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.     

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。     

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.     

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.     

Calling Behavior and Rhythms of Sex Pheromone Production in the Black Cutworm Moth in China

The hourly and daily variation of calling behavior and sex pheromone production by the female black cutworm moth, Agrotis ypsilon (Rottemberg), were investigated. Both calling behavior and titers of five sex pheromone components showed distinct diel rhythms, and peak periods of calling and pheromone titer were synchronous. Females began to call on the first night after eclosion and called mainly during the second half of the scotophase. The percentage of females calling increased in 1 to 3-d-old females and decreased in 3 to 7-d-old females. Females advanced their calling time with increasing age (1 to 7 d). GC-MS analysis of hexane extracts of pheromone glands revealed that the titers of the five sex pheromone components were very low on the first night after eclosion, but increased sharply and peaked on the third night. Titers decreased greatly with increasing age (3 to 7 d), but from the onset of the scotophase to 4.5 h into scotophase, titers remained invariate. However, from 4.5 to 7 h, pheromone titers, especially that of the primary component Z7-12:Ac, increased sharply and peaked. After the peak, the titers decreased greatly at 8 h, and thereafter decreased gradually to the level before 4.5 h. The quantity of each component almost reached zero after lights-on.     

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.     

Periodicity of oviposition,feeding, and calling by mated femaleHeliothis virescens in a field cage

This paper describes behaviors exhibited by mated, 3-day-old female Heliothis virescensin the presence of flowering cotton infield cages in mid-July. Females exhibit discrete periods of egg deposition, calling, and feeding during scotophase. Females exhibit behaviors such as walking while wing fanning, wing buzzing, antennal movement, bending of abdomen, and dragging of the ovipositor on the substrate before egg deposition. These behaviors are interspersed with flight and calling. The number and duration of some behaviors differ when the female is ovipositing on cotton plants versus cage screen. Egglaying occurs in several major bouts through the scotophase with periods of inactivity or other activities interspersed. Most eggs are laid before 0300 h. Significant calling is observed after 0100 h and continues until about 0430 h. Although females exhibit some feeding near sunset, the major feeding activity is seen just prior to and after sunup.     

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.     

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.     

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.     

Toward the Identification of the Sex Pheromone of Diatraea indigenella Dyar & Heinrich (Lepidoptera: Crambidae): Calling Behavior and Chemical Structure of a Major Component

Behavioral patterns and pheromone titer in females of the steam borer Diatraea indigenella Dyar & Heinrich were assessed for 7 days during scotophase under a 13:11 L:D photoperiod. Calling was observed from the first scotophase for most of the females. The highest percentage of calling females was recorded 6 h after the onset of scotophase. Calling bouts and length of calling were affected by age, decreasing dramatically after the sixth scotophase. By coupling chemical and electrophysiological techniques (GC–EAD, GC–MS) and olfactometer bioassays (Z,E)-9,11-hexadecadienal was identified as the main sex pheromonal component in the extracts of female glands. The concentration varied from 2.53 to 13.7 ng gland^?1 with a peak at the 6th hour of scotophase. In addition, two unidentified secondary active components were detected at very low concentrations. Behavioral assays showed that 86% of the male moths were more attracted to the gland extracts than to hexane (control), and 77% of the male moths were more attracted to the gland extract than to the synthetic major component (Z,E)-9,11-hexadecadienal. However, 68% of males preferred the synthetic major component over hexane. The identification of the major sex pheromonal component represents an important step toward the complete elucidation of the composition of the sex pheromone of D. indigenella in order to develop monitoring tools.     

Nocturnal behaviour of female Mythimna convecta

Nocturnal behaviour of Mythimna convecta (Walker) (Lepidoptera: Noctuidae) virgin females was studied in the laboratory under 20 °C and 16:8 LD conditions. The periodicity of activity, feeding, calling, pre-oviposition extrusion and oviposition varied with female age and hour of the scotophase. Females called for the first time between the 2nd and 11th scotophases with the peak in the 4th scotophase. Maximum calling occurred on the 7th hour of the scotophase. Young moths called more frequently with shorter bouts while old moths called less often but with longer bouts. In the presence of older females, moths spent significantly more time in pre-oviposition extrusion and resting and less in activity and feeding than they did when only females of the same age or younger were present. There were no significant differences for calling suggesting that pheromones of older calling females did not affect calling of younger females.     

Conspecific females promote calling behavior in the noctuid moth,Pseudaletia adultera

Changes in female calling behavior in response to the presence of conspecific pheromones (pheromone autodetection) have been demonstrated in a number of moth species. However, the observed changes vary between species, and several ecological and adaptive explanations for autodetection have been proposed. We studied the effect of conspecific females on the calling behavior of the noctuid moth Pseudaletia adultera (Schaus) (Lepidoptera: Noctuidae, Hadenini), by comparing the age of first calling, as well as the onset and pattern of calling, when females were held individually or in the presence of conspecifics. Grouped females started calling at a lower age, a higher percentage of females called during the scotophase, and they called longer compared to females held in isolation. We also demonstrated that female antennae respond to each of the three main components of the sex pheromone – (Z)‐11‐hexadecen‐1‐ol, (Z)‐11‐hexadecen‐1‐yl acetate, and (Z)‐11‐hexadecenal – and that the response patterns differed from those of male antennae. By calling more and extending her calling window in presence of conspecific females, a female may increase her chances of accessing males. However, the potential benefits need to be considered within an ecological context, considering factors such as migration, oviposition, and foraging.     

Emergence, Mating, and Postmating Behaviors of the Oriental Beetle (Coleoptera: Scarabaeidae)

In a previous field-trapping study of the oriental beetle, Exomala orientalis (Waterhouse), by using synthetic sex pheromone on golf course fairways, numerous males were observed and trapped during the hours of peak mating activity. However, very few beetles were observed in the same areas when synthetic pheromone was absent. To investigate the hypothesis that mating in nature occurs cryptically within vegetation at the soil surface, laboratory studies on female emergence and pheromone release, male emergence and mate-locating, and female and male mating behaviors were conducted. Mate acquisition and copulation occurred on the soil surface near the female emergence site, with both sexes engaging in pheromone-mediated behaviors after having emerged from the soil. A highly stereotyped female pheromone release, or calling, behavior was observed, consisting of insertion of the female's head into the soil and elevation of the tip of her abdomen into the air. Bioassays conducted in a wind tunnel that simulated a turf fairway environment showed that walking and flying were both important in the upwind response of males to females. Mating and copulation occurred without an obvious complex courtship, but observations of postmating behaviors suggested that mate guarding occurs.     

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.     

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     

Sexual behaviour and pheromone titre of the Spodoptera littoralis female moth

The sexual behaviour of females of the Egyptian cotton leafworm, Spodoptera littoralis (Boisduval), was studied in the laboratory. Calling of females was maximal on the 2–3rd night between 3 and 9 h into scotophase. Largest amounts of pheromone were found in the glands of 1–3 day-old 2–3 h into scotophase: a maximum of 6–8 ng of (Z,E)-9,11-tetradecadienyl acetate per female. Very low amounts of pheromone were detected 1 h before and at the end of scotophase. Mating of 2–3 day-old females, occurred mainly between 0 and 3 h into scotophase. Mating suppressed the pheromone titre drastically when measured 3 h after copulation but the titre increased significantly after 24 h, prior to egg laying. However, when egg laying commenced, the amount of pheromone detected was negligible. A high concentration of synthetic pheromone in closed containers did not affect calling of females. On the other hand mating was drastically suppressed in a pheromone-permeated atmosphere.

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Zusammenfassung Das Sexualverhalten der Weibchen des ägyptischen Baumwollwurms, Spodoptera littoralis (Boisduval) wurde unter Laborverhältnissen untersucht. Das maximales Rufen der Weibchen war in der 2–3 Nacht zwischen 3 und 9 Stunden der Skotophase. Die grössten Pheromonmengen wurden in den Drüsen der 1 bis 3 Tage alten nach 2–3 Stunden in der Skotophase gefunden und zwar maximal 6–8 ng (Z,E)-9,11-Tetradecadienyl Acetate. Ein drastischer Abfall des Pheromoninhalts wurde zwischen der 4 und 5 Nacht beobachtet. Sehr kleine Pheromonmengen wurden eine Stunde vor der Skotophase und nach ihrem Ablauf gefunden. Die Paarung 2–3 Tage alten wurde im allgemeinen zwischen Stunden 0 und 3 der Skotophase beobachtet. Drei Stunden nach der Paarung war der Pheromontiter drastisch herabgesetzt, er stieg jedoch nach 24 Stunden, vor der Eiablage bedeutend an. Sobald die Eiablage anfing, war das Pheromon jedoch kaum nachweisbar. Eine hohe Konzentration des synthetischen Pheromons in geschlossenen Gefässen beeinflusste das Rufen der Weibchen nicht. Anderseits war jedoch die Paarung in einer mit Pheromon durchgedrungenen Atmosphäre sehr stark herabgesetzt.

     

Circadian calling behavior of the adult female brown-banded cockroach,Supella longipalpa (F.) (Dictyoptera: Blattellidae)

The diel pattern of pheromone-releasing behavior (calling) of the adult female brown-banded cockroach, Supella longipalpa (F.),was examined. Calling occurs discontinuously throughout most of the scotophase in a 12L: 12D photoperiodic regime. Females exhibited a free-running calling rhythm after transfer to continuous light or dark conditions. Shifts in the temporal pattern of calling following changes in the timing of the photoperiodic cues indicated that lights-off is the Zeitgeber. Studies of insects under long- and short-day conditions suggest that, although insects within a population may call synchronously or asynchronously, respectively, the duration of an individual's calling bout is innately limited.     

Sex pheromone-releasing behaviour in females of the dermestid beetle,Trogoderma glabrum

Adult Trogoderma glabrum females assume stationary postures characterized by abdominal elevation and partial exposure of the ovipositor segments. The postural activity was studied in relation to sex pheromone production and was designated calling, or sex pheromone-releasing behaviour because it was accompanied by an increase in the rate of release of sex pheromone(s). Calling was largely restricted to an 8 hr interval centered toward the middle of a 16 hr photophase. Mating frequency and female pheromone content increased during the same interval. Because females extracted during the calling period yielded at least 10 times more pheromone than extracts prepared at other times, and because pheromone activity released during one calling period was estimated to be at least 10-fold higher than that which could be extracted from whole females several hours prior to the start of calling, heightened production of active pheromone(s) was postulated to occur during calling. Functional significance of the calling posture is discussed in relation to sex pheromone gland location.     

Release mechanism of sex pheromone in the female gypsy moth <Emphasis Type="Italic">Lymantria dispar</Emphasis>: a morpho-functional approach

A morpho-functional investigation of the sex pheromone-producing area was correlated with the pheromone release mechanism in the female gypsy moth Lymantria dispar. As assessed by male electroantennograms (EAG) and morphological observations, the pheromone gland consists of a single-layered epithelium both in the dorsal and ventral halves of the intersegmental membrane between the 8th and 9th abdominal segments. By using the male EAG as a biosensor of real-time release of sex pheromone from whole calling females, we found this process time coupled with extension movements of the ovipositor. Nevertheless, in females in which normal calling behavior was prevented, pheromone release was detected neither in absence nor in presence of electrical stimulation of the ventral nerve cord/terminal abdominal ganglion (TAG) complex. Tetramethylrhodamine-conjugated dextran amine stainings also confirm the lack of any innervation of the gland from nerves IV to VI emerging from the TAG. These findings indicate that the release of sex pheromone from the glands in female gypsy moths is independent of any neural control exerted by the TAG on the glands, at least by way of its three most caudally located pairs of nerves, and appears as a consequence of a squeezing mechanism in the pheromone-producing area.