Cuticular hydrocarbons of the paper wasp,Polistes fuscatus: A search for recognition pheromones

The cuticular chemicals of 124 individual wasps (foundresses and workers) from 23 colonies ofPolistes fuscatus were analyzed. The compounds identified, all of which were hydrocarbons, were similar to those of other vespid wasps in that the bulk of the hydrocarbons were 23–33 carbons in chain length. However, the hydrocarbon profile ofP. fuscatus differed from those of its congeners in its proportions of straight-chain alkanes, methylalkanes, and alkenes. Three of the 20 identified hydrocarbons, 13- and 15-MeC₃₁, 11,15- and 13,17-diMeC₃₁, and 13-, 15-, and 17-MeC₃₃, had properties postulated for recognition pheromones: colony specificity, efficacy in assigning wasps to the appropriate colony, heritability, lack of differences between foundresses and workers, and distinctive stereochemistry.     

Cuticular Hydrocarbons of Buffalo Fly, <Emphasis Type="Italic">Haematobia exigua</Emphasis>, and Chemotaxonomic Differentiation from Horn Fly, <Emphasis Type="Italic">H. irritans</Emphasis>

We determined the quantity and chemical composition of cuticular hydrocarbons of different strains, sexes, and ages of buffalo flies, Haematobia exigua. The quantity of cuticular hydrocarbons increased from less than 1 μg/fly for newly emerged flies to over 11 μg/fly in 13-d-old flies. The hydrocarbon chain length varied from C₂₁ to C₂₉, with unbranched alkanes and monounsaturated alkenes the major components. Newly emerged flies contained almost exclusively C₂₇ hydrocarbons. Increasing age was accompanied by the appearance of hydrocarbons with shorter carbon chains and an increase in the proportion of alkenes. 11-Tricosene and 7-tricosene were the most abundant hydrocarbons in mature H. exigua. Cuticular hydrocarbons of H. exigua are distinctly different from those of horn flies, Haematobia irritans. The most noticeable differences were in the C₂₃ alkenes, with the major isomers 11- and 7-tricosene in H. exigua and (Z)-9- and (Z)-5-tricosene in H. irritans, respectively. Cuticular hydrocarbon analysis provides a reliable method to differentiate the two species, which are morphologically difficult to separate. The differences in cuticular hydrocarbons also support their recognition as separate species, H. exigua and H. irritans, rather than as subspecies.     

Role of cuticular hydrocarbons of aphid parasitoids in their relationship to aphid-attending ants

Lysiphlebus cardui, the dominant aphidiid parasitoid of the black bean aphid,Aphis fabae cirsiiacanthoidis (Afc), on creeping thistle, is able to forage in ant-attended aphid colonies without being attacked by ants. Several behavioral observations and experimental studies led to the hypothesis thatL. cardui mimics the cuticular hydrocarbon profile of its host aphid. Chemical analysis of the cuticular extracts revealed that bothL. cardui and Afc exclusively possess saturated hydrocarbons:n-alkanes, monomethyl (MMA), dimethyl (DMA), and trimethyl alkanes (TMA). Comparison of the hydrocarbon profiles of parasitoid and aphid showed great qualitative resemblance between parasitoid and host:L. cardui possesses almost all host-specific compounds in addition to species-specific hydrocarbons of mainly higher molecular weight (>C₃₀). However, there is a lesser quantitative correspondence between parasitoid and host aphid. Furthermore, we analyzed the cuticular hydrocarbon profile of another parasitoid of Afc,Trioxys angelicae. This aphidiid species is vigorously attacked and finally killed by honeydewcollecting ants when encountered in aphid colonies. Its cuticular hydrocarbon profile is characterized by the presence of large amounts of (Z)-11-alkenes of chain lenghts C₂₇, C₂₉, C₃₁, and C₃₃, in addition to alkanes and presumably trienes. The role of the unsaturated hydrocarbons onT. angelicae as recognition cues for aphid-attending ants is discussed.     

Cuticular hydrocarbons of Drosophila birchii and D. serrata: identification and role in mate choice in D. serrata

The cuticular hydrocarbon compositions of two sympatric species of Australian Drosophila in the montium subgroup of the melanogaster group that use cuticular hydrocarbons in mate recognition have been characterized. Drosophila birchii has 34 components in greater than trace amounts, with a carbon number range of C₂₀ to C₃₃. Drosophila serrata has 21 components above trace level and a carbon number range of C₂₄ to C₃₁. These two species share eight hydrocarbon components, with all but two of them being monoenes. For both species, the (Z)-9-monoenes are the predominant positional isomer. The hydrocarbons of D. birchii are n-alkanes, n-alkenes (Z)-5-, (Z)-7-, (Z)-9-, and (Z)-11-), low to trace levels of homologous (Z,Z)-7,11- and (Z,Z)-9,13-dienes; and trace amounts of (Z,Z)-5,9-C_25:2, a major component of D. serrata. Only one methyl branched hydrocarbon was detected (2-methyl C₂₈), and it occurred at very low levels. The hydrocarbons of D. serrata are dominated by a homologous series of (Z,Z)-5,9-dienes, and notably, are characterized by the apparent absence of n-alkanes. Homologous series of (Z)-5-, (Z)-7-, and (Z)-9-alkenes are also present in D. serrata as well as 2-methyl alkanes. Drosophila serrata females display strong directional mate choice based on male cuticular hydrocarbons and prefer D. serrata males with higher relative abundances of the 2-methyl alkanes, but lower relative abundances of (Z,Z)-5,9-C_24:2 and (Z)-9-C_25:1.     

Paraffinic hydrocarbon composition of earthworms (Lumbricus terrestris)

The paraffinic hydrocarbon fraction of the lipids extracted from earthworms (Lumbricus terrestris) contains ca. 88%n-alkanes and 12% branched alkanes and other hydrocarbons. Then-alkanes range from C₁₃ through C₃₃, and their most interesting feature is the even-over-odd carbon number predominance in the C₁₃−C₂₄ range. The nonnormal hydrocarbons consist primarily of monomethyl-substituted alkanes. Other hydrocarbons that have been identified include the C₁₆. C₁₈, C₁₉ and C₂₀ isoprenoids and the C₁₈, C₂₀ and C₂₂ n-alkylcyclohexanes.     

Isolation and identification of a sex attractant of a mushroom-infesting sciarid fly

A sciarid fly,Lycoriella mali (Fitch), is one of the most destructive pests to the commercial mushroom,Agaricus bisporus (Lange) Singer. Sanitation procedures and pesticide applications were ineffectual in controlling this pest. A supplemental pest control method employing sex pheromones was suggested since previous work indicated the presence of a sex attractant in the female. Diagnostic reactions performed on female extracts indicated saturated hydrocarbons as active components. The biologically most active fractions eluted from the gas chromatograph between standard hydrocarbons C₁₅ and C₂₂. Hydrocarbons C₁₅, C₁₆, C₁₇, and C₁₈ were isolated and identified via TLC, GC, and GC-MS. Male response to standard hydrocarbons C₁₅ to C₂₆ indicated that C₁₇ is a major attractant. Male response to varying amounts of C₁₇ indicated a preference for levels 10^–6g and 10^–9g.     

Cuticular hydrocarbon profiles of dominant versus subordinate male Nauphoeta cinerea cockroaches

Interactions between male Nauphoeta cinerea cockroaches are characterized by an elaborate ritual that leads to a stable dominant–subordinate hierarchy between two individuals. Chemical signals involving volatile sex pheromones and cuticular hydrocarbons play an important role in establishing and maintaining dominance status. The present study was performed to identify cuticular hydrocarbons in two- and three-times dominant or subordinate individuals obtained by forcing dyadic encounters. Two methods, i.e., solid-phase microextraction (SPME) and organic solvent extraction, were used to isolate cuticular hydrocarbons. A total of 23 peaks of cuticular hydrocarbons were identified. Analysis showed quantitative differences in hydrocarbon profiles of three-times dominant and subordinate individuals according to extraction method and dominance status. Dominant individuals were characterized by higher proportions of the monomethylalkanes 11- and 13-MeC₃₆, 13- and 15-MeC₃₈, and 11-, 13-, and 15-MeC₃₅, while subordinate individuals had higher proportions of the following monomethylalkanes: 7-, 9-, and 11-MeC₃₁, 5-MeC₃₁, 3- and 8-MeC₃₂, and 9-, 10- , 11-, and 12-MeC₃₂. Discussion focuses on the reliability of hydrocarbons as indicators of dominance status and on their correlation with physiological processes.     

Cuticular hydrocarbons of gregarious and solitary locustsLocusta migratoria cinerascens

The cuticular hydrocarbons ofLocusta migratoria cinerascens—larvae and adults, males and females, gregarious and solitaries—have been investigated by combined gas chromatography-mass spectrometry. The hydrocarbons comprise 52–78% of the cuticular lipids and are divided inton-alkanes (28.7–47.3%), 3-, 4-, and 5-methylalkanes (11.3–15.8%), internally branched monomethylalkanes (13.7–19.9%), and internally branched dimethylalkanes (19.8–35.9%) with seven or nine methylenes between the two branch points. While the sexual dimorphism does not seem to be reflected in the cuticular hydrocarbon composition, clear quantitative variations favoring the longest chain alkanes have been observed between gregarious and solitary locusts, thus revealing a new phase character in these insects.     

Cuticular hydrocarbons ofReticulitermes virginicus (Banks) and their role as potential species- and caste-recognition cues

The cuticular hydrocarbon components of four castes ofReticulitermes virginicus (Banks) have been identified and quantitated. Components identified includen-alkanes; 2-, 3-, 11-, 13-, and 15-methyl-alkanes; 11,15-dimethylalkanes, (Z)-9-alkenes; (Z,Z)-7,9-dienes; and (E/Z)-6,9-dienes ranging in carbon number from C₂₁ to C₄₀. All caste forms ofR.virginicus contained the same components, but showed caste-specific proportions. Comparison of these hydrocarbons with those of the sympatric termiteR. flavipes (Kollar) suggest that cuticular hydrocarbons might serve as species- and caste-recognition cues. A bioassay was developed to test this species-recognition hypothesis, with the experimental results supporting the hypothesis.Isoptera: Rhinotermitidae.     

Gas chromatographic identification of fatty acids,fatty alcohols,and hydrocarbons ofHibiscus rosa-sinensis leaves

Hibiscus rosa-sinensis leaves (family Malvaceae) were analyzed for their fatty acid, fatty alcohol, and hydrocarbon contents. Wax hydrocarbons ranging from C₁₆ to C₃₂ with C₂₃, C₂₅, C₂₇, and C₃₁ as major components and wax alcohols between C₂₁ and C₃₀ with C₂₆, iso-C₂₈, and iso-C₃₀ as major components were found to be present in the petroleum ether fraction of the leaves. Fatty acids ranging from C₈ to C₂₈ with C₈, C₁₂, C₁₄, C₁₆, and C_18:2 as major components were found in the combined form. Two cyclic acids, sterculic and malvalic, have also been identified.     

Cuticular Hydrocarbons as Sex Pheromone of the Bee <Emphasis Type="Italic">Colletes cunicularius</Emphasis> and the Key to its Mimicry by the Sexually Deceptive Orchid, <Emphasis Type="Italic">Ophrys exaltata</Emphasis>

Male Colletes cunicularius bees pollinate the orchid, Ophrys exaltata, after being sexually deceived by the orchid’s odor-mimicry of the female bee’s sex pheromone. We detected biologically active volatiles of C. cunicularius by using gas chromatographic–electroantennographic detection (GC-EAD) with simultaneous flame ionization detection. After identification of the target compounds by coupled gas chromatography–mass spectrometry (GC-MS), we performed behavioral tests using synthetic blends of the active components. We detected 22 EAD active compounds in cuticular extracts of C. cunicularius females. Blends of straight chain, odd-numbered alkanes and (Z)-7-alkenes with 21–29 carbon atoms constituted the major biologically active compounds. Alkenes were the key compounds releasing mating behavior, especially those with (Z)-7 unsaturation. Comparison of patterns of bee volatiles with those of O. exaltata subsp. archipelagi revealed that all EAD-active compounds were also found in extracts of orchid labella. Previous studies of the mating behavior in C. cunicularius showed linalool to be an important attractant for patrolling males. We confirmed this with synthetic linalool but found that it rarely elicited copulatory behavior, in accordance with previous studies. A blend of active cuticular compounds with linalool elicited both attraction and copulation behavior in patrolling males. Thus, linalool appears to function as a long-range attractant, whereas cuticular hydrocarbons are necessary for inducing short-range mating behavior.     

Courtship Pheromones in Parasitic Wasps: Comparison of Bioactive and Inactive Hydrocarbon Profiles by Multivariate Statistical Methods

Cuticular hydrocarbons play a significant role in the regulation of cuticular permeability and also in the chemical communication of insects. In the parasitoid Lariophagus distinguendus (Hymenoptera: Pteromalidae), male courtship behavior is mediated by a female-produced sex pheromone. Previous studies have shown that the chemicals involved are already present in the pupal stage of both males and females. However, pheromonal activity in males decreases shortly after emergence. This pheromonal deactivation occurs only in living males, suggesting an active process rather than simple evaporation of bioactive compounds. Here, we present evidence that the sex pheromone of L. distinguendus is composed of a series of cuticular hydrocarbons. Filter paper disks treated with nonpolar fractions of cuticular extracts of freshly emerged males and females, 72-hr-old females, and yellowish pupae caused arrestment and stimulated key elements of courtship behavior in males, whereas fractions of 72-hr-old males did not. Sixty-four hydrocarbons with chain length between C₂₅ and C₃₇ were identified in the fractions by gas chromatography-mass spectrometry (GC-MS). Methyl-branched alkanes with one to four methyl groups were major components, along with traces of n-alkanes and monoalkenes. Principal component analysis, based on the relative amounts of the compounds, revealed that cuticular hydrocarbon composition differed among all five groups. By using partial least squares-discriminant analysis, we determined a series of components that differentiate bioactive and bioinactive hydrocarbon profiles, and may be responsible for pheromonal activity of hydrocarbon fractions in L. distinguendus.     

Colony-Specific Cuticular Hydrocarbon Profile in Formica argentea Ants

The cuticular hydrocarbons of the ant Formica argentea were identified by gas chromatography/mass spectrometry. Behavioral bioassays tested the role of each class of cuticular hydrocarbon in nestmate recognition, and statistical analyses looked for potential colony-specific signatures. The cuticular hydrocarbons of F. argentea consist of n-alkanes, alkenes, and methyl-branched alkanes. Behavioral bioassays demonstrated that changes in the alkene and methyl-branched alkane signature of F. argentea increased aggression, but changes in alkanes did not. Statistical analyses demonstrated that F. argentea workers present a colony-specific hydrocarbon profile based on their methyl-branched C₂₉ alkane signature. Using this signature alone, it is possible to group worker ants statistically by nest, suggesting that methyl-branched C₂₉ alkanes may be important in nestmate recognition for this species. These results support the idea that variation in positional isomers of cuticular hydrocarbons of the same carbon chain length may provide enough information for nestmate recognition. Although the addition of alkenes increased aggression in F. argentea, alkenes did not provide a colony-specific signature. This study reinforces the idea that investigators studying nestmate recognition should not examine cuticular hydrocarbon profiles as a whole but rather, should look for colony-specific signatures embedded in parts of the profile.     

Sex Pheromone of Glossina tachinoides: Isolation, Identification, and Synthesis

Study of lipids from male and female laboratory-reared flies led to the demonstration of a potent contact sex stimulant in extracts and cuticular hydrocarbons of the female tsetse fly Glossina tachinoides (Westwood) against conspecific males. Thin-layer and column chromatography indicated that extracts contained hydrocarbons and saponifiable lipids. Biological activity was found in the alkanes from females, including prominent branched-chain alkanes that were detected by gas chromatography (GC). The alkanes were separated and collected by preparative gas chromatography (GC), and only the 37-carbon region showed biological activity. GC–mass spectrometry showed the major peak contained a mixture of isomeric 11,23-, 13,25- plus a minor amount of 11,21-dimethylheptatriacontane. Two racemic isomers were synthesized, and bioassays showed that the greatest activity was possessed by the 11,23- isomer with somewhat less activity in 13,25-dimethyl heptatria-contane. Dose–response data showed ED₅₀ at 5 g per decoy with solvent-washed males, nonspecific females, or corks as decoys. These alkanes released sexual activity in males that comprised most of the behaviors released by a female fly of the same species.     

Gas chromatographic identification of fatty acids,fatty alcohols,and hydrocarbons ofConvolvulus pluricaulis (chois)

Convolvulus pluricaulis (Chois) (Family: Convolvulaceae) (Hindi: Shankhapushpi), widely grown in the northern part of India, was analyzed for its fatty acids and waxy constituents. Straight chain hydrocarbons (C₂₂–C₃₃), fatty acids (C₁₄–C₂₈), and fatty alcohols (C₂₄–C₃₂) were found in the whole plant 95% aqueous ethanol extract. Hydrocarbons (C₂₇, C₃₁, and C₃₃), fatty acids (C₁₄, C₁₆, and C_18:2), and alcohols (C₂₆, iso-C₂₈, iso-C₃₀, and C₃₂) were the major components.     

Cuticular hydrocarbons of the eastern subterranean termite,Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae)

Major cuticular hydrocarbon components in several castes ofReticulitermes flavipes (Kollar) have been identified and quantitated. Types of hydrocarbons present includen-alkanes, 2-methylalkanes, 3-methylalkanes, 5-methylalkanes, an alkene, and an alkadiene, with a range in carbon numbers from C₂₁ to C₂₆, This is the first report on insect cuticular hydrocarbons in which both 2- and 3-methylalkanes are present, as well as the first report of an insect with a conjugated alkadiene.     

Resolution of Epoxydienes by Reversed-Phase Chiral HPLC and its Application to Stereochemistry Assignment of Mulberry Looper Sex Pheromone

Resolution of insect pheromonal cis-epoxydiene racemates derived from (Z,Z,Z)-3,6,9-trienes was examined with a reversed-phase chiral HPLC column. The results showed that a Chiralcel OJ-R column was suitable for separating the enantiomers having a C₁₇–C₂₃ unsaturated straight chain except for 9,10-epoxydienes with a C₂₁–C₂₃ chain. To determine the absolute configuration of the separated enantiomers, each of the optically active epoxydienes was hydrogenated over Pd-BaSO₄ and its behavior was examined on this chiral column by cochromatography with the corresponding chiral epoxy compound having a saturated chain, which was prepared via a Sharpless epoxidation reaction. This analysis showed that the dextrorotatory C₁₇–C₂₃ 3,4- and 6,7-epoxydienes and C₁₇–C₂₀ 9,10-epoxydienes with shorter R _ts possess (3S,4R)-, (6S,7R)-, and (9R,10S) configurations, respectively, and the levorotatory enantiomers with longer R _ts possess the opposite configuration. An abdominal tip extract of the mulberry looper, Hemerophila artilineata Butler (Lepidoptera: Geometridae: Ennominae), included (9S,10R)-(Z,Z)-cis-9,10-epoxy-3,6-octadecadiene as a main sex pheromone component. The synthetic (9S,10R)-9,10-epoxydiene, rather than its antipode, elicited strong antennal and behavioral responses from the male moths in electrophysiological and field tests.     

Sex Pheromone of the Cranberry Blossom Worm, Epiglaea apiata

The cranberry blossom worm, Epiglaea apiata (Grote) (Lepidoptera: Noctuidae), is a major pest of cranberries in New Jersey. The female sexpheromone of this moth was identified as a blend of (Z)-9-hexadecenyl acetate (Z9-16:Ac), (Z)-9-tetradecenyl acetate (Z9-14:Ac), and tetradecyl acetate (14:Ac) by gas chromatographic–electroantennographic detection and gas chromatography–mass spectrometry. The ratio of the components in extracts of the female pheromone gland was determined to be 65 : 2 : 33 of the Z9-16:Ac, Z9-14:Ac, and 14:Ac, respectively. The double bond positions of the pheromone components were confirmed by dimethyl disulfide derivatization. In addition to the above three components, a mixture of C₄–C₁₀ aliphatic acids was present in both gland extracts and effluvia collections, and the acids elicited significant EAD responses from male moth antennae. However, addition of the C₄–C₁₀ aliphatic acids to the pheromone blend did not significantly increase trap captures. Three-hundred- and 1000-g doses of a synthetic blend containing Z9-16:Ac, Z9-14:Ac, and 14:Ac (65 : 2 : 33), on a rubber septum were more attractive to males than lower doses.     

Cuticular hydrocarbons ofAedes hendersoni cockerell andA. triseriatus (SAY)

Field-caught adult male and femaleAedes hendersoni are difficult to distinguish from the sibling speciesA. triseriatus. We found that mosquitoes from the same sex of the sibling species can not be readily separated either by unique cuticular hydrocarbon components or by differences in percent composition of those components. Multivariate analysis of the cuticular hydrocarbon data does not provide good separation. Cuticular hydrocarbons were identified using gas chromatography electron-impact mass spectrometry and gas chromatography chemical-ionization mass spectrometry. Flame-ionization capillary gas chromatography was used for quantitative analysis of individual mosquitoes. Sixty-four hydrocarbons with chain lengths from C₁₆ to greater than C₄₆ were common to both species. Identified hydrocarbon components weren-alkanes, monomethylalkanes, dimethylalkanes, trimethylalkanes, and alkenes.Diptera: Culicidae.     

Cuticular lipids of insects: VIII. Alkanes of the mormon cricketAnabrus simplex

The cuticular hydrocarbons of the Mormon cricket,Anabrus simplex, are all saturated and consist of n-alkanes (29+%), 3-methylalkanes (12%), internally branched monomethylalkanes (26+%), and dimethylalkanes (28+%). The principal n-alkane is the C₂₉ component, with a range from C₂₃ to C₃₃. The 3-methylalkanes range from C₂₈ to C₃₂, and the internally branched monomethyl-and dimethylalkanes range from C₂₉ to C₃₉. When the branched alkanes ofA. simplex are compared to those from other insects in the order Orthoptera, interesting patterns of methyl branching are observed. Scientific Journal Series 631, Agricultural Experiment Station, University of Montana, Bozeman, Montana 59715.