Defensive Compounds and Male-Produced Sex Pheromone of the Stink Bug, Agroecus griseus

Agroecus griseus is a serious corn pest in Brazil. Contents of the dorsal abdominal glands (DAGs) in nymphs, and the metathoracic gland (MTG) in adults of this species were characterized and quantified. Compounds found were similar to those of other Pentatomidae species and included aliphatic hydrocarbons, aldehydes, oxo-alkenals, and esters. However, two compounds were found in the MTG that have not been described previously for this family. Mass spectrometry, infrared spectroscopy, and gas chromatographic analysis using coinjection with authentic standards confirmed the identities of the compounds as enantiopure (S)-2-methylbutyl acetate and 3-methyl-2-butenyl acetate. The five nymphal instars showed significantly different ratios of components, mainly between those of the first and later instars. No significant differences were detected in MTG contents between sexes. Gas chromatography (GC) analysis of aeration extracts of males and females showed the presence of a compound released exclusively by males. Gas chromatography – electroantennographic detection (GC-EAD) assays indicated that the male-specific compound is bioactive in females, suggesting the presence of an attractant pheromone. The mass spectrum and infrared data for this compound matched with methyl 2,6,10-trimethyltridecanoate, a sex pheromone component previously detected in the stink bugs, Euschistus heros and E. obscurus. The synthetic standard coeluted with the natural pheromone on two different GC stationary phases, confirming the proposed structure. Y-tube olfactometer assays showed that the synthetic standard was strongly attractive to females, and GC-EAD tests produced responses with antennae from females similar to those of the natural pheromone.     

Male-Produced Sex Pheromone of the Carrion Beetles, Oxelytrum discicolle and its Attraction to Food Sources

Carrion beetles are part of the great diversity of insects collected on cadavers. In Brazil, beetles of the genus Oxelytrum have great forensic importance in post mortem interval (PMI) estimation. We investigated the system of chemical communication in the attraction of these necrophagous beetles. Gas chromatographic analysis (GC) of female and male aeration extracts revealed the presence of two male-specific compounds, produced in a ratio of 94:6. Bioassays showed that the combination of male produced volatiles and the odor of a food source (carcass volatiles) were attractive to females. Mass and infrared spectral analyses of the male-specific compounds suggested that they were both unsaturated hydrocarbons. Several micro-derivatizations were carried out with the natural products, and the target structures were identified as (Z)-1,8-heptadecadiene (major) and 1-heptadecene (minor). The structure of the minor component was assigned by co-injection with a commercial standard. A seven-step synthesis was developed to synthesize (Z)-1,8-heptadiene, which co-eluted with the major natural product on three different GC stationary phases. Y-tube olfactometer assays showed that the mixture of synthetic standards in the naturally occurring proportion was slightly attractive to females. The results contribute both to the understanding of the chemical ecology of O. discicolle and to its potential to improve the accuracy of PMI estimation.     

The Male-produced Sex Pheromone of the True Bug, Phthia picta, is an Unusual Hydrocarbon

Phthia picta is part of a complex of true bugs (Heteroptera) in Brazil that attack tomatoes, being particularly damaging because nymphs and adults feed on both leaves and fruit. Gas chromatography (GC) of aeration extracts of adult males vs. females revealed the presence of a male-specific compound. GC-electroantennographic detector experiments indicated that the antennae of females are highly sensitive to this male-specific compound. GC-mass spectrometry and GC-FTIR analyses suggested a methyl branched hydrocarbon structure for this compound. After synthesis of three different proposed structures, the natural product was indentified as 5,9,17-trimethylhenicosane, which was strongly attractive to females in Y-tube olfactometer bioassays. Analysis of dissected body parts of adults revealed that the pheromone is produced in the lateral accessory glands of the metathoracic scent gland of males only.     

Essential Amino Acid Methyl Esters: Major Sex Pheromone Components of the Cranberry White Grub, Phyllophaga anxia (Coleoptera: Scarabaeidae)

Chiral capillary gas chromatographic–electroantennographic detection (GC-EAD) analysis indicates that L-valine and L-isoleucine methyl esters are the major sex pheromone components released by females of the cranberry white grub, Phyllophaga anxia (LeConte). The GC retention times and GC-mass spectrometry of the two natural compounds were identical to those of authentic standards. Of five reproducible GC-EAD active components revealed with female volatiles, the L-valine and L-isoleucine methyl esters elicited the strongest male antennal responses. The ratio of L-valine and L-isoleucine methyl esters was determined to be 3:1 by analysis of pheromone gland extracts. Chirality was shown to be critical by GC-EAD, since only the L-form of these amino acid methyl esters elicited an EAD response. In field experiments conducted in Massachusetts, a synthetic 3:1 blend of L-valine and L-isoleucine methyl esters on a rubber septum was attractive to P. anxia males.     

Multiple Roles of a Male-Specific Compound in the Sexual Behavior of the Dried Bean Beetle, <Emphasis Type="Italic">Acanthoscelides Obtectus</Emphasis>

Males of Acanthoscelides obtectus (Coleoptera: Chrysomelidae, Bruchinae) emit methyl (E,R)-2,4,5-tetradecatrienoate that attracts females for mating. This study identified further roles for this compound in the sexual behavior of A. obtectus. Earlier observations revealed that males touched females with their antennae while tandem-running with them and initiated mounting and copulation, whereas they showed no such behavior toward other males. A series of subsequent laboratory choice tests were set up to establish if certain cuticular compounds aid contact sex recognition in A. obtectus. Males chose virgin females over other males. The activity toward females could be eliminated by rinsing with hexane, but was regained by application of female extract onto previously rinsed females. Gas chromatographic (GC) comparison of hexane extracts revealed the presence of two male-specific compounds, methyl (E,R)-2,4,5-tetradecatrienoate and octadecanal, which were absent from the behaviorally active female samples. Of the two compounds, methyl (E,R)-2,4,5-tetradecatrienoate was found to be responsible for the inhibition of male sexual behavior, similar to that observed with crude male extracts applied to virgin females. Furthermore, males preferred virgin over mated females. GC analyses revealed the presence of methyl (E,R)-2,4,5-tetradecatrienoate in mated females in amounts sufficient to curtail mating attempts. It appears that methyl (E,R)-2,4,5-tetradecatrienoate, besides being a male-produced sex pheromone, acts as a male-recognition signal in A. obtectus. Males also transfer it onto females during mating, resulting in mated females being avoided by courting males.     

Semiochemistry of the Goldeneyed Lacewing Chrysopa oculata: Attraction of Males to a Male-Produced Pheromone

Gas chromatographic-electroantennographic detection (G3C-EAD) experiments showed that antennae of males and females of the goldeneyed lacewing, Chrysopa oculata Say (Co. = Chrysopa), consistently responded to four compounds extracted from the abdominal cuticle of males:nonanal, nonanol, nonanoic acid, and (1R*,2S*,5R*,8R*)-iridodial. These compounds were not detected from abdominal cuticle of females. Thoracic extracts of both sexes contained antennal-stimulatory 1-tridecene and EAD-inactive skatole. Chrysopa oculata adults were most sensitive to (1R,2S,5R,8R)-iridodial standard at an EAD-response threshold between 0.1 and 1 pg, which was 10-100 times lower than thresholds for nonanal and nonanoic acid, and up to 10,000 times lower than thresholds for other compounds tested. A similar EAD response pattern was also found in another Chrysopa sp. (Co. quadripunctata Burmeister). In field-trapping experiments, (1R,2S,5R,8R)-iridodial was the only male-specific compound that attracted Co. oculata males. Males also were weakly attracted to (1R,4aS,7S,7aR)-nepetalactol (an aphid sex pheromone component), probably due to the 5% (1R,2S,5R,8R)-iridodial present in the synthetic sample as an impurity. A herbivore-induced plant volatile, methyl salicylate, increased attraction of males to (1R,2S,5R,8R)-iridodial, whereas 1-tridecene was antagonistic. No females were caught in the entire study. Scanning electron micrographs revealed numerous male-specific, elliptical epidermal glands on the 3rd-8th abdominal sternites of Co. oculata, which are likely the pheromone glands. Another lacewing species, Chrysoperla rufilabris (Burmeister) (Cl. = Chrysoperla), did not produce male-specific volatiles or possess the type of gland presumed to produce pheromone in Co. oculata males, but (Z)-4-tridecene was identified as a major antennal-stimulatory compound from thoracic extracts of both sexes of Cl. rufilabris. Thus, (1R,2S,5R,8R)-iridodial (or its enantiomer) is now identified as a male-produced male aggregation pheromone for Co. oculata, the first pheromone identified for lacewings.     

Circadian Release of Male-Specific Components of the Greater Date Moth,Aphomia (Arenipses) Sabella,Using Sequential SPME/GC/MS Analysis

The greater date moth (GDM), Aphomia sabella Hampson (Lepidoptera: Pyralidae: Galleriinae), is a serious pest of date palms, Phoenix dactylifera. The release of volatiles from both males and females was investigated using sequential SPME/GC/MS analysis. Males release a complex mixture of compounds in a circadian rhythm during the night between 03:00 and 05:00 hr. Six compounds were identified: benzaldehyde, sulcatol (6-methyl-5-hepten-2-ol), geranyl acetone [(E)-6,10-dimethyl-5,9-undecadien-2-one], phenylacetaldehyde, 2-phenylpropenal, and (R)-fuscumol [(R)-(E)-6, 10-dimethyl-5, 9-undecadien-2-ol]. Benzaldehyde, sulcatol, and geranyl acetone were found only in trace amounts. These compounds were in glands located in the forewing of males only. Small amounts of acetoin and 2,3-butanediol were found sporadically in the SPME/GC/MS analyses of volatiles from females, and these compounds probably originate from microorganisms. This is the first finding of a circadian release of male-specific compounds in moths. GC/EAD analyses with synthetic standards of compounds released by males showed that the female antenna is stimulated by all six compounds, while the male antenna responded only to phenylacetaldehyde. A possible pheromonal role for the male-specific compounds is suggested by the circadian rhythm of their release and the EAD response of females to them. However, trapping tests with the main male-specific compounds in screen cages in the laboratory or in the field did not reveal any significant behavioral responses from females or males. Copulation in the laboratory was observed only in the presence of date palm tissue, thus suggesting that sexual communication and mating of GDM moths probably occurs in the crown of date palms.     

Methyl 6-Methylsalicylate: A Female-Produced Pheromone Component of the Parasitoid Wasp <Emphasis Type="BoldItalic">Spalangia endius</Emphasis>

Sex-pheromone-related behavior and chemistry were studied in the wasp Spalangia endius Walker (Hymenoptera: Pteromalidae), a pupal parasitoid of the house fly, Musca domestica L. (Diptera: Muscidae). Males responded behaviorally to female extracts by arrestment, whereas females did not arrest to male extracts. In a comparison of male and female extracts by gas chromatography-mass spectrometry (GC-MS), two female-specific compounds were found. One was identified as methyl 6-methylsalicylate (gas chromatographic retention time and mass spectrum versus an authentic standard), but the chemical structure of the second compound is still unknown. Male antennae were sensitive to both compounds in electrophysiological tests (GC-EAD). Males responded behaviorally to methyl 6-methylsalicylate by arrestment, but did not arrest to the second compound. Methyl 6-methylsalicylate has been reported previously from some ant and beetle species, but never from the Pteromalidae. Chemical analysis of the extracts and the male behavioral results are consistent with the hypothesis that methyl 6-methylsalicylate functions as a female-emitted pheromone component at short range, but the exact role of both compounds in intersexual interactions in S. endius remains to be determined.     

Analysis of whole beeswax by gas liquid chromatography

Gas liquid chromatographic analysis of unfractionated beeswax (treated with diazomethane) using Dexsil 300 as liquid phase gives a good separation of hydrocarbons, free fatty acids as methyl esters, and long chain monoesters. These components can be estimated using internal standards and together account for ca. 65% of the wax. Petroleum hydrocarbon or fatty acid adulterants can be detected. Unsaturated hydrocarbons are partially resolved from the corresponding saturated compounds. Issued as NRCC No. 12775.     

Evidence for a Male-Produced Sex Pheromone in the Western Flower Thrips Frankliniella occidentalis

Olfactometer bioassays of walking adult western flower thrips Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) showed that virgin females (1- to 3-d postemergence) were attracted to the odor of 25 adult males, but not to the odor of 25 adult females, providing behavioral evidence for a male-produced sex pheromone in this species. In contrast to earlier findings, mixed-age adult males were attracted to the odor of adult males. GC analysis of odors collected on SPME fibers revealed two major components and five minor components that were present in the male odor and not in the female odor. The compounds were not present in hexane extracts of males, indicating that these compounds are produced on demand and not stored.     

The OV 275-packed stainless steel column intrans-fatty acid research: A note of caution

Gas chromatographic analysis of fatty acid methyl esters in a 6.1 m stainless steel column packed with 15% OV 275 and operated at 220 C resulted in poor recovery of polyunsaturated esters relative to their saturated or monoenoic counterparts. Relative responses of the esters declined with increasing unsaturation, were concentration-dependent at low concentrations and changed as the column aged. Decomposition of polyunsaturated compounds in the hot stainless steel column appeared to be the major reason for their poor recovery and renders this particular column of doubtful value in analysis of complex ester mixtures.     

Synthesis and Field Tests of Possible Minor Components of the Sex Pheromone of Prionus californicus

Earlier work has shown that adult male Prionus californicus Motschulsky (Coleoptera: Cerambycidae) are attracted to the female-produced compound (3R,5S)-3,5-dimethyldodecanoic acid, and to a synthetic mixture of the four stereoisomers of 3,5-dimethyldodecanoic acid. Here, we report the results of field trials that tested whether or not three structurally related compounds (methyl 3,5-dimethyldodecanoate, 3,5-dimethyltridecanoic acid, and 3,5-dimethylpentadecanoic acid), present in extracts of virgin females, are attractive, and whether or not they influence attraction to 3,5-dimethyldodecanoic acid. In a trial with single components, only traps baited with the acid or its methyl ester captured more beetles than did control traps; catches to the acid were five times higher than to the methyl ester. Another trial, excluding 3,5-dimethyldodecanoic acid, confirmed the activity of the methyl ester. Finally, addition of the three compounds to 3,5-dimethyldodecanoic acid, in the ratio found in extracts from female beetles, gave a catch similar to that of traps baited with 3,5-dimethyldodecanoic acid alone. Consequently, the function of these minor compounds remains undetermined.     

Identification of Host Blends that Attract the African Invasive Fruit Fly,Bactrocera invadens

Bactrocera invadens, an invasive fruit fly species in the Afro-tropical region belonging to the Bactrocera dorsalis complex, causes considerable damage to fruit production and productivity. We sought to find attractants from hosts of B. invadens that could serve as baits in traps for monitoring and management of this pest. The attractiveness of volatiles from four different fruit species (mango, guava, banana and orange) at two stages of ripeness (ripe or unripe) was tested in an olfactometer assay. All fruits were attractive against a clean air control. Using hexane extracts of volatile collections of fruits, we demonstrated that male flies preferred the volatiles of ripe guava and orange over unripe fruit extracts. There was a slight difference in preference between females and males; females preferred orange to guava and mango, whereas males preferred mango and guava to orange. Gas chromatography/electroantennographic detection (GC/EAD) and GC/mass spectrometry (GC/MS) were used to identify compounds to which B. invadens antennae were sensitive. GC/EAD recordings from distal and medio-central parts of the fly antenna showed responses to a number of compounds from each fruit species, with esters dominating the responses. Synthetic blends were made for each fruit species using the shared antennally active compounds in ratios found in the extracts. In the olfactometer, B. invadens was most attracted to the banana and orange blends, followed by the mango and guava blends. The synthetic banana blend was as attractive as the volatile collection of banana, although both were less attractive than the fruit. The results demonstrate that composing attractive blends from GC/EAD-active constituents shared by host fruits can be effective for formulating attractive synthetic host mimics for generalist fruit fly species, such as B. invadens.     

Identification of Queen Sex Pheromone Components of the Bumblebee Bombus terrestris

We investigated the origin and chemical composition of the queen sex pheromone of the primitively eusocial bumblebee, Bombus terrestris (Apidae). Physiologically and behaviorally active compounds were identified by coupled gas chromatography electroantennography (GC-EAD), gas chromatography-mass spectrometry (GC-MS), and laboratory behavioral tests. In the behavioral assays, virgin queens frozen previously at −20°C were highly attractive to males. Dummies impregnated with surface and cephalic extracts obtained from virgin queens that had been frozen at −50°C were more attractive to males than odorless dummies. Male mating behavior was stimulated by components of cephalic secretions that are smeared onto the cuticle surface by the queen. Overall, 21 compounds present in surface and cephalic extracts evoked electroantennographic responses in male antennae. These included saturated and unsaturated fatty acids, ethyl- and methyl esters of the fatty acids, heptacosene, 2-nonanone, and geranyl geraniol. A blend of synthetic versions of these compounds elicited typical male mating behavior. Since solvent-impregnated dummies were approached by the males, but did not release copulatory behavior, visual cues may be important in the initial step of stimulating male mating behavior. Close-range olfactory signals are more important for releasing male mating behavior as well as for species recognition. In further behavioral assays, the attractiveness of a frozen virgin queen decreased as the storage time at −20°C increased from 2 hr to 1 d. Therefore, the chemical composition of the sex pheromone may change during freezing as behaviorally active compounds may decompose.     

New Type of Sesiidae Sex Pheromone Identified from the Hornet Moth Sesia apiformis

Two components of the female-produced sex pheromone of the hornet moth, Sesia apiformis, were identified as (3Z,13Z)-octadeca-3,13-dien-1-ol (3Z,13Z-18:OH) and (2E,13Z)-octadeca-2,13-dienal (2E,13Z-18:Al), a pheromone structure new in Sesiidae. Pooled gland extracts showed the two major compounds in a proportion of ca. 2:3, while SPME-investigations on single calling females revealed a ratio of ca. 1:7. Although the single compounds were not attractive, a 2:3 mixture proved to be highly active towards males in field tests. Small amounts of (2E,13Z)-octadecadienol (2E,13Z-18:OH) were found in the sex pheromone gland of females, however, the biological significance of the compound remains unclear. Methyl sulfide was found to readily react with 2-alkenals, providing an effective new method for the characterization of this type of compound upon GC/MS. The derivatives, 1,1,3-tris(methylthio)alkanes, are the products of the addition of methyl sulfide to the double bond and the transformation of the carbonyl group into the corresponding bis(methylthio)acetal. The mass spectra of these compounds are characterized by diagnostic signals at m/z 107 and/or m/z 121. These fragments represent the first carbon unit or the first two carbon units of the derivative, respectively. The parent signal in the spectra of thiomethyl derivatives of 2-alkenals showing no other double bonds is represented by m/z M+ - 121, formed upon loss of the first two carbon units. By employing a solution of methyl sulfide in dimethyl sulfide, the double bond positions in 2E,13Z-18:Al could be fully characterized by GC/MS.     

Identification of (Z)-4- and 1-Tridecene in the Metathoracic Gland Secretions of Stink Bugs Employing the GC/FT-IR Technique

The composition of stink bug allomones is similar for most species and includes hydrocarbons, as well as saturated and unsaturated aldehydes and esters. Analysis of extracts of the metathoracic glands of seven pentatomid species from different genera by gas chromatography/Fourier transform-infrared (GC/FT-IR) showed that the compound previously thought to be 1-tridecene actually showed characteristic bands of an internal as well as terminal double bond, the former compound having (Z)-configuration. The mass spectrum of an epoxy-derivative of the natural material demonstrated that the internal double bound was located at C4. GC/FT-IR and co-injections with synthetic standards on different capillary columns proved that all these stink bugs had 1-tridecene and (Z)-4-tridecene in their defensive secretions.     

Oviposition stimulants for the black swallowtail butterfly: Identification of electrophysiologically active compounds in carrot volatiles

Headspace volatiles were collected from undamaged foliage of carrot,Daucus carota, a host-plant species of the black swallowtail butterfly,Papilio polyxenes. The volatiles were fractionated over silica on an open column, and the fractions were tested in behavioral assays withP. polyxenes females in laboratory experiments. The polar fractions, as well as the total mixture of volatiles, increased the landing frequency and the number of eggs laid on model plants with leaves bearing contact-oviposition stimulants. The nonpolar fraction, containing the most abundant compounds in carrot odor, was not stimulatory. Gas Chromatographic (GC) separation of the fractions was coupled with electroantennogram (EAG) recordings to identify the compounds perceived byP. polyxenes females. The EAG activity corresponded to the behavioral activity of the fractions. None of the nonpolar compounds, identified as various monoterpenes, evoked a major EAG response, but several constituents of the polar fractions elicited high EAG responses. Sabinene hydrate (both stereoisomers), 4-terpineol, bomyl acetate, and (Z)-3-hexenyl acetate were identified by GC-MS as active compounds.     

Aggregation Pheromone of the Bearded Weevil, <Emphasis Type="Italic">Rhinostomus barbirostris</Emphasis> (Coleoptera: Curculionidae): Identification,Synthesis, Absolute Configuration and Bioactivity

The bearded weevil, Rhinostomus barbirostris (Coleoptera: Curculionidae: Dryophthorinae), attacks coconut trees, oil palms and other species of Arecaceae. Besides direct damage, R. barbirostris may be a vector of diseases in coconut and oil palms, such as stem bleeding (resinosis) and red ring disease. Currently, the only method to control this weevil is by visual observation of damage and removal of infected plants. Semiochemical-based trapping could improve the effectiveness of monitoring and management of R. barbirostris. In comparisons of volatiles released by R. barbirostris males and females by gas chromatography (GC) two male-specific compounds were observed. GC-mass spectrometry (MS) and GC-Fourier transform-infrared (FTIR) analyses of the natural compounds suggested these were diastereoisomers of 5-hydroxy-4-methylheptan-3-one, also known as sitophilure, a pheromone component of other dryophthorine species. Synthesis of the mixture of all four stereoisomers of sitophilure was performed in two steps, and the chemical structures were confirmed by comparing GC retention times and MS and FTIR spectra of natural and synthetic compounds. The absolute configurations of the two male-specific compounds were elucidated by enantioselective GC; the major component was the (4S,5R)-isomer, and the minor component (4S,5S)-sitophilure. In analyses by GC-electroantennography (EAG) the antennae of male and female R. barbirostris only responded to the (4S,5R)-isomer of the synthetic sitophilure. The stereoisomeric mixture of sitophilure was attractive to both sexes of R. barbirostris in laboratory experiments in the presence of sugar cane volatiles, and a similar result was obtained in a preliminary field trapping test.     

Male-Produced Pheromone of <Emphasis Type="Italic">Spathius agrili</Emphasis>, A Parasitoid Introduced For The Biological Control Of The Invasive Emerald Ash Borer, <Emphasis Type="Italic">Agrilus planipennis</Emphasis>

The braconid wasp, Spathius agrili, has been released in the U.S. as a biocontrol agent for the invasive emerald ash borer (Coleoptera: Buprestidae: Agrilus planipennis), a destructive pest of ash trees (Fraxinus spp.). We identified and synthesized seven male-specific volatile compounds. Three of these, dodecanal, (4R,11E)-tetradecen-4-olide, and (Z)-10-heptadecen-2-one, were the key behaviorally active components in flight tunnel bioassays. Male specificity was demonstrated by gas chromatographic comparison of male and female volatile emissions and whole body extracts. Identifications were aided by coupled gas chromatographic-mass spectrometric (GC-MS) analysis, microchemical reactions, NMR, chiral GC analysis, and GC and MS comparison with authentic standards. Both the racemic and chiral forms of the γ-lactone, as well as both E- and Z-isomers were synthesized. Flight tunnel behavioral tests showed positive male and female S. agrili responses to both natural pheromone and synthetic blends, with upwind flight and landing on the source. Large field-cage tests, using yellow sticky traps baited with pheromone, captured approximately 50 % of the released male and female wasps in 24-h periods. The use of pheromone-baited traps in the field could simplify the current detection method for determining parasitoid establishment (i.e., laboriously felling and peeling ash trees for recovery of S. agrili from infested EAB larvae).     

Nonpolar-volatile lipids from soy protein isolates and hexane-defatted flakes

Lipid extracts from two samples of commercial soy protein isolates (SPI) and two samples of commercial hexane-defatted flakes were fractionated by silici acid-column chromatography. The material eluted with 100% chloroform was collected, further fractionated by silica solid-phase extractions, and analyzed by gas chromatography-mass spectroscopy by using mass spectra, retention times of authentic standards, and Kovats indices for identification. Thirty-eight compounds were identified and quantitated in the lipid fractions from soy protein isolates (SPI); 23 of these are reported for the first time as components of SPI. An additional 13 compounds are reported for the first time as components of hexane-defatted soybean flakes. The major classes of compounds reported for the first time associated with SPI include: butyl, methyl, and ethyl esters of fatty acids; phenols, diphenyls and phenyl esters; and abietic acid derivatives. Dehydroabietinal at 0.180 to 0.191 ppm of the protein isolates was the most abundant aldehyde in the SPI lipid extracts. The third most abundant aldehyde found in SPI after dehydroabietinal and hexanal was 2-butyl-2-octenal (0.065 to 0.086 ppm). Dehydroabietic acid methyl ester was present in SPI (0.309 to 0.459 ppm). Dehydroabietene (0.628 ppm) and abietatriene (0.396 ppm) were tentatively identified in one sample of hexane-defatted flakes.