Onset Of Scotophase Research Articles

Gymnandrosoma aurantianum (Lepidoptera: Tortricidae): Calling Rhythm and Effect of Age on Female Sex Pheromone Titer and Male Antennal Responses.

The macadamia nut borer, Gymnandrosoma aurantianum Lima (Lepidoptera: Tortricidae), is the main pest of Macadamia integrifolia Maiden & Betche (Proteales: Proteaceae) in Central America. Despite its importance, there is little information on its reproductive behavior. We studied the calling behavior and effect of age on female sex pheromone production and male antennal response to the pheromone. Calling behavior of G. aurantianum females occurred at the onset of scotophase, between 17:00 and 20:00h. The mean time spent calling was 64min. It was observed that 30% of the 50 females exhibited a calling posture characterized by extrusion of the pheromone gland from the tip of the abdomen and they spread their wings slightly. Female age had no influence on the sex pheromone production, while male antennal response increased with age and pheromone dosage. The information obtained in this work contributes to understanding the sexual behavior of G. aurantianum and thus to the creation of strategies to control this important pest in macadamia.

Water-oats harbors two strains of the striped stem borer Chilo suppressalis (Lepidoptera: Crambidae) with temporal divergence in mating behavior

The striped stem borer, Chilo suppressalis Walker, is a widespread insect pest in China, which feeds both on rice (Oryza sativa L.) and water-oats (Zizania latifolia Griseb.). The populations collected from rice (rice population, CSR) and water-oats (water-oats population, CSW) were observed for mating behavior. Results showed that the mating rhythm of CSR in scotophase was unimodal distribution, while that of CSW was bimodal distribution. The first mating peak of CSW occurred about 3.5 h after the onset of scotophase, which overlapped well with the single mating peak of CSR. The second mating peak of CSW occurred about 5.5 h after the onset of scotophase. The descendant populations from those three mating peaks were also observed for mating behavior, and the temporal patterns were found to be hereditable. In the second generation, mating rate was abnormally low in crossings between females of the first mating peak and males of the second mating peak. Pupae weight differed significantly between CSR and CSW in the first generation but did not in the second generation reared with the same food in laboratory. Our results indicated population collected from water-oats is mixed population, containing indigenous water-oats feeders and temporary residences from rice field. It was discussed that water-oats acts as a refuge crop to delay the resistance development to pesticides and Bt (Bacillus thuringiensis) rice.

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 7days 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 6h 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 13.7nggland(-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.

Analyzing Diurnal and Age-Related Pheromone Emission of the Olive Fruit Fly, Bactrocera oleae by Sequential SPME-GCMS Analysis

The olive fruit fly, Bactrocera oleae (Diptera: Tephritidae), uses 1,7-dioxaspiro[5.5]undecane ("olean"), produced primarily by females, as a sex pheromone. We used sequential solid phase microextraction-gas chromatography mass spectrometry (SPME-GCMS) analysis to show that female olive flies release about 1000 ng of pheromone at the onset of scotophase for several weeks, while males release about 1/100 as much during the first week after eclosion. The present research demonstrates details of employing SPME-GCMS with the partially known pheromone system of the olive fruit fly as a model for pheromone identification and diurnal release patterns in insects, especially fruit flies. The sequential SPME-GCMS method will readily allow detection and semi-quantification of semiochemicals released by insects in minute amounts throughout the diurnal cycle.

Bioavailability of backbone cyclic PK/PBAN neuropeptide antagonists - inhibition of sex pheromone biosynthesis elicited by the natural mechanism in Heliothis peltigera females

The bioavailability (i.e. ability to penetrate the insect cuticle, to reach the target organ and to exert bioactivity) of two backbone cyclic (BBC) pyrokinin/pheromone biosynthesis-activating neuropeptide (PK/PBAN) antagonistic peptides was tested by applying them topically to Heliothis peltigera females and monitoring the resulting inhibition of sex pheromone production elicited by the natural (endogenous) mechanism during scotophase. Peptides were applied at various time points before the onset of scotophase, in aqueous or organic solvents, and pheromone content was examined at the 5th or 6th hour of scotophase. Both peptides penetrated the cuticle very efficiently and inhibited sex pheromone biosynthesis elicited by the natural mechanism for up to 8 or 9 h after application. The degree of inhibition differed between solvents: those applied in double-distilled water (DDW) were more active than those applied in dimethylsulfoxide (inhibition by 53-73% and 15-38%, respectively, for BBC-25, and 46-67% and 36-40%, respectively for BBC-28). Peptides applied in dimethylsulfoxide and hexane exhibited slightly more persistent inhibitory activity than those applied in DDW. The solvents themselves did not affect sex pheromone production. Multiple applications (at -2, 0, +2 and +4 h) resulted in almost complete (87%) inhibition of sex pheromone biosynthesis, compared with 52% inhibition following a single application. The present study is the first demonstration of the ability of topically applied PK/PBAN antagonists to inhibit sex pheromone biosynthesis elicited by the natural mechanism in female moths, and provides important information on the bioavailability of BBC peptides and the mechanism responsible for sex pheromone production in these insects.

Phenology and population radiation of the nettle caterpillar, Darna pallivitta (Moore) (Lepidoptera: Limacodidae) in Hawai’i

The nettle caterpillar, Darna pallivitta (Moore) (Lepidoptera: Limacodidae), is an invasive pest with established populations on three Hawai’ian islands. Indigenous to Southeast Asia, D. pallivitta caterpillars cause defoliation of ornamental nursery stock and pose a human health hazard due to their urticating hairs that can cause painful skin reactions. Identification of the pheromone component n-butyl (E)-7,9-decadienoate (E7,9-10:COOnBu) from D. pallivitta has made it possible to investigate the phenology and population dynamics using baited traps. Male captures in Jackson traps baited with E7,9-10:COOnBu showed a vegetation preference for tall-grass fields and forest/grass interfaces over forest areas. Microlocation preferences were also found for trap height, with over 65% of males being caught in traps suspended at 1 m, compared with the traps at 3 and 5 m. Captures of male moths in traps baited with live females, and direct observations of female calling behavior, showed peak activities 6–7 h after the onset of scotophase. This is a much later communication period than for D. bradleyi and D. trima and may provide a mechanism by which D. pallivitta maintains reproductive isolation in areas where all three species are present. Coastal and inland transects established in eastern Hawai’i measured aspects of population fluctuations and radiation into new areas with relation to elevation and microclimate. Population expansion was measured by comparing moth population means and 80% population boundaries over time. Both population measures showed a higher expansion for the coastal transect. Differences in population expansion may be attributed in part to temperature and elevation, while precipitation does not seem to have a strong effect. Both the behavioral and ecological data collected can be used to optimize deployment of detection/control strategies and to predict population expansion/risk assessment for establishing quarantine protocols for the nettle caterpillar.

Structure, ratios and patterns of release in the sex pheromone of an aphid, Dysaphis plantaginea

Insect communication is primarily via chemicals. In Aphidinae aphids, the structure and ratio of iridoid (monoterpenoid) chemicals are known to be important components of the sex pheromone. However, for enhanced species specificity, it has been suggested that release of sex pheromone might be restricted to a narrow time period within the diel cycle. Here, we determine the structure, ratios and release patterns of iridoid chemicals produced by a serious global pest, the rosy apple aphid, Dysaphis plantaginea. Volatiles were collected from batches of oviparae (sexual females) and chemicals identified by gas chromatography, mass-spectrometry and microscale NMR spectroscopy. (1R,4aS,7S,7aR)-Nepetalactol and (4aS,7S,7aR)-nepetalactone were detected in a 3.7:1 ratio. To investigate timing of release, we constructed a sequential sampling device that allowed volatile chemicals to be captured hourly from 95 same-aged oviparae over 20 consecutive days. Release patterns of the two sex pheromone components show that D. plantaginea oviparae release high levels of the two components during photophase and low levels during scotophase. Release of the two components increased significantly during the first 3 h of photophase and thereafter remained at a high level until the onset of scotophase. The ratio of (1R,4aS,7S,7aR)-nepetalactol to (4aS,7S,7aR)-nepetalactone released did not change significantly between days two to 14 of the adult stadium, but from the 15th day onward there was a significant decrease in the relative amount of (1R,4aS,7S,7aR)-nepetalactol. Pheromone release was greatest on the eighth day of the adult stadium, with up to 8.4 ng of pheromone released per ovipara per hour. This is the first report on the full structural identification and ratios of volatile iridoid components collected from D. plantaginea oviparae and is also the most detailed temporal study on sex pheromone release from any aphid species. The lack of a temporally narrow and distinct period of very high sex pheromone release suggests that alternative mechanisms or factors for species recognition and isolation may be important. Findings are discussed broadly in relation to the biology of the aphid.

Comparisons of calling behaviour of different geographical populations of Helicoverpa armigera

Abstract: The cotton bollworm, Helicoverpa armigera, with worldwide distribution, evolves into different geotypes for adapting to the changes of geographical climates. Comparisons of calling behaviour of the insect collected from the temperate region in northern China (Beijing), the temperate region in north‐western China (Kashi) and the tropical region in southern China (Haikou) were investigated in the laboratory as a first step to understanding the influence of reproductive behaviour on its population differentiation. There were more than 80% of virgin females of each population that showed calling behaviour. The age at which the moths of all three populations initiated calling varied significantly. The durations of calling in scotophase and the percentages of females calling also differed between populations. Only a few females of the Beijing and Haikou populations called in the first 2 h after the onset of scotophase, whereas many Kashi females called at this time. However, the main calling peak occurred during the second half of scotophase for all three populations. Females of the Beijing and Haikou populations exhibited similar calling onset times at the same age, whereas the Kashi females initiated calling significantly earlier than those of Beijing and Haikou from nights 3 to 7. The durations of each calling bout and the time spent by both Beijing and Haikou populations were similar to each other at the same age, but were significantly shorter than that of the Kashi population from nights 3 to 7. These results suggest that there are genetic variations not only in pre‐period calling but also in the calling behaviour of H. armigera.

Diel Periodicity in the Production of Green Leaf Volatiles by Wild and Cultivated Host Plants of Stemborer Moths, Chilo partellus and Busseola fusca

The volatile chemicals produced by four poaceous plant species, blue thatching grass, Hyparrhenia tamba, Napier grass, Pennisetum purpureum, sorghum, Sorghum bicolor, and maize, Zea mays, which are host plants for the lepidopterous stemborers, Chilo partellus and Busseola fusca, were collected by air entrainment and analyzed by gas chromatography. The total quantities of volatiles collected hourly, over a 9-hr period, from P. purpureum and H. tamba showed an approximately hundredfold increase in the first hour of the scotophase. Thereafter, the amount decreased rapidly to levels present during photophase. Although onset of scotophase also triggered an increase in quantities of volatiles collected from two cultivars of S. bicolor and two out of three cultivars of Z. mays, these increases were less dramatic than in the two wild grasses, being only up to 10 times as much as in the last hour of photophase. Analysis showed that up to 95% of the increase in volatiles at the onset of the scotophase was due to just four compounds, the green leaf volatiles hexanal, (E)-2-hexenal, (Z)-3-hexen-1-ol, and (Z)-3-hexen-1-yl acetate, with the latter dominating the volatile profile. Volatiles from P. purpureum were also collected at 10-min intervals for 70 min spanning the transition from light to dark. The vast increase in production of the green leaf volatiles in this species occurs in the first 10 min of the scotophase followed by a rapid decline within the next 20 min. The relevance of these results to the control of stemborers in a "push-pull" strategy is discussed.

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.

Comportamento de chamamento de Thyrinteina arnobia (Stoll) (Lepidoptera: Geometridae) em Psidium guajava, Eucalyptus grandis e em dieta artificial

This work was carried out to determine and compare the effects of three diets (Psidium guajava and Eucalyptus grandis host-plant leaves and artificial diet) on the calling behavior and on the temporal pattern of calling behavior of Thyrinteina arnobia (Stoll). All activities of virgin females during six scotophases were observed in the laboratory at 5min. intervals until the females stopped calling in the following photophase, at 22 ± 1oC, 70 ± 5% RH and 10h scotophase. The diets affected the calling behavior of T. arnobia. Two positions of calling were observed. Calling of female virgins started in the first hour immediately after emergence. The calling pattern was characteristic of the continuous pattern. The type of diet affected the mean onset of calling time (pre-calling) and the total time calling of T. arnobia. Older females called earlier than younger after the onset of scotophase. The diets affected the color of pheromone gland.

Pheromone content of azinphosmethyl-susceptible and -resistant obliquebanded leafrollers (Lepidoptera: Tortricidae) as a function of time of day and female age

AbstractThe effect of time of day and age on the amounts and ratios of four pheromone compounds [(Z)-11-tetradecenyl acetate (Z11-14:Ac), (E)-11-tetradecenyl acetate (E11-14:Ac), (Z)-11-tetradecenol (Z11-14:OH), and (Z)-11-tetradecenal (Z11-14:Al)] was compared in azinphosmethyl-susceptible (susceptible) and -resistant (resistant) female obliquebanded leafrollers, Choristoneura rosaceana (Harris). The amounts of all four pheromone compounds varied during the hour before and five hours after the onset of scotophase. The glands of resistant females contained approximately one half the amount of Z11-14:Ac and Z11-14:OH as the glands of susceptible females during the second and third hours of scotophase, and between 50 and 70% as much Z11-14:Al as the glands of susceptible females during the hour before and second to fourth hours of scotophase. The glands of susceptible and resistant females contained similar amounts of E11-14:Ac. The relative amounts of each of the four pheromone compounds were affected by time of day but not by resistance status. There was a negative linear relationship between the amounts of each of the four compounds and female age in both types of females. The amounts of Z11-14:Ac and E11-14:Ac declined at similar rates with age in susceptible and resistant females; the amounts of Z11-14:OH and Z11-14:Al declined more rapidly with age in susceptible than in resistant females. The relative amounts of the four compounds were not affected by female age. Temporal variation in the relative amounts of pheromone in susceptible and resistant C. rosaceana may be associated with similar variation in the emission of pheromone and corresponding temporal variation in the relative attractiveness of the two types of females.

Diel rhythms of calling behavior and temporal change in pheromone production of the rice leaffolder moth, Cnaphalocrocis medinalis(Lepidoptera: Crambidae).

Calling activity in Cnaphalocrocis medinalis showed a distinct diel periodicity. Moths showed high activity during 5–7 h into the scotophase. To clarify the temporal change of pheromone titers in the pheromone gland within 1 d, age 4 females were used. The changes in the calling activity and titer of the four sex pheromone components, (Z)-11-octadecenal (Z11-18:Ald), (Z)-13-octadecenal (Z13-18:Ald), (Z)-11-octadecen-1-ol (Z11-18:OH) and (Z)-13-octadecen-1-ol (Z13-18:OH), in the pheromone glands were roughly synchronous. At age 4, however, the pheromone components could already be detected at the onset of scotophase, while calling began at 3 h into the scotophase. Furthermore, calling was most active between age 3 and age 7, whereas the highest level of pheromone titer at 6 h after light off was observed from age 3 to age 5. These findings suggest the presence of different controlling mechanisms between calling behavior and pheromone production. The ratio of the four sex pheromone components remained relatively constant at all times of the day and all ages.

Role of juvenile hormone-esterase in mating-stimulated egg development in the moth Heliothis virescens

Juvenile hormone (JH) titer in virgin females of Heliothis virescens is significantly lower than that in mated females of the same age. The JH titer in virgin females follows a diel pattern in which it begins to increase towards the end of photophase, remains high around the onset of scotophase, and declines during scotophase. The titer reaches its lowest levels at the onset of photophase, and remains low during the first half of photophase. In mated females, the diel pattern of JH titers is not as pronounced. JH-esterase (JHE) activity in mated females is significantly lower than that of virgin females during photophase; JHE levels in the former are similar to levels seen in newly emerged females. JHE activity in mated females also exhibits a diel pattern, in which activity is low during photophase and high at the onset of scotophase. Evidence for the indirect involvement of JHE in the mating-stimulated egg development is provided by the effect of selected JHE inhibitors in inhibiting JHE activity and stimulating egg production in virgin females.

Modulation of Flight Activity in Lobesia botrana Den. & Schiff. (Lepidoptera: Tortricidae) Females Studied in a Wind Tunnel

We studied modulations of flight activity in European grapevine moth females (EGVM) by individual observations in a wind tunnel. The effect of different factors was analyzed: variation in atmospheric pressure prior to the experiments, time of day, first experience of flight, age, mating, and odor of tansy, which attracts females. The circadian flight activity showed a peak the hour preceding the onset of scotophase and sustained activity occurred during the 6 h around this peak. Females with a flight experience in the tunnel took off more quickly than naive ones (3.9 ± 7.4 vs 20.3 ± 22.8 s). Three-day-old unmated females subjected to negative variations of atmospheric pressure (10 hPa) during the 4 h prior to the experiments increased their duration of flight (12.1 ± 8.7 vs 5.3 ± 3.4 s) compared to those not subjected to variation. One-day-old females were less active than older ones; flight was shorter than in 2-day-old females (2.7 ± 6.7 vs 5.1 ± 9.5 s) and fewer of them took off (28 vs 63%). Mating also affected the flight activity of 2-day-old females; mated females flew longer than virgins (12 ± 16.8 vs 5.1 ± 9.5 s) and took off more quickly (6.5 ± 14.4 vs 19.3 ± 20.1 s). Tansy odor in the tunnel did not significantly affect the flight behavior of virgin females, but it increased the proportion of mated females that initiated flight (87 vs 70%) and duration of flight (11.2 ± 24.4 vs 7.2 ± 13.7 s), and it reduced the latency to takeoff (2.1 ± 7.4 vs 8.1 ± 19.1 s). Flight duration in tansy odor was inversely correlated with the total number of eggs laid during the female's whole life. Our experimental settings did not allow observation of movements directed toward the odor source.

Female calling behaviour and male response to the sex pheromone in Thaumetopoea pityocampa (Den. & Schiff.) (Lep., Thaumetopoeidae)

Abstract: Female calling behaviour and male response to natural and synthetic pheromone sources were used for a Portuguese population of the winter pine processionary moth Thaumetopoea pityocampa (Den. & Schiff.). Virgin females 1–5 days old were studied, the mean calling longevity being 3.3 ± 0.7 days. Calling started ≅ 3 h after the onset of scotophase, and 7 h after emergence, lasting, nightly, for 6.4 ± 0.7 h, and was not affected by female age. A drop in air temperatures during the first half of scotophase and an increase in light intensity at dawn apparently determined the onset and termination of calling. Male flight activity began, on average, 3 h before the females started emitting pheromone, and was similarly affected by air temperatures and light intensity. The attractivity of traps baited with synthetic pheromone (TP056A; Yne 11, Z13–16AC) was compared with that of virgin females. Male flight activity was monitored in central and southern Portugal, using pheromone traps, and seen to last between 6 and 10 weeks, with a major peak occurring, in all sites, at the beginning of September.

Patterns of activity in host-seeking adult Ixodes scapularis (Acari: Ixodidae) and host-produced kairomones.

Adult blacklegged ticks, Ixodes scapularis Say, were confined to clay islands each surmounted with a vertical glass rod, and tick activities were videotaped continuously for 48 h. Some rods were treated basally or apically with substances rubbed from pelage associated with the tarsal or interdigital glands of white-tailed deer, Odocoileus virginianus (Zimmermann). Except for the activity immediately following their release, tick activity on both days was greatest during the period from 1700 to 2300 hours, which coincided with the onset of scotophase. Ticks were most active when rods had interdigital gland substances applied to their basal 2 cm, whereas they were least active when confined with rods treated with tarsal gland substances on their apical 2 cm. Overall, ticks spent more time on the apical 2 cm of the glass rods during the scotophase than during the photophase. The highest level of apical arrestment among treated and untreated rods occurred when the rod tips were treated with tarsal gland substances, with female ticks on the apical 2 cm of the rods 70-100% of every 3-h period beginning with the period from 2000 to 2300 hours on day 1. In contrast, when tarsal gland substances were applied to the basal 2 cm of the rods, the ticks spent < 40% of every period on day 2 on the rod tips.

Spring behavioral patterns of the apple blossom weevil

AbstractIndividual pairs of overwintered adult apple blossom weevils, Anthonomus pomorum (L.), confined with apple twigs under different ambient temperatures in the laboratory and on apple trees in the field, were observed through day and night for their spring activities. Flight behavior in relation to ambient temperature was also investigated under laboratory conditions using flight stands. Both sexes displayed predominantly nocturnal behavior patterns in both the laboratory and the field. Feeding, crawling, and mating activities increased following sunset in the field or onset of scotophase in the laboratory while resting occurred most frequently during daylight hours. Results of the laboratory experiments showed that temperature affected significantly the activity patterns. The diel pattern of activities became less distinctive at higher temperatures (above 15 °C), and total activities in crawling, feeding, and mating were suppressed significantly at lower temperatures (below 5 °C). Over 97% of the test weevils initiated take‐off response from flight stands at 20 °C within the 30 min trial period; however, flight initiation rarely occurred at temperatures 12 °C or below. Overall, results of the laboratory and field experiments indicate that A. pomorum is a remarkably cold‐adapted insect with ability to crawl, feed, and mate at a few degrees above freezing, a physiological attribute necessary for the exploitation of early stages of apple bud development in the cold early spring.

The photoperiodic clock in Chymomyza costata

Chymomyza costata enters larval diapause at short daylengths. Experiments using non-24-h light-dark cycles revealed that the duration of scotophase plays an essential role in the determination of diapause, and night-interruption experiments suggested that the process measuring night length was divided into two phases, A and B. The A phase lasts about 4 h from the onset of scotophase, and a 1 h light pulse in this phase is assumed sometimes to reset the clock and sometimes to have no effect (i.e. the light pulse seems to be sometimes disregarded). The B phase follows the A phase, and a 1 h light pulse in this phase is assumed sometimes to stop the clock and sometimes to be disregarded. In the B phases, a longer light pulse was more effective in stopping the clock than a shorter one. The effect of a circadian-oscillation system on the time-measurement system was not observed by resonance experiments. In experiments with a photoperiod of 2 or 4 h, a small peak of diapause incidence was observed when T (the length of one light-dark cycle) was 24 h. These results may suggest that the circadian oscillator involved in the photoperiodic time measurement in this species damps out after 24 h.

Studies on biogenic amines and metabolites in nervous tissue and hemolymph of male cabbage looper moths—III. Fate of injected octopamine, 5-hydroxytryptamine and dopamine

Adult male cabbage looper moths, Trichoplusia ni, were injected with two dosages of octopamine, or 5-hydroxytryptamine, or dopamine. The dosages were 1 and 10 μg, the latter a dosage that was previously shown to induce changes in nocturnal locomotor activity (5-hydroxytryptamine) and sensitivity to sex pheromone (octopamine). Injections were made into the hemolymph in the head capsule dorsal to the supraesophageal ganglion. Males were injected 1 hr prior to the onset of scotophase, and then brains + optic lobes, thoracic ganglia and hemolymph were analyzed at five time intervals over the following 6 hr. Levels of the three amines and their N-acetylated metabolites were quantified using HPLC with electrochemical detection. With the 1 μg dosage of the three amines, there was a significant increase in hemolymph values, but no changes in levels in the nervous system. With the 10 μg dosage, significant increases in each amine were found in the hemolymph, thoracic ganglia and brain + optic lobes. Levels of injected amines then rapidly decreased from hemolymph and nervous tissue. Within 2.5 hr following injections, levels of octopamine and dopamine in the brain + optic lobes and thoracic ganglia stabilized at twice the level in saline injected controls, 5-hydroxytryptamine levels were below control levels and hemolymph levels of each amine were not significantly different from controls. Decreases in amine levels were accompanied by significant increases in the N-acetylated form of each amine. In no instance did we observe a measurable peak for metabolites that would suggest the presence of MAO activity.