DIEL RHYTHMS OF CALLING BEHAVIOR AND SEX PHEROMONE PRODUCTION OF BEET ARMYWORM,SPODOPTERA EXIGUA (LEPIDOPTERA:NOCTUIDAE)*

Abstract Beet armyworm (BAW), Spodoptera exigua, is becoming one of more and more serious pests in China in recent years. As a part of research program of sex pheromone and its application of BAW in China, the hourly and daily variation of calling behavior and pheromone production of BAW females were investigated. Both calling behavior and titers of 4 sex pheromone components showed distinct diel rhythms, and the two peak periods were synchronous. In comparison, the calling activity lasted shorter period of time with a longer peak time, whereas the production of the sex pheromone lasted throughout the whole scotophase and part of the photophase with a very short peak time. The calling behavior began at the middle scotophase, reached the maximum at the middle‐later scotophase, and continued the maximal calling activity until the end of the scotophase. When the light was on, the calling percentage reduced sharply, and all females stopped calling 1 hour later. The variation patterns of the 4 pheromone components in the glands of the 3 day old moths were similar from one to another. From 0.5 h before to 4.5 h into scotophase, the titers increased slightly, but at 6.5 h they showed a significant increase up to the peak values of the scotophase. Soon at 8.5 h into the scotophase, they decreased significantly and thereafter gradually to undetectable level at 4.5 h into the next photophase. The daily change experiment showed that BAW females began calling at 0 scotophase, became fully active in calling at 3rd scotophase, and maintained the calling activity to 7th scotophase. There was no significant difference in pheromone titers among different day‐old moths.     

甜菜夜蛾雌蛾求偶行为及性信息素产生的时间节律(英文)

研究了甜菜夜蛾雌蛾求偶行为和腺体中性信息素滴度时日变化的规律。结果表明 ,雌蛾求偶行为和性信息素滴度均呈明显的昼夜节律 ,且均在暗期的中后期达到高峰。比较而言 ,雌蛾的求偶活动期较短 ,在暗期中期开始 ,暗期结束后很快停止 ;但峰期较长 ,从中后期达到高峰后一直保持到暗期结束。而腺体内 4种性信息素组份从暗期前 0 .5h到下一个光期 4.5h均有产生 ;但峰期很短 ,暗期 6.5h显著增加达到高峰后 ,在 8.5h又迅速回落。日变化研究表明 ,甜菜夜蛾当日龄即可求偶 ,3日龄起进入求偶盛期 ,至 7日龄末有明显减退。 0～ 3日龄雌蛾的平均初始求偶时间逐日显著提前 ,以后则稳定在暗期 5h左右。不同日龄间性信息素滴度的变化较小     

Sex pheromone titre in the glands of Spodoptera litura females: circadian rhythm and the effects of age and mating

The present study investigates the effects of age and mating status on the circadian variations of gland sex pheromone titre in female Spodoptera litura Fabricius. Similar to other nocturnal moths, S. litura females exhibit circadian variations of gland sex pheromone contents, with higher levels during scotophase and lower levels during photophase. The sex pheromone titre in the glands peaks during the first scotophase after eclosion and sharply declines afterwards. Higher pheromone contents during scotophase may facilitate female reproductive activities, and the negative relationship between pheromone titre and female calling is likely the result of pheromone release during female calling. Interestingly, the present study demonstrates that mated S. litura females have significantly higher sex pheromone titre in their pheromone glands (PGs) than virgin females. This finding contrasts with all previous studies of other insect species, in which mating generally reduces the sex pheromone titre in female PGs. In S. litura, mating and male accessory gland fluids can suppress female calling behaviours and re‐matings. These results suggest that the suppression of female calling behaviours by mating and male accessory gland fluids may significantly reduce the release of sex pheromones and thus result in higher sex pheromone titre in the PGs of mated females.     

Nocturnal Calling Behavior in Mantids

Females of Mantis religiosa and Empusa pennata were video taped for several 24 h periods to determine if they showed behaviors associated with pheromone release. In the photophase the abdomen of both species was motionless and rested in continuous contact with the wings. However, at the beginning of the scotophase the females bent the abdomen ventrally so that the space between the abdomen and the wings increased significantly with respect to the daytime posture. Calling behavior (abdominal bending) was maintained throughout the 8 h scotophase and ended abruptly at lights on. Females of M. religiosa did not start calling until they were 30 days of age. Calling disappeared in mated females, but it reappeared two weeks later. Males stayed motionless in response to the odors emitted by other males or by noncalling females, but walked when a calling female was placed in the air flow. These observations suggest that female mantids bend their abdomens at night to release a sex pheromone. The adaptive function of nocturnal sex pheromone release in sexually cannibalistic species that rely strongly on visual cues for mating is discussed.     

Calling behavior of the female german cockroach,Blattella germanica (Dictyoptera: Blattellidae)

Virgin German cockroach females, Blattella germanica(L.), were observed, for the first time, to exhibit a characteristic calling behavior during which females emit a volatile sex pheromone. Under a photoperiod of 12L12D, the percentage of 7-day-old virgin females that exhibited this behavior peaked before the end of the scotophase in a similar pattern to the diel periodicity of mating. A clear relationship was evident between calling and stages of sexual receptivity during successive gonotrophic cycles. Females initiated calling 5–6 days after the imaginal molt, when their basal oocytes were 1.6 mm long. If not mated, females continued to exhibit bouts of calling during the next 3–4 days until 24 h before ovulation. Calling was completely suppressed by mating as well as the presence of an egg case in the genital atrium in both virgin and mated gravid females. We suggest that calling and the emission of a volatile sex pheromone serve to attract males from a distance as well as to potentiate responses to contact sex pheromone in aggregations.     

褛裳夜蛾的交配行为及雄蛾对性腺提取物的反应节律

详细观察了褛裳夜蛾成虫的交配行为,利用风洞、触角电位技术研究了雄蛾对性腺提取物的反应节律,通过林间诱蛾试验进行了验证,旨在为褛裳夜蛾性信息素的精确提取及性信息素组份分离、鉴定提供依据。研究结果表明:成虫的求偶、交配行为均发生在暗期,有一定的节律性:雌蛾在羽化3d以后开始求偶,1周左右表现最为强烈,3-4日龄雌蛾在暗期4-6h开始求偶,最大求偶率在暗期6-8h;5-9日龄在进入暗期就开始求偶,最大求偶率出现在暗期4-6h。风洞试验表明,3-7日龄的雄蛾对性腺提取物均有明显的性行为反应,5日龄雄蛾在暗期4-6h对性腺提取物的反应最为强烈。3-6日龄的成虫在暗期4-6h开始交配,而7-8日龄的成虫于暗期2-4h开始交配,6日龄的成虫交配率最高,交配高峰在暗期4-8h。雄蛾对性腺提取物的触角电位反应也有一定的节律性:雄蛾对4日龄雌蛾性腺提取物开始有电生理反应,对6-7日龄暗期5h性腺提取物反应最为强烈。林间诱蛾试验测定了性腺提取物的引诱活性,7日龄雌蛾性腺提取物林间诱蛾量最高,引诱高峰在暗期4-6h,该结果也验证了褛裳夜蛾雄蛾对性腺提取物的反应节律。     

Temporal distribution of PBAN‐like immunoreactivity in the hemolymph of Mamestra brassicae females in relation to sex pheromone production and calling behavior

A direct enzyme‐linked immunosorbent assay has been developed and applied to the analysis of PBAN immunoreactivity in female hemolymph of the cabbage armyworm, Mamestra brassicae. PBAN‐IR determinations have been carried out with third scotophase insects at different times of the photoperiod. The rhythm of calling and the pattern of pheromone production by third scotophase females at different times of the photoperiod have also been determined. PBAN‐IR and calling are well correlated. However, whereas pheromone titers decrease, both PBAN‐IR levels and percentage of calling females remain high in the last hours of the scotophase. These results are discussed in the context of the regulation of sex pheromone biosynthesis in M. brassicae. Arch. Insect Biochem. Physiol. 40:80–87, 1999. © 1999 Wiley‐Liss, Inc.     

Mechanisms of premating isolation between Helicoverpa armigera (Hübner) and Helicoverpa assulta (Guenée) (Lepidoptera: Noctuidae)

Helicoverpa armigera and Helicoverpa assulta are sympatric sibling species, and in the laboratory they can interbreed and produce viable offspring. To assess the contributions of temporal barriers and sexual barriers to premating isolation, we investigated both the temporal rhythms of calling behavior and pheromone titers of H. armigera and H. assulta females and the behavioral responses of males to conspecific and heterospecific calling females in a wind tunnel. Both H. armigera and H. assulta females called throughout the scotophase, and there was more calling during the second half of the scotophase than during the first half. Maximal pheromone titer and maximal calling activity in H. armigera synchronously occurred at the sixth hour into the scotophase, whereas, in H. assulta, the maximal pheromone titer occurred 2 h before the peak of calling. Pheromone blend ratios of the two species were opposite and, within each species, changes in the ratio within the scotophase and at different ages were relatively small. Males of both H. armigera and H. assulta responded strongly to their conspecific calling females in the wind tunnel and completed the whole courtship sequence. In contrast, they did not land and had no copulation attempts in response to heterospecific calling females. These results show that the two species do not have obvious temporal differences in calling behavior and pheromone production, and the specificity of sex pheromone blend emitted by females plays a key role in their premating isolation. In addition, we summarized the potential isolation mechanisms of H. armigera and H. assulta.     

Diel periodicity and influence of age and mating on female sex pheromone titre in Estigmene acrea (Lep., Arctiidae)

Abstract:  Calling behaviour, diel periodicity, and effect of age and mating on female sex pheromone titre in Estigmene acrea (Drury) were studied under laboratory conditions. Forty-five per cent of females started calling during the first scotophase, but the highest number of calling females was observed during the second, third and fourth scotophases. Calling behaviour occurred from the third hour after dark until just before the end of the scotophase. However, females exhibited a bimodal pattern of calling with the first peak occurring between 4 and 6 h and a second peak at 10 h after the onset of scotophase. The mean onset of calling time differed significantly with age. Older females showed a tendency to call longer, but there was no significant difference. The amount of (Z,Z)-3,6-cis-9, 10-epoxyheneicosadiene in females was quantified from the first scotophase following emergence, until the fifth scotophase. Glands of 0-day-old females presented a higher content of pheromone compared with that found in glands of 1-, 2-, 3- and 4-day-old females. Pheromone titre was determined at 2-h intervals throughout the third scotophase and photophase. (Z,Z)-3,6-cis-9,10-epoxyheneicosadiene was found in the gland during the scotophase as well as the photophase. However, there was no consistent pattern of pheromone production throughout the scotophase or photophase. Mated females of E. acrea produced significantly less pheromone than virgin females.     

Pupal Period Affects Calling Behavior of the Wheat Moth, Pseudaletia sequax (Lepidoptera: Noctuidae)

The effects of pupal period and age on calling behavior of virgin females of Pseudaletia sequax were determined. Calling behavior of groups of females of similar age of pupation was observed every 10 min for six calling days. Females were considered calling when they assumed a characteristic position: wings and abdomen elevated, displaying the ovipositor and presumably releasing pheromone. Calling behavior was discontinuous. Females with a shorter pupal period took more time to start calling than females with a longer pupal period and called for a longer period. On the first day of calling, females took more time to initiate calling, on average during the seventh hour of the scotophase, whereas on the second day of calling, most females initiated calling during the fifth hour of the scotophase. On subsequent days of calling, the average time to initiate calling changed to the fourth hour of the scotophase. The mean time of calling per day decreased significantly with the number of days since first calling, and the mean number of calling bouts increased with days since first calling.     

The Timing of Calling and Mating in <Emphasis Type="Italic">Heterolocha jinyinhuaphaga</Emphasis> and the Influence of Environmental Determinants

We investigated the periodicities of calling and mating of Heterolocha jinyinhuaphaga (Lepidoptera: Geometridae) and the effects of temperature, relative humidity, and photoperiod on the timing of these behaviors. Females called on the first night after emergence, mainly during the second half of scotophase. The calling percentage increased on the second night and peaked on the third night, before decreasing. Mating had similar rhythms but peaked 1 h later than calling. As the moth aged, the mean onset times of calling and mating were advanced. Temperature, relative humidity, and photoperiod all affected the calling and mating. We found that 25°C was the most suitable temperature for calling and mating, whereas at higher or lower temperatures, the total calling percentage and the total mating percentage decreased, the onset time of calling was delayed, and mating duration decreased. Increased the relative humidity facilitated calling and mating. However, lengthened photoperiods inhibited the calling and mating.     

Effects of temperature and light on calling in the tiger moth Holomelina lamae (Freeman) (Lepidoptera: Arctiidae)

ABSTRACT. In Holomelina lamae Freeman daily eclosion of adults is gated, with males emerging before females. By advancing the onset of photophase and by delaying the onset of scotophase, it was demonstrated that lights-on acts as the main phase-setting cue for calling. Few females call on the day they eclose. Calling is initiated c. 9 h after the onset of photophase in 2-day-old females, and shifts to earlier times in older females. The duration of calling also increases with age. That calling is controlled by an endogenous circadian clock is indicated by its persistence in continuous light (LL) and dark (DD). In LL calling is dampened rapidly, but a single scotophase re-entrains the rhythm. Decreases in temperature advance the onset of calling and the mean hour of calling, while increases in temperature delay both. However, the magnitudes of such phase-shifts depended upon hour of the photoperiod. Moreover, cooling and heating appears to exert both transient and long-term effects on the calling rhythm. An 8 h period at a reduced temperature in LL induces calling in females whose calling is dampened, and entrains the calling rhythm. Females maintained in DD from second instar larvae to the adult stage exhibit a circadian calling rhythm set by eclosion.     

The effect of photoperiod on the calling behaviour of virgin females of the true armyworm,Pseudaletia unipuncta (Haw.) (Lepidoptera: Noctuidae)

The effect of photoperiod on the calling behaviour of Pseudaletia unipuncta virgin females was examined under five different photoperiodic regimes at 25°C, 65% r.h. The age at which females called for the first time following emergence varied with photoperiod; generally calling was later under long-scotophase conditions. However under a 6 h scotophase there was also a delay in calling and >63% of the females tested never called. There was a considerable variability in the daily calling patterns between the different photoperiods, and the mean onset time of calling was not constant with either “lights on” or “light off”. There was however a constancy of the mean onset time of calling relative to the mid-point of both the photo- and scotophase at all photoperiods tested, indicating that females could measure the absolute duration of either the photo- or scotophase. Transferring females from one photoperiodic condition to another once calling had been initiated, determined that it was the “lights off” signal that P. unipuncta females used to phase set the clock governing circadian calling behaviour.Females subjected to a decrease of 4 or 6 h in the length of the scotophase following the initiation of calling required several days to adjust to the new photoperiodic regime and a high proportion of females did not call during the night following the transfer. A 4 or 6 h increase in the scotophase did not inhibit calling on the night following the transfer but females still required several days to adjust completely. However, females experiencing a 2 h increase or decrease in the duration of the scotophase were able to maintain normal calling behaviour. The results of these experiments are discussed in relation to the seasonal biology of the true armyworm and the hypothesis that this is a migrant species.     

Rhythmicity of sex pheromone content in female Heliothis virescens: impact of mating

Abstract Pheromone production in virgin females of Heliothis virescens (F.) (Lepidoptera: Noctuidae) peaked between the fourth and seventh hours of scotophase on the second, third, fourth and fifth days following eclosion. The highest peak (186 ng) occurred on day 3 after eclosion. Z-11-Hexadecenal comprised the highest proportion of seven components in the pheromone glands. Disproportionately higher amounts of hexadecanal and Z-11-hexadecenol occurred during photo-phase and other periods when low quantities of total pheromone were recorded.
Mating suppressed pheromone production which remained low until 48 h after mating. Coupling females with males mated three times previously or with 6-day-old males was less effective in causing a drop in pheromone content which peaked again 24 h after mating. This suggests the transfer of a male factor, a pheromonostatic factor, that suppresses pheromone production in mated females and that the factor from older and previously mated males is less effective.     

Periodicity of pheromone release from female white peach scale

ABSTRACT The sex pheromone of the female white peach scale, Pseudaulacaspis pentagona (Targioni-Tozzetti), is released by newly-mature females to correspond with the daily eclosion rhythm of males. As with male eclosion, pheromone release commences relative to the onset of light and is suppressed by increasing temperature. Once pheromone release begins it is maintained until the initiation of the scotophase. Pheromone release does not occur during the scotophase. When sexually mature females remain unmated for 5 days, the release of pheromone begins earlier in the day than it does with newly mature females.     

Drosophila melanogaster sex peptide stimulates juvenile hormone synthesis and depresses sex pheromone production in Helicoverpa armigera

Previous studies demonstrate that virgin female adult Helicoverpa armigera (Lepidoptera: Noctuidae) moths exhibit calling behaviour and produce sex pheromone in scotophase from the day after emergence, and that mating turns off both of these pre-mating activities. In the fruit fly Drosophila melanogaster, a product of the male accessory glands, termed sex peptide (SP), has been identified as being responsible for suppressing female receptivity after transfer to the female genital tract during mating. Juvenile hormone (JH) production is activated in the D. melanogaster corpus allatum (CA) by SP in vitro. We herein demonstrate cross-reactivity of D. melanogaster SP in the H. armigera moth: JH production in photophase virgin female moth CA in vitro is directly activated in a dose-dependent manner by synthetic D. melanogaster SP, and concurrently inhibits pheromone biosynthesis activating neuropeptide (PBAN)-activated pheromone production by isolated pheromone glands of virgin females. Control peptides (locust adipokinetic hormone, AKH-I, and human corticotropin, ACTH) do not inhibit in vitro pheromone biosynthesis. Moreover, SP injected into virgin H. armigera females, decapitated 24 h after eclosion, or into scotophase virgin females, suppresses pheromone production. In the light of these results, we hypothesize the presumptive existence of a SP-like factor among the peptides transmitted to female H. armigera during copulation, inducing an increased level of JH production and depressing the levels of pheromone produced thereafter.     

大螟成虫性信息素生物合成和释放及求偶和交配行为的昼夜节律

【目的】探索大螟Sesamia inferens性信息素顺11-十六碳烯乙酸酯(Z11-16∶Ac)和顺11-十六碳烯醇(Z11-16∶OH)的合成和释放及求偶和交配行为的昼夜节律,及其与田间性信息素诱捕的关系。【方法】通过溶剂浸提和固相微萃取(solid phase microextraction, SPME)分析大螟雌蛾性信息素Z11-16∶Ac和Z11--16∶OH的滴度,结合行为观测和多地田间实时性信息素诱捕数据,调查大螟性信息素的生物合成、释放及求偶和交配行为的昼夜节律。【结果】大螟雌蛾腺体内性信息素Z11-16∶Ac和Z11-16∶OH含量可检测到的时间始于暗期前1 h,暗期后4 h快速增加,暗期8 h为第1次高峰,但光期1h又一次高峰,光期5 h还可以被显著检测到。分泌至腺体外的性信息素化合物可检测到的时间始于暗期后6 h,高峰期在暗期后10 h,光期后1 h性信息素Z11-16∶Ac滴度达到96.9±20.9 ng/雌。采用溶剂浸提法获得的Z11-16∶Ac和Z11-16∶OH的比例在暗期平均为2.8±1.9,在光期平均为2.5±0.9,统计上二者没有显著差异,而SPME法获得的Z11-16∶Ac和Z11-16∶OH的比例在暗期平均为8.5±1.2,在光期平均为5.7±0.6,统计上二者差异显著。产卵器伸出时间发生在暗期6-8 h,产卵器伸出持续时间平均为80.8±4.4 min。大螟的交配发生在暗期4-10 h,交配持续时间平均为83.4±5.0 min。广东、四川、浙江、江苏四省性诱自动计数的田间每日每小时实时计数数据显示,越冬代诱蛾比较集中,之后的世代则比较分散,田间雄蛾的性诱昼夜节律受地理环境、季节和世代等因子的影响。【结论】本研究发现大螟交配和性信息素释放的昼夜节律在时间上不一致,交配时间在暗期较早时段。雌蛾性信息素有效的释放时间范围比雄蛾对性信息素反应的要小。产卵器伸展与雌蛾性信息素化合物的释放速率加快和扩散 范围有关。     

Fatty acid and sex pheromone changes and the role of glandular lipids in the Z-strain of the European corn borer, Ostrinia nubilalis (Hübner)

Lipids in the sex pheromone gland of females of the Z-strain of Ostrinia nubilalis were analyzed for fatty acyl pheromone analogs (FAPAs) and other potential biosynthetic intermediates. More than 80% of the FAPAs were found in the triacylglycerols (TGs), with smaller amounts found in the phosphatidyl cholines, ethanolamines, and serines. Analysis of the TGs by lipase revealed that the two FAPAs were distributed fairly evenly among all three stereospecific positions. Comparison of changes in titers of key glandular fatty acids with those of pheromone components, with respect to photoperiodic time and age of females, showed that both FAPA and pheromone titers exhibited a cyclical pattern with peaks in the scotophase and valleys in the photophase. However, whereas pheromone titer tended to peak in the first half of the scotophase, FAPA titer peaked at the end of the scotophase. Significantly, the titer of the FAPA of the minor component, (E)-11-tetradecenyl acetate (3% of pheromone), was always much greater than the titer of the FAPA of the major component, (Z)-11-tetradecenyl acetate (97%), of the pheromone. Titer of myristate, an intermediate in pheromone biosynthesis, was also higher during the scotophase than the photophase. However, myristate titer showed a pronounced dip in the middle of the scotophase. These data suggest two roles for glandular lipids in sex pheromone biosynthesis in O. nubilalis. Firstly, they remove excess FAPA of the minor component so the fatty acid reductase system is not presented with a high ratio of this isomer (which would otherwise result from the reductase's own selectivity), which could cause changes in the final pheromone ratio. Secondly, hydrolysis of the large amounts of stored saturated fatty acids from the TGs may provide substrate for pheromone biosynthesis.     

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。     

Mating behaviour of the corn stalk borerSesamia nnonagrioides

The mating behaviour of the corn stalk borerSesamia nonagrioides (Lef.) [Lepidoptera:Noctuidae] was studied under laboratory conditions at 25 ± 1 °C, 65 ± 5% r.h. and 16:8 (L:D) regime. The females began calling during the first scotophase following emergence, the peak of calling occurred during the second scotophase and thereafter decreased. Maximum calling was observed between the fourth and sixth hour of the scotophase. The calling pattern varied with age. During the first and second scotophase most of the females were calling continuously, while during the third and fourth scotophase periodic calling was observed. The mean onset of calling was advanced and the mean length of calling per day was increased slightly as the female became older. Females held for 72 h in continuous darkness exhibited an endogenous circadian rhythm of calling. Matings began during the first scotophase following emergence and the peak of mating was observed during the second scotophase. Mated females did not remate. Few males mated more than once during the following scotophases.