Identification and electrophysiological studies of (4S,5S)-5-hydroxy-4-methyl-3-heptanone and 4-methyl-3,5-heptanedione in male lucerne weevils (original) (raw)
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Journal of Chemical Ecology
Antennal olfactory receptor neurons (ORNs) for pheromone-related and plant volatile compounds were identified and characterized in the lucerne weevil, Sitona discoideus (Gyllenhal), using the single sensillum recording technique. Our study using five pheromone-related compounds and 42 plant volatile compounds indicates that S. discoideus have highly specialized ORNs for pheromone and plant volatile compounds. Different groups of ORNs present in both males and females of S. discoideus were highly sensitive to 4-methylheptane-3,5-dione (diketone) and four isomers (RR, RS, SR and SS) of 5-hydroxy-4-methylheptan-3one, respectively. Our results also indicate that male S. discoideus, using the sensory input from antennal ORNs, can distinguish both diketone and the RR-isomer from others, and RS-and SS-isomers from others, although it was unclear if they can distinguish between RS-isomer and SS-isomer, or between diketone and the SR-isomer. It also appeared that female S. discoideus could distinguish between RS-isomer and SS-isomers. The antennae of S. discoideus thus contain sex-specific sets of ORNs for hostand non-host plant volatile compounds. Both sexes of S. discoideus have highly sensitive and selective ORNs for some green-leaf volatiles, such as (Z)-3-hexenol and (E)-2-hexenal. In contrast, male antennae of S. discoideus house three distinct groups of ORNs specialized for myrcene and (E)-β-ocimene, 2-phenylethanol, and phenylacetaldehyde, respectively, whereas female antennae contain three groups of ORNs specialized for (±)-linalool and (±)-α-terpineol, myrcene and (E)-β-ocimene, (±)-1octen-3-ol, and 3-octanone. Our results suggest that S. discoideus use a multi-component pheromone communication system, and a sex-specific set of ORNs with a narrow range of response spectra for host-plant location.
Journal of Insect Physiology, 2013
Antennal olfactory receptor neurons (ORNs) for pheromone and plant volatile compounds were identified and characterized in male and female clover root weevil, Sitona lepidus (Gyllenhal), using the single sensillum recording technique with five pheromone-related compounds, and 40 host and non-host plant volatile compounds. Overall, seven different types of olfactory sensilla containing specialized ORNs were identified in each sex of S. lepidus. Among them, three different types of sensilla in the males and two types in the females housed ORNs specialized for pheromone-related compounds. The ORNs in males were specialized for 4-methyl-3,5-heptanedione or one or more of four stereoisomers of 5-hydroxy-4-methyl-3-heptanone. In contrast, female sensilla did not contain ORNs sensitive to 4-methyl-3,5heptanedione while they contained ORNs sensitive to and specialized for the stereoisomers of (4S,5S)-5-hydroxy-4-methyl-3-heptanone. In addition to the pheromone-related ORNs, four types of olfactory sensilla contained ORNs responsive to plant volatile compounds in male S. lepidus, and five types in females. Most of the ORNs identified in S. lepidus showed a high degree of specificity to specific volatile compounds although some of the active compounds showed overlapping response spectra in the ORNs across different types of sensilla. The most active plant volatile compounds were the four green leaf volatile compounds, (E)-2-hexenol, (Z)-2-hexenol, (Z)-3-hexenol and (E)-2-hexenal, and isomers of two monoterpenols, (±)-linalool and (±)-a-terpineol, all eliciting strong responses from relatively large numbers of ORNs in male and female S. lepidus. Our study indicates that S. lepidus has a set of highly sensitive and selective ORNs for pheromone and plant volatile compounds. Further work is needed to elucidate the behavioral implications of these findings.
Journal of Comparative Physiology A, 2004
Single-cell electrophysiological recordings were obtained from olfactory receptor neurons in sensilla trichodea on male antennae of the heliothine species Heliothis subflexa and the closely related congener H. virescens. A large percentage of sensilla (72% and 81%, respectively, of all sensilla sampled) contained a single odor-responsive receptor neuron tuned to the major pheromone component of both species, Z-11-hexadecenal. A second population of sensilla on H. subflexa antennae (18%) housed receptor neurons that were tuned to Z-9-hexadecenal but also responded with less sensitivity to Z-9-tetradecenal. A similar population of sensilla (4%) on H. virescens male antennae housed receptor neurons that were shown to be tuned specifically only to Z-9-tetradecenal, with no response to even high dosages of Z-9-hexadecenal. A third population of sensilla (comprising 8% and 16% of the sensilla sampled in H. subflexa and H. virescens, respectively) housed two olfactory receptor neurons, one of which was tuned to Z-11-hexadecenyl acetate and the other tuned to Z-11hexadecenol. In H. subflexa the Z-11-hexadecenyl acetate-tuned neuron also responded to Z-9-tetradecenal with nearly equivalent sensitivity. The behavioral requirements of males of these two species for distinct pheromonal blends was, therefore, reflected by the subtle differences in the tuning properties of antennal olfactory receptor neurons.
Journal of Comparative Physiology A: Sensory, Neural, and Behavioral Physiology, 1999
Chemical communication in scarab beetles involves female-released long-distance sex pheromones. Electrophysiological recordings using tungsten microelectrodes demonstrated two types of olfactory receptor neurons in the scarab beetle Anomala cuprea, each spe-ci®c for one of the two pheromone components (R)-buibuilactone and (R)-japonilure, respectively. No neurons were found that responded speci®cally to enantiomers of the pheromone compounds, i.e. (S)buibuilactone and (S)-japonilure. Pheromone receptor neurons are present in high numbers on both the male and the female antenna, with a lower sensitivity in the females. As in bark beetles and moths, the pheromone receptor neurons in A. cuprea are very sensitive and selective. The dierence in response thresholds between (R)-and (S)-enantiomers is almost three orders of magnitude. Pheromone receptor neurons are found in sensilla placodea located in a de®ned area on each lamella in the antennal club. (R)-buibuilactone and (R)japonilure neurons are always found in dierent sensilla. Both types of sensilla contain two neurons, with the pheromone-sensitive neuron displaying a high spike amplitude and the second neuron, not responding to any of the tested compounds, always with a lower spike amplitude.
Journal of Chemical Ecology, 1993
Ips grandicollis. Recordings were made from olfactory receptor cells from nine regions of the antennae in response to stimulation with the semiochemicals ~-pinene, frontalin, endo-brevicomin, verbenone, trans-verbenol, cis-verbenol, ipsdienol, and ipsenol. In many cases, up to two cells were recorded concurrently from the same location. When compared to males, females had a greater percentage of cells responsive to the primary pheromones of Dendroctonus frontalis, frontalin and trans-verbenol, and of lps spp., ipsdienol and ipsenol. Among females, more cells responded to trans-verbenol and the lps-produced volatiles than to host or other D. frontalisproduced compounds. Olfactory cells of males responded mostly to cis-verbenol, followed by ~-pinene, verbenone, trans-verbenol, and endo-brevicomin. Of those cells responsive primarily to one compound, the greatest percentage were responsive to trans-verbenol in females and to verbenone in males. The response of the antennal olfactory receptor cells to semiochemicals used by male and female L grandicollis is consistent with the presence of these compounds during the host colonization period for each sex. Our results, which show a lack of specificity in most pheromone and host odor receptor cells, is in contrast with previously published accounts of olfactory receptor cell specificity in other Ips species.
Annals of the Entomological Society of America, 2004
The olfactory system of male and female Spodoptera frugiperda (J. E. Smith) was studied by examining the morphology and distribution of antennal sensilla and determining the responses of both sexes to conspeciÞc female sex pheromone components and plant volatiles using electroantennography (EAG). Seven types of sensilla were observed on the ßagellum of the antennae: trichodea, chaetica, coeloconica, styloconica, auricilica, squamiformia, and basiconica. Only one type of trichodea sensilla was found on the antennae of both sexes, but these sensilla were more abundant on male than on female. EAG records of both sexes to 10-g stimulus loads of six pheromone components showed that (Z)-7-dodecenyl acetate (Z7Ð12: Ac) and (Z)-9-dodecenyl acetate (Z9 Ð12: Ac) elicited larger responses than those evoked by (Z)-11-hexadecenyl acetate (Z11Ð16: Ac), (Z, E)-9,11-tetradecadienyl acetate (Z9, E11Ð14: Ac), (Z, E)-9,12-tetradecadienyl acetate (Z9, E12Ð14: Ac), and hexane in female antennae. In the case of male antennae, (Z)-9-tetradecenyl acetate (Z9 Ð14: Ac) and Z9, E12Ð14: Ac evoked larger EAG responses than those elicited by Z7Ð12: Ac, Z11Ð16: Ac, Z9, E11Ð14: Ac, and hexane. The compounds that selectively evoked larger EAG responses from males than females were Z9, E12Ð14: Ac, and Z9 Ð14: Ac. Dose-response experiments showed that, at the lowest dose tested, Z9 Ð14: Ac and Z9, E12Ð14: Ac elicited larger EAG responses than Z9 Ð12: Ac and Z7Ð12: Ac in male antennae. At the highest doses tested, the diene elicited the largest EAG responses. In the case of female antennae, the dose, but not the pheromone component, had a signiÞcant effect. Male and female responses to 10-g stimulus loads of 16 plant volatiles showed that hexan-1-ol evoked larger EAG responses in comparison with those elicited by hexanal, (E)-3-hexenol, 2-carene, phellandrene, limonene, -pinene, and hexane. The response of male antennae was signiÞcantly stronger than the female. Dose-response experiments showed that both sexes appeared to be most sensitive to alcohols, particularly at the highest dose tested.
Diatraea saccharalis, Sex Pheromone, (9Z,11E)-Hexadecadienal Virgin female gland extracts of sugarcane moth Diatraea saccharalis (Fabricius) (Lepidoptera: Pyralidae), from three locations in Brazil, have been analyzed. By GC-MS analysis and comparison of the chromatographic retention time of the components of the pheromone gland with those retention times of synthetic standards, we observed the presence of (Z)hexadec-11-enal (1), hexadecanal (2), (9E,11Z)-hexadecadienal (4), (9Z,11Z)-hexadecadienal and (9E,11E)-hexadecadienal , as minor components besides the major constituent (9Z,11E)-hexadecadienal (3) already reported. We found no variations in the composition of the gland extracts deriving from the three Brazilian populations and only two compounds, (Z)-hexadec-11-enal (1) and (9Z,11E)-hexadecadienal , elicited antennal responses (GC-EAD). In electroantennography (EAG), however, pure compounds 1 and 3, a binary mixture containing 1 and 3, and a mixture containing all of the six synthetic compounds 1Ð6 elicited a depolarization in male antennae of D. saccharalis, without any statistically different delay. The EAG responses to the other isomers of 9,11-hexadecadienal were small and not significantly different from the control, except for the (9Z,11Z)-isomer (5) which showed an relatively strong electroantennal activity.
Journal of Insect Physiology, 2001
Studies were conducted to investigate the electroantennographic (EAG) responses of adult female Helicoverpa armigera to a range of known and putative kairomone components. The studies show that at a given dose the EAG responses elicited by a series of straight-chain aliphatic primary alcohols were not dependent on volatility since butan-1-ol and pentan-1-ol elicited EAG responses that were significantly smaller than those elicited by hexan-1-ol. The amplitudes of responses to hexan-1-ol were found to be dose dependent with a dose of 10 Ϫ1 µmol at source in a non-volatile solvent eliciting the largest response. Similarly, changes in functionality in a range of C 6 straight-chain aliphatic compounds significantly changed the amplitude of response elicited, with aldehydes eliciting smaller responses than the related primary alcohols and saturated compounds eliciting higher responses than related unsaturated compounds. Of the range of nine host plant-produced terpenoids tested, ocimene and β-phellandrene elicited the highest responses and of the six aromatic compounds tested phenylacetaldehyde and benzaldehyde elicited the largest responses, at the doses tested. The significance of these findings for analysis of floral odours by gas chromatography linked to electroantennography as a means of identifying kairomone components attractive to H. armigera are discussed.
Journal of Insect Physiology, 1992
Electroantennogram and single sensillum recordings were performed on the male cigarette beetle, Lasioderma serricorne, antennae. Strong antenna1 responses were elicited by not only natural sex pheromone component (4S,SS,7S)-serricornin (SSS-serricornin) but also non-natural behavioural inhibitor, (4S,SS,7R)-serricornin (SSR-serricornin). In the case of mixture application of the SSS-and SSR-serricornin, integrated electroantennogram responses were observed. Single sensillum recording from male flagella sensilla showed that the majority of basiconic type sensilla responded to the behavioural inhibitor as well as to the sex pheromone. However, a few of them responded only to the inhibitor. The behavioural inhibitory action of SSR-serricornin toward the SSS-serricornin results from central integration of the information from separate receptor cells rather than blockage at the peripheral receptors.
1999
Electroantennograms (EAGs) were recorded from two predatory insect species, the twelve-spotted lady beetle, Coleomegilla maculata and the green lacewing, Chrysoperla carnea in response to semiochemicals emitted from one of their prey species, the pea aphid Acyrthosiphon pisum and their host plant. EAG responses were also recorded from C. maculata in response to extracts from individuals of the opposite sex and to extracts from an herbaceous plant, catnip Nepeta cataria. Extracts of catnip and two sex pheromone components of aphids, (4aS,75,7aR)-nepetalactone and (lR,4aS,7S,7aR)-nepetalactol, elicited significant EAG responses from the antennae of both predatory species. Of 10 corn volatile compounds tested, C. carnea adults responded most strongly to 2-phenylethanol and (E)-B-farnesene. A significant difference in EAG response to extracts of corn leaf collections was observed between male and female C. carnea. In C. maculata, significant EAG responses were elicited by most of the tested corn volatile compounds, except A-pinene and (E)-2-hexenal. The highest EAG responses were observed in response to (E)-B-farnesene, A-terpineol, 2-phenylethanol, and B-caryophyllene. Sexual differences in EAG responses of C. maculata were only found in response to l-octen-3-ol. Male antennae of C. maculata produced significant EAG responses to extracts from conspecific females, but not to males, which indicates that some chemicals from females could be involved in sexual communication. A significant EAG response also was recorded in response to the extracts of fluids produced during "reflex bleeding." Male and female antennae of both species exhibited similar dose-response curves to most of the selected compounds, although female C. maculata antennae exhibited higher thresholds in response to several compounds including A-terpineol, (Z )-3-hexenol, and (4aS,7S,7aR)-nepetalactone. Field tests showed that 2-phenylethanol was highly attractive to both sexes of the two investigated species. Only C. maculata was attracted to traps baited with A-terpineol.