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.

2-Nonanone is a Critical Pheromone Component for Cerambycid Beetle Species Native to North and South America.

An increasing body of evidence indicates that cerambycid beetles native to different continents may share pheromone components, suggesting that these compounds arose as pheromone components early in the evolution of the family. Here, we describe the identification and field testing of the pheromone blends of two species in the subfamily Cerambycinae that share 2-nonanone as an important component of their male-produced aggregation-sex pheromones, the South American Stizocera consobrina Gounelle (tribe Elaphidiini) and the North American Heterachthes quadrimaculatus Haldeman (tribe Neoibidionini). Along with 2-nonanone, males of S. consobrina also produce 1-(1H-pyrrol-2-yl)-1,2-propanedione, whereas males of H. quadrimaculatus produce 10-methyldodecanol. Field bioassays conducted in Brazil (targeting S. consobrina) and Illinois (targeting H. quadrimaculatus) demonstrated that adults of both species were attracted only by the blends of both their pheromone components, and not to the individual components. The use of the pyrrole as a critical component for the former species is further evidence that this compound is a common pheromone structure among cerambycines in different biogeographical regions of the world.

Identification of a Male-Produced Volatile Pheromone for Phymatodes dimidiatus (Coleoptera: Cerambycidae) and Seasonal Flight Phenology of Four Phymatodes Species Endemic to the North American Intermountain West.

Research over the last 15 yr has shown widespread pheromone parsimony within the coleopteran family Cerambycidae, with a number of highly conserved pheromone motifs, often shared within and across subfamilies, tribes, and genera. Our goals were to increase our understanding of the evolution of volatile pheromones within the Cerambycidae, their role in reproductive isolation and to identify pheromones for use in the development of lures for monitoring cerambycids. Over 3 yr, we tested 12 compounds known to be cerambycid pheromones as possible attractants at sites across Idaho. This study focused on species within the cerambycine genus Phymatodes (Tribe: Callidiini). We also collected and analyzed headspace volatiles of captured Phymatodes dimidiatus (Kirby). Our results demonstrate that (R)-2-methylbutan-1-ol is a male-produced volatile pheromone for P. dimidiatus. These results are consistent with prior research suggesting that (R)-2-methylbutan-1-ol and (R)-3-hydroxyhexan-2-one, individually or in a blend of both compounds, commonly serve as pheromones for Phymatodes spp. We captured Phymatodes starting in mid-May, continuing through mid-August. Our data indicate that flight periods of Phymatodes spp. in Idaho overlap. These species may be utilizing various mechanisms to ensure reproductive isolation, such as the production of different volatile pheromones, minor components, and/or proportions of components, utilizing different host species and/or host volatiles, differing daily activity periods, and/or occupying different heights in the tree canopy. Our results contribute to the basic understanding of the chemical and behavioral ecology of the Cerambycidae and can be applied to the development of pheromone lures for monitoring of economically important or endangered species.

Pheromone Composition and Chemical Ecology of Six Species of Cerambycid Beetles in the Subfamily Lamiinae.

Cerambycid beetles of the subfamily Lamiinae use male-produced aggregation-sex pheromones that are attractive to both sexes. Terpenoid pheromones have been identified from species in the tribes Acanthoderini and Acanthocinini native to North and South America, comprised of (E)-6,10-dimethyl-5,9-undecadien-2-one (geranylacetone), the structurally related 6-methylhept-5-en-2-one (sulcatone), and/or specific enantiomers or nonracemic ratios of enantiomers of the related compounds (E)-6,10-dimethyl-5,9-undecadien-2-ol (fuscumol), its acetate ester, (E)-6,10-dimethyl-5,9-undecadien-2-yl acetate (fuscumol acetate), and 6-methylhept-5-en-2-ol (sulcatol). Here, we present new information about the chemical ecology of six acanthoderine and acanthocinine species native to the eastern USA. The pheromone of Astyleiopus variegatus (Haldeman) previously was identified as a blend of (S)-fuscumol and (S)-fuscumol acetate, and we report here that geranylacetone is a synergistic component. Males of Aegomorphus modestus (Gyllenhal), Lepturges angulatus (LeConte), and Lepturges confluens (Haldeman) were found to produce similar blends composed of the enantiomers of fuscumol acetate and geranylacetone, whereas males of Astylidius parvus (LeConte) and Sternidius alpha (Say) produced both enantiomers of fuscumol together with (R)-fuscumol acetate and geranylacetone. Field experiments with synthesized chemicals revealed that species with similar pheromone composition nevertheless differed in their responses to individual components, and to various blends of components, and in how attraction was influenced by chemicals that were pheromone components of other species. Sulcatone and/or sulcatol antagonized attraction of some species to pheromones of the geranylacetone class, suggesting that there is an adaptive advantage in an ability to detect these heterospecific compounds, such as in avoiding cross attraction to other cerambycid species, as yet unknown, that use pheromones composed of both chemical classes.

The Role of Minor Pheromone Components in Segregating 14 Species of Longhorned Beetles (Coleoptera: Cerambycidae) of the Subfamily Cerambycinae.

We present research on the chemical ecology of 14 species of longhorned beetles (Coleoptera: Cerambycidae), in four tribes of the subfamily Cerambycinae, conducted in east-central Illinois over 8 yr. Adult males produce aggregation-sex pheromones that attract both sexes. Twenty independent field bioassays explored the pheromone chemistry of the species and tested the possible attractive or antagonistic effects of compounds that are not produced by a given species, but are pheromone components of other species. Analyses of beetle-produced volatiles revealed compounds that had not been reported previously from several of the species. The most common pheromone component was (R)-3-hydroxyhexan-2-one, but pheromones of some species included isomers of the related 2,3-hexanediols. Males of the congeners Phymatodes amoenus (Say) and Phymatodes testaceus (L.) produced pure (R)-2-methylbutan-1-ol. Enantiomers of 2-methylbutan-1-ol also proved to be powerful synergists for Megacyllene caryae (Gahan), Sarosesthes fulminans (F.), and Xylotrechus colonus (F.). The major components of pheromone blends were consistently present in collections of headspace volatiles from male beetles, and only the major components were inherently attractive to a subset of species when tested as single components. Minor components of some species acted as powerful synergists, but in other cases appeared not to influence attraction. Among the minor components identified in headspace extracts from males, 2,3-hexanedione and 2-hydroxyhexan-3-one appeared to be analytical artifacts or biosynthetic by-products, and were neither attractants nor synergists. The antagonistic effects of minor compounds produced by heterospecific males suggest that these compounds serve to maintain prezygotic reproductive isolation among some species that share pheromone components.

(S)-Sulcatol Is a Pheromone Component for Two Species of Cerambycid Beetles in the Subfamily Lamiinae.

Males of several species in the large cerambycid beetle subfamily Lamiine, native to South and North America, are known to produce aggregation-sex pheromones composed of three related structures: the sesquiterpene catabolic product geranylacetone, its corresponding alcohol (known as fuscumol), and the acetate ester of the alcohol (fuscumol acetate). Here, we show that males of two lamiine species native to the eastern USA, Astylopsis macula (Say) and Leptostylus transversus (Gyllenhal) (both tribe Acanthocinini), produce pheromones composed of the structurally related (S)-6-methylhept-5-en-2-ol ([S]-sulcatol). Males of both species also produced 6-methylhept-5-en-2-one (sulcatone), and males of A. macula produced trace amounts of (R)-fuscumol acetate. Field experiments demonstrated that both species were attracted by (S)-sulcatol. Sulcatone was not attractive as a single component, nor did it influence attraction of A. macula to (S)-sulcatol, while its effect on L. transversus was unclear. Data from the field experiments, and a separate experiment using traps fitted with a timer mechanism that rotated trap jars, revealed that the two species overlap only slightly in both seasonal and daily flight period, thus minimizing interspecific attraction. Racemic fuscumol acetate and fuscumol antagonized attraction of both species to sulcatol. The identification of sulcatol as a cerambycid pheromone extends the known range of pheromone components in the subfamily Lamiinae.

Identifying Possible Pheromones of Cerambycid Beetles by Field Testing Known Pheromone Components in Four Widely Separated Regions of the United States.

The pheromone components of many cerambycid beetles appear to be broadly shared among related species, including species native to different regions of the world. This apparent conservation of pheromone structures within the family suggests that field trials of common pheromone components could be used as a means of attracting multiple species, which then could be targeted for full identification of their pheromones. Here, we describe the results of such field trials that were conducted in nine states in the northeastern, midwestern, southern, and western United States. Traps captured 12,742 cerambycid beetles of 153 species and subspecies. Species attracted in significant numbers to a particular treatment (some in multiple regions) included 19 species in the subfamily Cerambycinae, 15 species in the Lamiinae, one species in the Prioninae, and two species in the Spondylidinae. Pheromones or likely pheromones for many of these species, such as 3-hydroxyhexan-2-one and syn- and anti-2,3-hexanediols for cerambycine species, and fuscumol and/or fuscumol acetate for lamiine species, had already been identified. New information about attractants (in most cases likely pheromone components) was found for five cerambycine species (Ancylocera bicolor [Olivier], Elaphidion mucronatum [Say], Knulliana cincta cincta [Drury], Phymatodes aeneus LeConte, and Rusticoclytus annosus emotus [Brown]), and five lamiine species (Ecyrus dasycerus dasycerus [Say], Lepturges symmetricus [Haldeman], Sternidius misellus [LeConte], Styloleptus biustus biustus [LeConte], and Urgleptes signatus [LeConte]). Consistent attraction of some species to the same compounds in independent bioassays demonstrated the utility and reliability of pheromone-based methods for sampling cerambycid populations across broad spatial scales.

(2E,6Z,9Z)-2,6,9-Pentadecatrienal as a Male-Produced Aggregation-Sex Pheromone of the Cerambycid Beetle Elaphidion mucronatum.

An increasing body of evidence suggests that the volatile pheromones of cerambycid beetles are much more diverse in structure than previously hypothesized. Here, we describe the identification, synthesis, and field testing of (2E,6Z,9Z)-2,6,9-pentadecatrienal as a male-produced aggregation-sex pheromone of the cerambycid Elaphidion mucronatum (Say) (subfamily Cerambycinae, tribe Elaphidiini). This novel structure is unlike any previously described cerambycid pheromone, and in field bioassays attracted only this species. Males produced about 9 µg of pheromone per 24 h period, and, in field trials, lures loaded with 10, 25, and 100 mg of synthetic pheromone attracted beetles of both sexes, whereas lures loaded with 1 mg of pheromone or less were not significantly attractive. Other typical cerambycine pheromones such as 3-hydroxy-2-hexanone, syn-2,3-hexanediol, and anti-2,3-hexanediol were not attractive to E. mucronatum, and when combined with (2E,6Z,9Z)-2,6,9-pentadecatrienal, the former two compounds appeared to inhibit attraction. Unexpectedly, adults of the cerambycine Xylotrechus colonus (F.) were attracted in significant numbers to a blend of 3-hydroxyhexan-2-one and (2E,6Z,9Z)-2,6,9-pentadecatrienal, even though there is no evidence that this species produces the latter compound. From timed pheromone trap catches, adults of E. mucronatum were determined to be active from dusk until shortly after midnight.

Evaluation of Methods Used in Testing Attraction of Cerambycid Beetles to Pheromone-Baited Traps.

Here, we describe several field experiments that evaluated potential problems with current methods of trapping cerambycid beetles using panel traps baited with synthesized pheromones. Positioning traps at least 5 m apart in linear transects was effective in preventing unbaited traps from intercepting beetles that were flying to baited traps, which would result in interference between treatments. There was no evidence that traps baited with a strong attractant drew beetles away from traps baited with weaker attractants, which would lead to the erroneous conclusion that the latter have no activity. Unbaited panel traps were minimally attractive to cerambycid beetles, and unlikely to intercept them passively in flight. Finally, dose-response experiments revealed that trap catch of cerambycids was positively associated with pheromone release rates. Overall, our results generally validated current methods of trapping cerambycids using traps baited with pheromones.

The Rare North American Cerambycid Beetle Dryobius sexnotatus Shares a Novel Pyrrole Pheromone Component with Species in Asia and South America.

The compound 1-(1H-pyrrol-2-yl)-1,2-propanedione ("pyrrole") is an important pheromone component of several Asian and South American species of longhorned beetles in the subfamily Cerambycinae. Here, we report the first confirmed identification of this compound as a pheromone component of a cerambycine species native to North America, the rare beetle Dryobius sexnotatus Linsley. Headspace volatiles from males contained (R)-3-hydroxyhexan-2-one and pyrrole (ratio 1:0.13), neither of which were detected in samples from a female. A field bioassay confirmed that adults of both sexes were attracted only to the binary blend of racemic 3-hydroxyhexan-2-one plus pyrrole, and not by either compound alone. Adults of another cerambycine, Xylotrechus colonus (F.), were attracted by 3-hydroxyhexan-2-one, consistent with this compound being the primary component of the pheromone of this species; attraction was not influenced by the presence of pyrrole. This study attests to the effectiveness of pheromone-baited traps in capturing rarely encountered species of cerambycids. It also provides further evidence that pyrrole represents another conserved pheromone motif within the Cerambycinae, now having been found in representatives of five cerambycid tribes from three continents.

Evidence that Cerambycid Beetles Mimic Vespid Wasps in Odor as well as Appearance.

We present evidence that cerambycid species that are supposed mimics of vespid wasps also mimic their model's odor by producing spiroacetals, common constituents of vespid alarm pheromones. Adults of the North American cerambycids Megacyllene caryae (Gahan) and Megacyllene robiniae (Forster) are conspicuously patterned yellow and black, and are believed to be mimics of aculeate Hymenoptera, such as species of Vespula and Polistes. Adult males of M. caryae produce an aggregation-sex pheromone, but both sexes produce a pungent odor when handled, which has been assumed to be a defensive response. Headspace aerations of agitated females of M. caryae contained 16 compounds with mass spectra characteristic of spiroacetals of eight distinct chemical structures, with the dominant compound being (7E,2E)-7-ethyl-2-methyl-1,6-dioxaspiro[4.5]decane. Headspace samples of agitated males of M. caryae contained five of the same components, with the same dominant compound. Females of M. robiniae produced six different spiroacetals, one of which was not produced by M. caryae, (2E,7E)-2-ethyl-7-methyl-1,6-dioxaspiro[4.5]decane, and five that were shared with M. caryae, including the dominant (2E,8E)-2,8-dimethyl-1,7-dioxaspiro[5.5]undecane. The latter compound is the sole spiroacetal produced by both males and females of a South American cerambycid species, Callisphyris apicicornis (Fairmaire & Germain), which is also thought to be a wasp mimic. Preliminary work also identified spiroacetals of similar or identical structure released by vespid wasps that co-occur with the Megacyllene species.

Synergism between Enantiomers Creates Species-Specific Pheromone Blends and Minimizes Cross-Attraction for Two Species of Cerambycid Beetles.

Research over the last decade has revealed extensive parsimony among pheromones within the large insect family Cerambycidae, with males of many species producing the same, or very similar aggregation pheromones. Among some species in the subfamily Cerambycinae, interspecific attraction is minimized by temporal segregation, and/or by minor pheromone components that synergize attraction of conspecifics or inhibit attraction of heterospecifics. Less is known about pheromone-based mechanisms of reproductive isolation among species in the largest subfamily, the Lamiinae. Here, we present evidence that the pheromone systems of two sympatric lamiine species consist of synergistic blends of enantiomers of (E)-6,10-dimethyl-5,9-undecadien-2-ol (fuscumol) and the structurally related (E)-6,10-dimethyl-5,9-undecadien-2-yl acetate (fuscumol acetate), as a mechanism by which species-specific blends of pheromone components can minimize interspecific attraction. Male Astylidius parvus (LeConte) were found to produce (R)- and (S)-fuscumol + (R)-fuscumol acetate + geranylacetone, whereas males of Lepturges angulatus (LeConte) produced (R)- and (S)-fuscumol acetate + geranylacetone. Field experiments confirmed that adult beetles were attracted only by their species-specific blend of the enantiomers of fuscumol and fuscumol acetate, respectively, and not to the individual enantiomers. Because other lamiine species are known to produce single enantiomers or blends of enantiomers of fuscumol and/or fuscumol acetate, synergism between enantiomers, or inhibition by enantiomers, may be a widespread mechanism for forming species-specific pheromone blends in this subfamily.

Candidate Attractant Pheromones of Two Potentially Invasive Asian Cerambycid Species in the Genus Xylotrechus.

Research during the 1980s showed that male Xylotrechus pyrrhoderus Bates (Coleoptera: Cerambycidae), a vineyard pest, produce (2S,3S)-2,3-octanediol and (S)-2-hydroxyoctan-3-one as possible pheromone components, but to our knowledge, field tests were not carried out. We confirmed that at least female X. pyrrhoderus were attracted by a 1:1 blend of these two compounds in field trials in Japan. Furthermore, more than 200 males and females of the congener Xylotrechus rufilius Bates were attracted by racemic 2-hydroxyoctan-3-one, and inhibited by syn-2,3-octanediol. Adult X. rufilius recently were intercepted in a shipment from China entering Baltimore, Maryland, raising concerns that this polyphagous species could establish in North America. Our results suggest that traps baited with 2-hydroxyoctan-3-one would be a valuable tool to assess whether X. rufilius has indeed become established, and to monitor for future introductions of X. rufilius.

(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.

Cerambycid Beetle Species with Similar Pheromones are Segregated by Phenology and Minor Pheromone Components.

Recent research has shown that volatile sex and aggregation-sex pheromones of many species of cerambycid beetles are highly conserved, with sympatric and synchronic species that are closely related (i.e., congeners), and even more distantly related (different subfamilies), using the same or similar pheromones. Here, we investigated mechanisms by which cross attraction is averted among seven cerambycid species that are native to eastern North America and active as adults in spring: Anelaphus pumilus (Newman), Cyrtophorus verrucosus (Olivier), Euderces pini (Olivier), Neoclytus caprea (Say), and the congeners Phymatodes aereus (Newman), P. amoenus (Say), and P. varius (F.). Males of these species produce (R)-3-hydroxyhexan-2-one as their dominant or sole pheromone component. Our field bioassays support the hypothesis that cross attraction between species is averted or at least minimized by differences among species in seasonal phenology and circadian flight periods of adults, and/or by minor pheromone components that act as synergists for conspecifics and antagonists for heterospecifics.

The shrinking world of girls at puberty: violence and gender-divergent access to the public sphere among adolescents in South Africa.

Participatory mapping was undertaken with single-sex groups of grade 5 and grade 8-9 children in KwaZulu-Natal. Relative to grade 5 students, wide gender divergence in access to the public sphere was found at grade 8-9. With puberty, girls' worlds shrink, while boys' expand. At grade 5, female-defined community areas were equal or larger in size than those of males. Community area mapped by urban grade 8-9 girls, however, was only one-third that of male classmates and two-fifths that of grade 5 girls. Conversely, community area mapped by grade 8-9 boys was twice that of grade 5 boys. Similar differences emerged in the rural site. No female group rated a single community space as more than 'somewhat safe'. Although curtailed spatial access is intended to protect girls, grade 8-9 girls reported most places in their small navigable areas as very unsafe. Expanded geographies of grade 8-9 boys contained a mix of safe and unsafe places. Reducing girls' access to the public sphere does not increase their perceived safety, but may instead limit their access to opportunities for human development. The findings emphasise the need for better violence prevention programming for very young adolescents.

Seasonal phenology of the cerambycid beetles of east-central Illinois.

We summarize field data on the species composition and seasonal phenology of the community of cerambycid beetles of east-central Illinois. Data were drawn from field bioassays conducted during 2009 - 2012 that tested attraction of adult beetles of diverse species to a variety of synthetic pheromones and host plant volatiles. A total of 34,086 beetles of 114 species were captured, including 48 species in the subfamily Cerambycinae, 41 species in the Lamiinae, 19 species in the Lepturinae, two species in the Spondylidinae, and one species each in the Necydalinae, Parandrinae, Prioninae, and the Disteniidae. Most of the best-represented species were attracted to pheromones that were included in field experiments, particularly species that use (R)-3-hydroxyhexan-2-one as a pheromone component. The species captured, and their patterns of abundance and seasonal phenology were similar to those in an earlier study conducted in Pennsylvania. The most abundant species identified in both studies included the cerambycines Elaphidion mucronatum (Say), Neoclytus a. acuminatus (F.), Neoclytus m. mucronatus (F.), and Xylotrechus colonus (F.). Cerambycine species became active in an orderly progression from early spring through late fall, whereas most lamiine species were active in summer and fall, and lepturine species were limited to summer. Potential cross attraction between some cerambycine species that shared pheromone components may have been averted by differences in seasonal activity period, and by minor pheromone components that acted as synergists for conspecifics and/or antagonists for heterospecifics. These results provide quantitative data on the abundance and seasonal phenology of a large number of species.