Showing papers by "Jocelyn G. Millar published in 2012"
TL;DR: These putative Ors sequenced from an antennal transcriptome of the cerambycid beetle Megacyllene caryae are the first to be functionally characterized from any species of beetle and lay the groundwork for understanding the evolution of pheromones within the Ceram bycidae.
105 citations
TL;DR: Results indicate that monochamol is a male-produced pheromone for both M. carolinensis and M. titillator, and that antennae of males and females of both species detect it.
Abstract: In recent years, several attractant pheromones have been identified for cerambycid beetles, including 2-(undecyloxy)-ethanol (hereafter monochamol) for Monochamus galloprovincialis (Olivier), M. alternatus Hope, and M. scutellatus (Say). This study screened eight known cerambycid pheromones or their analogues (including monochamol) as potential attractants for M. carolinensis Olivier and M. titillator (F.), in the presence and absence of the host volatile α-pinene. Monochamol attracted M. carolinensis in the presence and absence of α-pinene, whereas M. titillator was only attracted to the combination of monochamol and α-pinene. (2R*,3R*)-2,3-Hexanediol also attracted both M. carolinensis and M. titillator, but only in the presence of α-pinene. Subsequent coupled gas chromatography—mass spectrometry and gas chromatography—electroantennogram detection analyses of extracts of volatiles collected from both sexes demonstrated that male M. carolinensis and M. titillator release monochamol, and that ant...
74 citations
TL;DR: The goal was to identify effective detection tools for a broad array of cerambycid species by testing some known ceram bycid attractants and a pheromone in different trap designs placed across a range of habitats.
Abstract: Wood-boring beetles in the family Cerambycidae (Coleoptera) play important roles in many forest ecosystems. However, increasing numbers of invasive cerambycid species are transported to new countries by global commerce and threaten forest health in the United States and worldwide. Our goal was to identify effective detection tools for a broad array of cerambycid species by testing some known cerambycid attractants and a pheromone in different trap designs placed across a range of habitats. We compared numbers and species richness of cerambycid beetles captured with crossvane panel traps and 12-unit Lindgren multiple-funnel traps, placed either at ground level (1.5 m high) or canopy level (≈3–10 m high), at eight sites classified as either residential, industrial, deciduous forest, or conifer forest. We captured 3,723 beetles representing 72 cerambycid species from 10 June to 15 July 2010. Species richness was highest for the subfamilies Cerambycinae and Lamiinae, which accounted for 33 and 46% of...
65 citations
TL;DR: The authors identified and field tested 2-(undecyloxy)-ethanol (monochamol) as a sex-specific, aggregation pheromone component produced by males of Monochamus scutellatus (Say) (Coleoptera: Cerambycidae), a longhorned beetle native to North America.
Abstract: We report identification and field testing of 2-(undecyloxy)-ethanol (monochamol) as a sex-specific, aggregation pheromone component produced by males of Monochamus scutellatus scutellatus (Say) (Coleoptera: Cerambycidae), a longhorned beetle native to North America. A congener, Monochamus notatus (Drury), which uses the same hosts as M. s. scutellatus, also was attracted to this compound in field trials, suggesting it may be a pheromone component for this species as well. Panel traps were deployed along transects at each of five field sites in May 2010 to test attraction of native beetle species to a suite of cerambycid pheromone components, including monochamol, 3-hydroxyhexan-2-one, (2R*,3R*)- and (2R*, 3S*)-2,3-hexanediol, racemic (E/Z)-fuscumol, and (E/Z)-fuscumol acetate. In total, 209 adult M. s. scutellatus (136 females, 73 males) and 20 M. notatus (16 females, four males) were captured, of which 86 and 70%, respectively, were captured in traps baited with monochamol (means significantly different). Analysis of headspace volatiles from adult M. s. scutellatus by coupled gas chromatography-mass spectrometry and gas chromatography-electroantennogram detection confirmed that monochamol was produced only by males. Monochamol was not found in headspace extracts from adult M. notatus. This study provides further evidence that monochamol is a pheromone component common to several species in the genus Monochamus. The pheromone component should prove useful for monitoring native species for management purposes or conservation efforts, and for quarantine monitoring for exotic species.
64 citations
TL;DR: Positive dose-response relationships between the aldehyde blend and two hydrocarbon mixtures were found and the lowest doses that elicited synergism were 10−1 female equivalents (of body wax extracts) for the two hydrocarbons, and 10−2 female equivalents for the total unsaturated hydrocarbon mixture.
Abstract: Four trienyl hydrocarbons, (Z3, Z6, Z9)-tricosatriene (Z3, Z6, Z9-23:HC), (Z3, Z6, Z9)-pentacosatriene (Z3, Z6, Z9-25:HC), (Z3, Z6, Z9)-heptacosatriene (Z3, Z6, Z9-27:HC), and (Z3, Z6, Z9)-nonacosatriene (Z3, Z6, Z9-29:HC) were identified in a non-polar fraction of the body wax of male and female yellow peach moth, Conogethes punctiferalis. The relative amounts and ratios of these hydrocarbons differed between sexes. In females, the ratios in body wax and pheromone gland extracts were similar, with lesser amounts found in gland extracts. Synergistic effects of these hydrocarbons when added to the known aldehyde pheromone components were assessed in wind tunnel tests. A blend of (E)-10-hexadecenal (E10-16: Ald) and (Z)-10-hexadecenal (Z10-16: Ald) elicited upwind flight and orientation of males to the pheromone source, but arriving males did not remain close to source for very long. Among the hydrocarbons identified, only Z3, Z6, Z9-23:HC enhanced the activity of the aldehyde blend by increasing the time spent close to the source and the number of source contacts. Z3, Z6, Z9-23:HC and (Z9)-heptacosene (Z9-27:HC) also increased close-range responses to the aldehyde blend. The activity of the aldehyde blend plus these two hydrocarbons was similar to that of crude pheromone extract. Positive dose-response relationships between the aldehyde blend and two hydrocarbon mixtures were found. The lowest doses that elicited synergism were 10(-1) female equivalents (of body wax extracts) for the two hydrocarbons, and 10(-2) female equivalents for the total unsaturated hydrocarbon mixture.
46 citations
TL;DR: This study compares the cuticular hydrocarbon profiles of dominant and reproductive workers and queens of the ant Odontomachus brunneus with profiles of non-reproductive workers and demonstrates that workers gauge the reproductive activity of nestmates through changes in their cuticular Hydrocarbon profiles.
Abstract: Eusociality is characterized by a reproductive division of labor, wherein workers respond to the presence of reproductive individuals by refraining from reproduction themselves and restricting the reproductive efforts of others. Our understanding of how eusociality is maintained therefore depends on characterizing the mechanism by which workers detect the presence of a reproductive. Variations in cuticular hydrocarbons correspond to changes in reproductive ability in ants, and experimental studies are beginning to reveal the function of hydrocarbons as signals. In this study, we compare the cuticular hydrocarbon profiles of dominant and reproductive workers and queens of the ant Odontomachus brunneus with profiles of non-reproductive workers. Using split/reunification tests we document the existence of worker policing in both queenless and queenright colonies; supernumerary reproductives were treated aggressively by nestmates. Finally, we induce aggression and replicate queen-like submissive nestmate responses by supplementing the hydrocarbon profile of workers with (Z)-9-nonacosene, a compound that was significantly more abundant on the cuticles of reproductives. In three bioassays, we compare this manipulation to various control manipulations of the hydrocarbon profile and demonstrate that workers gauge the reproductive activity of nestmates through changes in their cuticular hydrocarbon profiles.
44 citations
TL;DR: The results suggest that different types of cerambycid pheromones can be combined to create effective multispecies lures for use in surveillance programs that target exotic ceram bycid species.
Abstract: 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.
42 citations
TL;DR: This is the second sex attractant pheromone structure identified from the subfamily Prioninae, and the results provide further evidence of pheromonal parsimony within the Cerambycidae, in this case extending across both subfamily and gender lines.
Abstract: 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.
39 citations
TL;DR: It is concluded that monochamol is a likely pheromone component for the three Monochamus species, and that monchamol plus host plant volatiles is an effective attractant for these and perhaps other North American Monochams species.
Abstract: Two species in the genus Monochamus Dejean (Coleoptera: Cerambycidae: Lamiinae) have recently been shown to have the same male-produced sex pheromone, 2-undecyloxy-1-ethanol (monochamol), suggesting that other congeners may share the same pheromone. We tested that hypothesis by conducting field bioassays of monochamol, in combination with bark-beetle pheromones and the host plant volatiles ethanol and a-pinene, in southern British Columbia, Canada. We captured 603 Monochamus clamator (LeConte), 63 Monochamus obtusus Casey, 245 Monochamus scutellatus (Say) (tribe Monochamini), and 42 Acanthocinus princeps (Walker) (tribe Acanthocinini). All three Mono- chamus species were significantly attracted to the combination of monochamol and host plant volatiles, whereas bark-beetle pheromones plus plant volatiles and plant volatiles alone were minimally attractive. Adding bark-beetle pheromones to the monochamol plus plant volatiles treatment synergised attraction of M. clamator, but not the other two Monochamus species. Acanthocinus princeps was most strongly attracted to the combination of bark-beetle pheromones and plant volatiles, and did not appear to be affected by the presence or absence of monochamol in baits. We conclude that monochamol is a likely pheromone component for the three Monochamus species, and that monochamol plus host plant volatiles is an effective attractant for these and perhaps other North American Monochamus species.
38 citations
TL;DR: It is shown that a second female‐produced compound, the polyunsaturated long‐chain hydrocarbon (3Z,6Z,9Z,12Z,15Z)‐pentacosapentaene (C25 pentaene), is a strong synergist to 9Z,11E‐14:OAc, and that both compounds are needed for significant attraction of males.
Abstract: The spruce coneworm, Dioryctria abietella Denis & Schiffermuller (Lepidoptera: Pyralidae), is a major pest in spruce seed orchards in Europe. Initial work on its pheromone ecology reported significant attraction of males to (9Z,11E)-tetradecadienyl acetate (9Z,11E-14:OAc), but this compound appeared to be a very weak attractant in field trials. In this study, we show that a second female-produced compound, the polyunsaturated long-chain hydrocarbon (3Z,6Z,9Z,12Z,15Z)-pentacosapentaene (C25 pentaene), is a strong synergist to 9Z,11E-14:OAc, and that both compounds are needed for significant attraction of males. In field-trapping experiments, the highest catches were obtained with high amounts of pentaene added to the acetate (acetate:pentaene ratio from 1 : 10 to 1 : 30) and the highest doses (1–3 mg per rubber septum dispenser) were the most attractive. Two potential behavioural synergists, (Z)-9-tetradecenyl acetate and (9Z,12E)-tetradecadienyl acetate, turned out to be behavioural antagonists and both reduced trap catch of D. abietella in a dose-dependent way when added individually to the binary blend. The recent discovery of the C25 pentaene as a pheromone component of D. abietella, as well as of three North American congeners, suggests that the use of a mixture of so-called type I and type II pheromone compounds is a widespread motif of sexual communication within the genus. The identification of a highly attractive sex pheromone will help in developing efficient strategies for monitoring and control of D. abietella populations in European spruce seed orchards. (Less)
22 citations
TL;DR: This compound is the first example of a new structural class of cerambycid pheromones, and is the second phersomone identified for a species in the subfamily Lepturinae.
Abstract: 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.
TL;DR: The identification of the sex pheromone of one of these species, Acutaspis albopicta (Cockerell), from a quarantine colony of these insects initiated from specimens collected from commercial shipments of Mexican avocados will provide a very sensitive and selective tool for detection of the scale to try and prevent its permanent establishment in California.
Abstract: As a result of relaxation of importation restrictions ordered by the Animal and Plant Health Inspection Service of the U.S. Department of Agriculture, shipments of fresh avocados from Mexico began entering California year-round in 2007, despite the fact that these shipments were heavily infested with a number of exotic and potentially invasive armored scale species that are not thought to be present in California. Here, we report the identification of the sex pheromone of one of these species, Acutaspis albopicta (Cockerell), from a quarantine colony of these insects initiated from specimens collected from commercial shipments of Mexican avocados. The compound was identified as [(1S,3S)-2,2-dimethyl-3-(prop-1-en-2-yl)cyclobutyl)]methyl (R)-2-methylbutanoate, and was similar in structure to the pheromones of several other scale and mealybug species. In laboratory bioassays, the pheromone was highly attractive to male scales in microgram doses. The pheromone will provide a very sensitive and selective tool for detection of the scale to try and prevent its permanent establishment in California.
TL;DR: Experiments with caged adults confirmed that females from this population of the grape mealybug could not reproduce parthenogenetically, and exposure to pheromone did stimulate males to emerge slightly sooner than control males, but pherOMone exposure had no effect on the longevity of males.
Abstract: This study characterized several parameters associated with reproductive behaviors of a Californian population of the grape mealybug, Pseudococcus maritimus (Ehrhorn). Experiments with caged adults confirmed that females from this population could not reproduce parthenogenetically. Both sexes were capable of mating multiple times on the same day and on sequential days. Median times between copulations were short (<10 min) on the first day that males were presented with females, but tended to increase with sequential copulation events. Unmated females lived for up to 19 wk, whereas mating and oviposition resulted in reduced longevity. We hypothesized that constant exposure to pheromone might stimulate males to leave their cocoons sooner and increase their activity levels compared with males that were not exposed to pheromone, resulting in shortened life-spans. However, whereas exposure to pheromone did stimulate males to emerge slightly sooner than control males, pheromone exposure had no effect on the longevity of males. The implications of the results of these experiments for pheromone-based methods of detection and control of mealybugs are discussed.
TL;DR: Acutaspis albopicta (Cockerell) is one of seven exotic scale species detected on shipments of ‘Hass’ avocados entering California from Mexico and the scale only reproduces sexually with unmated females producing no offspring.
Abstract: Acutaspis albopicta (Cockerell) is one of seven exotic scale species detected on shipments of ‘Hass’ avocados entering California from Mexico. Here, we present the results of experiments to elucidate basic life history parameters of this species. The scale only reproduces sexually with unmated females producing no offspring. Unmated females survived up to 14 wk after settling on host fruits, whereas males survived for up to 62 h, with the majority dying within 46 h after emergence. Females laid a mean of 52.0 ± 2.8 eggs (range, 5–171 eggs). Lower humidity (50%) was detrimental to the survival of male scales compared with high humidity (75%), especially during the pupal stage. The optimal temperature for development of both sexes was 25°C. At this temperature, females developed from first instars to adults in ≈28 d, whereas males emerged from their pupal cases after ≈37 d. The adjusted lower developmental thresholds for females and males were 13.2 and 13.4°C, respectively. The upper developmental threshold for both females and males was ≈32°C. Total development from first instar to adult female was 329 degree days and to emerged male, 433 degree days.
TL;DR: The synthetic pheromone lures proved to be an effective tool to locate and monitor this pest new to the continental United States.
Abstract: A pheromone-based system to locate and monitor Planococcus minor (Maskell), a pest of over 250 plants including citrus, grape, and cacao, was tested. The difficulty in distinguishing P. minor from the citrus mealybug, P. citri, makes finding and evaluating the impact of the pest challenging. Studies conducted in Puerto Rico determined that synthetic P. minor pheromone lures preaged 120 d in the field caught similar number of males as lures not aged (fresh). Molecular analysis of trapped mealybug males using mitochondrial cytochrome oxidase-1, the internal transcriber space two locus, and 28S-D2 gene showed the pheromone traps to be species specific. Traps baited with P. minor pheromone were used to monitor the pest in south Florida and to locate potential infestations. P. minor males were found at all locations studied in South Florida and were present in low numbers (1.03 ± 0.69 mean ± SE/trap/14 d). Over 14,000 terminals, fruit, and flowers were visually inspected over a 6 mo period of peak tra...
01 Jan 2012
TL;DR: In laboratory bioassays, male Pseudococcus viburni (Signoret) and Planococcus ficus Signoret were attracted to body sections of females that included the metathoracic legs, and males exhibited copulatory behavior towards these extracts.
Abstract: In laboratory bioassays, male Pseudococcus viburni (Signoret) and Planococcus ficus Signoret were attracted to body sections of females that included the metathoracic legs. Extracts of the metathoracic legs of female P. ficus were much more attractive to males than extracts of the other legs, and males exhibited copulatory behavior towards these extracts. Scanning electron microscopy showed the presence of translucent pores on the coxae of mature but not immature females. Collectively, the data suggest that the female-produced sex pheromones of these species are released from the metathoracic legs, probably from the translucent pores.