Female Gland Extracts Research Articles

Sex Pheromone of Lonomia obliqua: Daily Rhythm of Production, Identification, and Synthesis

The sex pheromone of Lonomia obliqua Walker (Lepidoptera: Saturniidae) was studied in the laboratory. All female calling occurred during the scotophase. Most females (70.6%) called first within 24 hr of eclosion. Calling varied with age of female, with older (5- to 6-day-old) females calling earlier in the scotophase and for longer durations than younger (0- to 1-day-old) females. The sex pheromone gland of 1- to 3-day-old virgin females was extracted during the calling peak. A Y-olfactometer bioassay showed significant attraction of males to a filter paper containing the female gland extract. Gas chromatographic-electroantennogram detection (GC-EAD) analysis of the extract indicated the presence of at least two possible pheromone components. Gas chromatographic-mass spectrometric analysis of the major GC-EAD-active peak indicated a hexadecenyl acetate; chemical derivatization indicated delta11 unsaturation. Synthetic samples of (E)- and (Z)-11-hexadecenyl acetate were obtained by coupling 10-bromo-1-decanol and 1-hexyne, utilizing lithium chemistry. The comparison of the retention time of dimethyl disulfide derivatives of the natural compound, to those of synthetic chemicals, confirmed the natural compound as (E)-11-hexadecenyl acetate. The minor component was identified as the related alcohol, (E)-11-hexadecenol. The ratio of the two components in female extract was 100:35. Preliminary tests of males in a Y-olfactometer showed that their response to a mixture of the two compounds was not significantly different from that to gland extract.

Identification of the Sex Pheromone of Copitarsia decolora (Lepidoptera: Noctuidae)

Chemical and electrophysiological analyses and field trials were used to identify the female sex pheromone of Copitarsia decolora (Guenée) (Lepidoptera: Noctuidae). Coupled gas chromatographic-electroantennographic detection (GC-EAD) analysis of the female gland extract showed the presence of two EAD-active peaks, which were identified by GC-mass spectrometric (MS) analysis as (Z)-9-tetradecenyl acetate (Z9–14:Ac) and (Z)-9-tetradecenol (Z9–14:OH). The field evaluation of the EAD-active compounds indicated that traps baited with either Z9–14:Ac or Z9–14:OH caught few males. In contrast, traps baited with the binary blend of both components caught significantly more males than traps baited with the single compounds. Captures in traps baited with a mixture of Z9–14:Ac and Z9–14:OH at 4:1, 10:1, and 100:1 ratios were not significantly different from the catches in traps baited with virgin females. Few males were captured in traps baited with a blend of Z9–14:Ac and Z9–14:OH at 1:4, 1:10, and 1:100 ratios.

Identification of the Sex Pheromone of <I>Copitarsia decolora</I> (Lepidoptera: Noctuidae)

Chemical and electrophysiological analyses and field trials were used to identify the female sex pheromone of Copitarsia decolora (Guenée) (Lepidoptera: Noctuidae). Coupled gas chromatographic-electroantennographic detection (GC-EAD) analysis of the female gland extract showed the presence of two EAD-active peaks, which were identified by GC-mass spectrometric (MS) analysis as (Z)-9-tetradecenyl acetate (Z9-14:Ac) and (Z)-9-tetradecenol (Z9-14:OH). The field evaluation of the EAD-active compounds indicated that traps baited with either Z9-14:Ac or Z9-14:OH caught few males. In contrast, traps baited with the binary blend of both components caught significantly more males than traps baited with the single compounds. Captures in traps baited with a mixture of Z9-14:Ac and Z9 -14:OH at 4:1, 10:1, and 100:1 ratios were not significantly different from the catches in traps baited with virgin females. Few males were captured in traps baited with a blend of Z9-14:Ac and Z9-14:OH at 1:4, 1:10, and 1:100 ratios.

Isolation, Identification, Synthesis, and Field Evaluation of the Sex Pheromone of the Brazilian Population of Spodoptera frugiperda

Several studies have shown intraspecific geographical variation in the composition of sex pheromones. Pheromone lures from North America and Europe were not effective against the fall armyworm Spodoptera frugiperda (Smith, 1797) (Lepidoptera: Noctuidae) in Brazil, so we examined the composition of the sex pheromone produced by females from Brazilian populations. Virgin female gland extracts contained (Z)-7-dodecenyl acetate (Z7-12:Ac), (E)-7-dodecenyl acetate (E7-12:Ac), dodecyl acetate, (Z)-9-dodecenyl acetate, (Z)-9-tetradecenyl acetate (Z9-14:Ac), (Z)-10-tetradecenyl acetate, tetradecyl acetate/(Z)-11-tetradecenyl acetate (Z11-16:Ac), and (Z)-11-hexadecenyl acetate. The relative proportions of each acetate were 0.8:1.2:0.6:traces:82.8:0.3:1.5:12.9, respectively. This is the first time that E7-12:Ac has been reported from the pheromone gland of S. frugiperda. Only three compounds, Z9-14:Ac, Z7-12:Ac, and E7-12:Ac, elicited antennal responses, and there were no differences in catch between traps baited with either Z7-12:Ac + Z9-14:Ac or Z7-12:Ac + Z9-14:Ac + Z11-16:Ac blends. However, the Z7-12:Ac + Z9-14:Ac + E7-12:Ac blend was significantly better than Z7-12:Ac + Z9-14:Ac, indicating that E7-12:Ac is an active component in the sex pheromone of the Brazilian populations of S. frugiperda.

Sex pheromone of the large aspen tortrix, Choristoneura conflictana(Lepidoptera: Tortricidae)

Three components that elicited antennal response from male Choristoneura conflictana were found from female gland extracts analyzed using a coupled gas chromatographic-electroantennographic detector system. The main component in gland extracts was (Z)-11-tetradecenal (Z11-14:Ald). Two minor components also elicited antennal response: (E)11-tetradecenal (E11-14:Ald) and (Z)-11- tetradecen-1-ol (Z11-14:OH). Analysis of effluvia indicated that calling virgin females release mostly Z11-14:Ald and trace amounts of Z11-14:OH. Field and wind tunnel behavioral studies showed that Z11-14:Ald alone attracted male moths in a dose response pattern. Tests comparing male response to blends of components detected in gland extracts showed that addition of 1.8% of E11-14:Ald to Z11-14:Ald did not influence male moths in the wind tunnel, but resulted in significantly lower trap captures in the field. The threecomponent blend [Z11-14:Ald (100), E11-14:Ald (1.8), Z11-14:OH (11)], was less attractive than Z11-14:Ald alone in both field and wind tunnel studies. Traps baited with two virgin female moths were equally attractive to males as traps baited with the three-component synthetic blend but less attractive than traps baited with Z11-14:Ald alone. Field tests of various blends of the two components (Z11-14:Ald, Z11-14:OH) detected in the females’ effluvia showed that the addition of 1–10% Z11-14:OH to Z11-14:Ald did not affect the males’ response to Z11-14:Ald. Our data demonstrate that female C. conflictana release sex pheromone components in a different ratio than they are stored in the pheromone gland. The sex pheromone is comprised of a single component, Z11-14:Ald, that can be used to monitor mated and virgin male C. conflictana throughout their flight period.

The odour makes the difference: male moths attracted by sex pheromones ignore the threat by predatory bats

How animals adjust their foraging or mate finding behaviour according to the risk of predation has received much attention recently. However, few studies have focused on the behaviour of prey when stimuli representing different adaptive behaviours originate from different sensory modalities. Here we present data on how male moths trade off odour‐mediated mate attraction and auditory‐mediated predator avoidance depending on the relative quality of the mate signal. Males of Agrotis segetum (Noctuidae) and Plodia interpunctella (Pyralidae), orienting towards a sex pheromone source in a flight tunnel, were exposed to ultrasound mimicking the echolocation calls of a bat, i.e. high predation risk. Males of both species accepted the predation risk when attracted to pheromone sources of high quality (female gland extract or complete synthetic blend at high dose), manifested in similar percentages reaching the pheromone source in moths with and without ultrasound exposure. In contrast, a lower proportion of ultrasound‐exposed males than unexposed ones located the pheromone source when moths were flying towards pheromone sources of low quality (incomplete synthetic blend or complete synthetic blend at low dose), due to more time invested in defence manoeuvres. Furthermore, the risk taking behaviours of these moth species seem to be similar in spite of the fact that their ultrasonic hearing systems have evolved independently.

Behavioural effects of minor sex pheromone components in Brazilian apple leafroller Bonagota cranaodes (Lep., Tortricidae)

Abstract: The behavioural response of Brazilian apple leafroller males, Bonagota cranaodes (Meyrick), to natural and synthetic sex pheromone was studied in a wind tunnel. Calling females elicited upwind flights followed by landing and wingfanning at the source in 72% of the males tested. Female gland extracts, with the main compound (E, Z)3,5dodecadienyl acetate released at 100 pg/min, attracted 57% of the males to the source. Few males (1%) were attracted to the main compound alone, released at the same rate. Even a synthetic blend of all five gland compounds eliciting an antennal response, formulated according to their proportion in female gland extracts, was barely attractive (7%). Comparison of this synthetic blend and female gland extracts indicates a behavioural role of other gland compounds. Male attraction was significantly increased (34%) in response to a 100 : 5 : 5 : 5‐blend of the main compound and three minor gland compounds, (Z)‐5‐dodecenyl acetate, (E, Z)‐3,5‐tetradecadienyl acetate, and (Z)‐9‐hexadecenyl acetate.

Sex pheromone of the oak processionary moth Thaumetopoea processionea. Identification and biological activity.

The sex pheromone of the oak processionary moth Thaumetopoea processionea has been characterized from female gland extracts as a mixture of (Z,Z)-11,13-hexadecadienyl acetate (1), (E,Z)-11,13-hexadecadienyl acetate (3) and (Z,Z)-11,13-hexadecadienol (2) in 88:7:5 ratio. The amount of the major compound 1 was 20-30 ng/gland. No trace of (Z,Z)-11,13-hexadecadienal was found in the extract, and therefore, T. processionea appears to be the only "summer" processionary moth lacking this compound as a pheromone compound. The alcohol 2 had also been previously found but is electrophysiologically inactive, and in wind tunnel assays it lowers the number of contacts with the source when mixed with the major compound 1. The major component 1 elicited males to display the complete behavioral sequence, but the amount of chemical needed was unexpectedly high in comparison to the activity displayed by virgin females and gland extracts. (E,E)-11,13-hexadecadienyl acetate (5) inhibits the attractant activity of the major component 1 when mixed with 1 in 1:10 and 1:1 ratios. The main constituent 1 is active in the field, but its tendency to isomerize into the corresponding E,E isomer (5) must be considered if effective formulations are to be prepared.

Field trials with the synthetic sex pheromone of the oak processionary moth Thaumetopoea processionea.

The biological activity of synthetic (Z,Z)-11,13-hexadecadienyl acetate, the major pheromone component found in female gland extracts of the oak processionary moth Thaumetopoea processionea, was evaluated in field trials. Traps baited with 10 mg of the chemical efficiently attracted a large number of males provided they were placed in the upper crown region of the oaks. Devices positioned 10-15 m high in the trees attracted significantly more males than those traps installed at 2 or 6-8 m above the ground. Pherocon traps were slightly more efficient than Delta traps, and lower or higher amounts of the attractant in the baits did not significantly influence the number of moths caught. The importance of the stereomeric purity of the lure and the easy isomerization of the (Z,Z)-acetate to other isomers, particularly to the E,E isomer, should be considered for the development of efficient formulations in the field.

Salivary gland hyaluronidase in various species of phlebotomine sand flies (Diptera: psychodidae)

Hyaluronidase activity was detected and partially characterized in salivary gland extracts of females of six sand fly species. In Phlebotomus papatasi and Lutzomyia longipalpis the enzyme was active over a broad pH range; the pH optimum was 5.0. Besides high cleaving activity towards hyaluronic acid, it hydrolyzed chondroitin sulfates A and C. Hyaluronidases of various sand fly species differed in structure and sensitivity to reducing conditions. In the subgenera Phlebotomus ( P. papatasi and P. duboscqi) and Adlerius ( P. halepensis) the predominant active form of the enzyme was monomeric with the same apparent molecular weight under nonreducing and reducing conditions (around 65 kDa for P. papatasi and P. duboscqi and 110 kDa for P. halepensis). In P. sergenti the enzyme occurred as a putative homodimer but remained active under reducing conditions when separated into 60 kDa subunits. In L. longipalpis and P. perniciosus the activity was detectable under non-reducing conditions only. In P. duboscqi, low enzyme activity was found also in males. Salivary gland hyaluronidases of sand flies share characteristics with endo-N-acetyl-hexosaminidases of mammalian sperm cells and corresponding venom enzymes of Hymenoptera. Hypothetically, they facilitate blood meal acquisition but also may modulate immune reactions of the host and promote pathogen transmission.

Identification of sex-pheromone components for Acleris fimbriana (Lepidoptera: Tortricidae)

AbstractFour compounds were identified from female sex-pheromone gland extracts of Acleris fimbriana Merick, an important pest in northern fruit orchards of China, by gas chromatography, gas chromatography – mass spectrometry, and flight-tunnel and field-trapping tests. These compounds were (E)-11,13-tetradecadienal (E11,13-14:Ald), (E)-11,13-tetradecadien-1-ol (E11,13-14:OH), (E)-11-tetradecenyl acetate (E11-14:Ac), and (E)-11,13-tetradecadienyl acetate (E11,13-14:Ac). In field-trapping tests, traps baited with E11,13-14:Ald alone produced the highest trap captures of male A. fimbriana, but the other three individual compounds did not capture any mates. Addition of E11,13-14:Ac to E11,13-14:Ald enhanced trap capture, whereas addition of E11-14:Ac had no effect. A ternary blend of E11,13-14:Ald, E11,13-14:Ac, and E11-l4:Ac in a 6:4:1 ratio captured 7.5 times mean males per trap than virgin females. E11,13-14:OH inhibited trap capture when it was added to E11,13-14:Ald or the ternary blend. This pheromone could be used to monitor populations of A. fimbriana and to control this important pest of fruits in China.

Electrophysiological studies and identification of possible sex pheromone components of Brazilian populations of the sugarcane borer, Diatraea saccharalis.

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 (5) and (9E,11E)-hexadecadienal (6), 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 (3), 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 1-6 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.

Sex Pheromone of Grape Berry Moth (Lepidoptera: Tortricidae)

Pheromone gland extracts of grape berry moth females, Endopiza viteana Clemens, contain the main pheromone component, Z9–12Ac, at ≈1.2 ng per female, together with both geometric isomers of 11–14Ac, and a number of saturated acetates and alcohols of the chain length 12–16. The analogous alcohol, Z9–12OH, was found in some gland extracts. Trap capture of males was significantly increased by adding 0.5 or 2 μg of Z11–14Ac to 10 μg of the main compound, Z9–12Ac; whereas, adding 0.5 or 2 μg of E11–14Ac had no significant effect. In contrast, the addition of 5% Z9–12OH to the main compound resulted in a strong reduction in trap capture. Traps baited with a blend of Z9–12Ac and its geomeric isomer, E9–12Ac, which was not detected in gland extracts, were significantly less attractive than traps baited with blends of Z9–12Ac and Z11–14Ac. Knowledge of pheromone components and antagonists is essential for development of the mating disruption technique. The compounds identified in E. viteana are behaviorally active in the three most important tortricid pests of grape, Vitis vinifera (L.), in Europe. It may thus be possible to use a single blend of synthetic pheromone for control of several species.

Laboratory and Field Study of the Attraction of Male Pea Midges, Contarinia pisi, to Synthetic Sex Pheromone Components

Behavioral activity of the recently identified sex pheromone components of the pea midge, Contarinia pisi, (2S,11S)-diacetoxytridecane, (2S,12S)-diacetoxytridecane, and 2-acetoxytridecane, was tested in wind tunnel and field-trapping experiments. In the wind tunnel, the attractancy of the three-component blend in a 7 : 10 : 0.1 ratio (following the above order, mimicking the ratios found in gland extract) did not differ significantly from female gland extract, whereas a mixture of the two major components (7 : 10) only attracted 2% of the males to the source. In the field, traps baited with the three-component blend caught by far the largest number of males. Traps baited with the two major components only caught slightly more than the blank traps, and catches in traps baited with 2-acetoxytridecane alone did not differ from catches in the blank traps. Traps baited with the racemate of all three components did not catch more than the blank traps, indicating that some of the enantiomers are inhibitory.

Appetitive Learning of Odours With Different Behavioural Meaning in Moths

Moth behaviour is to a great extent guided by olfactory stimuli with different relevance. We investigated whether olfactory learning of odours is influenced by the behavioural significance of the odorant. In proboscis extension conditioning experiments species-specific sex pheromones, which normally elicit an innate behaviour in males, and a flower odour were used as olfactory stimuli. After 10 conditioning trials, both sexes showed similar response levels to individual pheromone components and to the flower odour geraniol. However, when the female gland extract was used as conditioning stimulus, the response level was significantly lower than that for geraniol in both sexes. Significant learning nevertheless occurred in females, but not in males. Experiments with different numbers of training trials revealed that, in females, fewer learning trials with individual pheromone components were necessary for significant memory formation than in males.

Multicomponent Sex Pheromone in Codling Moth (Lepidoptera: Tortricidae)

Attraction of codling moth males, Cydia pomonella (L.), to calling conspecific females, female gland extracts, and synthetic pheromone was studied in a wind tunnel. A dose–response test using a single source showed that female gland extracts attracted more males than codlemone, (E,E)-8,10-dodecadienol, alone. In choice tests, males preferred both calling females and gland extracts over synthetic codlemone. Calling females were as attractive as pheromone gland extracts, at a release rate of 100 pg codlemone/min. A 5-component blend of codlemone, its E,Z-isomer, (E)-9-dodecenol, dodecanol and tetradecanol was more attractive than codlemone in the wind tunnel. This study shows that other compounds, in addition to codlemone, are involved in sex attraction of codling moth males. Control of codling moth by mating disruption with synthetic pheromone is close to a breakthrough, although the method is not efficient at high population densities. The finding that codling moth uses a multicomponent pheromone offers the opportunity to enhance the behavioral activity of current dispenser formulations.

Comparative Study of Pheromone Production and Response in Swedish and Zimbabwean Populations of Turnip Moth, Agrotis segetum

Analysis of female sex pheromone gland extracts of the turnip moth (or common cutworm), Agrotis segetum, from Zimbabwe revealed three compounds previously identified as sex pheromone components in the Swedish population, namely (Z)-5-decenyl acetate (Z5–10:OAc), (Z)-7-dodecenyl acetate (Z7–12:OAc), and (Z)-9-tetradecenyl acetate (Z9–14:OAc). However, the proportions from the Zimbabwean population (1:0.25:0.03) differ from those in the Swedish population (1:5:2.5). In addition, gas chromatography–mass spectrometric (GC-MS) analysis of the Zimbabwean female gland extracts revealed a trace of (Z)-5-dodecenyl acetate (Z5–12:OAc). This compound has recently been identified as a fourth sex pheromone component for the Swedish population. Single-sensillum recordings from both Zimbabwean and Swedish populations showed the presence of two types of antennal receptors responding to either Z5–10:OAc or Z7–12:OAc. In Zimbabwean males the Z7–12:OAc receptor neuron appeared to be confined to the basal and medial thirds of the antennal branches, while in Swedish males it was distributed along the entire antennal branch. Dose–response curves of Z5–10:OAc or Z7–12:OAc specific receptor neurons from males of both populations showed similar response profiles, but the neurons of the Zimbabwean population showed higher maximal responses. In flight tunnel tests with Zimbabwean males, the three-component Zimbabwean blend of Z5–10:OAc, Z7–12:OAc and Z9–14:OAc elicited significantly greater responses than the Swedish blend, but not significantly greater than pheromone glands from calling Zimbabwean females. (Z)-5-decenol (Z5–10:OH), a constituent of gland extracts, exerted an antagonistic effect in the flight tunnel. In field tests conducted in Sweden, local males were preferentially attracted to local females, while in Zimbabwe preferential attraction to local females was less pronounced. Local response to the Swedish and Zimbabwean synthetic four-component blends mirrored the responses to the local females. Zimbabwean males are much more strongly attracted to Z5–10:OAc alone than are Swedish males and the high concentrations of Z7–12:OAc and/or Z9–14:OAc present in the Swedish blend reduced attraction of Zimbabwean males. This reduced attraction appears to be counteracted by the trace amounts of Z5–12:OAc found in the Swedish four-component blend. Addition of Z5–12:OAc to the three-component Zimbabwean blend did not, however, significantly increase the trap catches of Zimbabwean males.

Duration of antibodies against 24 kd protein of Rhipicephalus sanguineus extract in dogs infested with the adult ticks.

A 24 kd protein from Rhipicephalus sanguineus (Rs24p) which was common to larvae, nymphs, male and female whole body and salivary gland extract of males and female was detected specifically in the serum from dogs after repeated infestation with adult R. sanguineus. The duration of antibodies against Rs24p in dogs infested with adults was examined by Western blotting analysis. Anti-Rs24p antibody was detected in two of 4 dogs during the period of 40 days in the first infestation. In the second infestation, all dogs showed positive reaction against Rs24p, but the duration of the antibodies varied greatly among the animals.

Chemical and behavioral evidence for a third pheromone component in a North American population of the black cutworm moth, Agrotis ipsilon

The sex pheromone of Agrotis ipsilon had been previously identified as a blend of (Z)-7-dodecenyl acetate (Z7–12:Ac) and (Z)-9-tetradecenyl acetate (Z9–14:Ac). A synthetic blend of Z7–12:Ac and Z9–14:Ac (30 μg:10 μg) is effective in attracting males in the field. In several countries, addition of (Z)-11-hexadecenyl acetate (Z11–16:Ac) to the previously identified blend increases male captures, but this had not been demonstrated in North America. We found Z11–16:Ac, in addition to Z7–12:Ac and Z9–14:Ac, from pheromone gland extracts of females from North America. The mean ratio of Z7–12:Ac, Z9–14:Ac, and Z11–16:Ac produced by individual females was 70.5:14.2:15.3, respectively. In Kentucky, addition of Z11–16:Ac (60 μg) to a two-component blend of Z7–12:Ac and Z9–14:Ac significantly increased the trap capture rate in the field. Traps baited with this three-component blend were 3.3 times (1995) and 4.6 times (1996) more effective in capturing male A. ipsilon than the two-component blend. This improved effectiveness resulted in detection of A. ipsilon in 60% more of the sampling periods in the two years. In the wind tunnel, males flew upwind and contacted a rubber septum loaded with a three-component blend including Z11–16:Ac significantly more frequently than they did to any two-component blend. These results demonstrate that Z11–16:Ac is a pheromone component in this North American population of A. ipsilon.

Olefinic acetates, Δ-9,11–14: OAc and Δ-7,9–12: OAc used as sex pheromone components in three geometrid moths,Idaea aversata, I. straminata, andI. biselata (Geometridae, Lepidoptera)

Pheromone compounds so far identified from most geometrid moths consist of all-Z diene, triene, or tetraene hydrocarbons with chain lengths of C17 to C21, and their monoepoxide derivatives biosynthesized from linoleic and linolenic acids. The present study reports the occurrence of olefinic acetates as sex pheromones in three species of Geometridae. (Z,Z)-9,11-tetradecadienyl acetate and (Z,Z)-7,9-dodecadienyl acetate found in female gland extracts ofIdaea aversata elicited significant responses from conspecific male antennae in gas chromatography with electroantennographic detection (GCEAD). In extracts ofI. straminata, (Z,Z)-7,9-dodecadienyl acetate, (E,Z)-7,9-dodecadienyl acetate, and (Z,Z)-7,9-dodecadienyl acetate were found, and the synthetic compounds elicited strong responses from conspecific male antennae. In the third species,I. biselata, only (Z,Z)-7,9-dodecadienyl acetate was found in the female extracts, and this compound elicited a strong EAD response from the conspecific male antenna. The identities of the pheromone components inI. aversata andI. straminata were further confirmed according to their characteristic ions after GC-MS analyses. Single sensillum recordings fromI. aversata showed two types of pheromone-detecting sensilla present on the male antenna. One type contained two receptor neurons, one of which was specifically tuned to (Z,Z)-9,11-tetradecadienyl acetate, the other to (Z,E)-9,11-tetradecadienyl acetate. A second type contained one neuron responding to (Z,Z)-7,9-dodecadienyl acetate. The two types were clearly different also with respect to external morphology, the former being considerably longer and having a larger base diameter. Also inI. straminata two physiological types of sensilla could be distinguished. One type contained two neurons, one of which responded to (Z,Z)-7,9-dodecadienyl acetate, the other to (Z,E)-9,11-tetradecadienyl acetate. The second type contained one neuron, responding to (Z,Z)-7,9-dodecadienyl acetate. No correlation between external morphology and physiological response of the investigated sensilla was observed inI. straminata. In field tests, a two-component blend containing (Z,Z)-9,11-tetradecadienyl acetate and (Z,Z)-7,9-dodecadienyl acetate in a ratio of 10:1 was attractive to males ofI. aversata. This two-component blend was also attractive to males ofI. straminata, but in a ratio of 1:1. High numbers of maleI. biselata were caught in traps baited with (Z,Z)-7,9-dodecadienyl acetate alone. The incorporation of deuterium labels into pheromone components after topical application of deuterium-labeled palmitic acid confirmed that the pheromone components ofI. aversata could be synthesized from this precursor, as has been previously observed for acetate pheromone components of many other moth species. Our results suggest that an evolutionary reversal back to the production of palmitic acid-derived pheromone components has occurred within the geometrid subfamily Sterrhinae.