Robb Bennett

(Z,Z)-4,7-Tridecadien-(S)-2-yl Acetate: Sex Pheromone of Douglas-Fir Cone Gall Midge, Contarinia oregonensis

Our objectives were to identify and field test the sex pheromone of female Douglas-fir cone gall midge, Contarinia oregonensis (Diptera: Cecidomyiidae). Coupled gas chromatographic–electroantennographic detection (GC-EAD) analyses of pheromone extract revealed a single compound (A) that elicited responses from male antennae. Hydrogenation of pheromone extract, followed by renewed GC-EAD analysis, revealed a new EAD-active compound with chromatographic characteristics identical to those of tridecan-2-yl acetate on five fused silica columns (DB-5, DB-210, DB-23, SP-1000, and Cyclodex-B). Syntheses, chromatography, and retention index calculations of all possible tridecen-2-yl acetates suggested that the candidate pheromone A was a tridecadien-2-yl acetate with nonconjugated double bonds. Synthetic candidate pheromone component (Z,Z)-4,7-tridecadien-2-yl acetate (Z4Z7) cochromatographed with A on all analytical columns and elicited comparable antennal activity. In GC-EAD analyses that separated the enantiomers (Z,Z)-4,7-tridecadien-(S)-2-yl acetate (2S-Z4Z7) and (Z,Z)-4,7-tridecadien-(R)-2-yl acetate (2R-Z4Z7) with baseline resolution, only 2S-Z4Z7 as a component in a racemic standard or in pheromone extract elicited antennal responses. In Douglas-fir seed orchards, sticky traps baited with 2S-Z4Z7 captured male C. oregonensis, whereas 2R-Z4Z7 was behaviorally benign. Comparable catches of males in traps baited with racemic Z4Z7 (50 μg) or virgin female C. oregonensis suggested that synthetic pheromone baits could be developed for monitoring C. oregonensis populations in commercial Douglas-fir seed orchards.

Sex pheromone of orange wheat blossom midge, Sitodiplosis mosellana.

Abstract Pheromone extract of the female orange wheat blossom midge, Sitodiplosis mosellana (Géhin) (SM) (Diptera: Cecidomyiidae), was analyzed by coupled gas chromatographic-electroantennographic detection (GC-EAD) and GC-mass spectrometry (MS), employing fused silica columns coated with DB-5, DB-210, DB-23 or SP-1000. These analyses revealed a single, EAD-active candidate pheromone which was identified as 2,7-nonanediyl dibutyrate. In experiments in wheat fields in Saskatchewan, traps baited with (2S,7S)-2,7-nonanediyl dibutyrate attracted significant numbers of male SM. The presence of other stereoisomers did not adversely affect trap captures. Facile synthesis of stereoisomeric 2,7-nonanediyl dibutyrate will facilitate the development of pheromone-based monitoring or even control of SM populations.

Impact of Leptoglossus occidentalis (Hemiptera: Coreidae) on Douglas-Fir Seed Production

Abstract We investigated the effect of feeding by the western conifer-seed bug, Leptoglossus occidentalis Heidemann, on seed production in developing cones of coastal Douglas-fir, Pseudostuga menziesii (Mirb.) Franco, with respect to seed bug life stage and sex (nymphs, adult females, and adult males) and timing of feeding (early, mid-, and late season cone development). Feeding by females on caged cones for a 2-wk period during late season cone development reduced the proportion of full seeds in cones by ≈70% compared with caged control cones. There was no significant difference among nymphs, adult females, and adult males with respect to the proportion of empty or partially fed-upon seeds produced during the same feeding period. Feeding by nymphs for 2 wk early in the season resulted in a threefold increase in the number of unextractable seeds fused to cones compared with the control. Weight measurements of harvested seeds indicated that radiography is an accurate tool to distinguish among Douglas-fir seeds that have sustained light, moderate, or severe damage. Determining the full impact of L. occidentalis on conifer seed production will require the development of a reliable method to distinguish between naturally aborted seeds and seeds emptied through feeding by seed bugs.

(2R, 7S)-diacetoxytridecane: Sex pheromone of the aphidophagous gall midge, Aphidoletes aphidimyza

In a recent study, evidence was presented that females of the aphidophagous midge Aphidoletes aphidimyza (Rondi) (Diptera: Cecidomyiidae) release a sex pheromone to attract mates. Our objectives were to identify and bioassay the pheromone. Coupled gas chromatographic–electroantenno- graphicDetection (GC-EAD) analyses of untreated and hydrogenated pheromone extract on three fused-silica columns (DB-5, DB-23, DB-210) revealed a single compound that elicited responses from male antennae. Retention index calculations of this candidate pheromone (CP) suggested that it was a di-acetate. Considering that most of the presently identified cecidomyiid pheromones consist of a 13-carbon chain with (at least) one acetate group in C2, we synthesized 2,6-, 2,7-, 2,8-, 2,9-, 2,10-, 2,11-, and 2,12-diacetoxytridecane. In GC analyses of these compounds, only 2,7-diacetoxytridecane cochomatographed with CP on all columns. In laboratory two-choice experiments with stereospecifically synthesized stereoisomers, only (2R,7S)-diacetoxytridecane elicited significant anemotatic responses by male A.aphidimyza. In trapping experiments in greenhouse compartments, only traps baited with (2R,7S)-diacetoxytridecane captured significant numbers of male A. aphidimyza, clearly revealing the absolute configuration of the pheromone. Failure of the stereoisomeric mixture (containing all four stereoisomers including the pheromone) to attract males is due to inhibitory characteristics of the (2R,7R)- and (2S,7R)-stereoisomers. The pheromone of zoophagous A. aphidimyza resembles those from phytophagous cecidomyiid midges, suggesting a common, diet-independent pathway for pheromone biosyntheses.

( S , S )-2,12-, ( S , S )-2,13-, and ( S , S )-2,14-Diacetoxyheptadecanes: Sex Pheromone Components of Red Cedar Cone Midge, Mayetiola thujae

We identified, synthesized, and field-tested the sex pheromone of female red cedar cone midge Mayetiola thujae (Hedlin) (Diptera: Cecidomyiidae), a pest insect in red cedar Thuja plicata seed orchards. Coupled gas chromatographic (GC)–electroantennographic detection analyses of pheromone extract revealed three components (A, B, C) that elicited responses from antennae of males, all of which occurred below the detection threshold of the mass spectrometer and thus had to be identified without spectroscopic data. Taking into account (1) their retention indices (RI) on three GC columns (DB-5, DB-23, and DB-210), (2) intercolumn RI differentials, and (3) the molecular structures of known cecidomyiid pheromones, we synthesized seven candidate pheromone components: 2,10-, 2,11-, 2,12-, 2,13-, 2,14-, 2,15- and 2,16-diacetoxyheptadecanes. Of these, 2,12-, 2,13-, and 2,14-diacetoxyheptadecane had RIs on all columns consistent with those of A, B, and C and elicited strong antennal responses when tested at picogram levels. In field experiments with the twelve stereoselectively synthesized stereoisomers, only the SS-stereoisomers of 2,12-, 2,13-, and 2,14-diacetoxyheptadecane attracted male M. thujae. The three-component SS-stereoisomer blend was more attractive than the 12-component blend of all stereoisomers, suggesting that one or several nonnatural stereoisomers are inhibitory. One-, two-, and three-component lures of the SS-stereoisomers were equally effective in attracting male M. thujae, indicating redundancy in the pheromone. Identification of the M. thujae sex pheromone will allow development of pheromone-based monitoring, and possibly control, of M. thujae populations in T. plicata seed orchards.

Evidence for a Host-Marking Pheromone in White Spruce Cone Fly, Strobilomyia neanthracina

Cone flies (Strobilomyia spp.) lay eggs on coniferous cones, and larvae must complete development within the cone on which the eggs are laid. Previous field surveys showed that egg distributions of several species are uniform, suggesting that females avoid ovipositing on cones with conspecific eggs or larvae. In both the field and laboratory, S. neanthracina females walked around cones following oviposition, touching their mouthparts to the cone as they walked. In laboratory bioassays, where females were presented with a cone on which they or another female had oviposited and touched with mouthparts, or one without an egg, females laid preferentially on cones without eggs. However, females laid randomly when presented with a cone on which a female had oviposited but been prevented from touching with her mouthparts following oviposition or another cone without an egg. This indicates that females deposit a host-marking pheromone with their mouthparts following oviposition and that this deters further oviposition on marked hosts. Laboratory and field bioassays indicated that the host-marking pheromone is located in the head and thorax of female flies.

Systematics of Nearctic Cybaeus (Araneae : Cybaeidae)

Spiders in the genus Cybaeus L. Koch (Araneae : Dictynoidea : Cybaeidae) are common forest-floor inhabitants in western North America and Japan. Here we establish an initial phylogenetic framework for North American Cybaeus. Morphological details for eight proposed species groups are given, and these results, combined with molecular analyses of one nuclear and one mitochondrial gene for six of the eight species groups, suggest that North American Cybaeus species are contained in two broad clades, one Holarctic and one Nearctic (primarily Californian). The Holarctic clade contains the tetricus and angustiarum species groups, which contain mostly widely distributed species. The Californian clade includes the adenes, aspenicolens, consocius, devius, septatus and tardatus species groups, all of which have very restricted ranges. The genus Cybaeus and the Palaearctic species C. tetricus (C.L. Koch) (type species of the genus) and C. angustiarum L. Koch are redescribed and illustrated. A key to species groups is provided. Nine new species endemic to the western Nearctic and included in the molecular analyses are described and illustrated: C. paralypropriapus Bennett, sp. nov. and C. waynei Bennett, sp. nov. (tetricus group); C. sanbruno Bennett, sp. nov. (adenes group); C. thermydrinos Bennett, sp. nov. (aspenicolens group); C. penedentatus Bennett, sp. nov. and C. vulpinus Bennett, sp. nov. (consocius group); C. chauliodous Bennett, sp. nov. and C. somesbar Bennett, sp. nov. (septatus group); and C. gidneyi Bennett, sp. nov. (unplaced).

Cybaeus (Araneae: Cybaeidae): the Nearctic species of the Holarctic clade

Species of North American Cybaeus L. Koch (Araneae: Dictynoidea: Cybaeidae) are classified in Holarctic and Californian clades. We review the Nearctic species of the Holarctic clade of these common moist-forest spiders. Twenty-one species grouped in informal tetricus (nine species) and angustiarum (twelve species) groups based on female genitalic characters are recognized, including four new species endemic to the western Nearctic: C. rothi Bennett sp. nov. (tetricus group) and C. charlesi Bennett sp. nov., C. harrietae Bennett sp. nov., and C. solanum Bennett sp. nov. (angustiarum group). Other Nearctic species in the tetricus group are C. cascadius Roth 1952, C. conservans Chamberlin & Ivie 1932, C. constrictus Chamberlin & Ivie 1942, C. eutypus Chamberlin & Ivie 1932, C. morosus Simon 1886, C. multnoma Chamberlin & Ivie 1942, C. paralypropriapus Bennett 2009, and C. waynei Bennett 2009. Other Nearctic species in the angustiarum group are C. bulbosus Exline 1935, C. giganteus Banks 1892, C. patritus Bishop & Crosby 1926, C. reticulatus Simon 1886, C. scopulatus Chamberlin & Ivie 1942, C. shoshoneus Chamberlin & Ivie 1932, C. signifer Simon 1886, C. silicis Barrows 1919, and C. sinuosus Fox 1937. Approximately half of the Nearctic Cybaeus species of the Holarctic clade are relatively widely distributed and frequently encountered; the remaining species have restricted ranges. Descriptions, illustrations, and range maps are provided for all species and identification keys are also included.

Vibratory communication signal produced by male western conifer seed bugs (Hemiptera: Coreidae)

We tested the hypothesis that the western conifer seed bug, Leptoglossus occidentalis Heidemann, uses a substrate-borne vibratory signal for short-range communication. To record such a signal we used computers equipped with data-acquisition hardware and software, microphones sensitive to sonic and (or) ultrasonic frequencies, membrane-type and piezoelectric speakers capable of emitting sonic and ultrasonic sound, and piezoelectric devices capable of emitting low-level, low-frequency vibrations. By tapping their abdomen on substrate, males produced a wide-band vibratory signal 20 dB (sound pressure level; 0 dB = 20 μPa) above ambient sound, with dominant frequencies of 115 ± 10 and 175 ± 15 Hz and a distinct temporal pattern. There was no evidence for (i) ultrasonic signal components; (ii) signals produced by females or nymphs, or (iii) repeated trains of signal pulses. In two-choice arena experiments, males and females preferred the played-back recording of the male-produced substrate-borne signal over si...

Attraction of male Mayetiola thujae (Diptera: Cecidomyiidae) to the sex-pheromone blend of (2S,12S)-, (2S,13S)-, and (2S,14S)-diacetoxyheptadecane is reduced in the presence of the SR-or RR-stereoisomers

In a field trapping experiment in an abandoned seed orchard of western red-cedar, Thuja plicata Donn × D. Don, in British Columbia, we show that attraction of male red-cedar cone midges, Mayetiola thujae (Hedlin), to the pheromone blend (2S,12S)-, (2S,13S)-, and (2S,14S)-diacetoxyheptadecane is reduced in the presence of a blend of all other stereoisomers, or of the three SR- or RR-stereoisomers. The three RS-stereoisomers, in contrast, had no significant effect. Thus, synthetic pheromone for monitoring M. thujae populations must not contain the SR- or RR-stereoisomers of 2,12-, 2,13-, and 2,14-diacetoxyheptadecane. This result will allow development of a less expensive design for synthesizing the pheromone.