Effect of varying proportions of the alcohol component on sex pheromone blend discrimination in male Oriental fruit moths

ABSTRACT. The flight response of individual male Oriental fruit moths, Grapholitha molesta (Busck), was observed in a sustained-flight tunnel to 100 blend–dosage combinations of the three sex pheromone components: (Z)- and (E)-8-dodecenyl acetate and (Z)-8-dodecen-l-ol (1, 3, 10, 30 and 100 μg of Z8-12: AC with, 2, 6, 10, 20% E and, 0, 3, 10, 30 or100% OH alcohol added). Complete flights to the source were observed only to blend combinations containing all three components. Males exhibited highest response levels to two dosages (3 and 10μg) of the natural 6% E blend and these levels were relatively unaffected by changes in the proportion of Z8-12: OH. Certain treatments surrounding the peak area also elicited high response levels compared to the 6% E treatments, but these were strongly dependent on the proportion of OH in the blend. Hierarchical cluster analysis was utilized to compare and group treatments that elicited similar levels of response over the entire flight sequence and to derive an area of blend-dosage combinations within the matrix tested that elicited peak levels of attraction. Analysis of the response patterns for suboptimal treatments adjacent to the area of optimal attraction showed that response specificity was controlled by two major effects on flight behaviour, one occurring early in the flight sequence affecting male orientation to the odour plume, and the other occurring later in the sequence as an arrestment of upwind flight. These effects were strongly influenced by changes in the OH component and the E isomer, with the latter playing the critical role in effecting flight behaviour. Temporal analysis of the flight response to treatments within the optimal area showed that whereas the % OH did not significantly affect the magnitude of response, increasing the level of Z8-12: OH in the blend did significantly increase the duration of each phase of the behavioural sequence. Considering both the magnitude and temporal aspects of male response, optimal attraction in male OFM was best characterized by a small area of treatments around the peak 6% E blends that contained 10% OH. Finally, field tests showed a high degree of correlation between trends in response with changing proportion of Z8-12: OH as observed in the flight tunnel. Peak dosages were generally higher in the field, however, compared to those in the flight tunnel.     

不同剂量和比例的性信息素对亚洲玉米螟雄蛾的行为作用(英文)

在风洞中观察了亚洲玉米螟雄蛾对不同剂量不同比例的二组份及三组份的人工合成性信息素（１４：ｏＡｃ, Ｅ－１２－１４： ｏＡｃ和 Ｚ－１２－１４：ｏＡｃ）的行为反应。 Ｚ－１２－１４： ｏＡｃ＋Ｅ－１２－１４： ｏＡｃ 二组份诱芯中以比例为３７．５％Ｅ到６２．５％Ｅ之间的诱芯效果最好,有７１％－７８％的雄蛾到达诱芯。三组份诱芯中以工４：Ａｃ： Ｚ－１２－１４： ｏＡｃ： Ｅ－１２－１４： ｏＡｃ＝１： ５： ４的效果最好,雄蛾到达诱芯的百分率（７１％）与二组份诱芯相比无显著差异。但是剂量反应实验显示三组份诱芯的有效剂量范围比二组份诱芯宽,二组分诱芯及三组份诱芯在风洞试验中的最佳剂量范围分别为 １００ｎｇ到 １０００ｎｇ和 １００ ｎｇ到 １０ ０００ｎｇ。低剂量的情况下三组份的诱芯效果要好于二组份诱芯。三组份诱芯对于低到 １ｎｇ的剂量仍能引起 １０％的雄蛾到达诱芯,而在此剂量下二组份诱芯不能引起定向及其以后的各步行为反应。     

BEHAVIOURAL EFFECT OF VARIOUS BINARY AND TERNARY SEX PHEROMONE BLENDS ON THE ASIAN CORN BORER (OSTRINZA FURNACALZS)

Abstract The response of individual male Asian corn borer moth was observed in a wind tunnel to various binary and ternary blends and dosages of synthetic sex pheromones, tetradecyl acetate. (E)-12-te-tradecenyl acetate and (Z)-12-tetradecenyl acetate. Lures containing two components (Z+E) blends elicit the highest behavioral responses at ratios in the scope of 37. 5% E to 62. 5% E and there was no significant difference in this scope according to source contact step. The highest responses to the lures of three components are observed at ratio 1 ^: 5 ^: 4 (14 ^: Ac/Z/E), which have no significant difference to the best lures of two components. But dose-response shows that the ternary blend has a wider response scope than the binary blend. The ternary blend can elicit behavioral response at dosage even as low as Ing, but the binary blend can not at the same dosage. The highest response scope is 100 to 1 000 ng for the binary blend and 100 to 10 000 ng for the ternary blend.     

Identification of a four-component sex pheromone blend in Bonagota cranaodes (Lepidoptera: Tortricidae)

Analysis of sex pheromone glands of the apple leafroller Bonagota cranaodes Meyrick by gas chromatography coupled with mass spectrometry or electroantennographic detection showed the presence of 14 structurally related acetates and alcohols of the chain length 10-18, including the main pheromone component (E,Z)-3,5-dodecadienyl acetate (E3,Z5-12Ac). Male antennae responded to the main compound, its Z,Z isomer, (E,Z) -3,5-tetradecadienyl acetate (E3,Z5-14Ac), and the monoenes (Z)-5-dodecenyl acetate (Z5-12Ac) and (Z)-9-hexadecenyl acetate (Z9-16Ac). Traps baited with a four-component blend of E3,Z5-12Ac, Z5-12Ac, E3,Z5-14Ac, and Z9-16Ac in a 100:5:5:100 ratio were significantly more attractive than the main compound alone. This improved trap lure is more suitable for monitoring population densities of B. cranaodes, and for detection of the onset of the seasonal flight period. A more complete pheromone blend is of importance also with respect to current attempts to develop mating disruption for control of this major pest of apple in Brazil.     

Chemical communication in heliothine moths. VII. Correlation between diminished responses to point-source plumes and single filaments similarly tainted with a behavioral antagonist

Addition of (Z)-11-hexadecenyl acetate (Z11-16:Ac) into a normally attractive binary blend of Heliothis virescens pheromone components resulted in a suppression of upwind flight and source location by males. Male response was reduced even at the lowest dosages of Z11-16:Ac tested but upwind flight and source location were most clearly reduced when the loading of Z11-16:Ac reached 10% or more of the (Z)-11-hexadecenal (Z11-16:Ald) loading (the major component present in the binary blend). Similar patterns of suppression in response were noted when Z11-16:Ac was added to binary blends of pheromone components at both 10 and 100 μg loadings of Z11-16:Ald. Males in casting flight following upwind flight in a mechanically generated pulsed plume, responded to the interception of a subsequent, single binary-blend filament by making a toward-source upwind surge. Responses of males to a single filament that was tainted by a level of Z11-16:Ac that had allowed some reduced level of upwind flight and source location to occur in the previous plume experiments were diminished compared with their control counterparts. Analysis of the flight tracks revealed that the surges in response to single tainted filaments were stunted because males made fewer significant changes in course angles steered, airspeeds generated, and in the tempo of counterturns executed. Accepted: 28 December 1996     

Sex pheromone of Etiella behrii, a pod borer of soybean in Indonesia: identification and field attraction

Four EAG-active components were detected in GC-EAG analyses of hexane extracts from virgin Etiella behrii (Zeller) (Lepidoptera: Pyralidae) females. These components were identified as dodecyl acetate (12:Ac), (E)-9-dodecenyl acetate (E9-12:Ac), either (Z)-9- or (E)-11-tetradecenyl acetate (Z9- or E11-14:Ac), and (Z)-11-tetradecenyl acetate (Z11-14:Ac) by comparison of retention indices on both nonpolar and polar GC columns. The available extract was insufficient for further GC-MS or other chemical analyses (<0.2 ng/female). In field tests carried out in East Java, a 10:90 mixture of E9-12:Ac and Z11-14:Ac showed attractiveness to male moths and addition of 12:Ac and/or E11-14:Ac significantly increased the trap catches while addition of Z9-14:Ac showed no significant effect. Maximum attraction was obtained with 5.35 or 10.7 g/rubber septum of a mixture of E9-12:Ac, Z11-14:Ac, 12:Ac and E11-14:Ac at the ratio of 10:90:0.7:6.3, respectively. The role of pheromone blends in species discrimination between E. behrii and the related E. zinckenella (Treitschke) is discussed.     

Effects of varying sex pheromone component ratios on the zigzagging flight movements of the oriental fruit moth,Grapholita molesta

As the ratio of (E)-8-dodecenyl acetate (E8–12Ac) to (Z)-8-dodecenyl acetate (Z8–12Ac) increased past optimal low levels in the pheromone blend, fewer males were able to fly 2.5 m upwind to the source. The tracks of males that flew in plumes of such high-(E)off-blends were slower and narrower than those of males flying to lower-(E)blends. The tracks were narrower, first of all, because as the proportion of E8–12Ac increased, the males steered more into the wind. More of their thrust was directed upwind and therefore their groundspeed to either side of the windline was reduced. In addition, males also reduced their airspeeds to high-(E)blends, which contributed to the decreased groundspeeds and narrower tracks. No significant changes in the frequency of counterturning were found in response to increasing proportions of E8–12Ac. The inability to continue upwind flight in a plume of an off ratio was indicated by in-flight arrestment in the plume. Arrestment resulted from changes in the course angles steered by the males and the airspeeds flown.     

Sustained-flight tunnel responses of male lightbrown apple moth to synthetic sex pheromone

ABSTRACT. The upwind flight response of individual male lightbrown apple moths, Epiphyas postvittana (Walker), to twenty combinations of the two pheromone components, (E)-11-tetradecenyl acetate (E11-14:OAc) and (E,E)-9,11-tetradecadienyl acetate (E,E-9,11–14:OAc), was observed in a sustained-flight tunnel. At the lowest dosage of E11-14:OAc tested (3 μg), a significantly greater percentage of males flew upwind to and landed at a source emitting 10% E1,E-9, 11–14:OAc than to all other sources. As the source dosage was increased, males showed decreased specificity of upwind flight to ratios of the two components. However, at the highest dosage of E11-14:OAc tested (300 μg), the response specificity of males shifted to blends containing lower percentages of E,E-9,11–14:OAc. The addition of tetradecyl acetate to a blend of the two components did not result in any detectable increase in male response. Analyses of the pheromone glands of individual female Iightbrown apple moths showed that females produced a range of ratios of E11-14;OAc:E,E-9,11–14:OAc from 100:2.2 to 100:11.4 with a median of approximately 100:7, reasonably paralleling the peak response of males. Pre-exposure of males to a blend of the two components, followed by exposure to E11-14:OAc alone (previously reported as a 'memory' effect) resulted in no significant response to E11-14:OAc alone.     

Response specificity of male olfactory receptor neurones for the major and minor components of a female pheromone blend

Abstract The sex attractant of the female redbanded leafroller moth, Argyrotaenia velutinana (Walker), is a blend of seven compounds. Specialized olfactory receptor neurones had been found for only two of the compounds, (Z)-11-tetradecenyl acetate (Z11-14:Ac) and (E)-11-tetradecenyl acetate (E11–14:Ac). These receptor neurones were always found in pairs within the long trichoid sensilla, which are the most abundant multi-pored sensilla on the male antenna. A systematic survey of all regions of the male antenna with standard extracellular recording techniques was undertaken to find receptor neurones responsive to the remaining five minor components of the female pheromone. Of the 113 long trichoid sensilla sampled, all contained two receptor neurones, one specialized for Z11–14:Ac and a second specialized for Ell –14:Ac. A comparable number of recordings were then obtained from the less abundant classes of multi-pored sensilla. Two new receptor neurone types were found, responsive to the minor pheromone components (E)-9-dodecenyl acetate (E9-12:Ac) and (Z)-9-dodecenyl acetate (Z9-12:Ac). Scanning electron micrographs indicated that these recordings were obtained from shorter, narrower trichoid sensilla. The majority of these sensilla appeared to contain three neurones capable of spontaneous action potential production. In each sensillum, only one receptor neurone appeared to respond to stimulation with a minor component of the female blend. The remaining two neurones did not respond to the chemical stimuli evaluated.     

A direct search approach to characterize the sex pheromone composition giving maximal male response

ABSTRACT. Response of male moths to sex pheromones differs markedly depending on blend composition. Natural selection can therefore be expected to favour males responding maximally to the blend produced by most females in the population. Thus it is relevant to quantify male response by the blend to which the males of a population respond maximally.
To do this, wind tunnel experiments were carried out where males were observed while responding to blends of synthetic compounds emitted from rubber septa. By stepwise improvement it was shown that the blend to which Yponomeuta cagnagellus responds maximally comprises (Z)11-tetradecenyl acetate (Z11-14Ac), ( E )11-tetradecenyl acetate (E11-14Ac), (Z)11-tetradecenol (Z11-140H), and tetradecyl acetate (14Ac) in the ratio 100(=50μg):1.5:20:45.
The innovate aspects of the method used to obtain this result, are the use of a direct search approach as an integral part of the experimental procedure and the use of a summary variable to characterize male response. These aspects are discussed using the data on the response of Y. cagnagellus males.     

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.     

Behaviour of male oriental fruit moth, Grapholita molesta, in overlapping sex pheromone plumes in a wind tunnel

The behaviour of Grapholita molesta (Busck) (Lepidoptera: Tortricidae) males was studied in overlapping sex pheromone plumes in a wind tunnel. The ultimate aim of the study was to assess the effect of different treatments on male behaviour and consider the observed changes within the context of the suggested mechanisms underlying mating disruption. Two baits were placed either in series or parallel using both synthetic pheromone blends and female extracts. One bait, the reference containing (Z)-8-dodecenyl acetate/(E)-8-dodecenyl acetate/(Z)-8-dodecenol in a ratio of 100/6/10 was kept constant at a dose of 100 g of the main component, giving a composition and a release rate close to that of a female. The dose of the other bait varied between 0.1 and 100 times the concentration of the reference and was a mixture of one, two or three pheromone components. Males clearly discriminated between different blends and doses in the overlapping plumes, for regardless if the lures were presented in series or in parallel they followed the complete plume. Complete suppression of the response to the reference was only achieved with 300 g of the optimal three-component blend on the other lure. When tested singly, a bait consisting of Z8-12:OAc/E8-12:OAc/Z8-12:O Hin a 100/0.2/0.4 ratio, attracted a high proportion of the males when placed 75 cm upwind of the male release site, but no males from 150 cm. Our data suggest that complete pheromone blends should be more effective than any incomplete blends in mating disruption formulations for G. molesta.     

A co-attractant mixture of (Z)-11-tetradecenyl acetate and (Z)-9-dodecenyl acetate for Neocalyptis angustilineata and Homona magnanima

While monitoring for the seasonal occurrence of the tea tortrix moth, Homona magnanima Diakonoff (Lepidoptera: Tortricidae), a number of Neocalyptis angustilineata (Walsingham) were attracted to traps baited with H. magnanima attractant, a 9:1 blend of (Z)-11-tetradecenyl acetate (Z11-14Ac) and (Z)-9-dodecenyl acetate (Z9-12Ac). We evaluated a 1:1 blend (1 mg) and a 9:1 blend (1 mg) of Z11-14Ac and Z9-12Ac for their attractiveness to the two moth species. H. magnanima was attracted only to the 9:1 blend. However, N. angustilineata was equally attracted to both blends. Thus, we report the 9:1 blend as a co-attractant for N. angustilineata and H. magnanima. This blend is the first finding for the attractant for N. angustilineata.     

Evolution of noctuid pheromone binding proteins: identification of PBP in the black cutworm moth,Agrotis ipsilon

Male black cutworm moths (Agrotis ipsilon, Lepidoptera, Noctuoidea, Noctuidae), which are attracted by a three-component pheromone blend ((Z)-7-dodecenyl acetate, Z7-12:Ac; (Z)-9-tetradecenyl acetate, Z9-14:Ac; (Z)-11-hexadecenyl acetate, Z11-16:Ac), express diverse antennal pheromone binding proteins (PBPs). Two PBP isoforms (Aips-1 and Aips-2) that show 46% identity were cloned from antennal cDNA of male A. ipsilon. The protein Aips-1 displays a high degree of identity (70-95%) with PBPs of other noctuiids, but shows only 42-65% identity with the PBPs of more phylogenetically distant species. The other protein, Aips-2, represents a distinct group of PBP that includes proteins from Sphingidae and Yponomeutidae. These differences observed suggest that each of the two PBPs may be tuned to a specific pheromone ligand.     

Evidence of olfactory antagonistic imposition as a facilitator of evolutionary shifts in pheromone blend usage in Ostrinia spp. (Lepidoptera: Crambidae)

Olfactory receptor neuron (ORN) response was measured to assess why some males ("rare males") of the Asian corn borer (ACB), Ostrinia furnacalis, have a broad behavioral response to fly upwind to both the ACB and the European corn borer (ECB), Ostrinia nubilalis, pheromone blends. We performed single-sensillum electrophysiological recordings on ACB males that had been behaviorally assessed for upwind flight response to the ACB blend [60:40 (Z)-12-tetradecenyl acetate (Z12-14:OAc) to (E)-12-tetradecenyl acetate (E12-14:OAc)], as well as to ECB (Z-strain) and ECB (E-strain) blends [3:97 and 99:1 (Z)-11-tetradecenyl acetate (Z11-14:OAc) to (E)-11-tetradecenyl acetate (E11-14:OAc)]. Sensilla from all types of males had large- and small-spike-sized ORNs responding strongly to Z12- or E12-14:OAc, but weakly to Z11- and E11-14:OAc. In the majority of males ("normal males") that flew upwind only to the ACB blend, Z11-14:OAc elicited responses in an intermediate spike-sized ORN associated with behavioral antagonism that is mainly tuned to (Z)-9-tetradecenyl acetate (Z9-14:OAc). In the rare-type ACB males that flew to both the ACB and ECB pheromone blends, Z11-14:OAc did not stimulate this ORN. Increased responsiveness to ancestral pheromone components by ORNs associated with behavioral antagonism could be instrumental in reproductive character displacement, or in reinforcement and reproductive isolation during speciation by helping to increase assortative mating between males and females in derived populations that use novel sex pheromone blends.     

大螟雄蛾触角对性外激素及其类似物的电生理反应

电生理试验显示出:大螟Sesamia inferens(Walker)雄蛾触角对Z11-16:Ac(A)oZ11-16:OH(B)激起强烈的触角电位(EAG)反应,Z11-16:ALD?,E11-16:Ac(D),Z9-14:Ac(E)和Z7-12:Ac(F)四种化合物也能激起较强的EAG反应;A化合物的刺激阈比B高,此两种化合物5:5比例时,激起的反应最强烈。电生理的试验推测,雄蛾触角对A和B两种化合物的感受,是通过触角内两种不同类型的嗅觉感受器。A和B不同比例混合后,田间诱蛾试验证明:在9:1,8:2,5:5的比例时,其诱蛾量远远超过单独的A化合物;E加入A与B的混合物中,起抑制诱蛾的效果,上述试验表明,Z11-16:OH是大螟的性诱剂。     

小地老虎中国种群性信息素的成分鉴定及田间试验（英文）

研究了小地老虎中国种群的性信息素组分,3日龄处女蛾单腺体性信息素提取物中性信息素的含量非常低。GC和GC-MS分析表明,小地老虎性信息素含有5种成分：顺-7-12碳乙酸酯（A）、顺-9-14碳乙酸酯（B）、顺-11-16碳乙酸酯（C）、顺-5-10碳乙酸酯（D）和顺-8-12碳乙酸酯（E）。它们的含量分别为：（0.245±0.098）、（0.080±0.031）、（0.089±0.03）、(0.085±0.031)和 (0.105±0.065)ng, 这5种物质的百分比分别为40.451±13.66、13.176±5.279、14.943±5.142、14.392±6.10和17.225±9.792,前3种物质的百分比为58.75±9.429、18.91±7.539和22.34±7.209。田间试验表明,性信息素单一组分均未诱到雄蛾,AB以3∶1的比例配成的诱芯对雄蛾有一定的引诱活性,一个诱捕器平均诱捕到2.6头。ABC组分以3∶1∶1的比例配成的诱芯对雄蛾引诱活性显著增强,一个诱捕器平均诱捕量为7.40头,是AB（3∶1）诱芯的2.8倍。诱芯中性信息素的含量对诱蛾活性有明显的影响,在剂量为200 µg时的平均诱捕量最高。     

The effects of different blend ratios and temperature on the active space of the Oriental fruit moth sex pheromone

Abstract The wing-fanning activation response of male Oriental fruit moths (OFM), Grapholita molesta (Busck), in the field to the three-component pheromone containing the female-produced ratio of components (Z8-12:OAc + 6% E8-12:OAc + 3% Z8-12:OH) was compared with the response to blends containing 2,10 and 20% E with 3% OH, and the 6% E blend containing 30 and 100% OH. Comparisons were made over three temperature ranges: 15–17, 20–21 and 26–28^oC. Both the maximum response distance and male response specificity were significantly altered by changes in odour quality as well as temperature. For blends containing different Z/E ratios the maximum response distance increased significantly with temperature. Response specificity was most pronounced at the 20–21^oC range, with males displaying a lower threshold for the natural 6% E ratio, evidenced by the fact that fewer males responded and at closer distances to the source with off-ratios. At 26–28^oC response specificity for the Z/E ratios was much reduced, primarily due to more males activating to off-ratios. With blends containing different proportions of Z8-12:OH in the 6% E blend, increasing temperature increased the maximum response distance for all treatments, but in addition increasing the proportion of OH alone from 3% to 30% significantly increased the maximum response distance over the three temperature ranges tested. This increase occurred without affecting the proportion of responders or the distribution of response distances around the mean value. However, with 100% OH added to the blend, whereas male response was high at 20–21^oC, the distribution of response distances was significantly more variable than with 3% or 30%, and male response was eliminated or very low at 15–17^oC and 26–28^oC. Our results support previous studies showing that peak response levels in this species are dependent on male perception of the natural blend of components, and that males have a high degree of specificity for the qualitative properties of the pheromone. However, the present results also extend those of previous flight tunnel tests in which response specificity was most pronounced in the upwind flight phase of the sequence, by showing that male OFM also display a     

Nomographic correspondence between specialist cell responses, electroantennograms and the probability of behavioral response: the importance of comparable stimuli and a benchmark

Responses from single receptor cells, electroantennograms (EAGs) and the proportion of upwind flight in a wind tunnel elicited by graded stimulus strengths of (Z)-7-dodecenyl acetate (Z7-12:Ac) were measured from male cabbage loopers, Trichoplusia ni (Hübner). The approach that was taken to illustrate the relationship between these three measures on the same scale was to express the airborne stimulus strength for all three measures in molar units. A collateral discovery was finding a linear relationship between spiking activity in the receptor cells and the proportion of the first two stages of upwind flight behavior.Two validations corroborate the approach. The first of these demonstrates that, with only three exceptions, there is agreement between behavioral and electrophysiological measures from several laboratories. At the same time, there is a demonstration highlighting the importance of the use of a stimulus benchmark in establishing the relevancy of an experimental stimulus strength to a natural context. The second validation shows that both electrophysiological and behavioral data can be used to estimate the same emission rate of Z7-12:Ac at low dosages from filter paper.     

Reidentification of the female sex pheromone of the Indian meal moth, Plodia interpunctella: evidence for a four-component pheromone blend

Pheromone gland extracts from calling female Plodia interpunctella contained at least seven compounds that consistently elicited electroantennographic responses from male antennae upon gas chromatographic analysis. Three of these compounds were found to be the previously identified gland constituents, i.e., (Z,E)-9,12-tetradecadienyl acetate (Z9,E12-14:OAc), (Z,E)-9,12-tetradecadienal (Z9,E12-14:Ald) and (Z,E)-9,12-tetradecadienol (Z9,E12-14:OH). A fourth EAD-active compound was identified as (Z)-9-tetradecenyl acetate (Z9-14:OAc). The homologue (Z)-11-hexadecenyl acetate (Z11-16:OAc) was also identified in the extracts, but showed no EAD activity. The identity of all five compounds was confirmed by comparison of GC retention times and mass spectra with those of synthetic standards. In flight tunnel tests there were no significant differences in response of male P. interpunctella to the bait containing all four EAD-active compounds and the responses to female gland extacts. A behavioural assay of different two-compound blends in the flight tunnel showed that only addition of the corresponding aldehyde to the major pheromone component Z9,E12-14:OAc raised the male response. A subtractive assay, however, revealed that the exclusion of any of the compounds from the complete four-compound blend reduced its activity significantly. We thus conclude that the female-produced sex pheromone of P. interpunctella consists of at least four components, i.e., Z9,E12-14:OAc, Z9,E12-14:Ald, Z9,E12-14:OH and Z9-14:OAc.In a field trapping test performed in a storage facility, the four-component blend attracted significantly more males of P. interpunctella than traps baited with Z9,E12-14:OAc alone. In contrast, the highest number of Ephestia kuehniella males was found in the traps baited with this major component, suggesting that the secondary pheromone components contribute to the species specificity of the blend.