Antennal responses of Cydia pomonella (L.) exposed to surfaces treated with methoxyfenozide

Electroantennogram (EAG) measurements were recorded from the antennae of male and female codling moth, Cydia pomonella L., to determine whether adult moths exposed to surfaces treated with the ecdysteroid agonist methoxyfenozide experience a decline in their antennal reception and thus olfactory sensitivity. Such a phenomenon would offer a possible mechanism for the previously reported decreased responsiveness from moths treated with methoxyfenozide to pheromone‐ and plant volatile‐based monitoring lures. Mean EAG data revealed that the antennae from methoxyfenozide‐treated male moths appear to be just as sensitive to various doses of synthetic codlemone as the antennae from the control and surfactant‐treated moths, but they appeared to be less sensitive to the pheromone component 12OH (collected from female effluvia) than the control male antennae. Mean male EAG responses to the pheromone components E8,E10‐12Al and codlemone collected from methoxyfenozide‐treated females were significantly less than the responses towards those two pheromone components collected from the control and surfactant‐treated females. Female moth exposure to methoxyfenozide did not negatively impact the sensitivity of female antennae to the plant volatile pear ester, but it did towards the apple volatile butyl hexanoate. Data from this study show that adult C. pomonella exposure to methoxyfenozide‐treated surfaces does appear to negatively impact, in a minor way, the (i) olfactory sensitivity (or detection) of male antennae towards some components of the female sex pheromone, (ii) the female antennal sensitivity towards a key apple volatile and (iii) the attractiveness of female pheromone effluvia.     

The role of the androconia in the mating behaviour of the European skipper, Thymelicus lineola, and evidence for a male sex pheromone

Abstract. Laboratory experiments were carried out to determine the role and characteristics of male scent scales (androconia), located in patches (stigmata) on the forewings of Thymelicus lineola (Ochsenheimer) (Lepidoptera: Hesperiidae). In behavioural tests, there were 30—40% fewer matings of virgin females by males with the stigmata removed or where females had their antennal sensilla covered with nail polish, when compared to sham-treated controls. These reductions occurred despite a large increase in male courtship activity. No physical contact was observed between male wings and female antennae during mating. A scanning electron microscope study of male wings and female antennae showed that: (1) lysis zones form over time on the androconia and pieces (osmo-phores) distal to these zones break off; (2) while few of these zones are present at emergence they are numerous in-day-old males; (3) during a single episode of courtship and mating approximately two-thirds of the available osmophores break off, yet the commonly observed courtship between males does not appear to result in osmophore release; and (4) osmophores were never observed on the female antennae. Electroantennogram recordings (EAGs) indicated that: (1) female antennae responded strongly to odours from male forewings but not from other parts of either males or females; (2) female antennae responded more strongly to young field-collected males than to newly-emerged or old, field-collected males; (3) female antennal response to male forewings was reduced if the androconia were scraped off, and was eliminated if the stigmata were removed; (4) male antennae gave weak EAG responses to both male and female forewings. We conclude that males release pheromone via the breakage of osmophores during courtship. We propose that the frequently observed refusals by females of courting males are at least partially dependent on the quantity or quality of male pheromone released, which are in turn correlated with the male's age and mating status.     

Perception of volatiles associated with sex and food by different adult forms of the black bean aphid, Aphis fabae

Abstract. Electroantennograms (EAGs) were recorded from adult male and asexual forms (winged and wingless virginoparae and gynoparae) of the black bean aphid, Aphis fabae , during stimulation with two sex pheromone components, (+)-(4a S ,7 S ,7a R )-nepetalactone and (-)-(1 R ,4a S ,7 S ,7a R )-nepetalactol, as well as six plant volatiles, i.e. ( E )-2-hexenal, ( E )-2-hexenol-1, ( Z )-3-hexenol-1, ( Z )-3-hexenyl acetate, hexanal and allyl isothiocyanate. The male antennae are 1000-10,000 times more sensitive to nepetalactol and nepetalactone than to the plant compound ( E )-2-hexenal. Besides this marked difference of EAG peak responses in males, the EAG rise and decay are slower for the sex pheromone components. Males are also much more sensitive to the sex pheromone components than asexual females. This high sensitivity correlates with a predominance of antennal secondary rhinaria, the major sites of pheromone perception in the male. However, it is the primary rhinaria on the antennae of the wingless asexual females that are responsible for pheromone perception. Male antennae are as responsive as the asexual female antennae to the plant volatiles. The specialization of the male for mate location is discussed.     

Electroantennogram responses to the sex pheromone and other odours in the American cockroach

Electroantennogram responses of adult American cockroaches were recorded for the sex pheromone and 30 kinds of monoterpenoids. Strong responses to the sex pheromone were obtained from the antennae of male adults, but not from females. The compounds possessing a hydroxyl or carbonyl group produced significant EAG responses in the antennae. Bornyl acetate, however, was an exception and gave strong responses in both male and female antennae. There was basically no difference between the antennal responsiveness to monoterpenoids tested in both sexes.     

Olfactory receptor responses of the nymphal American cockroach to sex pheromones and their mimics

1. EAG responses to highly purified sex pheromones (periplanone-A and -B), sex pheromone mimics [germacrene-D, (+)-verbanyl acetate and (+)-trans-verbenyl acetate] and general odor (camphor) were recorded from both sexes of adult and three nymphal stages (7, 10 and 11th instars) of the American cockroach. 2. The M/F ratios were evaluated for each stage by stimulation with the above chemicals. 3. The ratio values indicated undeveloped sex pheromone receptor on the antennae of 7th male instar and females of all the stages. On the other hand, precursory development of the receptor was expected on the antennae of males of the old-aged nymphal instars and full development on the adult male antennae.     

Ontogeny of electroantennogram responses in the moth, Manduca sexta

The antennae of the moth, Manduca sexta, and the sensilla and sensory neurons they contain, develop during metamorphosis from pupa to adult. To determine when, during their development, antennae become capable of generating electrical responses to various stimuli, we recorded the electroantennogram (EAG), believed to be the summed extracellular record of receptor potentials, from developing and mature antennae. Antennae from male and female moths are similarly responsive to trans-2-hexenal, while only males respond to Manduca sex pheromone; these two odorants presumably stimulate separate receptors. Mechanical stimulation also elicits and EAG response. EAG responses to olfactory and mechanical stimuli are detectable several days before eclosion but not until the neurons are morphologically and biochemically quite mature. Responses increase in magnitude until the end of metamorphosis and then change little during the first 3 days after emergence of the adult. Responses to different stimuli do not develop synchronously.     

Effects of sex pheromone in electrostatic powder on mating behaviour by Lobesia botrana males

Abstract:  In laboratory trials, mating behaviour of males of Lobesia botrana Den. and Schiff. (Lep., Tortricidae) was investigated after treatment with an electrostatically chargeable powder, Entostat^TM. Male moths were powdered with either blank Entostat or Entostat containing sex pheromone. Significantly more Entostat adhered to L. botrana males when sex pheromone was added to the powder compared with blank Entostat. Powdering male moths with Entostat, with or without sex pheromone, caused a significant reduction in antennal response when antennae were placed 2 cm away in downwind direction, while there was little effect when antennae were placed 25–100 cm from the EAG in downwind direction. In a flight study, powdering males of L. botrana caused significant increase in time before flight initiation and reduction in proportion of males making contact with calling females compared with untreated males. In a mating experiment in Petri dishes (to minimize required search time to locate female), significantly fewer females mated successfully (based on dissection of bursa copulatrix) when males had been treated with pheromone-loaded powder. Overall, powdering males of L. botrana caused considerable suppression of mating behaviour on various levels, and these suppressing effects were increased after adding sex pheromone to Entostat.     

Existence d''une phéromone sexuelle chezCaryedon serratus: Attractivité des femelles et réactivité des males

Résumé Les femelles deCaryedon serratus (Ol.) produisent, pendant la scotophase, une phéromone sexuelle volatile qui déclenche chez les males une chémoanémotaxie positive. Les effets de l'age sur l'attractivité des femelles et sur la réactivité des males ont été étudiés. Plus de soixante-dix pour cent des males commencent à réagir à la phéromone sexuelle dès les premières 24 heures qui suivent leur émergence. Une seule femelle sur 31 a été attractive à cet age. A 48 heures, le pourcentage des femelles attractives est de 38,7%. Il existe une variabilité inter et intra femelles dans la production de phéromone sexuelle (début, régularité). L'existence des récepteurs antennaires à la phéromone sexuelle chez le male est montrée par des études électrophysiologiques (EAG). La variabilité de la production de phéromone sexuelle est discutée.

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Summary The female ofCaryedon serratus release, from the beginning of scotophase, a sex pheromone witch triggers a positive chemoanemotaxy in males. The effects of age on female attractiveness and on male reactivity are studied. About 70.37% of males begin to react to the sex pheromone within the first 24 h after emergence. At this age, only one female out of 31 is attractive. At 48 h, the percentage of attractive females is 38.7%. There is inter and intra-female variation in sex pheromone production (beginning, regularity). The existence of receptors on male antennae for this pheromone is shown by electrophysiology (EAG). The variability in sex pheromone production is discussed.

     

Electroantennogram and behavioural responses of different forms of the bird cherry-oat aphid,Rhopalosiphum padi,to sex pheromone and a plant volatile

Winged (alate) virginoparae were induced in the laboratory by crowding the bird cherry-oat aphid, Rhopalosiphum padi (L.) under long-day conditions. Males and gynoparae (the winged female form that produces sexual females) were induced by short days. Electroantennogram (EAG) and behavioural responses were investigated in each of the three forms to two aphid sex pheromone components, (-)-(4aS,7S,7aR)-nepetalactol and (+)-(4aS,7S,7aR)-nepetalactone, and benzaldehyde, a volatile which is released by the winter host plant. All three compounds elicited EAG responses with the males showing the highest sensitivity to each compound. Both the nepetalactol and the nepetalactone elicited larger EAG responses in gynoparae than in the winged virginoparae but antennae from virginoparae were more responsive to benzaldehyde. Although the nepetalactone is not a sex pheromone component in R. padi the EAG responses were similar to those evoked by the nepetalactol, the sex pheromone, in all three aphid forms. In a linear-track olfactometer, significantly more male R. padi moved into air containing nepetalactol, nepetalactone or benzaldehyde than into a simultaneous choice of clean air (i.e. attraction) but nepetalactol was more attractive than nepetalactone. Males, however, showed no response to a mixture of nepetalactol and nepetalactone. Gynoparae were attracted only to the nepetalactol but were less sensitive than the males and showed no response to the nepetalactone or benzaldehyde. In contrast, alate virginoparae showed no behavioural responses to any of the compounds. The present study supports the idea that the male R. padi utilise both sex pheromone and benzaldehyde for mate/host-plant location in autumn. It also demonstrates, for the first time, polyphenic differences in the olfactory responses at the peripheral level between the two female forms. Such differences impact on the life-cycle strategy where winged virginoparae move between graminaceous summer host plants while gynoparae move from the summer hosts to the bird cherry, winter host. The latter move appears to be assisted by the sex pheromone released by sexual females, already present on that host, acting as an aggregation pheromone.     

Localization and fine structure of the female sex pheromone-producing glands in Bruchidius atrolineatus (PIC) (Coleoptera : Bruchidae)

The sex pheromone glands of female Bruchidius atrolineatus (Coleoptera: Bruchidae) have been localized by recording the electric response of the antenna of males subjected to a stream of air, containing the volatile sex pheromone (electroanntennography-EAG). Some 50 unicellular glands are distributed irregularly in the ventral and dorsal intersegmental membranes situated at the extremity of the pygidium, each gland containing a short ductule with an evacuation pore, 0.5–1 μm in diameter. The receiving canal is composed of a network of fine epicuticular filaments. The glands are type 3. The ultrastructure of these sex pheromone-producing glands is described in females whose production-emission activity had been previously verified with EAG. Deep basal invaginations and inflated intercellular spaces indicate the transport of substances from the hemolymph to the gland cells. The presence of numerous elongated mitochondria, diverse inclusions, vesicles containing crystalline bodies, and abundant apical microvilli, all reveal elevated cellular activity, which is never observed in young or diapausing females that do not produce sex pheromone. The ultrastructural differences in different types of females (sexually active or diapausing), combined with comparative EAG recordings obtained with intact females or those in which the suspected glandular zone was masked, made it possible to localize the glands.     

Pheromone production, male abundance, body size, and the evolution of elaborate antennae in moths

The males of some species of moths possess elaborate feathery antennae. It is widely assumed that these striking morphological features have evolved through selection for males with greater sensitivity to the female sex pheromone, which is typically released in minute quantities. Accordingly, females of species in which males have elaborate (i.e., pectinate, bipectinate, or quadripectinate) antennae should produce the smallest quantities of pheromone. Alternatively, antennal morphology may be associated with the chemical properties of the pheromone components, with elaborate antennae being associated with pheromones that diffuse more quickly (i.e., have lower molecular weights). Finally, antennal morphology may reflect population structure, with low population abundance selecting for higher sensitivity and hence more elaborate antennae. We conducted a phylogenetic comparative analysis to test these explanations using pheromone chemical data and trapping data for 152 moth species. Elaborate antennae are associated with larger body size (longer forewing length), which suggests a biological cost that smaller moth species cannot bear. Body size is also positively correlated with pheromone titre and negatively correlated with population abundance (estimated by male abundance). Removing the effects of body size revealed no association between the shape of antennae and either pheromone titre, male abundance, or mean molecular weight of the pheromone components. However, among species with elaborate antennae, longer antennae were typically associated with lower male abundances and pheromone compounds with lower molecular weight, suggesting that male distribution and a more rapidly diffusing female sex pheromone may influence the size but not the general shape of male antennae.     

榆木蠹蛾性信息素通讯系统的超微结构观察

为了解榆木蠹蛾Holcocerus vicarius （Walker）雌蛾性信息素分泌腺（性信息素释放系统）位置、 表面形态和超微结构及雄蛾触角感受器（性信息素接收系统）的种类、 形态、 分布及功能, 利用扫描电镜和透射电镜对榆木蠹蛾雌蛾性信息素分泌腺和雄蛾的触角进行观察。结果表明： 榆木蠹蛾雌蛾性信息素分泌腺位于腹尖末端第8～9节节间膜上的背面中央区域, 腺体表面分布着许多饱满的锥状突起, 2日龄处女雌蛾腺体细胞间有明显的胞连接, 细胞基底膜基褶较多, 质膜上分布着微绒毛, 并与内表皮连接, 内表皮上含有多层几丁质, 胞质中含有脂质粒、 大量空泡、 光面内质网、 粗面内质网及线粒体; 雄蛾触角鞭节上有5种感受器, 为毛形感器、 刺形感器、 锥形感器、 腔锥形感器和曲毛形感器, 其中毛形感器数量最多, 曲毛形感器最少。柄节和梗节被大量鳞片覆盖, 未观察到感器。榆木蠹蛾性信息素通讯系统的研究为榆木蠹蛾性信息素的生物合成、 性信息素的提取、 鉴定及成虫生殖交配生物学行为提供了依据。     

暗黑鳃金龟对性信息素的触角电生理及行为反应

为了分离鉴定暗黑鳃金龟的性信息素成分并对其功能进行验证,本研究对比摸索了3种触角的处理方法,并进行同一浓度（30 ng·μL^-1）二元混合物、不同配比的触角EAG测试。结果包括: 建立了一种鳃叶状触角的触角电位（EAG）测定方法,即将暗黑鳃金龟Holotrichia parallela触角的各鳃叶用针分离开后进行测定,这种方法测得的触角电位反应值较高。雄虫触角对L-异亮氨酸甲酯和(R)-(-)-芳樟醇为7∶1的二元混合物的反应值最高,和暗黑鳃金龟雌虫性信息素25个腺体提取液的EAG反应相当;对同一配比（7∶1）不同剂量刺激液的EAG测试表明,雄虫对浓度为30 ng·μL^-1的二元混合物刺激液的反应值最高。嗅觉反应结果进一步证实,试虫对L-异亮氨酸甲酯和(R)-(-)-芳樟醇7∶1的选择最高,选择系数达93.3%。研究结果为利用性信息素防治暗黑鳃金龟技术的开发提供了基础。     

Functional specialisation and polyphenism in aphid olfactory sensilla

Electroantennogram (EAG) responses to the aphid sex pheromone components, (1R,4aS,7S,7aR)-nepetalactol and (4aS,7S,7aR)-nepetalactone, and a plant volatile, (E)-2-hexenal, were investigated at three different positions (5/6th, 4/5th and 3/4th inter-segmental regions) along the antennae of four different morphs in two host-alternating aphid species, Aphis fabae Scopoli and Rhopalosiphum padi (L.). Position-dependent and morph-specific EAG responses were elicited in both species. The nepetalactol and nepetalactone isomers elicited large EAG responses at all three recording positions in males of both species, such that primary rhinaria as well as secondary rhinaria appeared to respond. Asexual female morphs showed relatively smaller EAG responses to these compounds. The secondary rhinaria, which have been reported as sex pheromone receptors in males, were not very different in their number and distribution between gynoparae and alate virginoparae, but the gynoparae showed significantly larger EAG responses to nepetalactol and nepetalactone. The alate virginoparae showed EAG responses that were similar to those of apterous virginoparae, which lack secondary rhinaria. Taking the EAG response profiles together with the distribution of the secondary rhinaria, it is suggested that the function of secondary rhinaria differs between the morphs. Secondary rhinaria appear to detect sex pheromone components in males and gynoparae but not in the alate virginoparae. If they are functional in the latter morph, they are likely to play a role in detecting specific, but as yet unknown, volatile compounds. Some 30 plant volatiles were tested but none evoked an EAG response that could be allocated to the secondary rhinaria. In contrast to the very different EAG response profiles to the pheromone compounds between morphs, EAG responses to (E)-2-hexenal were similar in all forms and both species. These findings suggest that this plant volatile was detected only by the two primary rhinaria, which are common to all morphs. The present study showed that EAG responses were not a simple summation of receptor potentials between recording and reference electrodes in aphids. The localised distribution pattern of olfactory receptor neurones around the recording electrode was also likely to contribute to the EAG responses.     

豆野螟成虫触角对植物挥发性和性信息素化合物的触角电位反应

以顺3-己烯乙酸酯为标准化合物,研究了豆野螟雌、雄成虫触角对不同浓度的植物挥发性和性信息素化合物组分的触角电位（EAG）反应.结果表明：豆野螟雌、雄成虫触角对植物挥发性气味具有强烈的EAG反应,但在大部分浓度下,雌、雄虫的反应没有显著差异.在测试的9种植物挥发性化合物中,雌、雄虫对高浓度反-2-己烯醛刺激的相对EAG反应的最大值分别达到250%和260%,且雌、雄虫触角对这种化合物的EAG反应的形状也有很大差异;但对豇豆花气味中的柏木烯和柏木脑没有明显的EAG反应.雌、雄蛾对性信息素都有明显反应,且雌、雄虫的反应存在显著差异,雄虫触角对性信息素化合物主要组分（反10,反12）-十六碳二烯醛的EAG反应的最大值达到250%,远超过雌虫反应的最大值(53%).雌、雄成虫这种神经感觉反应的差异反映了它们在感器结构、功能和行为上的差异.     

Isolation of sex pheromone mimic of the American cockroach by monitoring with male/female ratio in electroantennogram

The electroantennogram (EAG) technique was applied as a monitoring tool to isolate germacrene-D, a sex pheromone mimic of the American cockroach. Large values of the male/female ratio, and its index derived from EAG responses of adult males and females to a standard, indicated significant amounts of germacrene-D in plant fractions. Monitoring with behavioural assays and gas chromatographic analysis during the isolation confirmed that the EAG technique using the male/female index was a good indicator in the isolation of sexually active components.     

榆木蠹蛾生殖行为及性信息素产生与释放节律

通过室内饲养与野外观察榆木蠹蛾Holcocerus vicarius (Walker)成虫的羽化、交尾、产卵行为,触角电位反应测定处女雌蛾性信息素产生与释放节律,旨在为榆木蠹蛾性信息素的鉴定和合成奠定基础。结果表明：榆木蠹蛾羽化行为全天可见,主要集中在15:00－19:00。成虫羽化当日即可交尾,21:30－0:30进行婚飞和交尾,交尾高峰出现在晚23:00左右,光期未见交尾。随着日龄的增加,召唤时间前移并且延长,2～3日龄处女雌蛾召唤时间早于1日龄雌蛾,交尾时间较短;雌蛾在羽化1 d后达到性成熟,2日龄雌蛾交尾百分率最高,达41.8%。雌蛾将产卵器伸出寻找缝隙处产卵,分多处产卵,雌虫最高产卵量达720粒,最低产卵量为105粒,卵期为12～22 d不等,孵化率为72%～88%。羽化当晚的雌蛾体内性信息素含量较低,第2天最高,以后逐日下降;2日龄榆木蠹蛾处女雌蛾性信息素的产生量从晚17:00起逐渐增加, 21:30－22:00时最高, 22:00后逐渐减小。雄蛾触角电位反应在22:30最强。21:30－23:00是雌蛾产生和释放性信息素的高峰期。榆木蠹蛾的羽化、交尾存在一定的时辰节律,通过处女雌蛾的野外诱集试验证实了性信息素释放与交配行为在时辰节律上的一致性。     

Electroantennogram responses of the three migratory forms of the damson-hop aphid, Phorodon humuli, to aphid pheromones and plant volatiles

Electroantennogram (EAG) responses were recorded from alate fundatrigeniae (spring migrants), gynoparae (the winged female form that produces sexual females) and males, the three migratory forms of the damson-hop aphid, Phorodon humuli (Schrank). EAG responses of gynoparae and males showed typical dose response characteristics to (E)-2-hexenal, (-)-R-carvone, hexanenitrile and (1RS,4aR,7S,7aS)-nepetalactol, the sex pheromone of this species. The 34 plant volatiles elicited broadly similar EAG response profiles in the three migratory forms. Green leaf volatiles produced large responses in all forms; however, the relative order of responsiveness varied. EAG responses to isomers of the monoterpene carvone differed between forms, with males being most, and spring migrants least, responsive. The hop-plant volatile and aphid alarm pheromone, (E)-beta-farnesene, evoked similar EAG responses in all forms. By contrast, males were most responsive to the three sex pheromone components, (-)-(4aS,7S,7aR)-nepetalactol, (+)-(4aS,7S,7aR)-nepetalactone and (1RS,4aR,7S,7aS)-nepetalactol. Males were no more responsive to their own sex pheromone, (1RS,4aR,7S,7aS)-nepetalactol, than to the other aphid sex pheromone components tested. Spring migrants and gynoparae also responded to the three sex pheromone components. This study indicates that migratory forms of P. humuli detect a wide range of volatile compounds, and that they are equally well-adapted for the detection of volatiles associated with host and non-host plants and with other species of aphid.     

蜀柏毒蛾生殖行为及性信息素产生与释放节律

为了探索蜀柏毒蛾Parocneria orienta Chao性信息素产生和释放规律, 为利用性信息素监测和防治蜀柏毒蛾奠定基础, 本研究在野外及室内温度22±1℃、 相对湿度75%~80%、 光周期14L∶10D条件下观察研究了蜀柏毒蛾成虫的羽化、 求偶、 交尾、 产卵行为, 触角电位反应测定处女雌蛾性信息素产生与释放的时辰节律。结果表明： 蜀柏毒蛾羽化行为全天可见, 主要集中在1:00-5:00, 占总羽化量的44.94%, 7:30-11:00进行婚飞和交尾, 交尾高峰期出现在8:30左右, 交配时间少则2 h, 多则8 h, 求偶、 交配均发生在光期。随着日龄的增加, 召唤时间前移并且延长, 1日龄的处女雌蛾交尾时间较短; 雌蛾羽化当天就可交尾, 2日龄雌蛾交尾率最高, 达36.67%。雌蛾分多处产卵, 雌蛾一生最高产卵量达402粒, 最低产卵量为78粒。羽化当天的雌蛾体内性信息素含量较低, 第2天最高, 以后逐日下降; 2日龄蜀柏毒蛾处女雌蛾性信息素的产生量从7:00起逐渐增加, 8:30-9:30时最高, 9:30后逐渐减小。雄蛾对处女雌蛾腺体提取物的触角电位反应在8:30-9:00最强, 说明8:30-9:00是雌蛾产生和释放性信息素的高峰期。蜀柏毒蛾的羽化、 求偶、 交尾及性信息素的产生与释放存在一定的时辰节律, 野外处女雌蛾诱蛾试验证实了性信息素释放与交配行为在时辰节律上的一致性。     

松墨天牛是否存在雌性接触信息素?

将松墨天牛MonochamusalternatusHope的身体不同部位切除之后的交配试验显示,分别剪去头部、鞘翅以及前胸部后仍然可以正常交配,用雄虫的腹部代替雌虫的腹部后,仍然能够引起雄虫的交配趋势动作,但不能完成真正交配,因此推测雌性接触信息素如果存在,主要集中在雌虫身体后半部,尤其是中后胸部位。但是冻死后的雌虫不再引起雄虫的交配行为,而且冻死的雌虫与活雌虫同时放入培养皿中,雄虫喜欢与活雌虫交配,不选择冻死的雌虫,因此推测视觉在其松墨天牛的交配过程中扮演着重要的角色,而接触性信息素有可能并不存在。将雄虫的触角分别从第5~6节和第1节剪去的试验结果显示,雄虫仍然可以很快地找到雌虫,发生交配行为。这有2种可能的解释一是雄虫不仅仅靠触角来感受雌虫的接触信息素,头部下颚须和下唇须上或者足上也有可以感受信息素的感受器;二是雌虫不存在接触信息素,雄虫通过视觉就可以找到对方,完成交配过程。浸泡致死的雌虫不再引起雄虫的交配行为,并且将正己烷和乙醚的浓缩液滴加在浸泡致死的雌虫以及玻璃棒和鹅卵石的生测试验结果显示,都没有引起雄虫的交配行为。这进一步说明,松墨天牛可能并不存在体表接触信息素。性成熟后的松墨天牛雌雄成虫是靠衰弱寄主的强烈的挥发性气味聚集到寄主树干上,在树干这个较为狭小的环境里,有可能是通过视觉找到配偶,完成交配过程。