Hsiao-Yung Ho

Identification and Synthesis of the Sex Pheromone of the Passionvine Mealybug, Planococcus minor (Maskell)

The sex pheromone of the mealybug, Planococcus minor was isolated by fractionation of crude pheromone extract obtained by aeration of virgin females. The pheromone was identified as the irregular terpenoid, 2-isopropyl-5-methyl-2,4-hexadienyl acetate, by mass spectrometry, microchemical tests, and 1H NMR spectroscopy. The stereochemistry of the pheromone was assigned as (E) by comparison with synthetic standards of known geometry. The compound was highly attractive to males in laboratory bioassays, whereas the (Z)-isomer appeared to antagonize attraction.

Chemical identification of defensive secretion of stick insect,Megacrania tsudai Shiraki.

Volatile constituents of the defensive secretion of the stick insect,Megacrania tsudai Shiraki, in Taiwan have been analyzed by gas chromatography-mass spectrometry (GC-MS). In addition to the major component, actinidine, three more minor components of the secretion are identified as boschniakine and two stereoisomers of 1-acetyl-3-methylcyclopentane by comparing GC retention times with the authentic samples and synthetic compounds. Other components are also tentatively assigned as derivatives of actinidine.

Investigation of sex pheromone components of female asian corn borer,Ostrinia furnacalis (Hübner) (Lepidoptera: Pyralidae) in Taiwan

Abstract(E)-12-Tetradecenyl acetate (E12–14∶OAc), (Z)-12-tetradecenyl acetate (Z12–143nOAc), and tetradecanyl acetate (14∶OAc) were extracted and identified as major chemical components from female tips of the Asian corn borer,Ostrinia furnacalis (Hübner) (Lepidoptera: Pyralidae) in Taiwan, with a combined wash ratio of 48∶37∶15 and an individual female ratio of 45∶39∶16. The average amount ofE12-,Z12–14∶OAc and 14∶OAc in each female gland was 6.6±4.6, 5.8±3.5, and 2.4±1.7 ng/female, respectively. The mixture of these three synthetic chemicals not only gave strong activities in male antennae but also could catch significantly more males than virgin females in field-trapping tests. The field test also showed no significant difference in trapping ability among the three-component Taiwan formulations, the two-component Taiwan formulation (Z12–14∶OAc andZ1214∶OAc, 53∶47), and the Japan formulation (Z12–14∶ OAc andE 12–14∶OAc, 3:2).

Identification and Synthesis of the Sex Pheromone of the Madeira Mealybug, Phenacoccus Madeirensis Green

Two components were identified from aeration extracts of the virgin female Madeira mealybug, Phenacoccus madeirensis as trans-(1R,3R)-chrysanthemyl (R)-2-methylbutanoate and (R)-lavandulyl (R)-2-methylbutanoate (with a ratio of 3:1) by a combination of gas chromatography retention time matches, mass spectrometry, and microchemical tests. The structures and chirality of the compounds were confirmed by comparing with synthetic compounds. The synthetic trans-(1R,3R)-chrysanthemyl (R)-2-methylbutanoate was highly attractive to males in laboratory bioassays; the synthetic (R)-lavandulyl (R)-2-methylbutanoate was weakly attractive. No synergistic effect was observed when the mixture of the two compounds was tested.

Isolation, identification, and synthesis of sex pheromone components of female tea cluster caterpillar,Andraca bipunctata walker (Lepidoptera: Bombycidae) in Taiwan

Octadecanal (18:Ald), (E)-11-octadecenal (E11–18:Ald), (E)-14-octadecenal (E14–18:Ald) and (E,E)-11,14-octadecadienal (E11,E14–18:Ald) were isolated and identified as major components from the pheromone glands of the tea cluster caterpillar,Andraca bipunctata, in Taiwan by analyzing the mass spectra of gland components and their DMDS adducts. GC retention times and mass spectra of the components were in agreement with those of authentic synthetic compounds. The average amount of 18:Ald,E11–18:Ald,E14–18:Ald andE11,E14–18:Ald per female gland (1 to 3 days old) was 121±76, 50±20, 187±75, and 237±110 ng, respectively, in a ratio of 20:8:31:41. SyntheticE11,E14–18:Ald caught more males than each of the other three components or blank control in field trapping tests.E11,E14–18:Ald is reported as an insect sex pheromone for the first time. Male antenna responded toE11,E14–18:Ald strongly in an EAG analysis. Furthermore, 4 hr after the injection of PBAN (pheromone biosynthetic activating neuropeptide) into decapitated female moths (2 days old), the percentage of theE11,E14–C18 Ald in the gland extract increased from 0% to 75.5%, which was also significantly more than that of unligated and uninjected control at 55.1%. All these data indicated thatE11,E14–18:Ald is the sex pheromone of theAndraca bipunctata in Taiwan.

EFFECT OF REARING CONDITIONS ON PRODUCTION OF STERNAL GLAND SECRETION, AND IDENTIFICATION OF MINOR COMPONENTS IN THE STERNAL GLAND SECRETION OF THE PREDATORY STINK BUG Eocanthecona furcellata

Production of the male specific compound, 6,10,13-trimethyltetra- decyl isovalerate by the predatory stink bug Eocanthecona furcellata (Wolff) was dramatically affected by rearing conditions. Male bugs kept isolated after eclosion produced an average of 1,948 ng of 6,10,13-trimethyltetradecyl isovalerate per bug, whereas male bugs reared in groups of 5–8 bugs produced an average of only 4 ng of 6,10,13-trimethyltetradecyl isovalerate per bug. Same-sex or mixed-sex pairs of bugs produced less than 50 ng per bug. Male bugs kept isolated for 1~wk and then grouped for 1~wk produced 3 ng of 6,10,13-trimethyltetradecyl isovalerate per bug, whereas male bugs grouped first and then isolated produced 135 ng of 6,10,13-trimethyltetradecyl isovalerate. A total of 11 minor components in relative amounts of less than 1% of the major 6,10,13-trimethyltetradecyl isovalerate were found in the sternal gland secretion. These included 6,10,13-trimethyltetradecanol, acetate, propionate, and butyrate esters of 6,10,13-trimethyltetradecanol, and isovalerate or valerate esters of homologs of 6,10,13-trimethyltetradecanol.

Chirality and Bioactivity of the Sex Pheromone of Madeira Mealybug (Hemiptera: Pseudococcidae)

ABSTRACT Two compounds (trans-1R,3R-chrysanthemyl R-2-methylbutanoate and R-lavandulyl R-2-methylbutanoate) identified from aeration extracts of virgin female Madeira mealybug, Phenacoccus madeirensis Green (Hemiptera: Pseudococcidae), were synthesized and tested in field bioassays in northern Taiwan over a 1-mo period. In total, 1,492 male P. madeirensis were captured in sticky traps. Our results showed that 1 µg of synthetic trans-1R,3R-chrysanthemyl R-2-methylbutanoate released from a plastic tube dispenser was attractive to the mealybugs. Different stereoisomers of chrysanthemyl 2-methylbutanoate also were tested. The insect-produced stereoisomer was the most attractive of all the isomers tested, and the stereochemistry of the acid moiety proved to be more critical than that of the alcohol moiety. The minor component found in extracts, R-lavandulyl R-2-methylbutanoate, alone was not attractive to male Madeira mealybugs nor did it act synergistically or additively with the main component.

Volatiles in the dorsal abdominal glands and exuviae of Leptocoris abdominalis and Leptocoris augur (Heteroptera: Rhopalidae)

Abstract Compounds in the dorsal abdominal glands (DAGs) of adults and nymphs, and exuviae of two scentless plant bugs Leptocoris abdominalis (F.) and Leptocoris augur (F.) (Heteroptera: Rhopalidae), were studied by gas chromatography-mass spectrometry. For both species, two dorsal abdominal glands (median and posterior glands) are found in the nymphs, whereas in adults only the posterior gland is functional and the median gland is reduced. Monoterpenes are the major compounds in posterior glands for both species. For L. abdominalis &bgr;-pinene is most abundant monoterpene and for L. augur, limonene is most abundant monoterpene. Alkenals and alkenoic acids were found in median glands of both species. There was no sexual dimorphism in the morphology and the contents of the DAGs of adults. Analysis of the compounds found in the exuvia indicated that components in the median gland were shed with the exuvia. Quantitative analysis of the major monoterpenes and alkenals in the DAGs of different ages of L. abdominalis supported the observation that components in the posterior gland were retained in the insect after each molting. Possible functions of the components in the DAGs are discussed.

Identification of the Major Sex Pheromone Component of the Scale Insect, Aulacaspis murrayae Takahashi

Abstract(R)-Solanone was identified as a female-specific compound from aerations of virgin females of the scale insect, Aulacaspis murrayae Takahashi. The stereochemistry of the insect-produced solanone was confirmed to be (R) by comparison with synthesized racemic and chiral standards on a chiral stationary phase GC column. In bioassays, males were strongly attracted to a synthesized sample of (R)-solanone, demonstrating that this compound is a sex pheromone component for this species.