153 Female sex pheromones of two Japanese saturniid species, Rhodinia fugax and Loepa sakaei: identification, synthesis, and field
evaluation.
While 11 species in the family Saturniidae are found in Japan, no sex pheromones of the native species had been investigated previously. We collected
larvae of
Rhodinia fugax in Nagano and Tottori Prefecture, and of
Loepa sakaei in Okinawa Prefecture, and extracted sex pheromones of
these two species from virgin female moths. In gas chromatography-electroantennogram detection (GC-EAD) analyses, male antennae of each species
responded to one component in the respective pheromone extracts of conspecific females. Chemical analyses of the extracts by GC/mass spectrometry
revealed that the EAD-active compounds of
R. fugax and
L. sakaei were a hexadecadienal and a tetradecadienyl acetate, respectively. The
two species belong to the subfamily Saturniinae, and the mass spectra of both were similar to that of the 6,11-hexadecadienyl acetate identified from
Antheraea polyphemus, classified in the same subfamily, suggesting the same 6,11-dienyl structure for the C
16 aldehyde and a
4,9-dienyl structure for the C
14 acetate. Based on this assumption, four geometrical isomers of each dienyl compound were stereoselectively
synthesized via acetylene intermediates, compared to the natural products, and tested in the field. Male catches confirmed the pheromone structures of
the two Japanese saturniid species as (
6E,11Z)-6,11-hexadecadienal for
R. fugax and (
4E,9Z)-4,9-tetradecadienyl acetate for
L. sakaei. The compounds have a characteristic 1,6-dienyl motif common to the pheromones of Saturniinae species.
154 Identification of the sex pheromone of the diurnal hawk moth, Hemaris affinis.
Sex pheromones of nocturnal hawk moths have been identified previously, but not those of diurnal hawk moths. Here, we report laboratory analyses and
field testing of the sex pheromone of the diurnal hawk moth,
Hemaris affinis (Bremer 1861) (Lepidoptera: Sphingidae). Sex pheromone glands were
removed and extracted in hexane during peak calling activity of virgin female moths. Analysis of gland extracts by gas chromatography (GC) with
electroantennographic detection revealed three components that elicited responses from male moth antennae. These components were identified, based on
their mass spectra and retention indices on two GC columns, as (
Z)-11-hexadecenal and (
10E,12Z)- and
(
10E,12E)-10,12-hexadecadienals with a ratio of 45:20:35. In a field experiment, traps baited with the three-component synthetic blend, but none
of the single- or two-component blends, caught male moths. All three pheromone components have been identified previously in pheromones of other
Lepidoptera, including Sphingid moths, and thus the ternary blend is probably responsible for the species specificity of the pheromone of this moth.
155 (Z)-13-Hexadecenyl acetate: a novel moth sex pheromone component from Herpetogramma submarginale (Lepidoptera: Crambidae).
The sex pheromone of
Herpetogramma submarginale (Swinhoe) was studied by gas chromatography (GC) with electroantennographic detection and GC
coupled with mass spectrometry. Two pheromone candidates detected in the gland extracts of females were identified as (
Z)-13-hexadecenyl acetate
(Z13-16:OAc) and (
E)-13-hexadecenyl acetate (E13-16:OAc) in a ratio of 87:13 by mass spectral analysis of the natural pheromone components and
their dimethyldisulfide adducts. In field tests, Z13-16:OAc alone attracted
H. submarginale males and caught significantly more males than live
virgin females. Addition of E13-16:OAc did not enhance the attractiveness of Z13-16:OAc. Derivatives of Z13-16:OAc also were tested as potential
pheromone components. Addition of (
Z)-13-hexadecen-1-ol significantly reduced the number of males captured, and (
Z)-13-hexadecenal had no
effect on the attractiveness of the lure. These results suggest that the female-produced sex pheromone of
H. submarginale is Z13-16:OAc. This
hexadecenyl acetate is a novel moth sex pheromone component.
156 Chiral methyl-branched pheromones.
Insect pheromones are some of the most interesting natural products because they are utilized for interspecific communication between various insects,
such as beetles, moths, ants, and cockroaches. A large number of compounds of many kinds have been identified as pheromone components, reflecting the
diversity of insect species. While this review deals only with chiral methyl-branched pheromones, the chemical structures of more than one hundred
non-terpene compounds have been determined by applying excellent analytical techniques. Furthermore, their stereoselective syntheses have been achieved
by employing trustworthy chiral sources and ingenious enantioselective reactions. The information has been reviewed here not only to make them available
for new research but also to understand the characteristic chemical structures of the chiral pheromones. Since biosynthetic studies are still limited,
it might be meaningful to examine whether the structures, particularly the positions and configurations of the branched methyl groups, are correlated
with the taxonomy of the pheromone producers and also with the function of the pheromones in communication systems.
157 Hybrid sex pheromones of the hibiscus flower-bud borer, Rehimena surusalis.
The sex pheromone of the hibiscus flower borer
Rehimena surusalis (Walker) (Lepidoptera: Crambidae) was analyzed by gas chromatography with
electroantennographic detection (GC-EAD) and GC-mass spectrometry (GC/MS). Three EAD-active components were found in crude pheromone gland extracts of
calling females. GC/MS and GC analyses using synthetic chemicals and derivatization of the extracts identified three components as
(
10E,12Z)-hexadeca-10,12-dienal (E10,Z12-16:Ald), (
10E,12E)-hexadeca-10,12-dienyl acetate (E10,Z12-16:OAc), and
(
3Z,6Z,9Z)-tricosa-3,6,9-triene (Z3,Z6,Z9-23:HC). In field tests, male moths were strongly attracted to a ternary blend of E10,Z12-16:Ald,
E10,Z12-16:OAc, and Z3,Z6,Z9-23:HC at a ratio of 1:5:14, but single and binary blends showed only weak or no attraction.
158 Single-component pheromone consisting of bombykal in a diurnal hawk moth, Neogurelca himachala sangaica.
Recent work has suggested that hawk moths share pheromone components but are sexually separated by qualitative and quantitative differences in their
pheromone blends. During field assays on the sex pheromones of other species, a diurnal hawk moth,
Neogurelca himachala sangaica (Lepidoptera:
Sphingidae), was frequently captured, but the composition of the sex pheromone of this species was not known. Analysis of hexane extracts of the
pheromone glands of calling female by gas chromatography (GC) using an electroantennographic detector (EAD) revealed two components that elicited EAD
responses from male moth antennae. These components were identified by their mass spectra and retention indices on two GC columns as
(
10E,12Z)-10,12-hexadecadienal (E10,Z12-16:Ald) and a trace of its (
10E,12E)-isomer (E10,E12-16:Ald) in 98:2 ratio. In field experiments,
E10,Z12-16:Ald alone attracted male moths, and addition of E10,E12-16:Ald significantly reduced the attractiveness, even at the naturally-occurring
ratio. Analysis of the data using a generalized linear mixed model showed that E10,Z12-16:Ald positively contributed to attractiveness, whereas
E10,E12-16:Ald did so negatively, and it was concluded that the sex pheromone of
N. himachala sangaica consists solely of E10,Z12-16:Ald,
bombykal. The negative effect of E10,E12-16:Ald on attractiveness could promote the species-specificity of this single-component pheromone system.
159 GC/FT-IR analysis of novel 4,6,9-triene and 2,4,6,9-tetraene occurring in a female pheromone gland of Arctia plantaginis (Erebidae:
Arctiinae).
Fifteen subspecies of the wood tiger moth,
Arctia plantaginis (Lepidoptera: Erebidae: Arctiinae), have been recorded in the Northern Hemisphere.
An analysis of crude pheromone extracts by GC equipped with an electroantennographic (EAG) detector showed four EAG-active components (Comps.
I –
IV) that were commonly involved in the pheromone glands of two subspecies inhabiting Japan and Finland. Comp.
I is a major (>75%) and
the others are minor components (3 – 15%). Their mass spectra, measured by GC-MS, revealed the chemical structures of C
21 unsaturated
hydrocarbons as follows; 3,6,9-triene for Comp.
I, 4,6,9-triene for Comp.
II, 1,3,6,9-tetraene for Comp.
III, and 2,4,6,9-tetraene
for Comp.
IV. Comps.
I and
III are known Type II pheromone compounds, and their retention times coincide with those of the
authentic standards with all Z configurations. As a next step, the extract was analyzed by GC/FT-IR to determine the configuration of Comps.
II and
IV. Their IR spectra showed two characteristic C-H bending absorptions around 990 and 945 cm
−1 due to the conjugated
dienyl moieties; thus, Z and E configurations were assigned to the double bonds at the 2- and 4-positions, respectively. Their Z double bonds at the 6-
and 9-positions are indicated by no absorptions around 970 cm
-1, due to the isolated double bonds with E configurations. Finally, the
structures of Comps.
II and
IV were confirmed by synthesis using a double Wittig reaction. The synthetic
(4
E,6
Z,9
Z)-4,6,9-triene and (2
Z,4
E,6
Z,9
Z)-2,4,6,9-tetraene showed strong EAG activity, and their
chemical data coincided well with those of the natural Comps.
II and
IV, indicating the correctness of the structure determination by
GC/FT-IR analysis and its usefulness for Type II pheromone compounds.
160 Unsaturated cuticular hydrocarbon components of the sex pheromone of eggplant fruit borer, Leucinodes orbonalis Guenée (Lepidoptera:
Crambidae).
Leucinodes orbonalis is one of the most damaging insect pests affecting eggplant in the Mekong Delta of Vietnam. While (
E)-11-hexadecenyl
acetate (E11–16:OAc) and its alcohol, (
E)-11-hexadecenol (E11–16:OH), have been identified as major and minor sex pheromone components,
respectively, few males were attracted to a blend of these compounds in Vietnamese fields. In order to utilize synthetic pheromone of
L. orbonalis as a tool for sustainable pest management programs, we reexamined the pheromone of this species in order to search for other minor
components. Gas chromatography-electroantennogram detection and gas chromatography/mass spectrometry analyses of abdominal tip extract revealed the
presence of two electroantennogram-active compounds, E11–16:OAc and (3
Z,6
Z,9
Z)-3,6,9-tricosatriene (Z3,Z6,Z9–23:H) in a ratio of
100:2. An extract of the abdomen and thorax showed an additional electroantennogram-active component, (3
Z,6
Z,9
Z)-3,6,9-docosatriene
(Z3,Z6,Z9–22:H), with the three compounds (E11–16:OAc, Z3,Z6,Z9–23:H and Z3,Z6,Z9–22:H) being present in a ratio of 100:45:1, indicating that the
trienes were mainly present on the cuticular surface. In the field, traps baited with E11–16:OAc and the C
23 triene, in a mix of 10:1, caught
more male moths than traps baited with the acetate alone. A field evaluation of other polyunsaturated hydrocarbons showed that the C
22 triene
found in body extract also increased catches when added to the acetate, but no other hydrocarbons did. In contrast, to other studies with this moth, the
addition of E11–16:OH to E11–16:OAc plus the C
22 or C
23 triene, resulted in decreased trap catches.
161 Identification and field attraction of the female sex pheromone of a kiwifruit pest, Nokona feralis (Lepidoptera: Sesiidae).
Female sex pheromone of a clearwing moth
Nokona feralis (Leech) (Lepidoptera: Sesiidae), a pest of kiwifruit, was identified to be a 7:3 mixture
of (3
E,13
Z)-3,13-octadecadienyl acetate (E3,Z13-18:OAc) and (3
E,13
Z)-3,13-octadecadien-1-ol (E3,Z13-18:OH) by GC-EAD and
GC/MS analyses. Males were attracted to wide-range mixtures of E3,Z13-18:OAc and E3,Z13-18:OH, and a 7:3 mixture of those two compounds strongly
attracted the males in the field.
162 Chemical analysis of the female sex pheromone in Palpita nigropunctalis (Lepidoptera: Crambidae).
The lilac pyralid,
Palpita nigropunctalis Bremer (Lepidoptera: Crambidae), is a common pest of Oleaceae plants. A crude extract of the female sex
pheromone glands was examined by gas chromatography-electroantennogram detection (GC-EAD) and GC coupled to a mass spectrometer (GC/MS). The GC-EAD
analysis revealed three EAG active components (
I–
III) in a ratio of 1:0.2:0.01 (
I:
II:
III). GC/MS analysis
successfully recorded the mass spectra of
I and
II. For
I, ions at
m/z 238 (M
+) and 220 ([M-18]
+)
indicated the structure of a monoenyl aldehyde with a 16-carbon chain. For
II, M
+ was not detected, but ions at
m/z 222
([M-60]
+) and 61 ([AcOH+1]
+) suggested that
II was a monoenyl acetate with a 16-carbon chain. Further GC/MS analysis of the
extract treated with dimethyl disulfide revealed that the double bonds in both
I and
II are located at the same position of 11th-carbon.
In addition, the pheromone extract was examined by GC/Fourier transform-infrared spectrophotometer (GC/FT-IR). An IR spectrum of
I showed
characteristic absorption at 1716 and 966 cm
−1, indicating a formyl group and E configuration of the double bond, respectively. In the case
of
II, absorption at 1745 and 968 cm
−1 indicated an ester carbonyl and E configuration, respectively. Taken together and by comparison
with authentic standards,
I and
II were confirmed as (
E)-11-hexadecenal and (
E)-11-hexadecenyl acetate, respectively; while
III was speculated as (
E)-11-hexadecen-1-ol. The synthetic
I,
II and
III all coincided well with those of the natural
components in chemical data, and elicited strong electroantennographic activity in male
P. nigropunctalis.
163 Sex pheromone analysis and effective attraction of males of the cabbage webworm, Hellula undalis, inhabiting the Mekong Delta of Vietnam.
Hellula undalis is a harmful insect pest of green mustard in the Mekong Delta of Vietnam. In order to establish a tool for a sustainable pest
control program, the sex pheromone of
H. undalis inhabiting the Mekong Delta was examined. GC-EAD and GC–MS analyses of pheromone gland extracts
from the virgin females elucidated three new components, (
Z)-11-tetradecenyl acetate (Z11-14:OAc), (
Z)-11-hexadecenal (Z11-16:Ald), and
(11
E,13
E)-11,13-hexadecadien-1-ol, in addition to the known pheromone component (11
E,13
E)-11,13-hexadecadienal
(E11,E13-16:Ald). Double bond positions of the two monoenyl components were determined by GC–MS analysis of the pheromone extract treated with dimethyl
disulfide. On the other hand, GC–MS analysis of the female body extract detected the unsaturated hydrocarbon
(3
Z,6
Z,9
Z-3,6,9-tricosatriene (Z3,Z6,Z9-23:H). Field examinations of their synthetic compounds indicated the significant role of
E11,E13-16:Ald as a major component and a clear synergistic effect of the two monoenyl compounds as a minor component. Although the 3:3:7 mixture of
Z11-14:OAc, E11-16:Ald, and E11,E13-16:Ald captured the largest number of males among the tested mixtures, the activity was still quite a bit lower than
that of virgin females. However, the 3:3:7:1 mixture, which was prepared by adding a small amount of Z3,Z6,Z9-23:H to the 3:3:7 ternary lure, succeeded
in attracting males more powerfully than the females did. This strong synergistic effect was not observed when the triene was added to unmixed
E11,E13-16:Ald, indicating important roles of not only the triene but also the two monoenyl compounds as natural pheromone components.
164 Identification and behavioral assays of sex pheromone components in Smerinthus tokyonis.
Hawk moths (Sphingidae) are classified into the subfamilies Sphinginae, Macroglossinae and Smerinthinae. The sex pheromones of hawk moths have been
intensively investigated recently. However, these reports were biased to Sphinginae and Macroglossinae and there were no reports on Smerinthinae. In
this study, we identified sex pheromone components from the Smerinthinae
Smerinthus tokyonis for the first time. Observation of female calling
behavior showed that the behavior started immediately after the photo-phase started. Gas chromatography-electroantennography detector (GC-EAD) analysis
indicated that male antenna responded to three components in the pheromone gland extract. GC/ MS and GC analyses demonstrated that the three components
were (10
Z,12
E)-, (10
E,12
Z)-, and (10
Z,12
Z)-10,12-hexadecadienyl acetates (Z10,E12-16:OAc, E10,Z12-16:OAc, and
Z10,Z12-16:OAc, respectively) in a 6:7:87 ratio. We subsequently performed behavioral assays in mesh cages. We observed the orientation and contact
behavior of males in response to different pheromone sources, such as a solvent control, calling female, pheromone gland extract, and synthetic blend.
Males did not respond to the solvent control, but did respond to the other sources. Since more males responded more to the calling female than the
synthetic blend, additional cues seem to be required for complete mating behavior in
S. tokyonis. Nevertheless, the pheromone components
determined in this first study of a Smerinthinae species are important chemicals in mating communication.
165 Identification of a unique three-component sex pheromone produced by the tea black tussock moth, Dasychira baibarana (Lepidoptera:
Erebidae: Lymantriinae).
BACKGROUND: The tea black tussock moth
Dasychira baibarana Matsumura is a devastating pest in tea plantations that causes substantial economic
losses. Presently, there is no effective method to control this pest other than pesticide application. The identified sex pheromone of
D. baibarana could be used for detecting and monitoring this pest. RESULTS: Gas chromatography–electroantennogram detection showed that
D. baibarana male moth antennae responded strongly to three components in the female sex pheromone gland, which were identified as:
(3
Z,6
Z)-
cis-9,10-epoxyhenicosa-3,6-diene (Z3,Z6,epo9-21:H) (I),
(3
Z,6
Z,11
E)-
cis-9,10-epoxyhenicosa-3,6,11-triene (Z3,Z6,epo9,E11-21:H) (II) and
(3
Z,6
Z)-henicosa-3,6-dien-11-one (Z3,Z6-21:11-one) (III).
D. baibarana uses a unique composition of an epoxydiene, epoxytriene, and
dienone with the same 3,6-dienyl motif as its sex pheromone. The epoxytriene and dienone were not previously characterized as insect pheromone
components. Electroantennogram analysis showed that each synthetic compound strongly stimulated male antennae, and compounds II and III elicited
stronger responses than compound I. A wind tunnel bioassay and field trapping experiments proved that, ternary blends of compounds I–III attracted
D. baibarana. Efficient attraction was achieved with a rubber septum baited with 500 μg of a mixture of compounds I–III at the ratio 25:20:55.
CONCLUSION: The three identified compounds elicited an electroantennogram response in
D. baibarana male moth antennae, and a mixture of the three
components at the ratio 25:20:55 attracted
D. baibarana male moths in a wind tunnel assay and field trapping experiments. This blend could be
used for integrated management of
D. baibarana in tea plantations.
166 Mass trapping of the diamondback moth (Plutella xylostella L.) by a combination of its sex pheromone and allyl isothiocyanate in cabbage
fields in southern Vietnam.
A lure composed of (
Z)-11-hexadecenal, (
Z)-11-hexadecenyl acetate, and (
Z)-11-hexadecen-1-ol at a ratio of 5 : 5 : 1 at a dose of
0.01 mg was optimal for the attraction of the Vietnamese strain of the diamondback moth (DBM). The combination of the sex pheromone with a plant
volatile, allyl isothiocyanate, significantly increased the attraction of the pheromone trap. Females were also attracted, but they were only about 2%
of all moths captured. In plots with 120–130 traps per ha, mass trapping with the combined lures reduced the DBM larval densities in cabbage fields as
effectively as the spraying of insecticides 6 to 8 times. The weekly trap catches indicated that DBM adult densities in the mass-trapping fields were
low until 28 days after transplantation, and then were kept to a modest increase until day 49. This field study also shows that the trap catches were
well correlated with the DBM larval densities.
