of the subfamily Cerambycinae. Photographs of the type habitat, larvae and their galleries, and significant morphological characters are also provided.

Using Generic Pheromone Lures to Expedite Identification of Aggregation Pheromones for the Cerambycid Beetles Xylotrechus nauticus, Phymatodes lecontei, and Neoclytus modestus modestus

Males of several species of longhorned beetles in the subfamily Cerambycinae produce sex or aggregation pheromones consisting of 2,3-hexanediols and/or hydroxyhexanones. We tested the hypothesis that this diol/hydroxyketone pheromone motif is highly conserved within the subfamily, and the resulting prediction that multiple cerambycine species will be attracted to compounds of this type. We also tested the concept that live traps baited with generic blends of these compounds could be used as a source of live insects from which pheromones could be collected and identified. Traps placed in a mature oak woodland and baited with generic blends of racemic 2-hydroxyhexan-3-one and 3-hydroxyhexan-2-one captured adults of both sexes of three cerambycine species: Xylotrechus nauticus (Mannerheim), Phymatodes lecontei Linsley, and Phymatodes decussatus decussatus (LeConte). Odors collected from male X. nauticus contained a 9:1 ratio of two male-specific compounds, (R)- and (S)-3-hydroxyhexan-2-one. Field trials with synthetic compounds determined that traps baited with (R)-3-hydroxyhexan-2-one (94% ee), alone or in blends with other isomers, attracted similar numbers of X. nauticus of both sexes, whereas (S)-3-hydroxyhexan-2-one (94% ee) attracted significantly fewer beetles. Phymatodes lecontei and P. d. decussatus also were caught in traps baited with hydroxyhexanones, as well as a few specimens of two other cerambycine species, Neoclytus modestus modestus Fall (both sexes) and Brothylus gemmulatus LeConte (only females). Male N. m. modestus produced (R)-3-hydroxyhexan-2-one, which was not present in extracts from females. Neoclytus m. modestus of both sexes also responded to lures that included (R)-3-hydroxyhexan-2-one as one of the components. The only male-specific compound found in extracts from P. lecontei was (R)-2-methylbutan-1-ol, and adults of both sexes were attracted to racemic 2-methylbutan-1-ol in field bioassays. Surprisingly, P. lecontei of both sexes also were attracted to (R)- and (S)-3-hydroxyhexan-2-ones, although neither compound was detected in extracts from this species. Males of all five beetle species had gland pores on their prothoraces that were similar in structure to those that have been associated with volatile pheromone production in other cerambycine species. The attraction of multiple cerambycine species of two tribes to (R)-3-hydroxyhexan-2-one in this study, and in earlier studies with other cerambycine species, suggests that this compound is a widespread aggregation pheromone component in this large and diverse subfamily. Overall, the attraction of multiple species from different cerambycine tribes to this compound at a single field site supports the hypothesis that the hydroxyketone pheromone structural motif is highly conserved within this subfamily.

ROLE OF HOST PLANT VOLATILES IN MATE LOCATION FOR THREE SPECIES OF LONGHORNED BEETLES

Stressed woody plants represent an ephemeral and unpredictable resource for larvae of some species of longhorned beetles (Coleoptera: Cerambycidae) because prime subcortical tissues are rapidly degraded by a guild of xylophagous competitors. Selection favors efficient mechanisms of host and mate location to expedite colonization of hosts by larvae. Based on previous research, we hypothesize that mate location in some species of the subfamily Cerambycinae involves three sequential behavioral stages: (1) both sexes are attracted to larval hosts by plant volatiles; (2) males attract females over shorter distances with pheromones; and (3) males recognize females by contact pheromones in their epicuticular wax layer. We already have evidence of second-stage and third-stage behaviors in three species in this subfamily whose xylophagous larvae feed in hardwood trees: Xylotrechus colonus, Megacyllene caryae, and Neoclytus mucronatus mucronatus. In this report, we evaluate the first behavioral stage of mate location behavior (i.e., independent response of both sexes to host plant volatiles) for the same three species. Supporting our hypothesis, both males and females responded to volatiles emanating from hickory logs in Y-tube olfactometer bioassays.

Book Notices

University of California Publications in Entomology. Vol. 21. The Cerambycidae of North America. Part IV. Taxonomy and classification of the subfamily Cerambycinae, tribes Elaphidionini through Rhinotragini. By E. Gorton LinsleyUniversity of California Publications in Entomology. Vol. 30, No. 1. Taxonomy and bionomics of the genus Tetraopes (Cerambycidae: Coleoptera). By John A. Chemsak

Book Notice

University of California Publications in Entomology. Vol. 18. The Cerambycidae of North America. Part 1. Introduction. By E. Gorton Linsley.Vol. 19. The Cerambycidae of North America. Part II. Taxonomy and classification of the Parandrinae, Prioninae, Spondylinae, and Aseminae. By E. Gorton Linsley.Vol. 20. The Cerambycidae of North America. Part III. Taxonomy and classification of the subfamily Cerambycinae, tribes Opsimini through Megaderini. By E. Gorton Linsley.

Descriptions of Immature Forms and Biology of Xylotrechus colonus (Fab.) (Coleoptera: Cerambycidae)

During current studies of Cerambycidae at Laniel, Quebec, new information on the immature forms and biology of the common woodborer, Xylotrechus colonus (Fab.) was obtained. This species belongs to the tribe Clytini of the subfamily Cerambycinae, and was first described by Fabricius in 1775 as Callidium colonus. Packard (1890) described and figured the larva, pupa, and adult in a general way; the mature larva was described in detail by Craighead (1923). Synonomy and adult description were given by Hopping (1932).