Comparative analyses of the banded alder borer (Rosalia funebris) and Asian longhorned beetle (Anoplophora glabripennis) genomes reveal significant differences in genome architecture and gene content among these and other Cerambycidae.

Rosalia funebris (RFUNE; Cerambycidae), the banded alder borer, is a longhorn beetle whose larvae feed on the wood of various economically and ecologically significant trees in western North America. Adults are short-lived and not known to consume plant material substantially. We sequenced, assembled, and annotated the RFUNE genome using HiFi and RNASeq data. We documented genome architecture and gene content, focusing on genes putatively involved in plant feeding (phytophagy). Comparisons were made to the well-studied genome of the Asian longhorned beetle (AGLAB; Anoplophora glabripennis) and other Cerambycidae. The 814 Mb RFUNE genome assembly was distributed across 42 contigs, with an N50 of 30.18 Mb. Repetitive sequences comprised 60.27% of the genome, and 99.0% of expected single-copy orthologous genes were fully assembled. We identified 12,657 genes, fewer than in the four other species studied, and 46.4% fewer than for Aromia moschata (same subfamily as RFUNE). Of the 7,258 orthogroups shared between RFUNE and AGLAB, 1,461 had more copies in AGLAB and 1,023 had more copies in RFUNE. We identified 240 genes in RFUNE that putatively arose via horizontal transfer events. The RFUNE genome encoded substantially fewer putative plant cell wall degrading enzymes than AGLAB, which may relate to the longer-lived plant-feeding adults of the latter species. The RFUNE genome provides new insights into cerambycid genome architecture and gene content and provides a new vantage point from which to study the evolution and genomic basis of phytophagy in beetles.

Methionol, a Sulfur-Containing Pheromone Component from the North American Cerambycid Beetle Knulliana cincta cincta.

We describe the identification and field testing of 3-methylthiopropan-1-ol (methionol) as a male-produced aggregation-sex pheromone for the cerambycid beetle Knulliana cincta cincta (Drury) (subfamily Cerambycinae, tribe Bothriospilini). The corresponding sulfoxide, 3-methylsulfinylpropan-1-ol, was also produced sex-specifically by males, but its function remains unclear because the measured release rates of this compound from five different types of release devices were very low to undetectable. Unexpectedly, adults of the cerambycine Elaphidion mucronatum (Say) (Elaphidiini), primarily females, also were attracted by methionol, despite males of this species producing an aggregation-sex pheromone of entirely different structure, (2E,6Z,9Z)-2,6,9-pentadecatrienal.

(2S,4E)-2-Hydroxy-4-octen-3-one, a Male-Produced Attractant Pheromone of the Cerambycid Beetle Tylonotus bimaculatus.

We report the identification of a novel pheromone structure from males of the cerambycid beetle Tylonotus bimaculatus Haldeman (Cerambycinae: Hesperophanini), a species native to eastern North America. Volatiles collected from adult males contained (2S,4E)-2-hydroxyoct-4-en-3-one (71%), (3R,4E)-3-hydroxyoct-4-en-2-one (15%), (E)-4-octen-2,3-dione (13%), and 2,3-octanedione (1.5%). Four independent field bioassays with synthetic compounds confirmed that adults of both sexes were attracted by the racemate of the major component, (E)-2-hydroxyoct-4-en-3-one. No other cerambycid species were attracted in significant numbers. Attraction of both sexes is consistent with the male-produced pheromones of many other species in the subfamily Cerambycinae, but T. bimaculatus is unusual in having a pheromone chemistry that is so far unique among species in that subfamily.

North American Species of Cerambycid Beetles in the Genus Neoclytus Share a Common Hydroxyhexanone-Hexanediol Pheromone Structural Motif.

Many species of cerambycid beetles in the subfamily Cerambycinae are known to use male-produced pheromones composed of one or a few components such as 3-hydroxyalkan-2-ones and the related 2,3-alkanediols. Here, we show that this pheromone structure is characteristic of the cerambycine genus Neoclytus Thomson, based on laboratory and field studies of 10 species and subspecies. Males of seven taxa produced pheromones composed of (R)-3-hydroxyhexan-2-one as a single component, and the synthetic pheromone attracted adults of both sexes in field bioassays, including the eastern North American taxa Neoclytus caprea (Say), Neoclytus mucronatus mucronatus (F.), and Neoclytus scutellaris (Olivier), and the western taxa Neoclytus conjunctus (LeConte), Neoclytus irroratus (LeConte), and Neoclytus modestus modestus Fall. Males of the eastern Neoclytus acuminatus acuminatus (F.) and the western Neoclytus tenuiscriptus Fall produced (2S,3S)-2,3-hexanediol as their dominant or sole pheromone component. Preliminary data also revealed that males of the western Neoclytus balteatus LeConte produced a blend of (R)-3-hydroxyhexan-2-one and (2S,3S)-2,3-hexanediol but also (2S,3S)-2,3-octanediol as a minor component. The fact that the hydroxyketone-hexanediol structural motif is consistent among these North American species provides further evidence of the high degree of conservation of pheromone structures among species in the subfamily Cerambycinae.

(R)-desmolactone, a female-produced sex pheromone component of the cerambycid beetle Desmocerus californicus californicus (subfamily Lepturinae).

We report the identification, synthesis, and field bioassays of a female-produced sex attractant pheromone for the cerambycid beetle Desmocerus californicus californicus Horn. Headspace volatiles from females contained a sex-specific compound, (R)-desmolactone [(4R,9Z)-hexadec-9-en-4-olide], which elicited strong responses from the antennae of adult males in coupled gas chromatography-electroantennogram analyses. Short syntheses of both enantiomers were developed from commercial chiral synthons. In field bioassays, significant numbers of males were collected in traps baited with (R)-desmolactone, whereas the (S)-enantiomer attracted no males. The racemate was less attractive than the pure (R)-enantiomer, indicating some degree of antagonism by the unnatural enantiomer. This compound is the first example of a new structural class of cerambycid pheromones, and is the second pheromone identified for a species in the subfamily Lepturinae.

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.

cis-Vaccenyl acetate, a female-produced sex pheromone component of Ortholeptura valida, a longhorned beetle in the subfamily Lepturinae.

We report the identification, synthesis, and field bioassays of a female-produced sex attractant pheromone component of the cerambycid beetle Ortholeptura valida (LeConte). Headspace volatiles from females contained a female-specific compound, (Z)-11-octadecen-1-yl acetate, which elicited a strong response from antennae of adult males in coupled gas chromatography-electroantennogram analyses. In field bioassays, significant numbers of males were collected by traps baited with this compound. The pheromone represents a new structural class of cerambycid pheromones, and is the first pheromone identified for a cerambycid species in the subfamily Lepturinae.

Determination of the relative and absolute configurations of the female-produced sex pheromone of the cerambycid beetle Prionus californicus.

We previously identified the basic structure of the female-produced sex attractant pheromone of the cerambycid beetle, Prionus californicus Motschulsky (Cerambycidae: Prioninae), as 3,5-dimethyldodecanoic acid. A synthesized mixture of the four stereoisomers of 3,5-dimethyldodecanoic acid was highly attractive to male beetles. Here, we describe stereoselective syntheses of three of the four possible stereoisomers, and the results of laboratory and field bioassays showing that male beetles are attracted specifically to (3R,5S)-3,5-dimethyldodecanoic acid, but not to its enantiomer, (3S,5R)-3,5-dimethyldodecanoic acid, indicating that the (3R,5S)-enantiomer is the active pheromone component. The diastereomeric (3R,5R)- and (3S,5S)-enantiomers were excluded from consideration because their gas chromatographic retention times were different from that of the insect-produced compound. The mixture of the four stereoisomers of 3,5-dimethyldodecanoic acid was as attractive to male P. californicus as the (3R,5S)-enantiomer, indicating that none of the other three stereoisomers inhibited responses to the active enantiomer. Beetles responded to as little as 10 ng and 10 µg of synthetic 3,5-dimethyldodecanoic acid in laboratory and field studies, respectively. Field studies indicated that capture rate did not increase with dosages of 3,5-dimethyldodecanoic acid greater than 100 µg. In field bioassays, males of a congeneric species, P. lecontei Lameere, were captured in southern California but not in Idaho.

Identification of Tree Genera Used in the Construction of Solid Wood-Packaging Materials That Arrived at U.S. Ports Infested With Live Wood-Boring Insects.

Although international regulations have been successfully implemented to reduce the introduction and spread of plant pests through wood packaging material (WPM), wood-boring insects continue to be intercepted in WPM at U.S. ports of entry. Both hardwoods and softwoods are used in the construction of WPM for international trade; however, it is not clear if some types of wood pose higher risks than others for harboring wood borers. This study documented the taxonomic diversity of infested wood genera intercepted as a result of targeted WPM inspection at U.S. ports, and identified many of the wood-boring insects transported within them. The results of this study reveal associations among packaging woods, commodities, and shipment origins. The wood genera most frequently infested were Pinus Linnaeus (Pinales: Pinaceae), Picea Miller (Pinales: Pinaceae), and Populus Linnaeus (Malpighiales: Salicaceae), which were heavily represented as packaging for commodities such as stone, metal, vehicles, and machinery. In addition to these results, we summarized preferences by the wood borers to develop in living, stressed, dying, or dead hosts, the pest status of intercepted wood borers in their native and non-native ranges, and potential host range of intercepted wood borers to gauge potential for these taxa to become pests in North America. New possible host associations are reported for eight wood borer taxa. Taxonomy of host wood is presented as a new factor for consideration in pathway-level risk analysis of WPM, and the findings further reinforce the need for enhanced compliance with ISPM 15 to reduce entry of non-native wood-boring insects.

Identification and synthesis of a female-produced sex pheromone for the cerambycid beetle Prionus californicus.

Females of the large cerambycid beetle Prionus californicus produce a powerful sex pheromone that attracts males. The pheromone was adsorbed on solid phase microextraction (SPME) fibers inserted into the ovipositor sheath and analyzed by coupled gas chromatography-electroantennogram detection and GC-mass spectrometry. The pheromone was identified as an isomer of 3,5-dimethyldodecanoic acid by a combination of retention index comparisons and mass spectral interpretation. The mass spectrum was misleading because it exhibited enlarged fragment ions that were not representative of branch points or other obvious stabilizing structural elements. The structure was verified by synthesis of 3,5-dimethyldodecanoic acid as a mixture of all four possible isomers, and this mixture was highly attractive to male beetles in field bioassays. The SPME extracts also contained several other compounds that were tentatively identified as chain-extended homologs of the main pheromone component. This pheromone should prove useful for sampling and management of the beetle, which is an important pest of hops, and an occasional pest in a variety of orchard crops. Although this is the first female-produced pheromone to be identified from the Cerambycidae, there is considerable evidence for pheromone production by females of other species in the subfamily Prioninae. Thus, this pheromone and the associated methodology used in its identification should be useful in the identification of female-produced attractant pheromones from other members of the subfamily.

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.

Male Megacyllene robiniae (Coleoptera: Cerambycidae) use multiple tactics when aggressively competing for mates.

Adult male Megacyllene robiniae (Förster) (Coleoptera: Cerambycidae) that are paired with a female often are challenged by conspecific males that attempt to displace them. In staged laboratory bouts, challenging males used seven distinct tactics to displace defending males, including wedging their head between the defender and the female (termed wedging), straddling the mated pair and pulling the defender off (prying), pulling it with the mandibles, batting it with the antennae, or pushing, biting, or kicking the defender. Individual challengers attempted as many as six different tactics in a single bout, repeating certain tactics multiple times. They often attempted tactics that were not very effective. For example, prying was one of the most common attempted tactics but was rarely effective. However, few challengers attempted to push defenders off the female, even though that tactic often was effective. Challengers apparently were influenced by context in their choice of particular tactics. For example, males that approached the mated pair from the side were likely to use wedging, whereas those approaching head on were more likely to bat with the antennae. Choice of tactic apparently was not influenced by absolute size of challengers, nor was it strongly influenced by relative size of defenders. However, the effectiveness of tactics varied significantly with relative body size: larger challengers were most successful when prying or pushing, while smaller challengers were most successful when biting and kicking. By using different tactics, relatively small males were as adept as larger males at displacing rivals.

Isolation and identification of a male-produced aggregation-sex pheromone for the velvet longhorned beetle, Trichoferus campestris.

The velvet longhorned beetle, Trichoferus campestris (Faldermann) ("VLB"; Coleoptera: Cerambycidae), is native to eastern Asia where it infests and damages a wide range of deciduous and coniferous tree species, including orchard and timber species. Immature stages of VLB are transported to new countries via international commerce, and populations have established outside the native range of the species. Here, we show that identification of pheromones of invasive pest species can be expedited by knowledge of the semiochemistry of related taxa. Histological sectioning revealed subcuticular, male-specific prothoracic glands connected to pits in the cuticle, which, in related species, are diagnostic for production of male-produced aggregation-sex pheromones, usually characterized by 2,3-alkanediol/hydroxyketone structural motifs. However, in preliminary field bioassays, beetles were not attracted by any known cerambycid pheromones. Subsequently, we identified a novel variant of the hydroxyketone motif ("trichoferone") from headspace volatiles of males. In field bioassays, synthetic trichoferone was more attractive to both sexes of VLB than previously developed high-release-rate ethanol lures, and attraction was strongly female biased. This study demonstrated the utility of the prothoracic gland trait for predicting pheromone use in cerambycid species in the subfamily Cerambycinae, and that identification of pheromones of novel species can be expedited by knowledge of pheromones of related species. Trichoferone should prove to be a valuable tool for detection of VLB in regions where the beetle is or may become established.

The Common Natural Products (S)-α-Terpineol and (E)-2-Hexenol are Important Pheromone Components of Megacyllene antennata (Coleoptera: Cerambycidae).

We report here the pheromone of Megacyllene antennata (White) (Coleoptera: Cerambycidae), a species native to southwestern North America whose larvae feed in woody tissues of mesquite (Prosopis species; Fabaceae). Adult males sex-specifically produced a blend of eight common natural products, including the monoterpene alcohol (S)-α-terpineol; the monoterpenes (S)-limonene and terpinolene; the aromatic alcohols (R)-1-phenylethanol and 2-phenylethanol; and (E)-2-hexenol, (E)-2-hexenal, and 1-hexanol. Individual males produced the components in varying amounts, but (S)-α-terpineol and (E)-2-hexenal were always present and together constituted the majority of the blend. A synthetic reconstruction of the complete blend attracted both males and females of M. antennata during field bioassays, as did all subsets of the blend that included (S)-α-terpineol and (E)-2-hexenol. Adults were most strongly attracted to blends of the latter two compounds when in ratios approaching parity. Neither of the compounds were present in the bouquet of volatiles emitted by host plants of the larvae.

Assessing Flight Potential of the Invasive Asian Longhorned Beetle (Coleoptera: Cerambycidae) With Computerized Flight Mills.

The Asian longhorned beetle, Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae: Lamiinae), is an invasive woodborer that poses a serious threat to urban and natural landscapes. In North America, this beetle is a quarantine pest, and populations are subject to eradication efforts that consist of the identification, removal, and destruction of infested host material, and removal or prophylactic treatment of high-risk host plant species. To enhance Asian longhorned beetle eradication protocols in landscapes with extensive host availability, we assessed the dispersal potential of male and female adults of varying age, mating, and nutritional status using computerized flight mills. In total, 162 individuals were tethered to computerized flight mills for a 24-h trial period to collect information on total distance flown, flight times and velocities, and number and duration of flight bouts. Adult Asian longhorned beetles (in all treatments) flew an average of 2,272 m within a 24-h period, but are capable of flying up to 13,667 m (8.5 miles). Nutrition and age had the greatest impacts on flight, with Asian longhorned beetle adults >5 d of age that had fed having greater overall flight performance than any other group. However, mating status, sex, and body size (pre-flight weight and elytron length) had a minimal effect on flight performance. This information will be useful for refining quarantine zones surrounding areas of infestation, and for providing greater specificity as to the risk the Asian longhorned beetle poses within invaded regions.

Identification of wood-boring beetles (Cerambycidae and Buprestidae) intercepted in trade-associated solid wood packaging material using DNA barcoding and morphology.

Global trade facilitates the inadvertent movement of insect pests and subsequent establishment of populations outside their native ranges. Despite phytosanitary measures, nonnative insects arrive at United States (U.S.) ports of entry as larvae in solid wood packaging material (SWPM). Identification of wood-boring larval insects is important for pest risk analysis and management, but is difficult beyond family level due to highly conserved morphology. Therefore, we integrated DNA barcoding and rearing of larvae to identify wood-boring insects in SWPM. From 2012 to 2015, we obtained larvae of 338 longhorned beetles (Cerambycidae) and 38 metallic wood boring beetles (Buprestidae) intercepted in SWPM associated with imported products at six U.S. ports. We identified 265 specimens to species or genus using DNA barcodes. Ninety-three larvae were reared to adults and identified morphologically. No conflict was found between the two approaches, which together identified 275 cerambycids (23 genera) and 16 buprestids (4 genera). Our integrated approach confirmed novel DNA barcodes for seven species (10 specimens) of woodborers not in public databases. This study demonstrates the utility of DNA barcoding as a tool for regulatory agencies. We provide important documentation of potential beetle pests that may cross country borders through the SWPM pathway.

The History of Attack and Success of Emerald Ash Borer (Coleoptera: Buprestidae) on White Fringetree in Southwestern Ohio.

Emerald ash borer, Agrilus planipennis Fairmaire, is an invasive insect that has caused widespread mortality of ash species in North America. The ability of emerald ash borer to utilize white fringetree as an alternate host was reported recently. We aimed to determine how long white fringetree has been under attack from emerald ash borer, the degree of attack, and the overall success of this beetle on this novel host. Stems from three of nine infested white fringetrees collected from the Dayton and Cincinnati, OH, areas in the winter of 2015 yielded four live adult emerald ash borers after being held in rearing containers, and numerous older exit holes were observed. Measurement and aging of feeding galleries on these stems indicated that emerald ash borer has been using this species since 2011, at least, with peak gallery densities reached in 2012 and 2013 on most of the harvested trees. On average, 32 galleries per square meter were found in these stems with about one-third of them being indicative of fourth-instar larvae. This supports the assertion that emerald ash borer has been using white fringetree as a host plant with moderate to good success for as long as ash species in these particular areas have been utilized.

(R)-Desmolactone is a sex pheromone or sex attractant for the endangered valley elderberry longhorn beetle Desmocerus californicus dimorphus and several congeners (Cerambycidae: Lepturinae).

We report here that (4R,9Z)-hexadec-9-en-4-olide [(R)-desmolactone] is a sex attractant or sex pheromone for multiple species and subspecies in the cerambycid genus Desmocerus. This compound was previously identified as a female-produced sex attractant pheromone of Desmocerus californicus californicus. Headspace volatiles from female Desmocerus aureipennis aureipennis contained (R)-desmolactone, and the antennae of adult males of two species responded strongly to synthetic (R)-desmolactone in coupled gas chromatography-electroantennogram analyses. In field bioassays in California, Oregon, and British Columbia, traps baited with synthetic (R)-desmolactone captured males of several Desmocerus species and subspecies. Only male beetles were captured, indicating that this compound acts as a sex-specific attractant, rather than as a signal for aggregation. In targeted field bioassays, males of the US federally threatened subspecies Desmocerus californicus dimorphus responded to the synthetic attractant in a dose dependent manner. Our results represent the first example of a "generic" sex pheromone used by multiple species in the subfamily Lepturinae, and demonstrate that pheromone-baited traps may be a sensitive and efficient method of monitoring the threatened species Desmocerus californicus dimorphus, commonly known as the valley elderberry longhorn beetle.

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.

Predicted taxonomic patterns in pheromone production by longhorned beetles.

Males of five species of three tribes in the longhorned beetle subfamily Cerambycinae produce volatile pheromones that share a structural motif (hydroxyl or carbonyl groups at carbons two and three in straight-chains of six, eight, or ten carbons). Pheromone gland pores are present on the prothoraces of males, but are absent in females, suggesting that male-specific gland pores could provide a convenient morphological indication that a species uses volatile pheromones. In this article, we assess the taxonomic distribution of gland pores within the Cerambycinae by examining males and females of 65 species in 24 tribes using scanning electron microscopy. Gland pores were present in males and absent in females of 49 species, but absent in both sexes of the remaining 16 species. Pores were confined to indentations in the cuticle. Among the species that had male-specific gland pores were four species already known to produce volatile compounds consistent with the structural motif. These findings support the initial assumption that gland pores are associated with the production of pheromones by males. There were apparently no taxonomic patterns in the presence of gland pores. These findings suggest that volatile pheromones play an important role in reproduction for many species of the Cerambycinae, and that the trait is evolutionarily labile.